Coastal Seawater Samples Research Articles

Large Volume (20L+) Filtration of Coastal Seawater Samples

Large Volume (20L+) Filtration of Coastal Seawater Samples

Large Volume (20L+) Filtration of Coastal Seawater Samples

The workflow begins with the collection of coastal marine waters for downstream microbial community, nutrient and trace gas analyses. For this method, samples were collected from the deck of the HMS John Strickland operating in Saanich Inlet. This video documents large volume (> or = 20 L) filtration of microbial biomass, ranging between 0.22 microm and 2.7 microm in diameter, from the water column. Two 20 L samples can be filtered simultaneously using a single pump unit equipped with four rotating heads. Filtration is done in the field on extended trips, or immediately upon return for day trips. It is important to record the amount of water passing through each sterivex filter unit. To prevent biofilm formation between sampling trips, all filtration equipment must be rinsed with dilute HCl and deionized water and autoclaved immediately after use. This procedure will take approximately 5 hours plus an additional hour for clean up.

Preconcentration of Rare Earth Elements in Seawater with Chelating Resin Having Fluorinated β‐Diketone Immobilized on Styrene Divinyl Benzene for their Determination by ICP‐OES

AbstractAn analytical method has been developed for the preconcentration of rare earth elements (REEs) in seawater for their determination by inductively coupled plasma optical emission spectrometry (ICP‐OES). An indigenously synthesized chelating resin was used for the preconcentration of (REEs) which was based on immobilization of fluorinated β‐diketone group on solid support styrene divinyl benzene. Sample solutions (adjusted to optimized pH) were passed through a polyethylene column packed with 250 mg of the resin. Experimental conditions consisting of pH, sample flow rate, sample volume and eluent concentration were optimized. The established method has been applied for the preconcentration of light, medium and heavy REEs in coastal sea water samples for their subsequent determination by (ICP‐OES). Percentage recoveries of La, Ce, Nd, Sm, Eu, Gd, Dy, Er, Yb and Lu were ≥ 95%, a preconcentration factor of 200 times, and relative standard deviations < 5% were achieved.

Estimating the organic acid contribution to coastal seawater alkalinity by potentiometric titrations in a closed cell

This paper examines the performance of a previously reported, closed cell, potentiometric titration technique [J.M. Hernández-Ayón, S.L. Belli, A. Zirino, Anal. Chim. Acta 394 (1999) 101] for the simultaneous determination of pH, total inorganic carbon (TCO 2), total alkalinity (TA), and organic alkalinity (OA) in coastal seawater samples. A novel interpretation of the titration data, as recently proposed by Hernández-Ayón et al. [J.M. Hernández-Ayón, A. Zirino, A.G. Dickson, T. Camiro-Vagas, E. Valenzuela-Espinoza, Limnol. Oceanogr.: Methods 5 (2007) 225] who applied it to waters of unusually high organic matter content, was applied here to fjord surface waters collected over the duration of a phytoplankton bloom. The parameters pH and TCO 2 – combined with knowledge of boric, phosphate and silicate species concentrations – allowed calculation of all inorganic species that contributed to TA. This inorganic alkalinity term was then subtracted from TA to produce an estimation of OA. Although the OA values obtained were very small (2–22 ± 3 μmol L −1), they showed a reproducible trend over time in two simultaneous experiments. The organic acids that may have contributed to OA were characterised in back titrations of acidified and CO 2-stripped samples with CO 2-free NaOH. Two classes of organic titratable species, with p K a values around 4.0 ± 0.2 and 9.1 ± 0.2 were detected. The first occurred in concentrations that co-varied linearly ( r 2 = 0.75) with protein-like fluorescence, indicating a marine biological source, but were only weakly correlated ( r 2 = 0.46) to OA. By contrast, Class 2 organic species were not significantly correlated to any fluorescence component of either marine or terrestrial origin but were linearly correlated to OA ( r 2 = 0.69). These new results reveal that the method proposed by Hernández-Ayón et al. [J.M. Hernández-Ayón, A. Zirino, A.G. Dickson, T. Camiro-Vagas, E. Valenzuela-Espinoza, Limnol. Oceanogr.: Methods 5 (2007) 225] for estimating OA can provide a powerful and hitherto unused tool for analysing DOM dynamics and sources in most coastal environments, i.e. as a complement to the more widely used optical tools.

