Determination of nitrate in sea water by cadmium-copper reduction to nitrite

Wood, E.D.; Armstrong, Fräser A.; Richards, Fred

doi:10.1017/s002531540003352x

Cited by 1,149 publications

(460 citation statements)

References 12 publications

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“…Subsamples for nitrate and nitrite (NO 3 + NO 2 ) and phosphate (PO 4 ) determinations were frozen (-20°C) on board immediately after sampling in polyethylene bottles until further analyses in the laboratory. NO 3 was reduced to NO 2 according to Wood et al (1967), and NO 3 + NO 2 concentrations were determined on a Bran+Luebbe Autoanalyzer III, as well as PO 4 , according to Tréguer & Le Corre (1975). Measurement accuracy was ± 0.05 and ± 0.02 µmol l -1 for NO 3 + NO 2 and PO 4 , respectively.…”

Section: Methodsmentioning

confidence: 99%

Effect of solar ultraviolet radiation on bacterio- and phytoplankton activity in a large coral reef lagoon (southwest New Caledonia)

Conan¹,

Joux²,

Torréton³

et al. 2008

Aquat. Microb. Ecol.

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Measurements of underwater solar ultraviolet radiation (UV-R, 280 to 400 nm), particulate (PPP) and dissolved (DPP) primary and bacterial (BP) production allowed us to infer the respective contribution of UV-B (280 to 315 nm) and UV-A (315 to 400 nm) in algal-bacterial interactions in the southwest lagoon of New Caledonia. Differences in and between activities were assessed by in situ exposure of plankton to full sun radiation and shielded for UV-B or UV-R. We found a coherent response of phytoplankton and bacteria in total UV-R inhibition. The deepest limit of UV-R influence was 8 m, and inhibition increased with oligotrophy to reach 55% for phytoplankton and 75% for bacteria, at 1 m depth. UV-B contributed up to 50% to the inhibition, especially near the surface and at the oligotrophic station. The UV-A effect on PPP was stronger than that of UV-B; however, bacteria were more sensitive to UV-B than were phytoplankton. When considering UV-A and UV-B separately, the inhibition response was linear without threshold. However, a threshold of 0.002 for PPP and 0.004 for BP was obtained when considering the ratio UV-B:UV-A. The rate of PPP normalized to chlorophyll concentration (PP chl ) is proposed to reconcile the large range of inhibition encountered in the literature. A significant linear relationship predicted a PPP inhibition of 60% in surface water with no significant effect on excretion for cells characterized by a low PP chl , whereas PPP inhibition should be limited for cells characterized by a PP chl higher than 18 mg C (mg chl) -1 h -1 , even if excretion (DPP) could be slightly stimulated.

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Section: Methodsmentioning

confidence: 99%

Effect of solar ultraviolet radiation on bacterio- and phytoplankton activity in a large coral reef lagoon (southwest New Caledonia)

Conan¹,

Joux²,

Torréton³

et al. 2008

Aquat. Microb. Ecol.

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“…Samples were gently filtered into acid-washed polyethylene bottles and were analyzed immediately for dissolved inorganic nitrogen (DIN) as ammonium (NH:) and nitrate (NO, + NO;) and for urea concentrations. Alternatively, filtered samples were stored frozen (-20 "C) and analyzed within 24 h. NH: and NO, + NO; were measured with a Technicon Autoanalyzer@ I1 following the procedures outlined in Slawyk & MacIsaac (1972) and Wood et al (1967), respectively. Urea was determined by the diacetyl monoxime thiosemicarbizide technique described by Price & Harrison (unpubl.).…”

Section: Methodsmentioning

confidence: 99%

Time course of uptake of inorganic and organic nitrogen by phytoplankton in the Strait of Georgia: comparison of frontal and stratified communities

Price¹,

Cochlan²,

Harrison³

1985

Mar. Ecol. Prog. Ser.

