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In Situ Detection of Macronutrients and Chloride in Seawater by Submersible Electrochemical SensorsClick to copy article linkArticle link copied!
- Maria Cuartero*Maria Cuartero*(M.C.) E-mail: [email protected]. Tel.: +34669239019.Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva, SwitzerlandMore by Maria Cuartero
- Gaston CrespoGaston CrespoDepartment of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva, SwitzerlandMore by Gaston Crespo
- Thomas CherubiniThomas CherubiniDepartment of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva, SwitzerlandMore by Thomas Cherubini
- Nadezda PankratovaNadezda PankratovaDepartment of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva, SwitzerlandMore by Nadezda Pankratova
- Fabio ConfalonieriFabio ConfalonieriIdronaut, Via Monte Amiata 10, I-20047 Brugherio (Milano), ItalyMore by Fabio Confalonieri
- Francesco MassaFrancesco MassaDepartment of Earth, Environment and Life Sciences, University of Genoa, C.so Europa 26, 16132 Genoa, ItalyMore by Francesco Massa
- Mary-Lou Tercier-WaeberMary-Lou Tercier-WaeberDepartment of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva, SwitzerlandMore by Mary-Lou Tercier-Waeber
- Melina AbdouMelina AbdouUMR CNRS 5805 EPOC, Université de Bordeaux, Bat 18, Allée Geoffroy Saint-Hilaire, 33615 Pessac, FranceMore by Melina Abdou
- Jörg SchäferJörg SchäferUMR CNRS 5805 EPOC, Université de Bordeaux, Bat 18, Allée Geoffroy Saint-Hilaire, 33615 Pessac, FranceMore by Jörg Schäfer
- Eric Bakker*Eric Bakker*(E.B.) E-mail: [email protected]. Tel.: +41223796431.Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva, SwitzerlandMore by Eric Bakker
Abstract
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A new submersible probe for the in situ detection of nitrate, nitrite, and chloride in seawater is presented. Inline coupling of a desalination unit, an acidification unit, and a sensing flow cell containing all-solid-state membrane electrodes allows for the potentiometric detection of nitrate and nitrite after removal of the key interfering ions in seawater, chloride and hydroxide. Thus, the electrodes exhibited attractive analytical performances for the potentiometric detection of nitrate and nitrite in desalinated and acidified seawater: fast response time (t95 < 12 s), excellent stability (long-term drifts of <0.5 mV h–1), good reproducibility (calibration parameter deviation of <3%), and satisfactory accuracy (uncertainties <8%Diff compared to reference technique). The desalination cell, which can be repetitively used for about 30 times, may additionally be used as an exhaustive, and therefore calibration-free, electrochemical sensor for chloride and indirect salinity detection. The detection of these two parameters together with nitrate and nitrite may be useful for the correlation of relative changes in macronutrient levels with salinity cycles, which is of special interest in recessed coastal water bodies. The system is capable of autonomous operation during deployment, with routines for repetitive measurements (every 2 h), data storage and management, and computer visualization of the data in real time. In situ temporal profiles observed in the Arcachon Bay (France) showed valuable environmental information concerning tide-dependent cycles of nitrate and chloride levels in the lagoon, which are here observed for the first time using direct in situ measurements. The submersible probe based on membrane electrodes presented herein may facilitate the study of biogeochemical processes occurring in marine ecosystems by the direct monitoring of nitrate and nitrite levels, which are key chemical targets in coastal waters.
Copyright © 2018 American Chemical Society
Marine environments are vulnerable to a wide range of substances originating from anthropogenic activities that may have adverse effects on water quality. (1−3) While certain compounds are important for the dynamic functioning of aquatic ecosystems, the disturbance of its natural equilibrium may have serious impact on living organisms and ultimately on human health. This is the case for freshwater discharges of high macronutrient content from extensive activities such as agriculture. (4,5) Thus, uncompensated levels of inorganic nitrogen along recessed coastal water bodies, such as bays, estuaries, gulfs, sounds, or bights, may lead to the gradual eutrophication of the ecosystem if the connected ocean/sea is not able to naturally dilute these inputs. (6) It is important to identify the sources as well as day/night and tide-dependent concentration distributions of certain compounds such as nitrate and nitrite, at the appropriate temporal and spatial scale. This would greatly help in (i) the understanding of ecosystems disturbance, (ii) risk evaluation, and (iii) the management and mitigation of environmental impact, especially when anomalous concentrations exceeding the expected levels in coastal zones (i.e., 0.1–40 μM for nitrate and 0.01–4 μM for nitrite) occur. (7,8) Current existing monitoring programs mostly work with monthly measurements, which do not account for short-term variations of nitrate/nitrite and other chemical parameters in coastal water bodies.
For the reasons described above, there is an urgent need for analytical tools to monitor nitrate and nitrite in marine ecosystems. Detection achieved in real time and in situ is clearly preferred over centralized approaches, which require discrete sampling, in order to minimize the risk of sample contamination or degradation and drastically increase the frequency of data acquisition. (9) Few analytical techniques offer the required characteristics for their implementation in situ, and it is therefore important to exploit the application of those techniques that may provide local environmental observations through deployable devices. In this regard, flow injection systems based on the Griess reaction to detect nitrite and additionally incorporating a Cd reduction column to detect nitrate have been extensively adapted for in situ measurements. (10−14) However, the degree of complexity of these deployable devices is high and sometimes only the determination of total oxidized nitrogen (NO3– + NO2–) is accessible. (11) On the other hand, submersible ultraviolet nitrate analyzers that are chemicals free have also been proposed in the literature and are even commercialized. (15,16) Yet, the precision reported in seawater (2.4 μM) related to detector drift may not provide sufficiently accurate data.
The nitrate/nitrite microbiosensor developed by Revsbech et al. is another promising tool for in situ measurements as it has been demonstrated in specific cases such as sediment profiling. (17,18) However, the authors realistically stated that the construction of the electrodes is complicated and that the bacterial cultures used in the sensor should always be fresh. Moreover, incubation conditions change according to the expected temperature, and there are also other issues related to the sensor calibration. A macrosensor based on the same concept is currently commercially available to measure concentrations greater than 0.2 μM nitrate and nitrite, operating between 10 and 38 °C with signal drift < 20% per week and no pressure tolerance. (19) The sensor is not currently applicable for in situ measurements as the manufacturer suggests not to submerse it below 1 m but to perform sampling and on deck measurements (on site) instead. An alternative to the mentioned in situ probes may be the use of a submersible device based on electrochemical sensors and particularly all-solid-state electrodes based on ion-sensing membranes (ISMs), which have demonstrated excellent functionality for in situ environmental analysis in the past decade. (8,20)
Solid-state membrane electrodes are fabricated by modifying the surface of a conductive material (i.e., glassy carbon and gold) with a suitable ion-to-electron transduction material (i.e., conducting polymers and nanomaterials) and subsequently coated by the ISM, which typically contains a polymeric matrix, a plasticizer, an ion exchanger, and a selective chemical receptor (ionophore). (21,22) The response mechanism of ISMs is governed by a local ion distribution equilibrium at the sample–membrane interface. When operating at zero current potentiometry, an activity change of the primary ion in the aqueous solution ideally results in a well-defined change of the membrane potential that is governed by the Nernstian relationship. (23) Ion-sensing membranes may alternatively also be interrogated by dynamic electrochemistry by applying either a linear sweep or a constant potential or current, giving additional analytical information about the system. (24−26) Whatever the ISM readout, the required instrumentation is comparatively inexpensive, readily miniaturized, and easy to use. In addition, inherent characteristics of solid-state electrodes (versatility, simplicity, low cost, reduced size, fast response time, and insensitivity to pressure and light) (8,20) make them particularly suited for in situ aquatic analysis by submersible probes.
Field applications of potentiometric membrane sensors for in situ water monitoring have been reported in recent years. Athavale et al. described the implementation of all-solid-state ammonium-selective electrodes in a custom-built profiling ion analyzer (PIA) deployed in a stratified lake. (27,28) The observed depth profiles for ammonium concentration showed fine scale features, which would go unnoticed using discrete sampling-based analysis, allowing for the identification of hotspots and step gradients of ammonium levels in the lake. The direct contact of the membrane electrodes with the water column and the profiling by the PIA at a continuous speed make it possible to acquire high resolution depth profiles. More recently, our group has developed a submersible probe based on a potentiometric flow cell containing pH, carbonate, and calcium membrane electrodes applicable to seawater analysis. (29) The flow module in the probe permits the single-point recalibration of the electrodes and an improved biofouling resistance for long-term experiments. In situ temporal profiles of pH, carbonate, and calcium observed through the deployment of the device at different marine locations demonstrated that it is a promising tool for environmental analysis.
We present here a new submersible potentiometric probe for real time detection of nitrate and nitrite in seawater. Nitrate- and nitrite-selective miniaturized all-solid-state sensors based on nanomaterials are accommodated in a flow cell developed in house that allows the coupling of inline desalination and acidification pretreatments to reduce the limit of detection of the macronutrients in seawater as much as possible. (30,31) The desalination cell is here also used as a calibration-free electrochemical sensor for chloride detection, which is in turn correlated to salinity data. The developed fluidics system is incorporated into a deployable device, offering autonomous operation and a single-point recalibration of the nitrate and nitrite electrodes, therefore compensating for possible potential–time drifts in the electrodes’ responses. The system was deployed in the Arcachon Bay (France) for 23 h, recording nitrate, nitrite, and chloride levels along with the tidal changes in the lagoon and validated with traditional sampling techniques.
Experimental Section
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Description of the Potentiometric Sensors
Miniaturized glassy carbon electrodes were fabricated in house as previously reported (see the Supporting Information). (29) A film of modified carbon nanotubes (f-MWCNTs) was deposited on top of each electrode by drop casting 5 × 5 μL of the f-MWCNTs solution in THF (1 mg mL–1), (32) allowing each layer to dry for 10 min before depositing the next layer. Then, the corresponding membrane cocktail (see the Supporting Information for composition) was drop casted on the top of the f-MWCNTs film (4 × 10 μL), allowing each layer to dry for 20 min. The coated electrodes were conditioned overnight (∼12 h) in 10–3 M HCl, 10–4 M NaNO3, or 10–4 M NaNO2, correspondingly, before being accommodated in the flow cell.
Description of the Desalination and Acidification Units
The design of the desalination and acidification cells was previously reported. (30,31) Dimensions of this first prototype of the desalination cell were modified here in order to increase the volume of the desalinated seawater plug (see Supporting Information Figure S1). Thus, the cell contains the following parts between two acrylic pieces (60 × 120 × 20 mm3) tightly pressed by screws, in this order: Ag/AgCl foil (50 × 100 mm2); a piece of FKL membrane (cation-exchange membrane, 50 × 100 × 0.120 mm3) sandwiched between two serpentine channels made of natural latex rubber (50 × 100 mm2); and Ag foil (50 × 100 mm2). Note that the membrane divides the cell into two parts: (i) a compartment for seawater desalination (175 μL) in contact with the working electrode (Ag foil) and (ii) a reservoir for the reference solution (175 μL, 600 mM NaCl or seawater) in contact with the counter/reference electrode (Ag/AgCl foil).
Description of the Submersible Probe
The designed fluidics for chloride and nutrient detection is presented in Figure 1a. Pump 1 is used to flush the “in situ calibration solution” (stored in a bag), which is also used for the regeneration of the desalination unit (see below), while pump 2 is used for the acid (stored in another bag) needed in the acidification module as well as the seawater for both (i) to be measured in the potentiometric flow cell and (ii) to be utilized as reference solution in the desalination module. All this constitutes the external part of the fluidics, which is connected to the internal part by a special cap with nuts for water/air pressure resistance. (29) The internal fluidics is placed inside a submersible housing made of acetal copolymer (Delrin) (33) and is based on a two-position valve, the desalination module, the acidification module, and the potentiometric flow cell, in this order (Figure 1b). The valve is placed before the desalination cell, allowing for the switch between the “in situ calibration solution” (composition: 3 × 10–6 M NaNO3, 1 × 10–6 M NaNO2, and 5 × 10–3 M NaCl) and the seawater. The outlet of the desalination unit is connected to the inlet of the acidification unit. The outlet of the acidification unit is connected to the inlet of the potentiometric flow cell. There is also one channel containing the reference solution (seawater) needed for the desalination cell and another one to provide the acid solution (0.1 M HCl) for acidification. Both solutions are safely discharged into the environment together with the outlet of the potentiometric cell.
Figure 1
Figure 1. (a) Scheme of the developed fluidics for in situ measurements (NO = normally open, NC = normally closed, CAL SOL = calibration solution, RE = reference electrode). (b) Image of the submersible probe based on the valve (1), the desalination module (2), the acidification module (3), and the potentiometric flow cell (4). The system is placed inside the water- and pressure-proof cylindrical housing (5) made of acetylic copolymer (Deldrin). (33) (c) Probe incorporated into the titanium cage together with the pump and the CTD multiparemeter probe (6, filter for seawater; 7, pump; 8, unit containing the electrochemical sensors; 9, bag containing the calibration solution; 10, bag containing the HCl solution; 11, CTD). (d) Submersible device deployed in the Arcachon Bay from a boat using a small onboard crane.
We have recently reported on a submersible device for the detection of species relevant to the carbon cycle based on two physical parts (two different housings that are connected): one containing the electronics to control the system and the other containing the fluidics needed for the potentiometric sensing. (29) If this latter is disconnected, the submersible housing developed here to detect nutrients and chloride can instead be coupled to the electronics part. Indeed, the same electronics (hardware for pump and valve control, potentiometric measurements, voltammetric measurements, the adjustment of the experimental protocol, data acquisition, storage, and management) is combinable with either probe, (i) sensors for species relevant to the carbon cycle or (ii) chloride and nutrient sensors, for deployment in seawater.
Results and Discussion
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The need of reducing chloride and hydroxide levels to achieve adequate potentiometric detection of nutrients in environmental waters has recently been demonstrated. (30,31,34,35) The sensitivity of nitrate- and nitrite-selective electrodes drastically improves with diminishing concentrations of these two interferences while levels of other common ions present in environmental waters do not appreciably affect the response of the probes. (30,31)Figure 2 shows calibration graphs of miniaturized all-solid-state nitrate and nitrite potentiometric sensors incorporated in a flow cell described earlier (see Experimental Section). (29) In the case of nitrate, no response is observed in 600 mM NaCl background at pH 8 (seawater conditions). For chloride background concentrations that are reduced to millimolar levels, however, micromolar limits of detections are achieved (2 × 10–6 M). Even lower values are obtained (9 × 10–7 M) if additionally the pH is reduced to 5.5. In this latter case, a close to Nernstian electrode slope is observed (−55.4 mV).
Figure 2
Figure 2. Calibration graphs obtained for (a) nitrate and (b) nitrite using the developed flow potentiometric cell based on miniaturized all-solid-state electrodes.
With nitrite, the same decrease in chloride concentration improves the limit of detection from 5 × 10–4 to 1 × 10–5 M and values lower than micromolar (6 × 10–7 M) with a close to Nernstian slope (−55.7 mV) are observed at pH 5.5. Other analytical performances of the sensors such as response time, drift, and between-day reproducibility are adequate for in situ seawater analysis (see Table S1). The observed limits of detection are suitable to analyze nitrate and nitrite in seawater from locations such as coastal zones and areas strongly influenced by freshwater inputs, as well as to detect anomalous levels in aquatic systems with eutrophic features, (7) but are far from the nanomolar levels required in oligotrophic open ocean. (13) If inline pretreatments for sample desalination and acidification are coupled prior to the potentiometric flow cell, in situ detection may be accomplished in the mentioned cases.
In this context, we explore here the possibilities of coupling electrochemical desalination and passive acidification modules to the characterized potentiometric flow cell containing nitrate, nitrite, and additionally pH potentiometric sensors in order to enable in situ seawater analysis (the pH electrode is used to qualitatively control the final pH achieved after the pretreatment to confirm its correct operation; see below and the Supporting Information for more details). Thus, when a sufficiently positive constant potential is applied between the working and the reference electrodes of the desalination cell, chloride is removed from the seawater down to millimolar levels by exhaustive electrochemical plating as silver chloride on the working electrode (silver sheet). (30) Subsequently, the pH of the desalinated seawater plug is reduced to ∼5 owing to the cation-exchange process established between the sample and the acid form of the ion-exchange Donnan exclusion membrane. (31) While the general design of the acidification cell was as reported, (31) the design and materials of the desalination cell were further optimized compared to the prototype published previously, in order to increase the volume of the desalinated plug available for the potentiometric detection (see Experimental Section and Figure S1a). (30) Thus, the designed channels based on natural rubber (Figure S1b) and the use of bigger silver sheets as electrodes allow for the increase of the volume in the sample reservoir from ca. 80 to 175 μL.