Response of a copper(II) and iron(III) ion-selective electrode bielectrode array in saline media

A bielectrode array comprising a jalpaite membrane (i.e., Ag 1.5Cu 0.5S) copper(II) ion-selective electrode (ISE) and chalcogenide glass membrane (i.e., Fe 2.5(Se 60Ge 28Sb 12) 97.5) iron(III) ISE has been assembled by individually wiring each solid-state sensor into a single electrode body. Furthermore, a dual metal ion buffer calibration standard incorporating copper(II) and iron(III) coordinating ligands to regulate the levels of free copper(II) and iron(III) in the buffer has been developed to enable simultaneous calibration of the bielectrode ISE array. In this work, the bielectrode ISE array has been employed in the continuous flow analysis (CFA) of free copper(II) and iron(III) in seawater media. It is shown that the individual electrodes displayed Nernstian response in the metal ion buffer calibration standard over a wide dynamic range (viz., 10 −15 to 10 −5 M aCu 2+ and 10 −21 to 10 −11 M aFe 3+), and the results of repetitive CFA analyses of free copper(II) and iron(III) in seawater are commensurate with the typical values found in coastal seawater samples. Clearly, the bielectrode ISE array may be used in the simultaneous analysis of free copper(II) and iron(III) in seawater without fear of cross-interference between the solid-state sensors.

Determination of total silver and silver species in coastal seawater by inductively-coupled plasma mass spectrometry after batch sorption experiments with Chelex-100 resin

Sorption experiments in batch mode with Chelex-100 resin have been carried out for the determination of total Ag, labile and inert fractions in seawater from Ria de Vigo (NE Atlantic ocean) by inductively coupled plasma-mass spectrometry (ICP-MS). The method allows an accurate determination of the total Ag thus avoiding the effect of the saline matrix when direct determination by ICP-MS is performed. Similarly, the distribution patterns of Ag among species with different lability can be established in seawater as a function of pH. Species distribution and total Ag contents have been obtained in CRM CASS-4 (near shore seawater) and four coastal seawater samples. While the free silver ion concentration accounts for a significant fraction at low pH, the labile inorganic fraction is most important at natural pH (≈8) in non-polluted seawater. The inert and labile organic fractions were the most relevant in polluted coastal seawater. Complexation mechanisms of silver were also investigated from the sorption curves of silver on Chelex-100 according to the Gibbs-Donnan model. Two complexes were formed, AgL and AgL2 with the following intrinsic complexation constants log β(1np) = −2.11 and −10.02, respectively. The formation of the complex AgL predominates up to pH 4 but is negligible due to chloride ions effect, while the complex AgL2 predominates from pH 4.

Speciation of inorganic arsenic in coastal seawater from Ionian and Tyrrhenian Seas (Sicily, Italy) using derivative anodic stripping chronopotentiometry

The purpose of this paper was to use derivative anodic stripping chronopotentiometry (dASCP) as a sensitive and accurate technique, to determine the concentrations of dissolved As (III) and As (V) in coastal seawater samples from the Straits of Messina, the Ionian and the Tyrrhenian seas, and to investigate the relationship between the anthropogenic activities on the coastal areas and the concentration of dissolved inorganic arsenic in seawaters. The obtained data indicated that As (V) was the most abundant species, with concentration ranging from 26.7 to 307 nM, whereas As (III) levels were lower than 48 nM in all the samples. In particular, As (III) and As (V) levels significantly decreased from high to low anthropogenic activities zones (p < 0.00001, ANOVA), with the reference samples, from a wildlife reserve, showing the lowest values. Furthermore it was observed that human activities influenced inorganic arsenic speciation, since the zones that received high human input presented the highest As(V)/As (III) ratio.

