Cadmium, copper and iron in the Scotia Sea, Weddell Sea and Weddell/Scotia Confluence (Antarctica)

Nolting, R.F.; Baar, de Henricus; Bennekom, A.J. Van; Masson, Annick

doi:10.1016/s0304-4203(09)90019-6

Cited by 108 publications

(70 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…in the Antarctic Bottom Water AABW consistent Ž with its Weddell Sea source regions Westerlund and . Ohman, 1991;Nolting et al, 1991 . In the Indian sector of the Southern Ocean the total dissolvable Fe was found to be in the 0.4-6.2 nM range in the upper 250 m of the water column at stations extend-Ž ing from 498 to 668S at the 628E meridian Sarthou . et al, 1997 , and similar in value as the dissolved Fe Ž .…”

Section: Total Dissolõable and Particulate Fementioning

confidence: 99%

“…This is comparable to the dissolved Fe Ž . measured in the region Nolting et al, 1991 . In the more offshore waters of Drake Passage, in the austral summers of 1990 and 1991, Helbling et Ž . al.…”

Section: Limitation By Fe In the Remote Southern Oceanmentioning

confidence: 99%

“…In this frontal re-Ž . gion, both dissolved Fe Nolting et al, 1991 and particulate Al levels were found to be quite high Ž . Dehairs et al, 1992 .…”

Section: Limitation By Fe In the Remote Southern Oceanmentioning

confidence: 99%

“…Ž al., 1995 and nearshore neritic waters de Baar et . al., 1990;Buma et al, 1991;Nolting et al, 1991 , the Fe supply is adequate, and one encounters spring and summer blooms once the light climate has become more favorable. This leads to rapid removal of Ž Fe over several weeks time de Baar et al, 1995;.…”

Section: Iron Silicate Light Diatom Blooms and Global Element Budgetsmentioning

confidence: 99%

See 3 more Smart Citations

Low dissolved Fe and the absence of diatom blooms in remote Pacific waters of the Southern Ocean

et al. 1999

View full text Add to dashboard Cite

The remote waters of the Pacific region of the Southern Ocean are the furthest away from any upstream and upwind Ž continental Fe sources. This prime area for expecting Fe limitation of the plankton ecosystem was studied March-April . 1995 along a north-south transect at ; 898W. At the end of the austral summer the upper wind-mixed layers were in the order of ; 100 m deep, thus mixing the algae down into the dimly lit part of the euphotic zone where photosynthesis is severely restricted. The dissolved Fe was found at low concentrations ranging from 0.05 nM near the surface to 0.5 nM in Ž . deeper waters. Along the transect 528S-698S , the dissolved iron was enhanced in the Polar Front, as well as near the Ž . Antarctic continental margin 0.6-1.0 nM . In between, the southern ACC branch was depleted with iron; here the concentrations in surface waters were quite uniform at about 0.21 nM. This is only somewhat lower than the 0.49 nM Ž . Ž . October 1992 and 0.31 nM November 1992 averages in early spring in the southern ACC part of Atlantic 68W sections wde Baar, H.J.W., de Jong, J.T.M., Bakker, D.C.E.. Loscher, B.M., Veth, C., Bathmann, U., Smetacek, V., 1995. Importancë of iron for phytoplankton spring blooms and CO drawdown in the Southern Ocean. Nature 373, 412-415; Loscher, B.M., 2 de Jong, J.T.M., de Baar, H.J.W., Veth, C., Dehairs, F., 1997. The distribution of iron in the Antarctic Circumpolar Current.x Deep-Sea Research II 44, 143-188. . First, the lower ; 0.21 nM in March-April 1995 may partly be due to continuation of the seasonal trend where the phytoplankton growth, albeit modest, was removing Fe from the surface waters. Secondly, the 898W Pacific stations are further downstream continental or seafloor sources than the Atlantic 68W section. In the latter case, the ACC water had passed through the Drake Passage and also over the Sandwich Plateau. Indeed for Drake Passage, intermediate Fe concentrations have been reported by others. The generally somewhat lower surface water Fe at the ACC and PF at 898W is consistent with the distance from sources and the late summer. It also would explain the very low Ž . abundance of phytoplankton Chl a in the region and the conspicuous absence of plankton blooms. In the subAntarctic waters north of the Polar Front there are no diatoms, let alone diatom blooms, due to low availability of silicate. Thus, it Baar et al.r Marine Chemistry 66 1999 1-34 2 appears the biological productivity is suppressed due to iron deficiency, in combination with the severe seasonal effects of wind mixing on the light climate, as well as regional silicate limitation for diatoms. q

show abstract

Section: Total Dissolõable and Particulate Fementioning

confidence: 99%

Section: Limitation By Fe In the Remote Southern Oceanmentioning

confidence: 99%

“…In this frontal re-Ž . gion, both dissolved Fe Nolting et al, 1991 and particulate Al levels were found to be quite high Ž . Dehairs et al, 1992 .…”