The efficiency of the desalination process in this new cell was first explored in a 600 mM NaCl sample at different excitation pulses during several time periods. The chloride concentration in the desalinated plug was calculated from conductivity, by coupling the ion chromatography detector (see Supporting Information) to the outlet of the desalination cell. As observed in Figure S2a, the desalination efficiency increased with increasing applied potential up to 700 mV and then remained almost constant at higher values. Optimum efficiency at 800 mV was achieved after 300 s of electrolysis time (Figure S2b). A decrease of chloride concentration from 600 to 4.8 ± 0.1 mM (∼99.2% efficiency) was achieved using these conditions. A subsequent regeneration step at a cathodic potential of −900 mV for 600 s (doubling the time used for desalination) (34) in 5 mM NaCl assured the recovery of ∼99.5% of the chloride deposited on the working electrode, as calculated from conductivity measurements of the collected samples after this regeneration step.
The optimized protocol was then used for the desalination of actual seawater samples, obtaining a chloride concentration of 5.11 ± 0.23 mM (Figure S3 shows an example of the observed current profiles for desalination and regeneration processes). The lifetime of the cell operating in seawater is 30 cycles of desalination, likely due to the deterioration of the silver elements of the cell with the repetitive plating/release of chloride on their surfaces, which is an incomplete process (<99.5% of surface recovery). At the same time the membrane also deteriorates, as silver chloride complexes are being precipitated there because of the strong chloride gradient across the membrane. This limitation was already observed in the first reported prototype. (30) The lifetime of the desalination cell is currently the limiting factor for the lifetime of the detection system (comprising desalination + acidification + potentiometric detection) applied to in situ measurements. A replacement of the exhausted unit is therefore required to use the submersible device for longer periods.
If the desalination cell is interrogated using cyclic voltammetry rather than at constant potential, it may also function as a coulometric electrochemical chloride sensor. Panels a and b of Figure 3 show the voltammograms obtained at increasing concentrations of NaCl (scan rate = 2 mV s–1) using synthetic samples prepared from NaCl solutions as well as freshwater/seawater mixtures (the chloride concentration was calculated from ion chromatrography). The peak current and the integrated charge under the peak both follow a linear relationship with the chloride concentration in the sample. Moreover, the use of the integrated charge results in coulometric detection that can be utilized without recalibrating the cell during its lifetime and that is temperature-independent (i.e., integrated charge of 600 mM solution at 5–31 °C was 10.14 ± 0.01 C; scan rate = 2 mV s–1). Table S2 presents the calibration graphs obtained in the mentioned NaCl solutions over time using two desalination cells. The low variation found for the slope (1.2%) and the intercept (3.1%) over 3 weeks of operation, together with the fact that the calibration graphs obtained for different desalination cells are very close, point out the calibration-free ability of the exhaustive cell as chloride sensor.
Figure 3
Figure 3. Cyclic voltammograms observed at increasing chloride concentrations in (a) synthetic NaCl solutions and (b) freshwater/seawater mixtures. Reference solution = water sample that is measured. (c) Correlation between chloride concentrations measured using ion chromatography (IC) and the desalination cell (CV) in samples collected in the Gironde Estuary (France).
Cyclic voltammograms obtained for 600 mM NaCl at different scan rates are shown in Figure S4. As observed, it is necessary to operate at low scan rate (≤2 mV s–1) in order to obtain a constant charge of chloride deposited on the working electrode as AgCl (anodic scan) that is sufficiently close to the theoretical charge associated with the exhaustive deposition of the chloride contained in the entire volume of the cell (10.13 C). Note that the unequivocal use of low scan rates for exhaustive detection of halides based on thin layer samples that are controlled by cyclic voltammetry was already proposed in the literature and, hence, the behavior found here for chloride detection at different scan rates is in principle expected. (36) While this restricts the sample throughput of the chloride coulometric sensor, its use allows one to precisely quantify the chloride content of the sample in tandem with the analysis of macronutrient levels.
In order to validate chloride detection in environmental waters, the developed desalination unit was tested over the entire salinity gradient of the Gironde Estuary (France). Several samples ranging from minimum to maximum salinity (S = 0–35; see Table S3) were collected and additionally analyzed using ion chromatography (IC). As observed in Figure 3c, the linear correlation between the chloride concentrations calculated from IC and voltammetry measurements as well as the low average uncertainty, 1.7%Diff, validate the use of the desalination cell as chloride detector in samples ranging from freshwater to seawater. In addition, there is a correlation between salinity and chloride content (Figure 4a) that may be used to calculate salinity from chloride measurements and vice versa.
Figure 4
Figure 4. Plots of chloride versus salinity measured in (a) samples collected in the Gironde Estuary and (b) the 23 h deployment in the Arcachon Bay. Blue squares indicate predicted salinity values from the observed chloride–salinity linear relationship. Dashed line indicates the extrapolation of the chloride–salinity linear relationship to lower chloride values.
In this regard, there are two chief methods for determining the salt content (salinity) of water: total dissolved salts (TDS) and electrical conductivity measurements (EC). Indeed, EC can be used to give an estimate of TDS as measurement of TDS is tedious and cannot be carried out in the field (EC measurement is much quicker and simpler). While EC covers salinity ranges from ca. 25–42 with acceptable accuracy, its use in low salinity waters is however limited (37,38) and consequently the desalination unit may provide an alternative for in situ salinity measurements in most types of natural water. Optical sensors (39−41) are currently emerging for this same purpose, but they have not yet been implemented for in situ measurements and field data continue to be extracted from EC measurements using CTD multiparameter probes.
Figure 4a presents the plot of EC salinity versus measured chloride in the samples from the Gironde Estuary. The linear relationship is maintained for the higher salinity samples (from 15 to 35), while low salinity samples show some deviation (from 0 to 15 PSU) that is assigned to the less reliable use of EC under low salinity conditions. On the other hand, the accuracy in the integration of the voltammetric peak decreases with decreasing chloride concentration as a consequence of the flattening of the voltammetric wave, which becomes barely readable for chloride concentrations lower than 3 mM (see Figure S5), marking the lowest detectable chloride concentration by this desalination module.
Before the in situ implementation of the developed system composed of desalination cell, acidification cell, and potentiometric flow cell for nitrate, nitrite, and additionally chloride detection, laboratory validation of seawater sample analysis was performed. Table 1 collects the results obtained for seawater samples from different locations (calibrations of the sensors and experimental protocol for the sample analyses are detailed in the Supporting Information). The initial pH of the sample was measured using a pH meter while the pH electrode in the potentiometric flow cell controlled the pH after the pretreatment in these laboratory measurements. Nitrate and nitrite levels of the analyzed samples were additionally measured using colorimetry and chloride by IC. As observed in the table, a good correlation with the selected reference technique was obtained in all the cases, with uncertainties <8%Diff. The measured pH after the desalination-acidification pretreatment was always close to 5, confirming that the system functioned properly. If for any reason the desalination module would fail, the pH of the treated seawater sample would approach 2 because the higher Na+ content in the sample will result in a larger H+ exchange with the membrane. (28) This dysfunction would be immediately identified, therefore preventing the calculation of erroneous nitrate and nitrite levels. The desalinated and acidified plug is associated with a drastic change in the signal (Figure S6): i.e., nitrate and nitrite potentiometric responses are higher as a consequence of the decrease of chloride and hydroxide concentrations in the modified plug; on the other hand, the potential readout of the pH electrode is higher because the pH obtained after acidification is lower than the one for unmodified seawater as mentioned above.
Table 1. Nitrate and Nitrite Analysis in Several Samples (n = 3) from Different Locations: Costa Calida (Murcia, Spain), Plentzia Bay (Bilbao, Spain), and Genoa Harbor (Italy)
| chloride (mM) | pH | NO3– (μM) | NO2– (μM) | ||||||
|---|---|---|---|---|---|---|---|---|---|
| sample | salinity | CV | IC | beforea | after | potentiometry | colorimetry | potentiometry | colorimetry |
| 1 | 35.2 | 586.9 | 583.1 | 8.11 | 4.82 | 12.3 ± 1.6 | 13.1 ± 2.0 | 1.15 ± 0.09 | 1.23 ± 0.10 |
| 2 | 32.2 | 527.0 | 532.3 | 7.98 | 4.91 | 5.7 ± 0.7 | 5.5 ± 1.0 | 0.71 ± 0.07 | 0.68 ± 0.10 |
| 3 | 34.3 | 569.2 | 575.2 | 8.15 | 4.87 | 2.1 ± 0.3 | 2.3 ± 0.7 | <0.5 | 0.11 ± 0.10 |
a
pH meter.
In Situ Measurements of Nitrate, Nitrite, and Chloride in the Arcachon Bay (France)
In situ operation of the sensors was demonstrated during a 23 h deployment in the Arcachon Bay. For this purpose, the system (desalination unit + acidification unit + potentiometric cell) was implemented in a submersible housing (see Figure 1b), similar to that previously developed for the potentiometric detection of species relevant to the carbon cycle in seawater, (29) and mounted in a titanium cage for the joint deployment with other probes (i.e., CTD multiparameter probe); see Experimental Section and Figure 1a–d for more details. The submersible device was deployed from a boat (the R/V Planula IV), by means of a small crane, that was anchored in a stationary position (44°40.822’N 1°06.007’W) (see Figure 1d). The experimental protocol followed for the in situ detection of chloride and nutrients as well as the data treatment is detailed in the Supporting Information. While NO3– and NO2– potentiometric sensors are recalibrated once the system is incorporated in the titanium cage and during the deployment in order to correct for temporal effects in the potentiometric readouts, chloride detection does not need any in situ recalibration as mentioned above.
In situ temporal profiles observed for temperature (CTD), pH (CTD), salinity (CTD), chloride, and nitrate are presented in Figure 5. Nitrite levels were lower than the limit of detection of the potentiometric sensor, as later confirmed by analyzing the samples by colorimetry (see Table S4). All measured parameters were tide-dependent and are therefore related to tidal flushing effects as reflected in the observed cycles. The first local minimum temperature and maximum pH coincide with the first maximum salinity at high tide conditions, when the seawater from the Atlantic Ocean floods the point of observation in the Arcachon Bay (between 22:30 and 23:00 h, after ∼4 h of deployment). Consequently, the water in the bay compares more to seawater than to freshwater effluents in the lagoon, i.e., lower temperature, slightly higher pH, and higher salinity. Thereafter, temperature gradually increased to the first maximum, pH decreased to the first minimum, and salinity decreased to the first minimum coinciding with low tide conditions (between 02:30 and 03:00 h, after ∼10 h of deployment), as a consequence of a higher influence of the freshwater effluents in the lagoon. Temperature then progressively decreased, pH increased, and salinity increased while reaching the second high tide during the deployment (between 09:30 and 10:00 h, after ∼17 h of deployment). Finally, the temperature gradually increased again, pH decreased, and salinity decreased with the next low tide coming into the bay. The tide-related variations for temperature and pH are weak and do not exceed 3 °C and 0.2 units, respectively, coinciding with other reported observations. (42)
Figure 5
Figure 5. In situ temporal profiles obtained for (a) temperature (CTD), (b) pH (CTD), (c) salinity and chloride, and (d) nitrate during the deployment of 23 h (starting from May 15, 2017 at 16:00 to May 16, 2017 at 15:00) in the Arcachon Bay (44°40.822’N 1°06.007’W). The deployment depth was 2.3 ± 0.3 m. The dissolved O2 concentration was 7.5 ± 0.3 ppm, corresponding to 101.2 ± 3.2% for oxygen saturation within the monitoring window. Light hours are shaded in gray. (51) The local times for high and low tides (HT and LT, respectively) were determined according to the tidal record at Jetée d’Eyrac (44°40′N 1°10′W) and considering the temporal evolution of the seawater level in the Arcachon Bay. (52,53)
The same tide-dependent cycles observed for salinity were obtained for the chloride concentration measured in situ with the desalination module, showing a clear relationship between salinity and chloride as has been already found for the samples collected in the Gironde Estuary. Moreover, the linear correlations found in both cases (Figure 4) are almost identical, confirming its universal use to calculate chloride concentrations from salinity measurements and vice versa:
Gironde Estuary:
(1)
Arcachon Bay:
(2)
Regarding the temporal profile observed for nitrate (Figure 5d), the registered levels were also clearly tide-dependent. Validation of in situ nitrate measurements was performed by analyzing the samples collected during the deployment using both the system operating ex situ and colorimetry (see the Supporting Information). No correlations with in situ measurements are shown because sampling times do not perfectly match and a dashed line is drawn instead (Figure 5d) to demonstrate that, in the three cases (in situ, ex situ, and colorimetry measurements), nitrate levels follow the same trend and the obtained values are comparable. Note that the minimum nitrate levels detected by the developed nitrate sensor (<2 μM) are close to the limit of detection and there is an implicit error in the calculation of these concentrations as a consequence of the deviation of the electrode response from linearity, which may be further corrected for better accuracy. (43)
Maximum concentrations occurred at low tide as a consequence of the higher nitrate loading in effluents and underground freshwater discharges in the bay. Thus, the bell shape of this temporal profile is due to the “tidal flushing” effect in the lagoon. The observed concentrations at low tide (5–9 μM) are in accordance with those reported by Deborde et al. (5–10 μM) during low tide of a tidal creek (1 day/night cycle) in spring and summer in samples from the Arcachon Bay. (44) In this regard, inputs of inorganic nitrogen in the Arcachon Bay have been studied over the years using ex situ analysis after sampling (45−47) and nutrient export to the Atlantic coastal zone has been modeled. (48) Nutrients variability linked to freshwater inputs and its relation with phytoplankton primary production has been also studied for the same purpose. (49)
A regional monitoring program (SOMLIT, Service d’Observation en Milieu Littoral) provides nitrate, nitrite, other nutrient levels, and major physical parameters measured monthly, and the information is published online. (50) However, to the best of our knowledge, the results collected in the present work constitute the first in situ study of nitrate levels in the Arcachon Bay during a deployment in which salinity–chloride is additionally measured in exactly the same water. In addition, the developed submersible probe may therefore serve as a tool to study the role of the Atlantic Ocean as a (partial) sink of nutrient effluents from the lagoon as well as to follow eutrophication gradients in the water column through in situ data in real time. It could also serve as an alert system for increasing nutrient concentrations and, more generally, to better understand and model nitrate/nitrite biogeochemical cycles in order to detect and prevent any shift in their levels. This type of system would be of major usefulness in coastal systems influenced by human activity inputs such as agriculture regarding quality status requirements.
Conclusions
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We have developed submersible potentiometric sensors to detect nitrate and nitrite in seawater after inline pretreatment to achieve an electrochemical desalination and passive acidification. The suppression of key interfering ions present in seawater, chloride and hydroxide, makes it possible to reach improved limits of detection and to allow for in situ detection of these macronutrients in seawater. In addition, the desalination cell interrogated with cyclic voltammetry provides a calibration-free sensor for chloride detection in environmental water ranging from freshwater to seawater, constituting an alternative to the restricted use of a conductometric sensor in waters of lower salinity. On the other hand, both the desalination and acidification modules may be coupled to other analytical techniques that need any pretreatment for in situ detection of other ions. Moreover, slight modifications of the designed prototypes may allow for the decrease of any redox active ions deposited as silver salt on the working electrode (i.e., other halides) and the depletion/release of any interfering/needed ion in the sample in order to improve the sensing sensitivity.
The submersible device developed here is capable of autonomous operation during deployment, with routines for repetitive measurements, data storage and management, and computer visualization of the data in real time. Currently, a full cycle lasts 1 h and 40 min for the sequence: chloride detection, desalination, acidification, nitrate and nitrite potentiometric detection, and regeneration of the desalination unit (20 min less without chloride detection). With the actual design, the desalination unit needs to be replaced by a new unit for long-term measurements involving more than 30 desalination cycles. Future developments will therefore mainly benefit from a more robust desalinator design.
The environmental application of the proposed sensors was accomplished first in the laboratory using water samples from different regions, Costa Calida (Spain), Plentzia (Spain), Genoa Harbor (Italy), and the Gironde Estuary (France), and then during a 23 h deployment in the Arcachon Bay (France) by means of the implementation of the sensors in an autonomous submersible device developed in collaboration with the company Idronaut (Italy). The following outcomes were obtained from the observed in situ temporal profiles in the Arcachon Bay: (i) Nitrate and chloride levels were tide-dependent and maximum nitrate levels were found at low tide, when there are larger freshwater effluents with higher nutrient loading in the lagoon. (ii) The observed cycles in salinity coincide with chloride levels. A linear correlation between chloride and salinity may be useful to predict chloride from salinity measurements and vice versa. (iii) Nitrites levels were lower than the limit of detection of the potentiometric sensor (<0.6 μM). Equilibrium disturbances in nitrate or nitrite levels in coastal areas with high productivity, such as the Arcachon Bay, could have major socioeconomic effects. This fact strengthens the need for reliable, efficient tools such as the newly developed submersible probe, providing complementary data to existing monitoring programs on biogeochemical cycles of nutrients in coastal areas.