Photochemical production of molecular hydrogen in lake water and coastal seawater

Samples of lake water and coastal seawater from Nova Scotia, Canada, were irradiated with natural or artificial sunlight to investigate the potential for photochemical hydrogen production. Hydrogen photo-production was observed in all natural water samples. Rates of hydrogen formation were highest in coloured lake water (range: 98–163 pmol L − 1 h − 1 ) and lower in seawater (range: 19–45 pmol L − 1 h − 1 ). Dilutions of the most highly coloured lake sample (Kejimkujik Lake) showed a positive linear relationship between H 2 production rates and CDOM concentration. Photo-production rates normalised to UV absorption coefficients at 350 nm indicated that the photochemical efficiency of hydrogen formation varied between samples, perhaps due to differences in the CDOM composition. Photochemical hydrogen formation was also seen in solutions of syringic acid and acetaldehyde: two low-molecular-weight carbonyl compounds found in natural waters. Photochemistry may therefore offer least a partial explanation for the persistently high levels of hydrogen observed in the low-latitude surface ocean.

Determination of Copper in Seawater Using a Sequential Injection System Incorporating a Sample Pretreatment Module Coupled to Electrothermal Atomic Absorption Spectrometry

An automated sequential injection system incorporating a sample pretreatment module was developed for the separation and preconcentration of ultra-trace copper in seawater without dilution. Cu-PDC (pyrrolidine dithiocarbamate) chelate was retained in a PTFE-beads-packed column in the module, which was later eluted with a small amount of methanol, and the eluate was quantified using electrothermal atomic absorption spectrometry (ETAAS). An enrichment factor of 20, a limit detection of 0.015 μg l −1, and a sampling frequency of 26 per hour were obtained with a sampling volume of 1.0 ml within the concentration range of 0.05–1.00 μg l −1, achieving a precision of 1.8% RSD ( n = 7) at the level of 0.50 μg l −1. The system was validated by analyzing a certified reference material of seawater, NASS-5, and was further demonstrated by spiking recoveries in a coastal seawater sample employing various dilution factors.

Isolation of Methylophaga spp. from Marine Dimethylsulfide-Degrading Enrichment Cultures and Identification of Polypeptides Induced during Growth on Dimethylsulfide

Dimethylsulfide (DMS)-degrading enrichment cultures were established from samples of coastal seawater, nonaxenic Emiliania huxleyi cultures, and mixed marine methyl halide-degrading enrichment cultures. Bacterial populations from a broad phylogenetic range were identified in the mixed DMS-degrading enrichment cultures by denaturing gradient gel electrophoresis (DGGE). Sequences of dominant DGGE bands were similar to those of members of the genera Methylophaga and Alcanivorax. Several closely related Methylophaga strains were obtained that were able to grow on DMS as the carbon and energy source. Roseobacter-related populations were detected in some of the enrichment cultures; however, none of the Roseobacter group isolates that were tested were able to grow on DMS. Oxidation of DMS by Methylophaga sp. strain DMS010 was not affected by addition of the inhibitor chloroform or methyl tert-butyl ether, suggesting that DMS metabolism may occur by a route different from those described for Thiobacillus species and other unidentified marine isolates. Addition of DMS and methanethiol to whole-cell suspensions of strain DMS010 induced oxygen uptake when strain DMS010 was grown on DMS but not in cells grown on methanol. The apparent K(m)s of strain DMS010 for DMS and for methanethiol were 2.1 and 4.6 microM, respectively, when grown on DMS. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the biomass of strain DMS010 and analysis of peptide bands by mass spectrometry techniques and N-terminal sequencing provided the first insight into the identity of polypeptides induced during growth on DMS. These included XoxF, a homolog of the large subunit of methanol dehydrogenase for which a biological role has not been identified previously.