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In both frontal and stratified water of the Strait of Georgia, changes in dissolved nitrogen concentrations provided evidence for the simultaneous uptake of ammonium, nitrate and urea by a summer phytoplankton community. Chlorophyll a specific uptake rates of ammonium and urea were ca 2 and 2.4 times greater in stratified water than in frontal water, whereas chlorophyll a specific nitrate uptake rates were ca 1.6 times greater in frontal water. Ammonium and urea regeneration rates, calculated using a mass balance approach, were similar in frontal water, but urea regeneration rates were 2 to 5 times greater in the stratified water during the first 12 h of the experiment. Increases in particulate nitrogen could not be accounted for by corresponding decreases in total concentration of dissolved inorganic nitrogen and urea, or by 15N accumulation in the particulates. In frontal water the change in total dissolved inorganic nitrogen and urea consistently overestimated the change in particulate nitrogen, and in stratified water the change in total dissolved inorganic nitrogen and urea consistently underestimated the change in particulate nitrogen. These data suggest that the plankton community In frontal water was losing nitrogen in the form of dissolved organic nitrogen. By contrast, the plankton community in stratified water took up nitrogen compounds which were not measured as part of the total dissolved inorganic and urea nitrogen, but were most likely dissolved organic nitrogen compounds. Results stress the importance of determining uptake rates of all 3 nitrogen substrates (NHfi, N O and urea) using 15N isotopes and by simultaneously measuring the change in concentration of these compounds throughout the incubation period.

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“…Porewater ammonium and ortho-phosphate concentrations were measured colorimetrically (Skalar and Seal autoanalyzer), using ammonium-molybdate and salicylate (Lamers et al, 1998). Nitrate was determined by sulphanilamide, after reduction of nitrate to nitrite in a cadmium column (Wood et al, 1967).…”

Section: Sediment Treatments: Nutrient and Organic Matter Additionmentioning

confidence: 99%

Toxic effects of increased sediment nutrient and organic matter loading on the seagrass Zostera noltii

et al. 2014

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As a result of anthropogenic disturbances and natural stressors, seagrass beds are often patchy and heterogeneous. The effects of high loads of nutrients and organic matter in patch development and expansion in heterogeneous seagrass beds have, however, poorly been studied. We experimentally assessed the in situ effects of sediment quality on seagrass (Zostera noltii) patch dynamics by studying patch (0.35 m diameter) development and expansion for 4 sediment treatments: control, nutrient addition (NPK), organic matter addition (OM) and a combination (NPK+OM).OM addition strongly increased porewater sulfide concentrations whereas NPK increased porewater ammonium, nitrate and phosphate concentrations. As high nitrate concentrations suppressed sulfide production in NPK+OM, this treatment was biogeochemically comparable to NPK. Sulfide and ammonium concentrations differed within treatments, but over a 77 days period, seagrass patch survival and expansion were impaired by all additions compared to the control treatment.Expansion decreased at porewater ammonium concentrations >2000 mol L -1 .Mother patch biomass was not affected by high porewater ammonium concentrations as a result of its detoxification by higher seagrass densities. Sulfide 2 concentrations >1000 mol L -1 were toxic to both patch expansion and mother patch. We conclude that patch survival and expansion are constrained at high loads of nutrients or organic matter as a result of porewater ammonium or sulfide toxicity.

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Determination of nitrate in sea water by cadmium-copper reduction to nitrite

Abstract: An accurate, dependable determination of 0-60 / Show more

Cited by 1,149 publications

References 12 publications

Effect of solar ultraviolet radiation on bacterio- and phytoplankton activity in a large coral reef lagoon (southwest New Caledonia)

Effect of solar ultraviolet radiation on bacterio- and phytoplankton activity in a large coral reef lagoon (southwest New Caledonia)

Time course of uptake of inorganic and organic nitrogen by phytoplankton in the Strait of Georgia: comparison of frontal and stratified communities

Toxic effects of increased sediment nutrient and organic matter loading on the seagrass Zostera noltii

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