Supporting Information
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The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.analchem.7b05299.
Materials and reagents, validation protocols, electrode preparation, experimental protocols for laboratory and in situ measurements, analytical performance of the sensors, information about collected samples, nitrite detection in Arcachon Bay, design and optimization of the desalination cell and chloride detection, and validation of in situ measurements (PDF)
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Author Information
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- Maria Cuartero - Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva, Switzerland; Present Address: School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Teknikringen 30, SE-100 44, Stockholm, Sweden;
http://orcid.org/0000-0002-3858-8466;
- Eric Bakker - Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva, Switzerland;http://orcid.org/0000-0001-8970-4343;
- Gaston Crespo - Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva, Switzerland; Present Address: School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Teknikringen 30, SE-100 44, Stockholm, Sweden;http://orcid.org/0000-0002-1221-3906
Acknowledgments
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We thank the Swiss National Science Foundation, the European Union (FP7-GA 614002-SCHeMA project) for the financial support of this research. M.C. thanks WPCRN Network (Grant K-2017-0804). We are also grateful to the crew of the R/V Planula IV and T. Gil-Diaz for their assistance and pleasant company during the field campaign in Arcachon; M. Castellano and C. Mirasole for the field assistance in other field campaigns organized in Italy as part of the SCHeMA project; T. Gantner for the draw of the desalination cell; and the Idronaut team. F.M. especially thanks P. Povero.
References
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This article references 53 other publications.
- 1Orr, J. C.; Fabry, V. J.; Aumont, O.; Bopp, L.; Doney, S. C.; Feely, R. A.; Gnanadesikan, A.; Gruber, N.; Ishida, A.; Joos, F.; Key, R. M.; Lindsay, K.; Maier-Reimer, E.; Matear, R.; Monfray, P.; Mouchet, A.; Najjar, R. G.; Plattner, G. K.; Rodgers, K. B.; Sabine, C. L.; Sarmiento, J. L.; Schlitzer, R.; Slater, R. D.; Totterdell, I. J.; Weirig, M. F.; Yamanaka, Y.; Yool, A. Nature 2005, 437, 681– 686, DOI: 10.1038/nature04095Google Scholar1Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organismsOrr, James C.; Fabry, Victoria J.; Aumont, Olivier; Bopp, Laurent; Doney, Scott C.; Feely, Richard A.; Gnanadesikan, Anand; Gruber, Nicolas; Ishida, Akio; Joos, Fortunat; Key, Robert M.; Lindsay, Keith; Maier-Reimer, Ernst; Matear, Richard; Monfray, Patrick; Mouchet, Anne; Najjar, Raymond G.; Plattner, Gian-Kasper; Rodgers, Keith B.; Sabine, Christopher L.; Sarmiento, Jorge L.; Schlitzer, Reiner; Slater, Richard D.; Totterdell, Ian J.; Weirig, Marie-France; Yamanaka, Yasuhiro; Yool, AndrewNature (London, United Kingdom) (2005), 437 (7059), 681-686CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)Today's surface ocean is satd. with respect to calcium carbonate, but increasing atm. carbon dioxide concns. are reducing ocean pH and carbonate ion concns., and thus the level of calcium carbonate satn. Exptl. evidence suggests that if these trends continue, key marine organisms-such as corals and some plankton-will have difficulty maintaining their external calcium carbonate skeletons. Here we use 13 models of the ocean-carbon cycle to assess calcium carbonate satn. under the IS92a business-as-usual scenario for future emissions of anthropogenic carbon dioxide. In our projections, Southern Ocean surface waters will begin to become undersatd. with respect to aragonite, a metastable form of calcium carbonate, by the year 2050. By 2100, this undersatn. could extend throughout the entire Southern Ocean and into the subarctic Pacific Ocean. When live pteropods were exposed to our predicted level of undersatn. during a two-day shipboard expt., their aragonite shells showed notable dissoln. Our findings indicate that conditions detrimental to high-latitude ecosystems could develop within decades, not centuries as suggested previously.
- 2Halpern, B. S.; Walbridge, S.; Selkoe, K. A.; Kappel, C. V.; Micheli, F.; D’Agrosa, C.; Bruno, J. F.; Casey, K. S.; Ebert, C.; Fox, H. E.; Fujita, R.; Heinemann, D.; Lenihan, H. S.; Madin, E. M. P.; Perry, M. T.; Selig, E. R.; Spalding, M.; Steneck, R.; Watson, R. Science 2008, 319, 948– 952, DOI: 10.1126/science.1149345Google Scholar2A Global Map of Human Impact on Marine EcosystemsHalpern, Benjamin S.; Walbridge, Shaun; Selkoe, Kimberly A.; Kappel, Carrie V.; Micheli, Fiorenza; D'Agrosa, Caterina; Bruno, John F.; Casey, Kenneth S.; Ebert, Colin; Fox, Helen E.; Fujita, Rod; Heinemann, Dennis; Lenihan, Hunter S.; Madin, Elizabeth M. P.; Perry, Matthew T.; Selig, Elizabeth R.; Spalding, Mark; Steneck, Robert; Watson, RegScience (Washington, DC, United States) (2008), 319 (5865), 948-952CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Management and conservation of the world oceans require synthesis of spatial data on the distribution and intensity of anthropogenic activity and overlap of human impacts on marine ecosystems. An ecosystem-specific, multi-scale spatial model was developed to synthesize 17 global datasets of anthropogenic drivers of ecol. change for 20 marine ecosystems. This anal. indicated no area was unaffected by human influence and that a large fraction (41%) was strongly affected by multiple drivers; however, large areas of relatively little human impact remain, particularly near the poles. The anal. process and resulting maps provide flexible tools for regional and global efforts to allocate conservation resources; implement ecosystem-based management; and inform marine spatial planning, education, and basic research.
- 3Webber, H. H.; Thurman, H. V. Marine Biology, 2nd ed.; Harpercollins: New York, 1991.Google ScholarThere is no corresponding record for this reference.
- 4Tilman, D. Proc. Natl. Acad. Sci. U. S. A. 1999, 96, 5995– 6000, DOI: 10.1073/pnas.96.11.5995Google ScholarThere is no corresponding record for this reference.
- 5Andersen, J. H.; Fossing, H.; Hansen, J. W.; Manscher, O. H.; Murray, C.; Petersen, D. L. J. Ambio 2014, 43, 906– 913, DOI: 10.1007/s13280-014-0514-yGoogle ScholarThere is no corresponding record for this reference.
- 6Smith, V. H.; Tilman, G. D.; Nekola, J. C. Environ. Pollut. 1999, 100, 179– 196, DOI: 10.1016/S0269-7491(99)00091-3Google ScholarThere is no corresponding record for this reference.
- 7Saliot, A. The Mediterranean Sea; Springer: Berlin, 2005.Google ScholarThere is no corresponding record for this reference.
- 8Cuartero, M.; Bakker, E. Current Opinion in Electrochemistry 2017, 3, 97– 105, DOI: 10.1016/j.coelec.2017.06.010Google ScholarThere is no corresponding record for this reference.
- 9Albaiges, J. Int. J. Environ. Anal. Chem. 2008, 88, 598, DOI: 10.1080/03067310801993459Google ScholarThere is no corresponding record for this reference.
- 10David, A. R. J.; McCormack, T.; Morris, A. W.; Worsfold, P. J. Anal. Chim. Acta 1998, 361, 63– 72, DOI: 10.1016/S0003-2670(98)00023-3Google ScholarThere is no corresponding record for this reference.
- 11Ma, J.; Adornato, L.; Byrne, R. H.; Yuan, D. X. TrAC, Trends Anal. Chem. 2014, 60, 1– 15, DOI: 10.1016/j.trac.2014.04.013Google Scholar11Determination of nanomolar levels of nutrients in seawaterMa, Jian; Adornato, Lori; Byrne, Robert H.; Yuan, DongxingTrAC, Trends in Analytical Chemistry (2014), 60 (), 1-15CODEN: TTAEDJ; ISSN:0165-9936. (Elsevier B. V.)A review. Nutrients (phosphate, nitrate, nitrite, ammonium and silicate) exert strong controls on oceanic primary productivity. In oligotrophic areas, which cover approx. 40% of the world's oceans, nutrient concns. can drop to nanomolar levels or lower due to biol. uptake, so highly sensitive methods and technologies are urgently needed for nutrient measurements in such areas. In this work, we review procedures for phosphate and nitrite/nitrate analyses published since the review of Patey et al. [32], and procedures for anal. of ammonium and silicate at nanomolar levels. Our review includes aspects of measurement protocols that bear strongly on the quality of analyses of trace nutrients, including contamination of reagents, sample storage, and prepn. of nutrient-free seawater. This review excludes methods that have limits of detection greater than 1 μM, and methods that are not specific to seawater.
- 12Jannasch, H. W.; Johnson, K. S.; Sakamoto, C. M. Anal. Chem. 1994, 66, 3352– 3361, DOI: 10.1021/ac00092a011Google ScholarThere is no corresponding record for this reference.
- 13Beaton, A. D.; Cardwell, C. L.; Thomas, R. S.; Sieben, V. J.; Legiret, F. E.; Waugh, E. M.; Statham, P. J.; Mowlem, M. C.; Morgan, H. Environ. Sci. Technol. 2012, 46, 9548– 9556, DOI: 10.1021/es300419uGoogle ScholarThere is no corresponding record for this reference.
- 14Li, Q. P.; Hansell, D. A.; Zhang, J. Z. Limnol. Oceanogr.: Methods 2008, 6, 319– 326, DOI: 10.4319/lom.2008.6.319Google Scholar14Underway monitoring of nanomolar nitrate plus nitrite and phosphate in oligotrophic seawaterLi, Qian P.; Hansell, Dennis A.; Zhang, Jia-ZhongLimnology and Oceanography: Methods (2008), 6 (July), 319-326CODEN: LOMIBY; ISSN:1541-5856. (American Society of Limnology and Oceanography)To study nutrient dynamics and cycling in oligotrophic open ocean environments, continuous measurements of nanomolar nitrate, nitrite, and phosphate are valuable. However, such studies are usually impeded by the detection limits of conventional nutrient-sensors and analyzers. Here, we developed a shipboard deployable underway system for simultaneously monitoring nitrate plus nitrite and phosphate at nanomolar concns. by the coupling of an optimized flow injection anal. system with two long-path liq. waveguide capillary cells (LWCC). The detection limits are ∼2 nM for nitrate plus nitrite and ∼1.5 nM for phosphate, resp. Results from real-time surveys of waters over the west Florida continental shelf and the oligotrophic Sargasso Sea are presented. This system has also been successfully used to analyze more than 1000 discrete seawater samples manually during 2 cruises in the North Atlantic.
- 15Sea-Bird Scientific. http://www.seabird.com/suna (accessed Sep. 1, 2017).Google ScholarThere is no corresponding record for this reference.
- 16Johnson, K. S.; Coletti, L. J.; Jannasch, H. W.; Sakamoto, C. M.; Swift, D. D.; Riser, S. C. J. Atmos. Ocean. Technol. 2013, 30, 1854– 1866, DOI: 10.1175/JTECH-D-12-00221.1Google ScholarThere is no corresponding record for this reference.
- 17Nielsen, M.; Larsen, L. H.; Jetten, M. S. M.; Revsbech, N. P. Appl. Environ. Microbiol. 2004, 70, 6551– 6558, DOI: 10.1128/AEM.70.11.6551-6558.2004Google ScholarThere is no corresponding record for this reference.
- 18Revsbech, N. P.; Glud, R. N. Limnol. Oceanogr.: Methods 2009, 7, 761– 770, DOI: 10.4319/lom.2009.7.761Google Scholar18Biosensor for laboratory and lander-based analysis of benthic nitrate plus nitrite distribution in marine environmentsRevsbech, Niels Peter; Glud, Ronnie NohrLimnology and Oceanography: Methods (2009), 7 (Nov.), 761-770CODEN: LOMIBY; ISSN:1541-5856. (American Society of Limnology and Oceanography)We present a psychotropic bacteria-based biosensor that can be used in low-temp. seawater for the anal. of nitrate + nitrite (NOx-). The sensor can be used to resolve concns. below 1 μmol L-1 at low temp. (<2.5°C) and high salinity (35‰), and in situ use in the deep sea was demonstrated by measuring NOx- profiles in sediment at 1500 m depth, where the temp. was 2.5°C. Anal. of marine sediment at 70 m depth showed very heterogeneous NOx- profiles, most of which exhibited pronounced maxima due to nitrification in the oxic surface layer. At this shallow water site, the in situ profiles were similar to profiles measured in the lab., but generally lab. profiles appeared more uniform, presumably as a result of reduced fauna activity and disturbance of the microstructure of the sediment surface during core recovery.
- 19Unisense. http://www.unisense.com/NOx (accessed Feb. 4, 2017).Google ScholarThere is no corresponding record for this reference.
- 20Crespo, G. A. Electrochim. Acta 2017, 245, 1023– 1034, DOI: 10.1016/j.electacta.2017.05.159Google Scholar20Recent Advances in Ion-selective membrane electrodes for in situ environmental water analysisCrespo, Gaston A.Electrochimica Acta (2017), 245 (), 1023-1034CODEN: ELCAAV; ISSN:0013-4686. (Elsevier Ltd.)A review. Ion-selective membrane electrodes (ISEs) have become very attractive sensing platforms for environmental water anal. This review mainly presents recent advances in polymeric-based ISEs relevant to H2O research and primarily focused on alkali and alkali earth-metal cations, ammonium ions, halide anions and certain oxoanions involved in biogeochem. cycles (e.g. nutrients (NO-2, NO-3), C (HCO-3/CO2-3) and P (HPO2-4/H2PO-4)). Clearly, ISEs have the potential to be the icon of decentralized ion chem. information for H2O research as in the case of wearable ISE sensors. The modern development of robust ISEs (mainly in all-solid-state format) has allowed an easy implementation either into submersible or nonsubmersible probes that maintain, to an acceptable degree, the required anal. performance. Remarkable benefits, such as avoidance of sample contamination, sample preservation and detn. of perturbations of chem. speciation, are significant to enhancing the fundamental knowledge of ongoing biogeochem. process. A perspective on the current requirements of ISEs in terms of anal. performance and engineering construction is provided initially and is followed by recent contributions listed according to the sampling methodol., including (i) on-board/on-site sampling with subsequent coverage of decentralized anal. (on moving or fixed platforms) and (ii) in situ monitoring with submersible sensing probes. On the one hand, there is difficulty in making a general statement about ISEs for H2O research, specifically in terms of whether they are suitable. This lies in the complexity and heterogeneity of the samples. Accordingly, particular scenarios are discussed. However, it is also evident that further steps are still needed at the fundamental level, including development of receptors, robust membranes and novel alternatives that would enable the sensing of ions at deep-sea. Importantly, there is a plenty of room for improvement and new approaches; and it should be stressed that the recent progress in H2O research using ISEs was owing to multidisciplinary efforts. Facing this challenge is very exciting and the development of ISE platforms that enable working in real conditions is quite plausible.
- 21Bobacka, J.; Ivaska, A.; Lewenstam, A. Chem. Rev. 2008, 108, 329– 351, DOI: 10.1021/cr068100wGoogle Scholar21Potentiometric Ion SensorsBobacka, Johan; Ivaska, Ari; Lewenstam, AndrzejChemical Reviews (Washington, DC, United States) (2008), 108 (2), 329-351CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review. The aim of this review is to highlight some of these modern topics in the field of potentiometric ion sensors. This review is focused on recent achievements since the beginning of this millennium and emphasizes the results from the last 5 years (2002-2006). Section 2 gives a crit. overview, placed in a historical perspective, on the theory of the potentiometric response, including classical equil. models as well as advanced nonequil. models. Section 3 deals with recent advances in the field of solid-contact ion-selective electrodes (ISEs), emphasizing the application of conducting polymers as ion-to-electron transducers. Recent developments in the area of miniaturized ISEs, including applications in flow anal., life science, and biol., are discussed in section 4. Finally, the new wave of ISEs is commented on in section 5. The authors hope that the issues discussed will illustrate the great possibilities offered by modern ISEs and encourage further innovations in the rapidly expanding field of chem. sensors in the years to come.