Consequences of respiration in the light on the determination of production in pelagic systems

Abstract. Oxygen microprobes were used to estimate Community Respiration (R), Net Community Production (NCP) and Gross Primary Production (GPP) in coastal seawater samples. Using this highly stable and reproducible technique to measure oxygen change during alternating dark and light periods, we show that respiration in the light could account for up to 640% of respiration in the dark. The light enhanced dark respiration can remain elevated for several hours following a 12 h period of illumination. Not including Rlight into calculations of production leads to an underestimation of GPP, which can reach up to 650% in net heterotrophic systems. The production: respiration (P:R) ratio is in turn affected by the higher respiration rates and by the underestimation of GPP. While the integration of Rlight into the calculation of P:R ratio does not change the metabolic balance of the system, it decreases the observed tendency, thus net autotrophic systems become less autotrophic and net heterotrophic systems become less heterotrophic. As a consequence, we propose that efforts have to be focused on the estimation and the integration of Rlight into the determination of GPP and R for a better understanding of the aquatic carbon cycle.

On-site polymer-coated hollow fiber membrane microextraction and gas chromatography–mass spectrometry of polychlorinated biphenyls and polybrominated diphenyl ethers

Porous polypropylene hollow fiber membrane coated with a conjugated polymer was used as an on-site sampling device for the extraction of polychlorinated biphenyls and polybrominated biphenyl ethers from coastal sea water samples. The coated hollow fiber membrane was placed in a vial containing the sample, and the target compounds extracted via manual shaking of the vials at the site of sample collection. For each extraction, two fibers were used. After extraction, the fibers with the adsorbed analytes were brought back to the laboratory for further processing. Care was taken to preserve the integrity of the analytes and to avoid contamination during transport; after extraction, the fibers were carefully removed and placed in air-tight crimper vials which were stored in an ice-box. The analytes were desorbed by solvent in the laboratory and analyses were carried out using gas chromatography/mass spectrometry. This method was highly reproducible with relative standard deviations in the range of 1–9%. Recoveries from spiked water samples ranged from 83% to 98%. Low limits of detections between 0.04 and 0.21 ng l −1 were achieved. The extraction efficiency was compared with solid-phase microextraction.

AGNES: A technique for determining the concentration of free metal ions. The case of Zn(II) in coastal Mediterranean seawater

Absence of Gradients and Nernstian Equilibrium Stripping (AGNES) is a recently suggested electroanalytical technique designed for the determination of the free concentration of heavy metals (such as Zn, Cd or Pb) which is here developed and applied to seawater samples. A key improvement for the implementation of AGNES with complex matrices is the development of a new blank, called the shifted blank (presented in this work for the first time), which can be applied to the same sample where the measurement is intended. The careful selection of the required parameters for the determination of the free Zn concentration (or activity) at the nanomolar level is described in detail. The methodology has been validated with a synthetic solution containing Zn and nitrilotriacetic acid (NTA) and then applied, as a first case, to two coastal seawater samples taken close to Barcelona and Tarragona (Catalonia, North-Eastern Spain) finding values in the range of 1–3 nM, representing around 25% of total Zn. This technique can, in the near future, be crucial in helping to elucidate the role of the free zinc(II) concentration in natural waters.

Flow Analysis Method Using Chelating CIM Monolithic Disks for Monitoring Dissolved Labile Copper in Environmental Water Samples

A low pressure flow analysis system incorporating a chelating monolithic disc for the selective retention and elution of Cu(II) from within environmental samples, is reported. Three monolithic discs were modified with either picolinic acid, dipicolinic acid, or dodecyliminodiacetic acid and the extraction and elution efficiency of Cu(II) on the three chelating phases compared. The dipicolinic acid disc showed the highest capacity and linear range for Cu(II) and was incorporated into a flow analysis system, using chemiluminescence detection based on the measurement of light emitted from the Cu(II) catalysed oxidation of 1,10‐phenanthroline by hydrogen peroxide. The system gave a linear response (R 2=0.998) over the concentration range 0‐125 µg L−1 in simulated seawater, with detection limits for Cu(II) of 5 µg L−1 in a sample volume of just 220 µL. Accuracy was determined using a standard reference material (SRM 1640) and the method applied to estuary and coastal seawater samples.