Section: Limitation By Fe In the Remote Southern Oceanmentioning

confidence: 99%

Section: Iron Silicate Light Diatom Blooms and Global Element Budgetsmentioning

confidence: 99%

See 2 more Smart Citations

Low dissolved Fe and the absence of diatom blooms in remote Pacific waters of the Southern Ocean

et al. 1999

View full text Add to dashboard Cite

show abstract

“…Ž The effects of iron additions on phytoplankton de Baar et al, 1990;Buma et al, 1991;Timmermans et al, 1994;Scharek et al, . 1997 , the distribution of iron and other trace ele-Ž ments in the water column Saager et al, 1989;Nolting et al, 1991;de Baar et al, 1995;Loscher eẗ . al., 1997 and the chemical speciation of iron in Ž seawater Gledhill and van den Berg, 1995; in press are central themes in our work.…”

Section: Introductionmentioning

confidence: 99%

Responses of marine phytoplankton in iron enrichment experiments in the northern North Sea and northeast Atlantic Ocean

et al. 1998

View full text Add to dashboard Cite

Short-term iron enrichment experiments were carried out with samples collected in areas with different phytoplankton activity in the northern North Sea and northeast Atlantic Ocean in the summer of 1993. The research area was dominated by high numbers of pico-phytoplankton, up to 70,000 ml y1 . Maximum chlorophyll a concentrations varied from about 1.0 mg y1 Ž . l in a high-reflectance zone caused by loose coccoliths, remnants from a bloom of Emiliania huxleyi and about 3.5 mg l y1 in a zone in which the phytoplankton were growing, to about 0.5 mg l y1 in the northeast Atlantic Ocean. From the high-reflectance zone to the northeast Atlantic Ocean, nitrate concentrations increased from 0.5 mM to 6.0 mM. Concentrations of reactive iron in surface water showed an opposite trend and decreased from about 2.6 nM in the high-reflectance zone to -1.0 nM in the northeast Atlantic Ocean. In the research area, no signs of true iron deficiency were found, but iron enrichments in the high-reflectance zone, numerically dominated by Synechococcus sp., resulted in increased nitrate uptake. Ammonium uptake was hardly affected. Strong support for the effect of Fe on cell physiology is Ž . given by the increase in the f-ratio. Net growth rates of the phytoplankton changes in cell numbers over 24 h were almost unchanged. Phytoplankton collected from the northeast Atlantic Ocean, did not show changes in the nitrogen metabolism upon addition of iron. Net growth rates in these incubations were low or negative, with only slightly higher values with additional iron. q

show abstract

Cadmium regeneration within the North Atlantic

Roshan

2015

Global Biogeochemical Cycles

View full text Add to dashboard Cite

Cadmium (Cd) incorporated into the benthic microfossils has been widely used in reconstructing the past water circulation in the North Atlantic. This requires a major control by conservative mixing over regeneration process on the seawater cadmium distribution in the North Atlantic. Through coupling the recently reported Cd data at depths below 300 m with quantitative water mass analysis along the GA03 transect, we tested two models for cadmium cycling within the North Atlantic: conservative mixing alone and conservative mixing plus regeneration which is termed as regenerative mixing. The results show that the regenerative mixing model reproduces the observations (slope = 0.99 and R2 = 0.97) much better than the conservative mixing model (slope = 0.99 and R2 = 0.88). The regenerative mixing model was applied to estimate the amount of dissolved cadmium regenerated “within” the North Atlantic. This regionally regenerated cadmium contributes to ~10% and >50% of the total cadmium in the North Atlantic at depths >1000 m and 300–1000 m, respectively, indicating that the microfossil‐reconstructed seawater Cd can be attributed to the mixing from the South Atlantic to the North Atlantic with high accuracy for depths below 1000 m, while within 300–1000 m cadmium is more controlled by the regeneration process than the mixing process, complicating the attribution of the microfossil‐reconstructed seawater Cd to the changes in water mass geometry within this 300–1000 m depth range. A regionally and vertically constant Cd/PO43− regeneration ratio ~262 pM/µmol/kg was derived from the regenerative mixing model which is comparable with ratios estimated in the recent studies for the North Atlantic.

show abstract

Cadmium, copper and iron in the Scotia Sea, Weddell Sea and Weddell/Scotia Confluence (Antarctica)

Cited by 108 publications

References 45 publications

Low dissolved Fe and the absence of diatom blooms in remote Pacific waters of the Southern Ocean

Low dissolved Fe and the absence of diatom blooms in remote Pacific waters of the Southern Ocean

Responses of marine phytoplankton in iron enrichment experiments in the northern North Sea and northeast Atlantic Ocean

Cadmium regeneration within the North Atlantic

Contact Info

Product

Resources

About