- 22Bakker, E.; Pretsch, E. Angew. Chem., Int. Ed. 2007, 46, 5660– 5668, DOI: 10.1002/anie.200605068Google ScholarThere is no corresponding record for this reference.
- 23Buck, R. P.; Lindner, E. Pure Appl. Chem. 1994, 66, 2527– 2536, DOI: 10.1351/pac199466122527Google ScholarThere is no corresponding record for this reference.
- 24Cuartero, M.; Crespo, G. A.; Bakker, E. Chimia 2015, 69, 203– 206, DOI: 10.2533/chimia.2015.203Google ScholarThere is no corresponding record for this reference.
- 25Crespo, G. A.; Bakker, E. RSC Adv. 2013, 3, 25461– 25474, DOI: 10.1039/c3ra43751eGoogle Scholar25Dynamic electrochemistry with ionophore based ion-selective membranesCrespo, Gaston A.; Bakker, EricRSC Advances (2013), 3 (48), 25461-25474CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)This review outlines key principles and recent advances in the use of dynamic electrochem. with polymeric liq. membranes. Ideally polarizable membranes are most attractive in fundamental studies of ion transfer and when the accumulation of the ion in the receiving phase is of key interest, for example in stripping ion transfer voltammetry. All solid-state membranes doped with conducting polymers have exhibited attractive low detection limit for hydrophilic ions. On the other hand, initially non-polarized interfaces are most useful when one aims to effect a concn. change of an ionic species in the sample phase. Conveniently, these types of membranes can be interrogated with potentiometry and sequentially with dynamic techniques such as chronopotentiometry. This can be used to obtain speciation information as they allow one, in principle, to assess total labile and free ion concns. in the same expt. A no. of electrochem. techniques were reported and include controlled potential techniques such as cyclic voltammetry, normal pulse voltammetry, stripping voltammetry, and thin layer coulometry as well as current controlled ones such as pulsed chronopotentiometry and flash chronopotentiometry. All of these techniques have their purpose and strength.
- 26Bakker, E. Anal. Chem. 2016, 88, 395– 413, DOI: 10.1021/acs.analchem.5b04034Google ScholarThere is no corresponding record for this reference.
- 27Athavale, R.; Dinkel, C.; Wehrli, B.; Bakker, E.; Crespo, G. A.; Brand, A. Environ. Sci. Technol. Lett. 2017, 4, 286– 291, DOI: 10.1021/acs.estlett.7b00130Google Scholar27Robust Solid-Contact Ion Selective Electrodes for High-Resolution In Situ Measurements in Fresh Water SystemsAthavale, Rohini; Dinkel, Christian; Wehrli, Bernhard; Bakker, Eric; Crespo, Gaston A.; Brand, AndreasEnvironmental Science & Technology Letters (2017), 4 (7), 286-291CODEN: ESTLCU; ISSN:2328-8930. (American Chemical Society)Biogeochem. processes are often confined to very narrow zones in aquatic systems. Therefore, highly resolved in situ measurements are required to study these processes. Potentiometric solid-contact ion selective electrodes (SC-ISEs) are promising tools for such measurements. SC-ISEs show good performance in analyses under controlled exptl. conditions. Very few sensor designs, however, can sustain the challenges of natural water matrixes and external environmental conditions during in situ applications. We fabricated ammonium and pH selective SC-ISEs with functionalized multiwalled carbon nanotubes (f-MWCNT) as a solid contact. Their functionality was tested in the lab. and applied in situ for vertical profiling in a eutrophic lake. Sensors were insensitive to strong redox changes, high sulfide concns., and bright daylight conditions during the application in the lake. In addn., sensors are easily fabricated and exhibit short response times (<10 s). The proposed design of SC-ISEs based on f-MWCNTs is quite suitable for high-resoln. in situ profiling of ionic species in fresh water lakes.
- 28Athavale, R.; Kokorite, I.; Dinkel, C.; Bakker, E.; Wehrli, B.; Crespo, G. A.; Brand, A. Anal. Chem. 2015, 87, 11990– 11997, DOI: 10.1021/acs.analchem.5b02424Google ScholarThere is no corresponding record for this reference.
- 29Cuartero, M.; Pankratova, N.; Cherubini, T.; Crespo, G. A.; Massa, F.; Confalonieri, F.; Bakker, E. Environ. Sci. Technol. Lett. 2017, 4, 410– 415, DOI: 10.1021/acs.estlett.7b00388Google Scholar29In Situ Detection of Species Relevant to the Carbon Cycle in Seawater with Submersible Potentiometric ProbesCuartero, Maria; Pankratova, Nadezda; Cherubini, Thomas; Crespo, Gaston A.; Massa, Francesco; Confalonieri, Fabio; Bakker, EricEnvironmental Science & Technology Letters (2017), 4 (10), 410-415CODEN: ESTLCU; ISSN:2328-8930. (American Chemical Society)We report on the development of a submersible probe for the simultaneous potentiometric detection of carbonate, calcium, and pH in seawater. All-solid-state electrodes incorporating nanomaterials provide an adequate response time (<10 s), stability (drifts of <0.9 mV h-1), reproducibility (calibration parameter deviation of <0.7%), and accuracy (deviation of <8% compared to ref. techniques) for real-time monitoring of seawater using a flow system. The functioning of the deployable prototype was checked in an outdoor mesocosm and via long-term monitoring in Genoa Harbor. The electrodes worked properly for 3 wk, and the system demonstrated the capability to autonomously operate with routines for repetitive measurements, data storage, and management. In situ profiles obsd. in Genoa Harbor and Arcachon Bay were validated using on site and ex situ techniques. The validation of in situ-detected carbonate is a challenge because both re-equilibration of the sample with atm. CO2 and the use of apparent thermodn. consts. for speciation calcns. lead to some differences (<20% deviation). The submersible probe is a promising tool for obtaining rapid and trustworthy information about chem. levels in marine systems. Moreover, the fluidic approach allows for the integration of other ion sensors that may require sample pretreatment.
- 30Cuartero, M.; Crespo, G. A.; Bakker, E. Anal. Chem. 2015, 87, 8084– 8089, DOI: 10.1021/acs.analchem.5b01973Google ScholarThere is no corresponding record for this reference.
- 31Pankratova, N.; Cuartero, M.; Cherubini, T.; Crespo, G. A.; Bakker, E. Anal. Chem. 2017, 89, 571– 575, DOI: 10.1021/acs.analchem.6b03946Google Scholar31In-Line Acidification for Potentiometric Sensing of Nitrite in Natural WatersPankratova, Nadezda; Cuartero, Maria; Cherubini, Thomas; Crespo, Gaston A.; Bakker, EricAnalytical Chemistry (Washington, DC, United States) (2017), 89 (1), 571-575CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)We report on a novel approach for in-line sample acidification that results in a significant improvement of the limit of detection of potentiometric anion-selective electrodes aiming at detg. nutrients in natural waters. The working principle of the developed acidification module relies on the cation-exchange process between the sample and an ion-exchange Donnan exclusion membrane in its protonated form. The resulting in-line acidification of natural waters with millimolar NaCl level (freshwater, drinking water, aquarium water as well as dechlorinated seawater) decreases the pH down to ∼5. Using the acidification module the limit of detection of nitrite-selective electrodes significantly improves by ≥2 orders of magnitude with respect to that obsd. at environmental pH. The originality of the proposed flow cell lies in the possibility to adjust the pH of the sample by modifying its exposure time with the membrane by varying the volumetric flow rate. Facile coupling with a detection technique of choice, miniaturized configuration and simple implementation for long-term monitoring with submersible probes for environmental anal. are possible anal. configurations. This approach was applied to the potentiometric detection of nitrite in aquarium and dechlorinated seawater.
- 32Yuan, D. J.; Anthis, A. H. C.; Ghahraman Afshar, M.; Pankratova, N.; Cuartero, M.; Crespo, G. A.; Bakker, E. Anal. Chem. 2015, 87, 8640– 8645, DOI: 10.1021/acs.analchem.5b01941Google ScholarThere is no corresponding record for this reference.
- 33Tercier, M.-L.; Buffle, J.; Graziottin, F. Electroanalysis 1998, 10, 355– 363, DOI: 10.1002/(SICI)1521-4109(199805)10:6<355::AID-ELAN355>3.0.CO;2-FGoogle Scholar33A novel voltammetric in situ profiling system for continuous real-time monitoring of trace elements in natural watersTercier, Mary-Lou; Buffle, Jacques; Graziottin, FlavioElectroanalysis (1998), 10 (6), 355-363CODEN: ELANEU; ISSN:1040-0397. (Wiley-VCH Verlag GmbH)A novel voltammetric in-situ profiling system (VIP System) for continuous real-time monitoring of trace elements in fresh and seawater down to 500 m depth is described. The VIP System was designed using advanced microprocessor and telemetry technol. The heart of the submersible voltammetric probe is a Hg-plated Ir-based microsensor covered with an antifouling gel membrane. This gel integrated microsensor allows direct voltammetric measurements of trace metals in complex media without phys. and chem. interferences of the test soln. A detailed description of the system is given and examples of environmental applications are reported for in-situ trace metal monitoring in O2 satd. seawater as well as for in-situ profiling of Mn2+ in anoxic lake water. In-situ measurements of mobile fraction of trace metals can be achieved down to low concn. levels of ≈5 ppt.
- 34Grygolowicz-Pawlak, E.; Sohail, M.; Pawlak, M.; Neel, B.; Shvarev, A.; de Marco, R.; Bakker, E. Anal. Chem. 2012, 84, 6158– 6165, DOI: 10.1021/ac301096rGoogle ScholarThere is no corresponding record for this reference.
- 35Pankratova, N.; Ghahraman Afshar, M.; Yuan, D. J.; Crespo, G. A.; Bakker, E. Acs Sensors. 2016, 1, 48– 54, DOI: 10.1021/acssensors.5b00015Google Scholar35Local Acidification of Membrane Surfaces for Potentiometric Sensing of Anions in Environmental SamplesPankratova, Nadezda; Ghahraman Afshar, Majid; Yuan, Dajing; Crespo, Gaston A.; Bakker, EricACS Sensors (2016), 1 (1), 48-54CODEN: ASCEFJ; ISSN:2379-3694. (American Chemical Society)The work dramatically improves the lower detection limit of anion selective membranes at environmental pH by using local acidification to suppress hydroxide interference at the membrane surface. Three sep. localized acidification strategies are explored to achieve this, with ionophore-based membrane electrodes selective for nitrite and dihydrogen phosphate as guiding examples. In a 1st approach, a concd. acetic acid soln. (∼1 M) is placed in the inner filling soln. of the PVC-based membrane electrode, forcing a significant acid gradient across the membrane. A 2nd strategy achieves the same type of passive acidification by using an external proton source (fast diffusive doped polypropylene membrane) placed in front of a potentiometric solid contact anion selective electrode where the thin layer gap allows one to observe spontaneous acidification at the opposing detection electrode. The 3rd approach shares the same configuration, but protons are here released by electrochem. control from the selective proton source into the thin layer sample. All three protocols improve the limit of detection by >2 orders of magnitude at environmental pH. Nitrite and dihydrogen phosphate detns. in artificial and natural samples are demonstrated.
- 36Cuartero, M.; Crespo, G. A.; Ghahraman Afshar, M.; Bakker, E. Anal. Chem. 2014, 86, 11387– 11395, DOI: 10.1021/ac503344fGoogle Scholar36Exhaustive Thin-Layer Cyclic Voltammetry for Absolute Multianalyte Halide DetectionCuartero, Maria; Crespo, Gaston A.; Ghahraman Afshar, Majid; Bakker, EricAnalytical Chemistry (Washington, DC, United States) (2014), 86 (22), 11387-11395CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)Water anal. is one of the greatest challenges in the field of environmental anal. In particular, seawater anal. is often difficult because a large amt. of NaCl may mask the detn. of other ions, i.e., nutrients, halides, and carbonate species. The authors demonstrate here the use of thin-layer samples controlled by cyclic voltammetry to analyze water samples for chloride, bromide, and iodide. The fabrication of a microfluidic electrochem. cell based on a Ag/AgX wire (working electrode) inserted into a tubular Nafion membrane is described, which confines the sample soln. layer to <15 μm. By increasing the applied potential, halide ions present in the thin-layer sample (X-) are electrodeposited on the working electrode as AgX, while their resp. counterions are transported across the perm-selective membrane to an outer soln. Thin-layer cyclic voltammetry allows one to obtain sepd. peaks in mixed samples of these three halides, finding a linear relation between the halide concn. and the corresponding peak area from ∼10-5 to 0.1M for bromide and iodide and from 10-4 to 0.6M for chloride. This technique was successfully applied for the halide anal. in tap, mineral, and river water as well as seawater. The proposed methodol. is abs. and potentially calibration-free, as evidenced by an obsd. 2.5% relative std. deviation cell to cell reproducibility and independence from the operating temp.
- 37Millero, F. J. Limnol. Oceanogr. 1984, 29, 1317– 1321, DOI: 10.4319/lo.1984.29.6.1317Google Scholar37The conductivity-density-salinity-chlorinity relationships for estuarine watersMillero, Frank J.Limnology and Oceanography (1984), 29 (6), 1317-21CODEN: LIOCAH; ISSN:0024-3590.The relative cond. and d. of estuarine waters formed by mixing world river water with std. seawater were detd.. The results are used to examine the cond.-d.-salinity-chlorinity relationships of estuarine waters of known compn. with seawater dild. with pure water (i.e., the new International Equation of State and Practical Salinity Scale). The max. difference between the true salinity and the value derived from cond. was 0.047 in dil. solns.; the max. d. difference between the measured and calcd. values was 35 × 10-6 g/cm3. These results are compared with measurements of waters from the St. Lawrence estuary.
- 38Cox, R. A.; Culkin, F.; Riley, J. P. Deep-Sea Res. Oceanogr. Abstr. 1967, 14, 203– 220, DOI: 10.1016/0011-7471(67)90006-XGoogle Scholar38Electrical conductivity/chlorinity relation in natural sea waterCox, Roland A.; Culkin, Frederick; Riley, John P.Deep-Sea Research and Oceanographic Abstracts (1967), 14 (2), 203-20CODEN: DROAAK; ISSN:0011-7471.Details are given for the collection and treatment of samples, the calibration and operation for cond. measurements with the N.I.O. Thermostat Salinity Meter, and the detn. of chlorinity by using a modification of the Hermann potentiometric method (J. Cons., Cons. Perma. Int. Explor. Mer 17, 223-30(1951)). The results are tabulated in relation to latitude, longitude, and depth of the samples. In the prepn. of the new International Oceanographic Tables (UNESCO 1966), only data referring to samples collected within 200 m. of the surface was used. The final math. expression of chlorinity and salinity to cond. ratio is S = c0 + c1R15 + c2R215 + ...c5R515, where S is the salinity, R15 the cond. ratio at 15° and c are consts. of the values: c0 = -0.08996, c1 = 28.29720, c2 = 12.80832, c3 = -10.67869, c4 = 5.98624, and c5 = -1.32311. The temp. coeff. of cond. ratio was also detd. with an Autolab Inductive Salinometer. The results in their final form are presented as an expression of Δ15 as a function of Rt and t°, where Δ15 = R15 - Rt. Observed and calcd. values of 105Δ15 are tabulated. The precision of the chlorinity detn. is ∼0.001‰. Deep samples show a slightly but significantly different relation between cond. and chlorinity from surface samples, showing that deep sea water has on av. a slightly higher conductivity. This is almost certainly due to their higher Ca/chlorinity ratio.
- 39Qian, Y.; Zhao, Y.; Wu, Q. L.; Yang, Y. Sens. Actuators, B 2018, 260, 86– 105, DOI: 10.1016/j.snb.2017.12.077Google Scholar39Review of salinity measurement technology based on optical fiber sensorQian, Yu; Zhao, Yong; Wu, Qi-lu; Yang, YangSensors and Actuators, B: Chemical (2018), 260 (), 86-105CODEN: SABCEB; ISSN:0925-4005. (Elsevier B.V.)A review of the salinity measurement technol. based on the optical fiber sensor is presented. The principles of optical fiber measurement, the structures of probes and the characteristics of various sensing structures are concerned. Firstly, this paper discusses the relationship between the salinity and refractive index, and the effect of ion pairs on the refractive index. Secondly, four methods of direct or non-direct measurements of salinity are summarized, including optical refraction method, optical fiber grating, optical interference and surface plasmon effect. Subsequently, the article compares performances of various sensing structures and analyses the advantages and disadvantages of different sensors. Finally, a prospect of salinity measurement requirement and the development direction of fiber-optic sensors in this area are addressed.