Microbial status in seawater and coastal sediments during pre‐ and post‐tsunami periods in the Bay of Bengal, India

AbstractTsunami, the natural disaster, which occurred on December 26, 2004 in the Indian Ocean, caused severe damage to mankind in the coastal areas. Total loss of life and economic loss because of this disaster have been estimated by various agencies but its effect on microbial density has not been probed. With our previous results on microbial populations in four locations of the Chennai coast of the Bay of Bengal, India in the pre‐tsunami period, the change in microbial populations was studied after the tsunami at regular intervals in the same locations. Coastal sediment and seawater samples were collected from four different locations after 5–10 h and thereafter at intervals of every 7 days up to 28 days post‐tsunami. Bacteria, fungi and actinomycetes were isolated from the marine samples by serial dilution on respective media. Before the tsunami, the bacterial population was higher in seawater samples than the sediments, whereas fungi and actinomycetes were recorded only in the sediments. The microbial population remarkably increased 5–10 h post‐tsunami in all the marine samples irrespective of the location. However, it slowly declined in the subsequent days and became similar to that of the population recorded before the tsunami. The population of gram‐positive bacteria increased whereas the gram‐negative bacterial population decreased after the tsunami. Further, populations of pathogenic bacteria such as coliform and vibrios did not increase after the tsunami. It has been observed that the increase in populations of bacteria and actinomycetes even after 28 days of tsunami may be due to the introduction of foreign microorganisms that developed the ability to survive in the extreme environment by exhibiting special characteristics such as pigmentation and production of exopolysaccharides.

228Ra and 226Ra in coastal seawater samples from the Ubatuba region: Brazilian southeastern coastal region

The present work reports 228Ra and 226Ra results obtained during the 4th Submarine Groundwater Discharge (SGD) intercomparison experiment realized in Ubatuba, November 2003, aiming to test the methodologies on a fractured crystalline rocks system. Although with distinct objectives, it was decided to participate in this experiment in order to verify if radium isotopes could be used to determine water mixing rates in this region and to test the laboratory capability to perform, later on, a marine dispersion model validation at Angra dos Reis reactor site, located nearby. The results show that the SGD model constrains seems to be valid, at least for a distance of 20 km offshore, that corresponds to the distance between the reactor site and Ilha Grande, a 193-km2 island existing at this site and probably an additional SGD source. Salinity, barium and silica results are also reported and their relation to 228Ra concentrations is discussed.

Pretreatment Method for Determination of Trace Elements in Seawater Using Solid Phase Extraction Column Packed with Polyamino-Polycarboxylic Acid Type Chelating Resin

A pretreatment method of Al, Mn, Fe, Ni, Cu, Zn, Mo, Cd, Pb, and U in seawater has been investigated using the solid phase extraction column packed with polyamino-polycarboxylic acid type chelating resin. The dependence of pH on the recovery differed in each analytes. However, all analytes were simultaneously extracted at pH 5.5. Hence the optimum condition was decided at pH 5.5. Na, K, Ca, and Mg, which are major components in the seawater were not extracted at pH 7 and below. After the column was cleaned with 10 ml of pure water, the optimum concentration of nitric acid as eluate was 3 M. The analytes concentration in standard reference materials (Seawater NRC-CNRC, CASS-4) pretreated by the presented method was measured with the ion source mass spectrometer and the analytical values were well agreed with the certified values and the reference values without the interference of major components. Moreover, in the analysis of the analytes in the coastal sea water sample, a high recovery of 93∼107% was obtained.

Direct determination of vitamin B1in seawater by solid-phase extraction and high-performance liquid chromatography quantification

Vitamin B1 (thiamine) is one of the organic micronutrients essential for growth of algae. However, there is no direct method for the quantification of this vitamin in natural waters. Bioassay is the only protocol currently available to measure B1 in the marine environment. We have developed a new method for the direct determination of B1, along with vitamin B12 (cobalamin) in seawater. Solid-phase extraction with a column of C18 resin followed by elution with methanol was used to extract dissolved B1 from seawater. The eluted vitamin was then analyzed by reversed phase high-performance liquid chromatography (HPLC) using ammonium acetate (0.05 M) and methanol as mobile phases in pressure gradient mode. Ultraviolet-visible (UV-Vis) detection at 270 nm was used to quantify B1 levels. The calibration curve was linear from 0 to 0.60 µM and the detection limit of the protocol was on the order of 0.083 pM. This new method was successfully applied to the determination of vitamin B1 in filtered coastal seawater, porewater, and river water samples. Concentrations of vitamin B1 in those aquatic environments ranged from 0.15 nM in river to 0.75 nM in porewaters, with spike recoveries ranging from 93% to 98%.

