Nutrient anomalies in Fragilariopsis kerguelensis blooms, iron deficiency and the nitrate/phosphate ratio (A. C. Redfield) of the Antarctic Ocean

Baar, de Henricus; Leeuwe, van Maria; Scharek, Renate; Goeyens, Léo; Bakker, Karel; Fritsche, Peter

doi:10.1016/s0967-0645(96)00102-6

Cited by 115 publications

(75 citation statements)

References 75 publications

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“…In the central Weddell Sea the N:P depletion ratio exhibits a range of 9-13 (Fig. 4a), which is lower than the N:P ratio of about 14 prevailing further north in the Atlantic sector of the Southern Ocean (De Baar et al 1997). Only in the nearmargin region (38-45°W) the values are higher and approaching the canonical RedWeld ratio N:P = 16.…”

Section: Nutrient Depletion Ratiosmentioning

confidence: 85%

Whole season net community production in the Weddell Sea

et al. 2007

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Depletions of total CO 2 , nitrate, phosphate and silicate in the surface layer were calculated for cruise ANT XXII/3 with FS Polarstern in March 2005 for estimating the annual net community production. East-west across the Weddell Sea the variation of all depletions is similar, but this holds to a lesser extent for silicate. Depletions in March 2005 are 2-3 times larger than those in January 1993 for the same transect. Very low N:P and C:P depletion ratios seem to point to dominance of diatoms, in the central Weddell Sea more than in the margin. Estimates of annual net community productions are about 1.8 and 3.5 mol C m ¡2 year ¡1 for the interior Weddell Sea and a near-margin region, respectively. The region does not comply with the classical view of a marginal ice zone with high productivity. Net community production is similar to annual export production, implying that remineralization in the ensuing winter be minor.

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Section: Nutrient Depletion Ratiosmentioning

confidence: 85%

Whole season net community production in the Weddell Sea

et al. 2007

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“…As a second approach to separate the anthropogenic carbon from other effects, we estimated the expected overall mean natural carbon change consistent with the change in NO − 3 concentration based on the Redfield ratios of C:N:P = 106:14:1 for the Atlantic sector of the SO north of the APF (De Baar et al 1997), which are slightly different from the classical ratios (Redfield 1963). An increase in NO − 3 at a rate of 0.08 ± 0.06 μmol kg −1 year −1 would result in an increase in DIC of 0.61 ± 0.45 μmol kg −1 year −1 ( DIC Redfield = 15.3 ± 11.3 μmol kg −1 in 25 years).…”

Section: Discussionmentioning

confidence: 99%

Variability of nutrients and carbon dioxide in the Antarctic Intermediate Water between 1990 and 2014

et al. 2018

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Antarctic Intermediate Water (AAIW) formation constitutes an important mechanism for the export of macronutrients out of the Southern Ocean that fuels primary production in low latitudes. We used quality-controlled gridded data from five hydrographic cruises between 1990 and 2014 to examine decadal variability in nutrients and dissolved inorganic carbon (DIC) in the AAIW (neutral density range 27 < γ n < 27.4) along the Prime Meridian. Significant positive trends were found in DIC (0.70 ± 0.4 μmol kg −1 year −1 ) and nitrate (0.08 ± 0.06 μmol kg −1 year −1 ) along with decreasing trends in temperature (−0.015±0.01 • C year −1 ) and salinity (−0.003±0.002 year −1 ) in the AAIW. Accompanying this is an increase in apparent oxygen utilization (AOU, 0.16 ± 0.07 μmol kg −1 year −1 ). We estimated that 75% of the DIC change has an anthropogenic origin. The remainder of the trends support a scenario of a strengthening of the upper-ocean overturning circulation in the Atlantic sector of the Southern Ocean in response to the positive trend in the Southern Annular Mode. A decrease in net primary productivity (more nutrients unutilized) in the source waters of the AAIW could have contributed as well but cannot fully explain all observed changes.

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“…We suggest that the biological uptake of Cd and P is independent of the dissolved Cd : PO 4 ratio. As a consequence, the results argue against the use of empirical Rayleigh fractionation models or models with fixed phytoplankton uptake ratios to account for regional variability in surface water dissolved Cd : PO 4 .The distribution of cadmium in the ocean mimics that of the algal nutrient phosphate (PO 4 ) (Boyle et al 1976;Bruland et al 1978;de Baar et al 1994). Like PO 4 , vertical distributions are typified by surface depletions that increase rapidly to maximum concentrations in the main thermocline…”

mentioning

confidence: 95%

“…The distribution of cadmium in the ocean mimics that of the algal nutrient phosphate (PO 4 ) (Boyle et al 1976;Bruland et al 1978;de Baar et al 1994). Like PO 4 , vertical distributions are typified by surface depletions that increase rapidly to maximum concentrations in the main thermocline…”

Section: Introductionmentioning

confidence: 99%

Effect of iron limitation on the cadmium to phosphorus ratio of natural phytoplankton assemblages from the Southern Ocean

Cullen

Chase

Coale

et al. 2003

Limnology & Oceanography

116

122

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There is considerable interest in the biogeochemical cycling of cadmium (Cd) and phosphate (PO 4 ) in surface waters, driven in part by the ongoing development of a paleonutrient proxy that utilizes Cd preserved in fossil planktonic foraminifera to determine past PO 4 utilization efficiencies in ocean surface waters. The present article reports the results of a field study into the effects of Fe limitation on the Cd : P composition of natural assemblages of marine phytoplankton in the Antarctic Zone of the Pacific sector of the Southern Ocean. Iron enrichment to shipboard incubation bottles led to increases in community growth rate and final biomass. After 10.7 d of incubation, the climax community was dominated by large diatoms of the genus Fragillariopsis, Pseudonitzschia, and Nitzschia. Direct measurements of phytoplankton metal : P ratios from controlled shipboard experiments indicate that Cd : P, Co : P, and Zn : P ratios decreased from control values with increasing initial dissolved Fe concentrations in the incubation bottles, by factors of ϳ2-10 at highest Fe additions. We suggest that the effect of Fe limitation on resident diatoms is to decrease growth rate, leading to elevated cellular Cd content. The dissolved Cd : P ratio in iron-limited surface waters of the Southern Ocean may, therefore, respond to the supply of Fe to the resident phytoplankton community, which has implications for the developing paleonutrient proxy. We suggest that the biological uptake of Cd and P is independent of the dissolved Cd : PO 4 ratio. As a consequence, the results argue against the use of empirical Rayleigh fractionation models or models with fixed phytoplankton uptake ratios to account for regional variability in surface water dissolved Cd : PO 4 .The distribution of cadmium in the ocean mimics that of the algal nutrient phosphate (PO 4 ) (Boyle et al. 1976;Bruland et al. 1978;de Baar et al. 1994). Like PO 4 , vertical distributions are typified by surface depletions that increase rapidly to maximum concentrations in the main thermocline

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Nutrient anomalies in Fragilariopsis kerguelensis blooms, iron deficiency and the nitrate/phosphate ratio (A. C. Redfield) of the Antarctic Ocean

Cited by 115 publications

References 75 publications

Whole season net community production in the Weddell Sea

Whole season net community production in the Weddell Sea

Variability of nutrients and carbon dioxide in the Antarctic Intermediate Water between 1990 and 2014

Effect of iron limitation on the cadmium to phosphorus ratio of natural phytoplankton assemblages from the Southern Ocean

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