- 40Muller, B. J.; Rappitsch, T.; Staudinger, C.; Ruschitz, C.; Borisov, S. M.; Klimant, I. Anal. Chem. 2017, 89, 7195– 7202, DOI: 10.1021/acs.analchem.7b01373Google ScholarThere is no corresponding record for this reference.
- 41Woody, C.; Shih, E.; Miller, J.; Royer, T.; Atkinson, L. P.; Moody, R. S. Mar. Technol. Soc. J. 2000, 34, 26– 33, DOI: 10.4031/MTSJ.34.2.4Google ScholarThere is no corresponding record for this reference.
- 42Manaud, F.; Bouchet, J.-M.; Deltreil, J.-P.; Maurer, D.; Trut, G.; Auby, I.; Dreno, J.-P.; Masson, N.; Pellier, C.; L’Yavan, C. J. Etude Integree Du Bassin d’arcachon, Tome II; Ifremer: Arcachon, France, 1997.Google ScholarThere is no corresponding record for this reference.
- 43Barbooti, M. Environmental applications of instrumental chemical analysis; CRC Press: Boca Raton, FL, USA, 2015.Google ScholarThere is no corresponding record for this reference.
- 44Deborde, J.; Anschutz, P.; Auby, I.; Gle, C.; Commarieu, M. V.; Maurer, D.; Lecroart, P.; Abril, G. Mar. Chem. 2008, 109, 98– 114, DOI: 10.1016/j.marchem.2007.12.007Google ScholarThere is no corresponding record for this reference.
- 45Castel, J.; Caumette, P.; Herbert, R. Hydrobiologia 1996, 329, ix– xxviii, DOI: 10.1007/BF00034542Google ScholarThere is no corresponding record for this reference.
- 46Rimmelin, P.; Dumon, J. C.; Maneux, E.; Goncalves, A. Estuarine, Coastal Shelf Sci. 1998, 47, 649– 659, DOI: 10.1006/ecss.1998.0384Google Scholar46Study of annual and seasonal dissolved inorganic nitrogen inputs into the Arcachon Lagoon, Atlantic coast (France)Rimmelin, P.; Dumon, J.-C.; Maneux, E.; Goncalves, A.Estuarine, Coastal and Shelf Science (1998), 47 (5), 649-659CODEN: ECSSD3; ISSN:0272-7714. (Academic Press)This study detd., by applying a direct method, dissolved inorg. N (DIN) inputs reaching a coastal lagoon, Arcachon Bay, France. Yearly monitoring of different sources (groundwater, surface water, atm. water) quantified the annual DIN discharge and the variations of DIN discharges throughout the yr. Arcachon Bay received 870 tons N in 1996. Study of the 2 main hydrol. seasons (high and low water-table periods) showed that 78% of this annual discharge occurred during the wet period (Dec.-Apr.). River DIN inputs accounted for >90% of the total annual discharge; during the wet period, river input accounted for 95% of total DIN inputs. Thus, rivers are the most important source of DIN for Arcachon Bay and the principal factor in the Bay's eutrophication. Reasons for this are: an important water discharge (>74% of total freshwater discharge) and relatively high DIN concns. (95 μM on av.) vs. groundwater and atm. water (33 and 43 μM, resp.). The atm. source accounted for 9% of the annual DIN discharge with wide variations throughout the year, accounting for 5% in the wet period and 26% in the dry period (May-Nov.). This fluctuation is due to a rise in the DIN atm. flux which increased from 32 to 49 tons N. Further, this study proved that groundwater flowing into Arcachon Bay is not DIN-polluted. Combined with the values mentioned above, the low groundwater discharge (<3% of total annual discharge) yielded a slight contribution (<1%). (c) 1998 Academic Press.
- 47Rysgaard, S.; RisgaardPetersen, N.; Sloth, N. P. Hydrobiologia 1996, 329, 133– 141, DOI: 10.1007/BF00034553Google Scholar47Nitrification, denitrification, and nitrate ammonification in sediments of two coastal lagoons in Southern FranceRysgaard, Soeren; Risgaard-Petersen, Nils; Sloth, Niels PeterHydrobiologia (1996), 329 (1-3), 133-141CODEN: HYDRB8; ISSN:0018-8158. (Kluwer)Seasonal and diurnal variations in sediment-water fluxes of O2, NO-3, and NH+4 as well as rates of nitrification, denitrification, and nitrate ammonification were detd. in two different coastal lagoons of southern France:. The seagrass (Zostera noltii) dominated tidal Bassin d'Arcachon and the dystrophic Etang du Prevost. Overall, denitrification rates in both Bassin d'Arcachon (<0.4 mmol m-2 d-1) and Etang du Prevost (<1 mmol m-2 d-1) were low. This was mainly caused by a combination of low NO-3 concns. in the water column and a low nitrification activity within the sediment. In both Bassin d'Arcachon and Etang du Prevost, rates of nitrate ammonification were quant. as important as denitrification. Denitrification played a minor role as a nitrogen sink in both systems. In the tidal influenced Bassin d'Arcachon, Z. noltii was quant. more important than denitrification as a nitrogen sink due to the high assimilation rates of the plants. Throughout the year, Z. noltii stabilized the mudflats of the bay by its well-developed root matrix and controlled the nitrogen cycle due to its high uptake rates. In contrast, the lack of rooted macrophytes, and dominance of floating macroalgae, made nitrogen cycling in Etang du Prevost more unstable and unpredictable. Inhibition of nitrification and denitrification during the dystrophic crisis in the summer time increased the inorg. nitrogen flux from the sediment to the water column and thus increased the degree of benthic-pelagic coupling within this bay. During winter, however, benthic microalgae colonizing the sediment surface changed the sediment in the lagoon from being a nitrogen source to the overlying water to being a sink due to their high assimilation rates. It is likely, however, that this assimilated nitrogen is liberated to the water column at the onset of summer thereby fueling the extensive growth of the floating macroalgae, Ulva sp. The combination of a high nitrogen coupling between sediment and water column, little water exchange and low denitrification rates resulted in an unstable system with fast growing algal species such as phytoplankton and floating algae.
- 48Canton, M.; Anschutz, P.; Coynel, A.; Polsenaere, P.; Auby, I.; Poirier, D. Biogeochemistry 2012, 107, 361– 377, DOI: 10.1007/s10533-010-9558-7Google Scholar48Nutrient export to an Eastern Atlantic coastal zone: first modeling and nitrogen mass balanceCanton, Mathieu; Anschutz, Pierre; Coynel, Alexandra; Polsenaere, Pierre; Auby, Isabelle; Poirier, DominiqueBiogeochemistry (2012), 107 (1-3), 361-377CODEN: BIOGEP; ISSN:0168-2563. (Springer)We have studied 15 catchments supplying freshwater to a French Atlantic coastal lagoon, where increase in nitrogen loads due to agriculture is supposed to have destabilized the ecosystem in the last decades. The catchment is a lowland composed of Pleistocene sands with an av. slope of 0.25%. To study the nutrient export in relation to land-use surface waters were sampled bi-weekly between Oct. 2006 and Jan. 2009 and land-use was established by plane photographs and Geog. Information System (GIS). Cultivated pine forests represent more than 80% of the total surface and 7% of the catchment area has been deforested recently. Significant areas of some catchments are used for maize crop. Housing is confined to the coastal zone. Maize and forest crop give a robust signature in terms of nitrate export. In view of modeling the nutrient fluxes, we have established the mean export rate for every land-use: forested parcels, deforested parcels, cultivated surfaces, and housing areas export 45, 93, 2850, and 61 kg N-nitrate km-2 year-1, resp. Exports of ammonium, dissolved org. N (DON), and dissolved inorg. P (DIP) could not be related to land use. The mean export is 13, 100, and 0.57 kg km-2 year-1 for N-ammonium, DON, and DIP, resp. The modeling of nitrogen flux is in good agreement with our measures for the largest catchment, which supplies about 90% of the total continental DIN flux. However, small catchments are more dynamic due to hydrol. conditions and the model is less accurate. This work has permitted to complete and unify scattered studies about nutrient cycling in this area. Thus we have established and compared the nitrogen budget of cornfields and cultivated pine forest. We have emphasized that (i) fertilizer use should be reduced in cornfields because they stock between 200 and 6400 kg DIN km-2 year-1, and (ii) the nitrogen budget in pine forest mostly depends on tree harvesting and symbiotic N-fixation, which is poorly constrained. Export of N by rivers represents a small contribution to the N budget of soils.
- 49Gle, C.; Del Amo, Y.; Sautour, B.; Laborde, P.; Chardy, P. Estuarine, Coastal Shelf Sci. 2008, 76, 642– 656, DOI: 10.1016/j.ecss.2007.07.043Google ScholarThere is no corresponding record for this reference.
- 50SOMLIT. http://somlit.epoc.u-bordeaux1.fr/fr/ (accessed Nov. 15, 2017).Google ScholarThere is no corresponding record for this reference.
- 51TuTiempo. http://www.tutiempo.net/arcachon.html?datos=calendario-cal (accessed Jun. 1, 2017).Google ScholarThere is no corresponding record for this reference.
- 52Marée.info. http://www.maree.info/136?d=20170515 (accessed Jun. 1, 2017).Google ScholarThere is no corresponding record for this reference.
- 53Marée.info. http://www.maree.info/136?d=20170516 (accessed Jun. 1, 2017).Google ScholarThere is no corresponding record for this reference.
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(18)
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(22)
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(20)
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(31)
https://doi.org/10.1002/aenm.202301438
- Yiqun Liu, Hailong Lu, Yue Cui. A Review of Marine In Situ Sensors and Biosensors. Journal of Marine Science and Engineering 2023, 11
(7)
, 1469. https://doi.org/10.3390/jmse11071469
- Ciprian Briciu-Burghina, Sean Power, Adrian Delgado, Fiona Regan. Sensors for Coastal and Ocean Monitoring. Annual Review of Analytical Chemistry 2023, 16
(1)
, 451-469. https://doi.org/10.1146/annurev-anchem-091922-085746
- Jun Hyuk Heo, Minchul Sung, Tran Quang Trung, Yullim Lee, Do Hyeon Jung, Hajeong Kim, Sandeep Kaushal, Nae‐Eung Lee, Jin Woong Kim, Jung Heon Lee, Soo‐Yeon Cho. Sensor design strategy for environmental and biological monitoring. EcoMat 2023, 5
(5)
https://doi.org/10.1002/eom2.12332
- Tara Forrest, Thomas Cherubini, Stéphane Jeanneret, Elena Zdrachek, Polyxeni Damala, Eric Bakker. A submersible probe with in-line calibration and a symmetrical reference element for continuous direct nitrate concentration measurements. Environmental Science: Processes & Impacts 2023, 25
(3)
, 519-530. https://doi.org/10.1039/D2EM00341D
- Anurag Adiraju, Rohan Munjal, Christian Viehweger, Ammar Al-Hamry, Amina Brahem, Jawaid Hussain, Sanhith Kommisetty, Aditya Jalasutram, Christoph Tegenkamp, Olfa Kanoun. Towards Embedded Electrochemical Sensors for On-Site Nitrite Detection by Gold Nanoparticles Modified Screen Printed Carbon Electrodes. Sensors 2023, 23
(6)
, 2961. https://doi.org/10.3390/s23062961
- Polyxeni Damala, Elena Zdrachek, Eric Bakker. Commercially Available Nitrate Ionophores in Potentiometric Sensors are not Superior to Common Ion‐exchangers. Electroanalysis 2023, 35
(2)
https://doi.org/10.1002/elan.202200247
- Yeji Park, Minki Jun, Taehyun Kwon, Jin Young Kim, Kwangyeol Lee. Heterostructured nanocatalysts to boost the hydrogen evolution reaction in neutral electrolyte. Chem Catalysis 2023, 3
(2)
, 100499. https://doi.org/10.1016/j.checat.2022.100499
- Satya Lakshmi Pasarakonda, Srikanth Ponnada, Demudu Babu Gorle, Rapaka S. Chandra Bose, Anjali Palariya, Maryam Sadat Kiai, Hima Bindu Gandham, Murugavel Kathiresan, Rakesh K Sharma, Annapurna Nowduri. On the role of graphene oxide in bifunctional Ni/MOF/rGO composites in electrochemical nitrate detection and oxygen evolution reaction. New Journal of Chemistry 2023, 47
(2)
, 725-736. https://doi.org/10.1039/D2NJ04648B
- Hao‐Yu Wang, Ming‐Lei Sun, Jin‐Tao Ren, Zhong‐Yong Yuan. Circumventing Challenges: Design of Anodic Electrocatalysts for Hybrid Water Electrolysis Systems. Advanced Energy Materials 2023, 13
(4)
https://doi.org/10.1002/aenm.202203568
- Raquel R. A. Soares, Robert G. Hjort, Cícero C. Pola, Dapeng Jing, Victor S. Cecon, Jonathan C. Claussen, Carmen L. Gomes. Ion-selective electrodes based on laser-induced graphene as an alternative method for nitrite monitoring. Microchimica Acta 2023, 190
(1)
https://doi.org/10.1007/s00604-022-05615-9
- Zhehao Zhang, Elena Boselli, Ian Papautsky. Potentiometric Sensor System with Self-Calibration for Long-Term, In Situ Measurements. Chemosensors 2023, 11
(1)
, 48. https://doi.org/10.3390/chemosensors11010048
- Jianyun Liu, Shuo Duan, Hao Shi, Tanyuan Wang, Xiaoxuan Yang, Yunhui Huang, Gang Wu, Qing Li. Rationally Designing Efficient Electrocatalysts for Direct Seawater Splitting: Challenges, Achievements, and Promises. Angewandte Chemie 2022, 134
(45)
https://doi.org/10.1002/ange.202210753
- Jianyun Liu, Shuo Duan, Hao Shi, Tanyuan Wang, Xiaoxuan Yang, Yunhui Huang, Gang Wu, Qing Li. Rationally Designing Efficient Electrocatalysts for Direct Seawater Splitting: Challenges, Achievements, and Promises. Angewandte Chemie International Edition 2022, 61
(45)
https://doi.org/10.1002/anie.202210753
- Karolina Pietrzak, Klaudia Morawska, Szymon Malinowski, Cecylia Wardak. Chloride Ion-Selective Electrode with Solid-Contact Based on Polyaniline Nanofibers and Multiwalled Carbon Nanotubes Nanocomposite. Membranes 2022, 12
(11)
, 1150. https://doi.org/10.3390/membranes12111150
- Samaneh Mozaffari, Mohammad Reza Nateghi. Recent Advances in Solar Rechargeable Seawater Batteries Based on Semiconductor Photoelectrodes. Topics in Current Chemistry 2022, 380
(5)
https://doi.org/10.1007/s41061-022-00380-y
- Chani Park, Hyosang Yoon, Md. Abu Zahed, Shipeng Zhang, Sanghyuk Yoon, Dongkyun Kim, Daeheum Kim, Jaeyeong Park. A Highly Stable and Flexible Ca
2+
Ion-Selective Sensor Based on Treated PEDOT:PSS Transducing Layer. IEEE Sensors Journal 2022, 22
(12)
, 11213-11221. https://doi.org/10.1109/JSEN.2021.3075297
- Shuo-En Wu, Alan Shiller, Andrew Barnard, Jason D. Azoulay, Tse Nga Ng. Point-of-use printed nitrate sensor with desalination units. Microchimica Acta 2022, 189
(6)
https://doi.org/10.1007/s00604-022-05314-5
- Linzhou Zhuang, Shiyi Li, Jiankun Li, Keyu Wang, Zeyu Guan, Chen Liang, Zhi Xu. Recent Advances on Hydrogen Evolution and Oxygen Evolution Catalysts for Direct Seawater Splitting. Coatings 2022, 12
(5)
, 659. https://doi.org/10.3390/coatings12050659
- Lina Cao, Hongyong Xiang, Jingwen Xu, Yufu Gao, Chenlu Lin, Kun Li, Zhiwei Li, Nana Guo, P. David, Chunguang He, Haijun Yang, . Nutrient Detection Sensors in Seawater Based on ISI Web of Science Database. Journal of Sensors 2022, 2022 , 1-12. https://doi.org/10.1155/2022/5754751
- José Antonio González-Franco, Alberto Ruiz, Joaquín Ángel Ortuño. Dynamic Potentiometry with an Ion-Selective Electrode: A Tool for Qualitative and Quantitative Analysis of Inorganic and Organic Cations. Chemosensors 2022, 10
(3)
, 116. https://doi.org/10.3390/chemosensors10030116