Multielement Determination of Trace Metals in Seawater by Inductively Coupled Plasma Mass Spectrometry after Tandem Preconcentration Using a Chelating Resin

Abstract A tandem preconcentration method using a chelating resin was exploited for simultaneous multielement determination of trace metals in seawater by inductively coupled plasma mass spectrometry (ICP-MS). In the first preconcentration step, 500 mL of seawater sample was adjusted to pH 6.0, and the adsorption of trace metals on 0.4 g of Chelex-100 resin in dry weight was carried out at 55 °C. After equilibrium, the resin was collected on a glass filter and rinsed with 30 mL of ammonium acetate solution (pH 6.0) to reduce major elements such as Na, K, Mg, and Ca that had been partly adsorbed on the resin. Then, trace metals on the resin were eluted with 7.5 mL of 2 M nitric acid and collected in a 30 mL polypropylene bottle. In the second preconcentration step, the mixture of the filtrate and the rinsing solution obtained in the first step was adjusted to pH 4.0, and metal adsorption on another 0.4 g of Chelex-100 resin was carried out at 20 °C. In a similar manner to the first step, the resin collected on a glass filter was rinsed with 10 mL of ammonium acetate solution (pH 4.0), and trace metals adsorbed on the resin were eluted with 6 mL of 2 M nitric acid. This eluate was taken into the same polypropylene bottle as used in the first step. The final sample volume thus obtained was 15 mL including 1.5 mL of internal standard solution. Then a 33-fold preconcentration factor was achieved, where the recoveries for 33 elements were larger than 80%. The analytical results for trace metals in coastal seawater reference material (CASS-4) were in fairly good agreement with the certified or information values after correction with the recovery values. The coastal seawater samples from the Ise Bay and the Take Island were also analyzed by the present method. The concentrations for 20 trace metals in the Ise Bay coastal seawater were found to be more than 2-fold larger than those in the Take Island coastal seawater, indicating considerable anthropogenic pollution in the Ise Bay area.

A global survey of perfluorinated acids in oceans

Perfluorinated acids and their salts have emerged as an important class of global environmental contaminants. Biological monitoring surveys conducted using tissues of marine organisms reported the occurrence of perfluorooctanesulfonate (PFOS) and related perfluorinated compounds in biota from various seas and oceans, including the Arctic and the Antarctic Oceans. Occurrence of perfluorinated compounds in remote marine locations is of concern and indicates the need for studies to trace sources and pathways of these compounds to the oceans. Determination of sub-parts-per-trillion (ng/L) or parts-per-quadrillion (pg/L) concentrations of aqueous media has been impeded by relatively high background levels arising from procedural or instrumental blanks. Our research group has developed a reliable and highly sensitive analytical method by which to monitor perfluorinated compounds in oceanic waters. The method developed is capable of detecting PFOS, perfluorohexanesulfonate (PFHS), perfluorobutanesulfonate (PFBS), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), and perfluorooctanesulfonamide (PFOSA) at a few pg/L in oceanic waters. The method was applied to seawater samples collected during several international research cruises undertaken during 2002–2004 in the central to eastern Pacific Ocean (19 locations), South China Sea and Sulu Seas (five), north and mid Atlantic Ocean (12), and the Labrador Sea (20). An additional 50 samples of coastal seawater from several Asian countries (Japan, China, Korea) were analyzed. PFOA was found at levels ranging from several thousands of pg/L in water samples collected from coastal areas in Japan to a few tens of pg/L in the central Pacific Ocean. PFOA was the major contaminant detected in oceanic waters, followed by PFOS. Further studies are being conducted to elucidate the distribution and fate of perfluorinated acids in oceans.