- Simranjeet Singh, Amith G. Anil, Vijay Kumar, Dhriti Kapoor, S. Subramanian, Joginder Singh, Praveen C. Ramamurthy. Nitrates in the environment: A critical review of their distribution, sensing techniques, ecological effects and remediation. Chemosphere 2022, 287 , 131996. https://doi.org/10.1016/j.chemosphere.2021.131996
- Longbin Xu, Shiyu Gan, Lijie Zhong, Zhonghui Sun, Yitian Tang, Tingting Han, Kanglong Lin, Chunxian Liao, Dequan He, Yingming Ma, Wei Wang, Li Niu. Conductive metal organic framework for ion-selective membrane-free solid-contact potentiometric Cu2+ sensing. Journal of Electroanalytical Chemistry 2022, 904 , 115923. https://doi.org/10.1016/j.jelechem.2021.115923
- Hao-Yu Wang, Chen-Chen Weng, Jin-Tao Ren, Zhong-Yong Yuan. An overview and recent advances in electrocatalysts for direct seawater splitting. Frontiers of Chemical Science and Engineering 2021, 15
(6)
, 1408-1426. https://doi.org/10.1007/s11705-021-2102-6
- Saikat Bolar, Subhasis Shit, Naresh Chandra Murmu, Tapas Kuila. Progress in theoretical and experimental investigation on seawater electrolysis: opportunities and challenges. Sustainable Energy & Fuels 2021, 5
(23)
, 5915-5945. https://doi.org/10.1039/D1SE01347E
- Grzegorz Lisak. Reliable environmental trace heavy metal analysis with potentiometric ion sensors - reality or a distant dream. Environmental Pollution 2021, 289 , 117882. https://doi.org/10.1016/j.envpol.2021.117882
- Juan Yue, Ling Yu, Li Li, Pai Liu, Qian Mei, Wen-Fei Dong, Ru Yang. One-Step Synthesis of Green Fluorescent Carbon Dots for Chloride Detecting and for Bioimaging. Frontiers in Chemistry 2021, 9 https://doi.org/10.3389/fchem.2021.718856
- R.K.A. Amali, H.N. Lim, I. Ibrahim, N.M. Huang, Z. Zainal, S.A.A. Ahmad. Significance of nanomaterials in electrochemical sensors for nitrate detection: A review. Trends in Environmental Analytical Chemistry 2021, 31 , e00135. https://doi.org/10.1016/j.teac.2021.e00135
- Muhamad Afiq Akbar, Nurul Yuziana Mohd Yusof, Fathul Karim Sahrani, Gires Usup, Asmat Ahmad, Syarul Nataqain Baharum, Nor Azlan Nor Muhammad, Hamidun Bunawan. Insights into Alexandrium minutum Nutrient Acquisition, Metabolism and Saxitoxin Biosynthesis through Comprehensive Transcriptome Survey. Biology 2021, 10
(9)
, 826. https://doi.org/10.3390/biology10090826
- Elena Zdrachek, Eric Bakker. Ion-to-electron capacitance of single-walled carbon nanotube layers before and after ion-selective membrane deposition. Microchimica Acta 2021, 188
(5)
https://doi.org/10.1007/s00604-021-04805-1
- Maria Cuartero. Electrochemical sensors for in-situ measurement of ions in seawater. Sensors and Actuators B: Chemical 2021, 334 , 129635. https://doi.org/10.1016/j.snb.2021.129635
- Hong Wei, Dawei Pan, Haitao Han. Electrochemical monitoring of marine nutrients: From principle to application. TrAC Trends in Analytical Chemistry 2021, 138 , 116242. https://doi.org/10.1016/j.trac.2021.116242
- Sören Dresp, Peter Strasser. Electro-catalysts for oxygen electrodes in seawater electrolyzers (OER) and reversible electrolyzers (OER/ORR). 2021, 83-103. https://doi.org/10.1016/B978-0-12-818496-7.00008-4
- M A Parvez Mahmud, Fatemeh Ejeian, Shohreh Azadi, Matthew Myers, Bobby Pejcic, Rouzbeh Abbassi, Amir Razmjou, Mohsen Asadnia. Recent progress in sensing nitrate, nitrite, phosphate, and ammonium in aquatic environment. Chemosphere 2020, 259 , 127492. https://doi.org/10.1016/j.chemosphere.2020.127492
- Chani Park, Hyosang Yoon, Md Abu Zahed, Jaeyeong Park. A Highly Stable Ca
2+
Ion-Selective Flexible Sensor Based on Treated PEDOT:PSS Transducing Layer. 2020, 1-4. https://doi.org/10.1109/SENSORS47125.2020.9278751
- E. A. Jaramillo, A. C. Noell. Development of Miniature Solid Contact Ion Selective Electrodes for
in situ
Instrumentation. Electroanalysis 2020, 32
(9)
, 1896-1904. https://doi.org/10.1002/elan.201900761
- Simone Aiassa, Rossana Terracciano, Sandro Carrara, Danilo Demarchi. Biosensors for Biomolecular Computing: a Review and Future Perspectives. BioNanoScience 2020, 10
(3)
, 554-563. https://doi.org/10.1007/s12668-020-00764-8
- Chunbo Jiang, Yinghe He, Yang Liu. Recent advances in sensors for electrochemical analysis of nitrate in food and environmental matrices. The Analyst 2020, 145
(16)
, 5400-5413. https://doi.org/10.1039/D0AN00823K
- Yuzhou Shao, Yibin Ying, Jianfeng Ping. Recent advances in solid-contact ion-selective electrodes: functional materials, transduction mechanisms, and development trends. Chemical Society Reviews 2020, 49
(13)
, 4405-4465. https://doi.org/10.1039/C9CS00587K
- Di Wu, Kequan Xia, Chengzhu Fang, Xuegang Chen, Ying Ye. Rapid Removal of Azophloxine via Catalytic Degradation by a Novel Heterogeneous Catalyst under Visible Light. Catalysts 2020, 10
(1)
, 138. https://doi.org/10.3390/catal10010138
- Shuang Liu, Yong-Liang Yu, Jian-Hua Wang. An atomic fluorescence spectrometer for monitoring nitrogen nutrients via NO vapor generation. Analytica Chimica Acta 2019, 1064 , 17-24. https://doi.org/10.1016/j.aca.2019.02.057
- Ling Tong, Shuhua Sun, Min Qiao, Junmei Fan, Liping Ding. Selective turn-on sensing of Cu2+ and Cl− by a ferrocene-modified pyrene derivative. Journal of Photochemistry and Photobiology A: Chemistry 2019, 374 , 131-137. https://doi.org/10.1016/j.jphotochem.2019.01.036
- Marc Parrilla, Maria Cuartero, Gaston A. Crespo. Wearable potentiometric ion sensors. TrAC Trends in Analytical Chemistry 2019, 110 , 303-320. https://doi.org/10.1016/j.trac.2018.11.024
- María Cuartero, Marc Parrilla, Gaston A. Crespo. Wearable Potentiometric Sensors for Medical Applications. Sensors 2019, 19
(2)
, 363. https://doi.org/10.3390/s19020363
- María Cuartero, Gastón A. Crespo. All-solid-state potentiometric sensors: A new wave for in situ aquatic research. Current Opinion in Electrochemistry 2018, 10 , 98-106. https://doi.org/10.1016/j.coelec.2018.04.004
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Abstract
Figure 1
Figure 1. (a) Scheme of the developed fluidics for in situ measurements (NO = normally open, NC = normally closed, CAL SOL = calibration solution, RE = reference electrode). (b) Image of the submersible probe based on the valve (1), the desalination module (2), the acidification module (3), and the potentiometric flow cell (4). The system is placed inside the water- and pressure-proof cylindrical housing (5) made of acetylic copolymer (Deldrin). (33) (c) Probe incorporated into the titanium cage together with the pump and the CTD multiparemeter probe (6, filter for seawater; 7, pump; 8, unit containing the electrochemical sensors; 9, bag containing the calibration solution; 10, bag containing the HCl solution; 11, CTD). (d) Submersible device deployed in the Arcachon Bay from a boat using a small onboard crane.
Figure 2
Figure 2. Calibration graphs obtained for (a) nitrate and (b) nitrite using the developed flow potentiometric cell based on miniaturized all-solid-state electrodes.
Figure 3
Figure 3. Cyclic voltammograms observed at increasing chloride concentrations in (a) synthetic NaCl solutions and (b) freshwater/seawater mixtures. Reference solution = water sample that is measured. (c) Correlation between chloride concentrations measured using ion chromatography (IC) and the desalination cell (CV) in samples collected in the Gironde Estuary (France).
Figure 4
Figure 4. Plots of chloride versus salinity measured in (a) samples collected in the Gironde Estuary and (b) the 23 h deployment in the Arcachon Bay. Blue squares indicate predicted salinity values from the observed chloride–salinity linear relationship. Dashed line indicates the extrapolation of the chloride–salinity linear relationship to lower chloride values.
Figure 5
Figure 5. In situ temporal profiles obtained for (a) temperature (CTD), (b) pH (CTD), (c) salinity and chloride, and (d) nitrate during the deployment of 23 h (starting from May 15, 2017 at 16:00 to May 16, 2017 at 15:00) in the Arcachon Bay (44°40.822’N 1°06.007’W). The deployment depth was 2.3 ± 0.3 m. The dissolved O2 concentration was 7.5 ± 0.3 ppm, corresponding to 101.2 ± 3.2% for oxygen saturation within the monitoring window. Light hours are shaded in gray. (51) The local times for high and low tides (HT and LT, respectively) were determined according to the tidal record at Jetée d’Eyrac (44°40′N 1°10′W) and considering the temporal evolution of the seawater level in the Arcachon Bay. (52,53)
References
This article references 53 other publications.
- 1Orr, J. C.; Fabry, V. J.; Aumont, O.; Bopp, L.; Doney, S. C.; Feely, R. A.; Gnanadesikan, A.; Gruber, N.; Ishida, A.; Joos, F.; Key, R. M.; Lindsay, K.; Maier-Reimer, E.; Matear, R.; Monfray, P.; Mouchet, A.; Najjar, R. G.; Plattner, G. K.; Rodgers, K. B.; Sabine, C. L.; Sarmiento, J. L.; Schlitzer, R.; Slater, R. D.; Totterdell, I. J.; Weirig, M. F.; Yamanaka, Y.; Yool, A. Nature 2005, 437, 681– 686, DOI: 10.1038/nature040951Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organismsOrr, James C.; Fabry, Victoria J.; Aumont, Olivier; Bopp, Laurent; Doney, Scott C.; Feely, Richard A.; Gnanadesikan, Anand; Gruber, Nicolas; Ishida, Akio; Joos, Fortunat; Key, Robert M.; Lindsay, Keith; Maier-Reimer, Ernst; Matear, Richard; Monfray, Patrick; Mouchet, Anne; Najjar, Raymond G.; Plattner, Gian-Kasper; Rodgers, Keith B.; Sabine, Christopher L.; Sarmiento, Jorge L.; Schlitzer, Reiner; Slater, Richard D.; Totterdell, Ian J.; Weirig, Marie-France; Yamanaka, Yasuhiro; Yool, AndrewNature (London, United Kingdom) (2005), 437 (7059), 681-686CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)Today's surface ocean is satd. with respect to calcium carbonate, but increasing atm. carbon dioxide concns. are reducing ocean pH and carbonate ion concns., and thus the level of calcium carbonate satn. Exptl. evidence suggests that if these trends continue, key marine organisms-such as corals and some plankton-will have difficulty maintaining their external calcium carbonate skeletons. Here we use 13 models of the ocean-carbon cycle to assess calcium carbonate satn. under the IS92a business-as-usual scenario for future emissions of anthropogenic carbon dioxide. In our projections, Southern Ocean surface waters will begin to become undersatd. with respect to aragonite, a metastable form of calcium carbonate, by the year 2050. By 2100, this undersatn. could extend throughout the entire Southern Ocean and into the subarctic Pacific Ocean. When live pteropods were exposed to our predicted level of undersatn. during a two-day shipboard expt., their aragonite shells showed notable dissoln. Our findings indicate that conditions detrimental to high-latitude ecosystems could develop within decades, not centuries as suggested previously.
- 2Halpern, B. S.; Walbridge, S.; Selkoe, K. A.; Kappel, C. V.; Micheli, F.; D’Agrosa, C.; Bruno, J. F.; Casey, K. S.; Ebert, C.; Fox, H. E.; Fujita, R.; Heinemann, D.; Lenihan, H. S.; Madin, E. M. P.; Perry, M. T.; Selig, E. R.; Spalding, M.; Steneck, R.; Watson, R. Science 2008, 319, 948– 952, DOI: 10.1126/science.11493452A Global Map of Human Impact on Marine EcosystemsHalpern, Benjamin S.; Walbridge, Shaun; Selkoe, Kimberly A.; Kappel, Carrie V.; Micheli, Fiorenza; D'Agrosa, Caterina; Bruno, John F.; Casey, Kenneth S.; Ebert, Colin; Fox, Helen E.; Fujita, Rod; Heinemann, Dennis; Lenihan, Hunter S.; Madin, Elizabeth M. P.; Perry, Matthew T.; Selig, Elizabeth R.; Spalding, Mark; Steneck, Robert; Watson, RegScience (Washington, DC, United States) (2008), 319 (5865), 948-952CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Management and conservation of the world oceans require synthesis of spatial data on the distribution and intensity of anthropogenic activity and overlap of human impacts on marine ecosystems. An ecosystem-specific, multi-scale spatial model was developed to synthesize 17 global datasets of anthropogenic drivers of ecol. change for 20 marine ecosystems. This anal. indicated no area was unaffected by human influence and that a large fraction (41%) was strongly affected by multiple drivers; however, large areas of relatively little human impact remain, particularly near the poles. The anal. process and resulting maps provide flexible tools for regional and global efforts to allocate conservation resources; implement ecosystem-based management; and inform marine spatial planning, education, and basic research.
- 3Webber, H. H.; Thurman, H. V. Marine Biology, 2nd ed.; Harpercollins: New York, 1991.There is no corresponding record for this reference.
- 4Tilman, D. Proc. Natl. Acad. Sci. U. S. A. 1999, 96, 5995– 6000, DOI: 10.1073/pnas.96.11.5995There is no corresponding record for this reference.
- 5Andersen, J. H.; Fossing, H.; Hansen, J. W.; Manscher, O. H.; Murray, C.; Petersen, D. L. J. Ambio 2014, 43, 906– 913, DOI: 10.1007/s13280-014-0514-yThere is no corresponding record for this reference.
- 6Smith, V. H.; Tilman, G. D.; Nekola, J. C. Environ. Pollut. 1999, 100, 179– 196, DOI: 10.1016/S0269-7491(99)00091-3There is no corresponding record for this reference.
- 7Saliot, A. The Mediterranean Sea; Springer: Berlin, 2005.There is no corresponding record for this reference.
- 8Cuartero, M.; Bakker, E. Current Opinion in Electrochemistry 2017, 3, 97– 105, DOI: 10.1016/j.coelec.2017.06.010There is no corresponding record for this reference.
- 9Albaiges, J. Int. J. Environ. Anal. Chem. 2008, 88, 598, DOI: 10.1080/03067310801993459There is no corresponding record for this reference.
- 10David, A. R. J.; McCormack, T.; Morris, A. W.; Worsfold, P. J. Anal. Chim. Acta 1998, 361, 63– 72, DOI: 10.1016/S0003-2670(98)00023-3There is no corresponding record for this reference.
- 11Ma, J.; Adornato, L.; Byrne, R. H.; Yuan, D. X. TrAC, Trends Anal. Chem. 2014, 60, 1– 15, DOI: 10.1016/j.trac.2014.04.01311Determination of nanomolar levels of nutrients in seawaterMa, Jian; Adornato, Lori; Byrne, Robert H.; Yuan, DongxingTrAC, Trends in Analytical Chemistry (2014), 60 (), 1-15CODEN: TTAEDJ; ISSN:0165-9936. (Elsevier B. V.)A review. Nutrients (phosphate, nitrate, nitrite, ammonium and silicate) exert strong controls on oceanic primary productivity. In oligotrophic areas, which cover approx. 40% of the world's oceans, nutrient concns. can drop to nanomolar levels or lower due to biol. uptake, so highly sensitive methods and technologies are urgently needed for nutrient measurements in such areas. In this work, we review procedures for phosphate and nitrite/nitrate analyses published since the review of Patey et al. [32], and procedures for anal. of ammonium and silicate at nanomolar levels. Our review includes aspects of measurement protocols that bear strongly on the quality of analyses of trace nutrients, including contamination of reagents, sample storage, and prepn. of nutrient-free seawater. This review excludes methods that have limits of detection greater than 1 μM, and methods that are not specific to seawater.
- 12Jannasch, H. W.; Johnson, K. S.; Sakamoto, C. M. Anal. Chem. 1994, 66, 3352– 3361, DOI: 10.1021/ac00092a011There is no corresponding record for this reference.
- 13Beaton, A. D.; Cardwell, C. L.; Thomas, R. S.; Sieben, V. J.; Legiret, F. E.; Waugh, E. M.; Statham, P. J.; Mowlem, M. C.; Morgan, H. Environ. Sci. Technol. 2012, 46, 9548– 9556, DOI: 10.1021/es300419uThere is no corresponding record for this reference.
- 14Li, Q. P.; Hansell, D. A.; Zhang, J. Z. Limnol. Oceanogr.: Methods 2008, 6, 319– 326, DOI: 10.4319/lom.2008.6.31914Underway monitoring of nanomolar nitrate plus nitrite and phosphate in oligotrophic seawaterLi, Qian P.; Hansell, Dennis A.; Zhang, Jia-ZhongLimnology and Oceanography: Methods (2008), 6 (July), 319-326CODEN: LOMIBY; ISSN:1541-5856. (American Society of Limnology and Oceanography)To study nutrient dynamics and cycling in oligotrophic open ocean environments, continuous measurements of nanomolar nitrate, nitrite, and phosphate are valuable. However, such studies are usually impeded by the detection limits of conventional nutrient-sensors and analyzers. Here, we developed a shipboard deployable underway system for simultaneously monitoring nitrate plus nitrite and phosphate at nanomolar concns. by the coupling of an optimized flow injection anal. system with two long-path liq. waveguide capillary cells (LWCC). The detection limits are ∼2 nM for nitrate plus nitrite and ∼1.5 nM for phosphate, resp. Results from real-time surveys of waters over the west Florida continental shelf and the oligotrophic Sargasso Sea are presented. This system has also been successfully used to analyze more than 1000 discrete seawater samples manually during 2 cruises in the North Atlantic.
- 15Sea-Bird Scientific. http://www.seabird.com/suna (accessed Sep. 1, 2017).There is no corresponding record for this reference.
- 16Johnson, K. S.; Coletti, L. J.; Jannasch, H. W.; Sakamoto, C. M.; Swift, D. D.; Riser, S. C. J. Atmos. Ocean. Technol. 2013, 30, 1854– 1866, DOI: 10.1175/JTECH-D-12-00221.1There is no corresponding record for this reference.
- 17Nielsen, M.; Larsen, L. H.; Jetten, M. S. M.; Revsbech, N. P. Appl. Environ. Microbiol. 2004, 70, 6551– 6558, DOI: 10.1128/AEM.70.11.6551-6558.2004There is no corresponding record for this reference.
- 18Revsbech, N. P.; Glud, R. N. Limnol. Oceanogr.: Methods 2009, 7, 761– 770, DOI: 10.4319/lom.2009.7.76118Biosensor for laboratory and lander-based analysis of benthic nitrate plus nitrite distribution in marine environmentsRevsbech, Niels Peter; Glud, Ronnie NohrLimnology and Oceanography: Methods (2009), 7 (Nov.), 761-770CODEN: LOMIBY; ISSN:1541-5856. (American Society of Limnology and Oceanography)We present a psychotropic bacteria-based biosensor that can be used in low-temp. seawater for the anal. of nitrate + nitrite (NOx-). The sensor can be used to resolve concns. below 1 μmol L-1 at low temp. (<2.5°C) and high salinity (35‰), and in situ use in the deep sea was demonstrated by measuring NOx- profiles in sediment at 1500 m depth, where the temp. was 2.5°C. Anal. of marine sediment at 70 m depth showed very heterogeneous NOx- profiles, most of which exhibited pronounced maxima due to nitrification in the oxic surface layer. At this shallow water site, the in situ profiles were similar to profiles measured in the lab., but generally lab. profiles appeared more uniform, presumably as a result of reduced fauna activity and disturbance of the microstructure of the sediment surface during core recovery.
- 19Unisense. http://www.unisense.com/NOx (accessed Feb. 4, 2017).There is no corresponding record for this reference.
- 20Crespo, G. A. Electrochim. Acta 2017, 245, 1023– 1034, DOI: 10.1016/j.electacta.2017.05.15920Recent Advances in Ion-selective membrane electrodes for in situ environmental water analysisCrespo, Gaston A.Electrochimica Acta (2017), 245 (), 1023-1034CODEN: ELCAAV; ISSN:0013-4686. (Elsevier Ltd.)A review. Ion-selective membrane electrodes (ISEs) have become very attractive sensing platforms for environmental water anal. This review mainly presents recent advances in polymeric-based ISEs relevant to H2O research and primarily focused on alkali and alkali earth-metal cations, ammonium ions, halide anions and certain oxoanions involved in biogeochem. cycles (e.g. nutrients (NO-2, NO-3), C (HCO-3/CO2-3) and P (HPO2-4/H2PO-4)). Clearly, ISEs have the potential to be the icon of decentralized ion chem. information for H2O research as in the case of wearable ISE sensors. The modern development of robust ISEs (mainly in all-solid-state format) has allowed an easy implementation either into submersible or nonsubmersible probes that maintain, to an acceptable degree, the required anal. performance. Remarkable benefits, such as avoidance of sample contamination, sample preservation and detn. of perturbations of chem. speciation, are significant to enhancing the fundamental knowledge of ongoing biogeochem. process. A perspective on the current requirements of ISEs in terms of anal. performance and engineering construction is provided initially and is followed by recent contributions listed according to the sampling methodol., including (i) on-board/on-site sampling with subsequent coverage of decentralized anal. (on moving or fixed platforms) and (ii) in situ monitoring with submersible sensing probes. On the one hand, there is difficulty in making a general statement about ISEs for H2O research, specifically in terms of whether they are suitable. This lies in the complexity and heterogeneity of the samples. Accordingly, particular scenarios are discussed. However, it is also evident that further steps are still needed at the fundamental level, including development of receptors, robust membranes and novel alternatives that would enable the sensing of ions at deep-sea. Importantly, there is a plenty of room for improvement and new approaches; and it should be stressed that the recent progress in H2O research using ISEs was owing to multidisciplinary efforts. Facing this challenge is very exciting and the development of ISE platforms that enable working in real conditions is quite plausible.
- 21Bobacka, J.; Ivaska, A.; Lewenstam, A. Chem. Rev. 2008, 108, 329– 351, DOI: 10.1021/cr068100w21Potentiometric Ion SensorsBobacka, Johan; Ivaska, Ari; Lewenstam, AndrzejChemical Reviews (Washington, DC, United States) (2008), 108 (2), 329-351CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review. The aim of this review is to highlight some of these modern topics in the field of potentiometric ion sensors. This review is focused on recent achievements since the beginning of this millennium and emphasizes the results from the last 5 years (2002-2006). Section 2 gives a crit. overview, placed in a historical perspective, on the theory of the potentiometric response, including classical equil. models as well as advanced nonequil. models. Section 3 deals with recent advances in the field of solid-contact ion-selective electrodes (ISEs), emphasizing the application of conducting polymers as ion-to-electron transducers. Recent developments in the area of miniaturized ISEs, including applications in flow anal., life science, and biol., are discussed in section 4. Finally, the new wave of ISEs is commented on in section 5. The authors hope that the issues discussed will illustrate the great possibilities offered by modern ISEs and encourage further innovations in the rapidly expanding field of chem. sensors in the years to come.
- 22Bakker, E.; Pretsch, E. Angew. Chem., Int. Ed. 2007, 46, 5660– 5668, DOI: 10.1002/anie.200605068There is no corresponding record for this reference.
- 23Buck, R. P.; Lindner, E. Pure Appl. Chem. 1994, 66, 2527– 2536, DOI: 10.1351/pac199466122527There is no corresponding record for this reference.
- 24Cuartero, M.; Crespo, G. A.; Bakker, E. Chimia 2015, 69, 203– 206, DOI: 10.2533/chimia.2015.203There is no corresponding record for this reference.
- 25Crespo, G. A.; Bakker, E. RSC Adv. 2013, 3, 25461– 25474, DOI: 10.1039/c3ra43751e25Dynamic electrochemistry with ionophore based ion-selective membranesCrespo, Gaston A.; Bakker, EricRSC Advances (2013), 3 (48), 25461-25474CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)This review outlines key principles and recent advances in the use of dynamic electrochem. with polymeric liq. membranes. Ideally polarizable membranes are most attractive in fundamental studies of ion transfer and when the accumulation of the ion in the receiving phase is of key interest, for example in stripping ion transfer voltammetry. All solid-state membranes doped with conducting polymers have exhibited attractive low detection limit for hydrophilic ions. On the other hand, initially non-polarized interfaces are most useful when one aims to effect a concn. change of an ionic species in the sample phase. Conveniently, these types of membranes can be interrogated with potentiometry and sequentially with dynamic techniques such as chronopotentiometry. This can be used to obtain speciation information as they allow one, in principle, to assess total labile and free ion concns. in the same expt. A no. of electrochem. techniques were reported and include controlled potential techniques such as cyclic voltammetry, normal pulse voltammetry, stripping voltammetry, and thin layer coulometry as well as current controlled ones such as pulsed chronopotentiometry and flash chronopotentiometry. All of these techniques have their purpose and strength.
- 26Bakker, E. Anal. Chem. 2016, 88, 395– 413, DOI: 10.1021/acs.analchem.5b04034There is no corresponding record for this reference.
- 27Athavale, R.; Dinkel, C.; Wehrli, B.; Bakker, E.; Crespo, G. A.; Brand, A. Environ. Sci. Technol. Lett. 2017, 4, 286– 291, DOI: 10.1021/acs.estlett.7b0013027Robust Solid-Contact Ion Selective Electrodes for High-Resolution In Situ Measurements in Fresh Water SystemsAthavale, Rohini; Dinkel, Christian; Wehrli, Bernhard; Bakker, Eric; Crespo, Gaston A.; Brand, AndreasEnvironmental Science & Technology Letters (2017), 4 (7), 286-291CODEN: ESTLCU; ISSN:2328-8930. (American Chemical Society)Biogeochem. processes are often confined to very narrow zones in aquatic systems. Therefore, highly resolved in situ measurements are required to study these processes. Potentiometric solid-contact ion selective electrodes (SC-ISEs) are promising tools for such measurements. SC-ISEs show good performance in analyses under controlled exptl. conditions. Very few sensor designs, however, can sustain the challenges of natural water matrixes and external environmental conditions during in situ applications. We fabricated ammonium and pH selective SC-ISEs with functionalized multiwalled carbon nanotubes (f-MWCNT) as a solid contact. Their functionality was tested in the lab. and applied in situ for vertical profiling in a eutrophic lake. Sensors were insensitive to strong redox changes, high sulfide concns., and bright daylight conditions during the application in the lake. In addn., sensors are easily fabricated and exhibit short response times (<10 s). The proposed design of SC-ISEs based on f-MWCNTs is quite suitable for high-resoln. in situ profiling of ionic species in fresh water lakes.
- 28Athavale, R.; Kokorite, I.; Dinkel, C.; Bakker, E.; Wehrli, B.; Crespo, G. A.; Brand, A. Anal. Chem. 2015, 87, 11990– 11997, DOI: 10.1021/acs.analchem.5b02424There is no corresponding record for this reference.
- 29Cuartero, M.; Pankratova, N.; Cherubini, T.; Crespo, G. A.; Massa, F.; Confalonieri, F.; Bakker, E. Environ. Sci. Technol. Lett. 2017, 4, 410– 415, DOI: 10.1021/acs.estlett.7b0038829In Situ Detection of Species Relevant to the Carbon Cycle in Seawater with Submersible Potentiometric ProbesCuartero, Maria; Pankratova, Nadezda; Cherubini, Thomas; Crespo, Gaston A.; Massa, Francesco; Confalonieri, Fabio; Bakker, EricEnvironmental Science & Technology Letters (2017), 4 (10), 410-415CODEN: ESTLCU; ISSN:2328-8930. (American Chemical Society)We report on the development of a submersible probe for the simultaneous potentiometric detection of carbonate, calcium, and pH in seawater. All-solid-state electrodes incorporating nanomaterials provide an adequate response time (<10 s), stability (drifts of <0.9 mV h-1), reproducibility (calibration parameter deviation of <0.7%), and accuracy (deviation of <8% compared to ref. techniques) for real-time monitoring of seawater using a flow system. The functioning of the deployable prototype was checked in an outdoor mesocosm and via long-term monitoring in Genoa Harbor. The electrodes worked properly for 3 wk, and the system demonstrated the capability to autonomously operate with routines for repetitive measurements, data storage, and management. In situ profiles obsd. in Genoa Harbor and Arcachon Bay were validated using on site and ex situ techniques. The validation of in situ-detected carbonate is a challenge because both re-equilibration of the sample with atm. CO2 and the use of apparent thermodn. consts. for speciation calcns. lead to some differences (<20% deviation). The submersible probe is a promising tool for obtaining rapid and trustworthy information about chem. levels in marine systems. Moreover, the fluidic approach allows for the integration of other ion sensors that may require sample pretreatment.
- 30Cuartero, M.; Crespo, G. A.; Bakker, E. Anal. Chem. 2015, 87, 8084– 8089, DOI: 10.1021/acs.analchem.5b01973There is no corresponding record for this reference.
- 31Pankratova, N.; Cuartero, M.; Cherubini, T.; Crespo, G. A.; Bakker, E. Anal. Chem. 2017, 89, 571– 575, DOI: 10.1021/acs.analchem.6b0394631In-Line Acidification for Potentiometric Sensing of Nitrite in Natural WatersPankratova, Nadezda; Cuartero, Maria; Cherubini, Thomas; Crespo, Gaston A.; Bakker, EricAnalytical Chemistry (Washington, DC, United States) (2017), 89 (1), 571-575CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)We report on a novel approach for in-line sample acidification that results in a significant improvement of the limit of detection of potentiometric anion-selective electrodes aiming at detg. nutrients in natural waters. The working principle of the developed acidification module relies on the cation-exchange process between the sample and an ion-exchange Donnan exclusion membrane in its protonated form. The resulting in-line acidification of natural waters with millimolar NaCl level (freshwater, drinking water, aquarium water as well as dechlorinated seawater) decreases the pH down to ∼5. Using the acidification module the limit of detection of nitrite-selective electrodes significantly improves by ≥2 orders of magnitude with respect to that obsd. at environmental pH. The originality of the proposed flow cell lies in the possibility to adjust the pH of the sample by modifying its exposure time with the membrane by varying the volumetric flow rate. Facile coupling with a detection technique of choice, miniaturized configuration and simple implementation for long-term monitoring with submersible probes for environmental anal. are possible anal. configurations. This approach was applied to the potentiometric detection of nitrite in aquarium and dechlorinated seawater.
- 32Yuan, D. J.; Anthis, A. H. C.; Ghahraman Afshar, M.; Pankratova, N.; Cuartero, M.; Crespo, G. A.; Bakker, E. Anal. Chem. 2015, 87, 8640– 8645, DOI: 10.1021/acs.analchem.5b01941There is no corresponding record for this reference.
- 33Tercier, M.-L.; Buffle, J.; Graziottin, F. Electroanalysis 1998, 10, 355– 363, DOI: 10.1002/(SICI)1521-4109(199805)10:6<355::AID-ELAN355>3.0.CO;2-F33A novel voltammetric in situ profiling system for continuous real-time monitoring of trace elements in natural watersTercier, Mary-Lou; Buffle, Jacques; Graziottin, FlavioElectroanalysis (1998), 10 (6), 355-363CODEN: ELANEU; ISSN:1040-0397. (Wiley-VCH Verlag GmbH)A novel voltammetric in-situ profiling system (VIP System) for continuous real-time monitoring of trace elements in fresh and seawater down to 500 m depth is described. The VIP System was designed using advanced microprocessor and telemetry technol. The heart of the submersible voltammetric probe is a Hg-plated Ir-based microsensor covered with an antifouling gel membrane. This gel integrated microsensor allows direct voltammetric measurements of trace metals in complex media without phys. and chem. interferences of the test soln. A detailed description of the system is given and examples of environmental applications are reported for in-situ trace metal monitoring in O2 satd. seawater as well as for in-situ profiling of Mn2+ in anoxic lake water. In-situ measurements of mobile fraction of trace metals can be achieved down to low concn. levels of ≈5 ppt.
- 34Grygolowicz-Pawlak, E.; Sohail, M.; Pawlak, M.; Neel, B.; Shvarev, A.; de Marco, R.; Bakker, E. Anal. Chem. 2012, 84, 6158– 6165, DOI: 10.1021/ac301096rThere is no corresponding record for this reference.
- 35Pankratova, N.; Ghahraman Afshar, M.; Yuan, D. J.; Crespo, G. A.; Bakker, E. Acs Sensors. 2016, 1, 48– 54, DOI: 10.1021/acssensors.5b0001535Local Acidification of Membrane Surfaces for Potentiometric Sensing of Anions in Environmental SamplesPankratova, Nadezda; Ghahraman Afshar, Majid; Yuan, Dajing; Crespo, Gaston A.; Bakker, EricACS Sensors (2016), 1 (1), 48-54CODEN: ASCEFJ; ISSN:2379-3694. (American Chemical Society)The work dramatically improves the lower detection limit of anion selective membranes at environmental pH by using local acidification to suppress hydroxide interference at the membrane surface. Three sep. localized acidification strategies are explored to achieve this, with ionophore-based membrane electrodes selective for nitrite and dihydrogen phosphate as guiding examples. In a 1st approach, a concd. acetic acid soln. (∼1 M) is placed in the inner filling soln. of the PVC-based membrane electrode, forcing a significant acid gradient across the membrane. A 2nd strategy achieves the same type of passive acidification by using an external proton source (fast diffusive doped polypropylene membrane) placed in front of a potentiometric solid contact anion selective electrode where the thin layer gap allows one to observe spontaneous acidification at the opposing detection electrode. The 3rd approach shares the same configuration, but protons are here released by electrochem. control from the selective proton source into the thin layer sample. All three protocols improve the limit of detection by >2 orders of magnitude at environmental pH. Nitrite and dihydrogen phosphate detns. in artificial and natural samples are demonstrated.
- 36Cuartero, M.; Crespo, G. A.; Ghahraman Afshar, M.; Bakker, E. Anal. Chem. 2014, 86, 11387– 11395, DOI: 10.1021/ac503344f36Exhaustive Thin-Layer Cyclic Voltammetry for Absolute Multianalyte Halide DetectionCuartero, Maria; Crespo, Gaston A.; Ghahraman Afshar, Majid; Bakker, EricAnalytical Chemistry (Washington, DC, United States) (2014), 86 (22), 11387-11395CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)Water anal. is one of the greatest challenges in the field of environmental anal. In particular, seawater anal. is often difficult because a large amt. of NaCl may mask the detn. of other ions, i.e., nutrients, halides, and carbonate species. The authors demonstrate here the use of thin-layer samples controlled by cyclic voltammetry to analyze water samples for chloride, bromide, and iodide. The fabrication of a microfluidic electrochem. cell based on a Ag/AgX wire (working electrode) inserted into a tubular Nafion membrane is described, which confines the sample soln. layer to <15 μm. By increasing the applied potential, halide ions present in the thin-layer sample (X-) are electrodeposited on the working electrode as AgX, while their resp. counterions are transported across the perm-selective membrane to an outer soln. Thin-layer cyclic voltammetry allows one to obtain sepd. peaks in mixed samples of these three halides, finding a linear relation between the halide concn. and the corresponding peak area from ∼10-5 to 0.1M for bromide and iodide and from 10-4 to 0.6M for chloride. This technique was successfully applied for the halide anal. in tap, mineral, and river water as well as seawater. The proposed methodol. is abs. and potentially calibration-free, as evidenced by an obsd. 2.5% relative std. deviation cell to cell reproducibility and independence from the operating temp.
- 37Millero, F. J. Limnol. Oceanogr. 1984, 29, 1317– 1321, DOI: 10.4319/lo.1984.29.6.131737The conductivity-density-salinity-chlorinity relationships for estuarine watersMillero, Frank J.Limnology and Oceanography (1984), 29 (6), 1317-21CODEN: LIOCAH; ISSN:0024-3590.The relative cond. and d. of estuarine waters formed by mixing world river water with std. seawater were detd.. The results are used to examine the cond.-d.-salinity-chlorinity relationships of estuarine waters of known compn. with seawater dild. with pure water (i.e., the new International Equation of State and Practical Salinity Scale). The max. difference between the true salinity and the value derived from cond. was 0.047 in dil. solns.; the max. d. difference between the measured and calcd. values was 35 × 10-6 g/cm3. These results are compared with measurements of waters from the St. Lawrence estuary.
- 38Cox, R. A.; Culkin, F.; Riley, J. P. Deep-Sea Res. Oceanogr. Abstr. 1967, 14, 203– 220, DOI: 10.1016/0011-7471(67)90006-X38Electrical conductivity/chlorinity relation in natural sea waterCox, Roland A.; Culkin, Frederick; Riley, John P.Deep-Sea Research and Oceanographic Abstracts (1967), 14 (2), 203-20CODEN: DROAAK; ISSN:0011-7471.Details are given for the collection and treatment of samples, the calibration and operation for cond. measurements with the N.I.O. Thermostat Salinity Meter, and the detn. of chlorinity by using a modification of the Hermann potentiometric method (J. Cons., Cons. Perma. Int. Explor. Mer 17, 223-30(1951)). The results are tabulated in relation to latitude, longitude, and depth of the samples. In the prepn. of the new International Oceanographic Tables (UNESCO 1966), only data referring to samples collected within 200 m. of the surface was used. The final math. expression of chlorinity and salinity to cond. ratio is S = c0 + c1R15 + c2R215 + ...c5R515, where S is the salinity, R15 the cond. ratio at 15° and c are consts. of the values: c0 = -0.08996, c1 = 28.29720, c2 = 12.80832, c3 = -10.67869, c4 = 5.98624, and c5 = -1.32311. The temp. coeff. of cond. ratio was also detd. with an Autolab Inductive Salinometer. The results in their final form are presented as an expression of Δ15 as a function of Rt and t°, where Δ15 = R15 - Rt. Observed and calcd. values of 105Δ15 are tabulated. The precision of the chlorinity detn. is ∼0.001‰. Deep samples show a slightly but significantly different relation between cond. and chlorinity from surface samples, showing that deep sea water has on av. a slightly higher conductivity. This is almost certainly due to their higher Ca/chlorinity ratio.
- 39Qian, Y.; Zhao, Y.; Wu, Q. L.; Yang, Y. Sens. Actuators, B 2018, 260, 86– 105, DOI: 10.1016/j.snb.2017.12.07739Review of salinity measurement technology based on optical fiber sensorQian, Yu; Zhao, Yong; Wu, Qi-lu; Yang, YangSensors and Actuators, B: Chemical (2018), 260 (), 86-105CODEN: SABCEB; ISSN:0925-4005. (Elsevier B.V.)A review of the salinity measurement technol. based on the optical fiber sensor is presented. The principles of optical fiber measurement, the structures of probes and the characteristics of various sensing structures are concerned. Firstly, this paper discusses the relationship between the salinity and refractive index, and the effect of ion pairs on the refractive index. Secondly, four methods of direct or non-direct measurements of salinity are summarized, including optical refraction method, optical fiber grating, optical interference and surface plasmon effect. Subsequently, the article compares performances of various sensing structures and analyses the advantages and disadvantages of different sensors. Finally, a prospect of salinity measurement requirement and the development direction of fiber-optic sensors in this area are addressed.
- 40Muller, B. J.; Rappitsch, T.; Staudinger, C.; Ruschitz, C.; Borisov, S. M.; Klimant, I. Anal. Chem. 2017, 89, 7195– 7202, DOI: 10.1021/acs.analchem.7b01373There is no corresponding record for this reference.
- 41Woody, C.; Shih, E.; Miller, J.; Royer, T.; Atkinson, L. P.; Moody, R. S. Mar. Technol. Soc. J. 2000, 34, 26– 33, DOI: 10.4031/MTSJ.34.2.4There is no corresponding record for this reference.
- 42Manaud, F.; Bouchet, J.-M.; Deltreil, J.-P.; Maurer, D.; Trut, G.; Auby, I.; Dreno, J.-P.; Masson, N.; Pellier, C.; L’Yavan, C. J. Etude Integree Du Bassin d’arcachon, Tome II; Ifremer: Arcachon, France, 1997.There is no corresponding record for this reference.
- 43Barbooti, M. Environmental applications of instrumental chemical analysis; CRC Press: Boca Raton, FL, USA, 2015.There is no corresponding record for this reference.
- 44Deborde, J.; Anschutz, P.; Auby, I.; Gle, C.; Commarieu, M. V.; Maurer, D.; Lecroart, P.; Abril, G. Mar. Chem. 2008, 109, 98– 114, DOI: 10.1016/j.marchem.2007.12.007There is no corresponding record for this reference.
- 45Castel, J.; Caumette, P.; Herbert, R. Hydrobiologia 1996, 329, ix– xxviii, DOI: 10.1007/BF00034542There is no corresponding record for this reference.
- 46Rimmelin, P.; Dumon, J. C.; Maneux, E.; Goncalves, A. Estuarine, Coastal Shelf Sci. 1998, 47, 649– 659, DOI: 10.1006/ecss.1998.038446Study of annual and seasonal dissolved inorganic nitrogen inputs into the Arcachon Lagoon, Atlantic coast (France)Rimmelin, P.; Dumon, J.-C.; Maneux, E.; Goncalves, A.Estuarine, Coastal and Shelf Science (1998), 47 (5), 649-659CODEN: ECSSD3; ISSN:0272-7714. (Academic Press)This study detd., by applying a direct method, dissolved inorg. N (DIN) inputs reaching a coastal lagoon, Arcachon Bay, France. Yearly monitoring of different sources (groundwater, surface water, atm. water) quantified the annual DIN discharge and the variations of DIN discharges throughout the yr. Arcachon Bay received 870 tons N in 1996. Study of the 2 main hydrol. seasons (high and low water-table periods) showed that 78% of this annual discharge occurred during the wet period (Dec.-Apr.). River DIN inputs accounted for >90% of the total annual discharge; during the wet period, river input accounted for 95% of total DIN inputs. Thus, rivers are the most important source of DIN for Arcachon Bay and the principal factor in the Bay's eutrophication. Reasons for this are: an important water discharge (>74% of total freshwater discharge) and relatively high DIN concns. (95 μM on av.) vs. groundwater and atm. water (33 and 43 μM, resp.). The atm. source accounted for 9% of the annual DIN discharge with wide variations throughout the year, accounting for 5% in the wet period and 26% in the dry period (May-Nov.). This fluctuation is due to a rise in the DIN atm. flux which increased from 32 to 49 tons N. Further, this study proved that groundwater flowing into Arcachon Bay is not DIN-polluted. Combined with the values mentioned above, the low groundwater discharge (<3% of total annual discharge) yielded a slight contribution (<1%). (c) 1998 Academic Press.
- 47Rysgaard, S.; RisgaardPetersen, N.; Sloth, N. P. Hydrobiologia 1996, 329, 133– 141, DOI: 10.1007/BF0003455347Nitrification, denitrification, and nitrate ammonification in sediments of two coastal lagoons in Southern FranceRysgaard, Soeren; Risgaard-Petersen, Nils; Sloth, Niels PeterHydrobiologia (1996), 329 (1-3), 133-141CODEN: HYDRB8; ISSN:0018-8158. (Kluwer)Seasonal and diurnal variations in sediment-water fluxes of O2, NO-3, and NH+4 as well as rates of nitrification, denitrification, and nitrate ammonification were detd. in two different coastal lagoons of southern France:. The seagrass (Zostera noltii) dominated tidal Bassin d'Arcachon and the dystrophic Etang du Prevost. Overall, denitrification rates in both Bassin d'Arcachon (<0.4 mmol m-2 d-1) and Etang du Prevost (<1 mmol m-2 d-1) were low. This was mainly caused by a combination of low NO-3 concns. in the water column and a low nitrification activity within the sediment. In both Bassin d'Arcachon and Etang du Prevost, rates of nitrate ammonification were quant. as important as denitrification. Denitrification played a minor role as a nitrogen sink in both systems. In the tidal influenced Bassin d'Arcachon, Z. noltii was quant. more important than denitrification as a nitrogen sink due to the high assimilation rates of the plants. Throughout the year, Z. noltii stabilized the mudflats of the bay by its well-developed root matrix and controlled the nitrogen cycle due to its high uptake rates. In contrast, the lack of rooted macrophytes, and dominance of floating macroalgae, made nitrogen cycling in Etang du Prevost more unstable and unpredictable. Inhibition of nitrification and denitrification during the dystrophic crisis in the summer time increased the inorg. nitrogen flux from the sediment to the water column and thus increased the degree of benthic-pelagic coupling within this bay. During winter, however, benthic microalgae colonizing the sediment surface changed the sediment in the lagoon from being a nitrogen source to the overlying water to being a sink due to their high assimilation rates. It is likely, however, that this assimilated nitrogen is liberated to the water column at the onset of summer thereby fueling the extensive growth of the floating macroalgae, Ulva sp. The combination of a high nitrogen coupling between sediment and water column, little water exchange and low denitrification rates resulted in an unstable system with fast growing algal species such as phytoplankton and floating algae.
- 48Canton, M.; Anschutz, P.; Coynel, A.; Polsenaere, P.; Auby, I.; Poirier, D. Biogeochemistry 2012, 107, 361– 377, DOI: 10.1007/s10533-010-9558-748Nutrient export to an Eastern Atlantic coastal zone: first modeling and nitrogen mass balanceCanton, Mathieu; Anschutz, Pierre; Coynel, Alexandra; Polsenaere, Pierre; Auby, Isabelle; Poirier, DominiqueBiogeochemistry (2012), 107 (1-3), 361-377CODEN: BIOGEP; ISSN:0168-2563. (Springer)We have studied 15 catchments supplying freshwater to a French Atlantic coastal lagoon, where increase in nitrogen loads due to agriculture is supposed to have destabilized the ecosystem in the last decades. The catchment is a lowland composed of Pleistocene sands with an av. slope of 0.25%. To study the nutrient export in relation to land-use surface waters were sampled bi-weekly between Oct. 2006 and Jan. 2009 and land-use was established by plane photographs and Geog. Information System (GIS). Cultivated pine forests represent more than 80% of the total surface and 7% of the catchment area has been deforested recently. Significant areas of some catchments are used for maize crop. Housing is confined to the coastal zone. Maize and forest crop give a robust signature in terms of nitrate export. In view of modeling the nutrient fluxes, we have established the mean export rate for every land-use: forested parcels, deforested parcels, cultivated surfaces, and housing areas export 45, 93, 2850, and 61 kg N-nitrate km-2 year-1, resp. Exports of ammonium, dissolved org. N (DON), and dissolved inorg. P (DIP) could not be related to land use. The mean export is 13, 100, and 0.57 kg km-2 year-1 for N-ammonium, DON, and DIP, resp. The modeling of nitrogen flux is in good agreement with our measures for the largest catchment, which supplies about 90% of the total continental DIN flux. However, small catchments are more dynamic due to hydrol. conditions and the model is less accurate. This work has permitted to complete and unify scattered studies about nutrient cycling in this area. Thus we have established and compared the nitrogen budget of cornfields and cultivated pine forest. We have emphasized that (i) fertilizer use should be reduced in cornfields because they stock between 200 and 6400 kg DIN km-2 year-1, and (ii) the nitrogen budget in pine forest mostly depends on tree harvesting and symbiotic N-fixation, which is poorly constrained. Export of N by rivers represents a small contribution to the N budget of soils.
- 49Gle, C.; Del Amo, Y.; Sautour, B.; Laborde, P.; Chardy, P. Estuarine, Coastal Shelf Sci. 2008, 76, 642– 656, DOI: 10.1016/j.ecss.2007.07.043There is no corresponding record for this reference.
- 50SOMLIT. http://somlit.epoc.u-bordeaux1.fr/fr/ (accessed Nov. 15, 2017).There is no corresponding record for this reference.
- 51TuTiempo. http://www.tutiempo.net/arcachon.html?datos=calendario-cal (accessed Jun. 1, 2017).There is no corresponding record for this reference.
- 52Marée.info. http://www.maree.info/136?d=20170515 (accessed Jun. 1, 2017).There is no corresponding record for this reference.
- 53Marée.info. http://www.maree.info/136?d=20170516 (accessed Jun. 1, 2017).There is no corresponding record for this reference.
Supporting Information
Supporting Information
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.analchem.7b05299.
Materials and reagents, validation protocols, electrode preparation, experimental protocols for laboratory and in situ measurements, analytical performance of the sensors, information about collected samples, nitrite detection in Arcachon Bay, design and optimization of the desalination cell and chloride detection, and validation of in situ measurements (PDF)
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