Temporal distribution of trace metals in Antarctic coastal waters

Grotti, Marco; Soggia, Francesco; Abelmoschi, Maria Luisa; Rivaro, Paola; Magi, Emanuele; Frache, Roberto

doi:10.1016/s0304-4203(01)00063-9

Cited by 88 publications

(70 citation statements)

References 28 publications

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“…We note that Fe concentrations in these experiments were above the range of concentrations encountered in the Southern Ocean, although they are in the range of concentration found in Antarctic fast ice (Grotti et al, 2001;van der Merwe et al, 2011a,b;Noble et al, 2013). All conclusions in this study are derived from a high concentration scenario in regards to added DFe and PFe, but nonetheless, our results provide key information on the general chemistry of the involved processes.…”

Section: Conversion Of Dissolved Fe To Particulate Formsupporting

confidence: 45%

Organic Matter Controls of Iron Incorporation in Growing Sea Ice

et al. 2018

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This study presents the first laboratory-controlled sea-ice growth experiment conducted under trace metal clean conditions. The role played by organic matter in the incorporation of iron (Fe) into sea ice was investigated by means of laboratory ice-growth experiments using a titanium cold-finger apparatus. Experiments were also conducted to understand the role of extracellular polymeric substances (EPS) in the enrichment of ammonium in sea ice. Sea ice was grown from several seawater solutions containing different quantities and qualities of particulate Fe (PFe), dissolved Fe (DFe) and organic matter. Sea ice and seawater were analyzed for particulate organic carbon and nitrogen, macro-nutrients, EPS, PFe, and DFe, and particulate aluminum. The experiments showed that biogenic PFe is preferentially incorporated into sea ice compared to lithogenic PFe. Furthermore, sea ice grown from ultra-violet (UV) and non-UV treated seawaters exhibits contrasting incorporation rates of organic matter and Fe. Whereas, the effects of UV-treatments were not always significant, we do find indications that the type or organic matter controls the enrichment of Fe in forming sea ice. Specifically, we come to the conclusion that the incorporation of DFe is favored by the presence of organic ligands in the source solution.

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Section: Conversion Of Dissolved Fe To Particulate Formsupporting

confidence: 45%

Organic Matter Controls of Iron Incorporation in Growing Sea Ice

et al. 2018

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“…Moreover, studies that sampled near known Fe sources (sea ice, shallow bathymetry), as compared to those undertaken in open, probably Fe depleted (Sedwick et al, 2011), polynya waters also contributes to dFe variability. Accordingly, the high dFe values for February (Grotti et al, 2001) are probably more indicative of sampling close to fast ice rich in continental Fe, rather than a seasonal trend. Nevertheless, dFe values can remain low throughout the period OctoberJanuary (Fig.…”

Section: A Tagliabue Et Al: a Global Compilation Of Dissolved Iron mentioning

confidence: 95%

A global compilation of dissolved iron measurements: focus on distributions and processes in the Southern Ocean

et al. 2012

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Abstract. Due to its importance as a limiting nutrient for phytoplankton growth in large regions of the world's oceans, ocean water column observations of concentration of the trace-metal iron (Fe) have increased markedly over recent decades. Here we compile >13 000 global measurements of dissolved Fe (dFe) and make this available to the community. We then conduct a synthesis study focussed on the Southern Ocean, where dFe plays a fundamental role in governing the carbon cycle, using four regions, six basins and five depth intervals as a framework. Our analysis highlights depth-dependent trends in the properties of dFe between different regions and basins. In general, surface dFe is highest in the Atlantic basin and the Antarctic region. While attributing drivers to these patterns is uncertain, inter-basin patterns in surface dFe might be linked to differing degrees of dFe inputs, while variability in biological consumption between regions covaries with the associated surface dFe differences. Opposite to the surface, dFe concentrations at depth are typically higher in the Indian basin and the Subantarctic region. The inter-region trends can be reconciled with similar ligand variability (although only from one cruise), and the inter-basin difference might be explained by differences in hydrothermal inputs suggested by modelling studies ) that await observational confirmation. We find that even in regions where many dFe measurements exist, the processes governing the seasonal evolution of dFe remain enigmatic, suggesting that, aside from broad Subantarctic -Antarctic trends, biological consumption might not be the major driver of dFe variability. This highlights the apparent importance of other processes such as exogenous inputs, physical transport/mixing or dFe recycling processes. Nevertheless, missing measurements during key seasonal transitions make it difficult to better quantify and understand surface water replenishment processes and the seasonal Fe cycle. Finally, we detail the degree of seasonal coverage by region, basin and depth. By synthesising prior measurements, we suggest a role for different processes and highlight key gaps in understanding, which we hope can help structure future research efforts in the Southern Ocean.

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“…Pre-concentration of DFe and TaLFe from seawater was carried out by a modified combination of Chelex-100 (Na + form, 100-200 mesh size, Bio-Rad) batch (Baffi and Cardinale, 1990;Grotti et al, 2001) and column technique (Öztürk, 1995, 2002). Before the Chelex treatment, ∼500 ml of the acidified samples were microwaved for 2.5 min at 1100 W (∼60 • C), allowed to cool for 30 min, and then microwaved again for 2.5 min in order to break down the remaining strong ligand-Fe complexes and colloidal iron.…”

Section: Dfe and Talfe Sampling And Determinationmentioning

confidence: 99%

Natural iron enrichment around the Antarctic Peninsula in the Southern Ocean

et al. 2010

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Abstract. As part of the US-AMLR program in JanuaryFebruary of 2006, 99 stations in the South Shetland IslandsAntarctic Peninsula region were sampled to understand the variability in hydrographic and biological properties related to the abundance and distribution of krill in this area. Concentrations of dissolved iron (DFe) and total acidleachable iron (TaLFe) were measured in the upper 150 m at 16 of these stations (both coastal and pelagic waters) to better resolve the factors limiting primary production in this area and in downstream waters of the Scotia Sea. The concentrations of DFe and TaLFe in the upper mixed layer (UML) were relatively high in Weddell Sea Shelf Waters (∼0.6 nM and 15 nM, respectively) and low in Drake Passage waters (∼0.2 nM and 0.9 nM, respectively). In the Bransfield Strait, representing a mixture of waters from the Weddell Sea and the Antarctic Circumpolar Current (ACC), concentrations of DFe were ∼0.4 nM and of TaLFe ∼1.7 nM. The highest concentrations of DFe and TaLFe in the UML were found at shallow coastal stations close to Livingston Island (∼1.6 nM and 100 nM, respectively). The ratio of TaLFe:DFe varied with the distance to land: ∼45 at the shallow coastal stations, ∼15 in the high-salinity waters of Bransfield Strait, and ∼4 in ACC waters. Concentrations of DFe increased slightly with depth in the water column, while that of TaLFe did not show any consistent trend with depth. Our Fe data are discussed in regard to the hydrography Correspondence to: M. V. Ardelan (murato@nt.ntnu.no) and water circulation patterns in the study area, and with the hypothesis that the relatively high rates of primary production in the central regions of the Scotia Sea are partially sustained by natural iron enrichment resulting from a northeasterly flow of iron-rich coastal waters originating in the South Shetland Islands-Antarctic Peninsula region.

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Temporal distribution of trace metals in Antarctic coastal waters

Cited by 88 publications

References 28 publications

Organic Matter Controls of Iron Incorporation in Growing Sea Ice

Organic Matter Controls of Iron Incorporation in Growing Sea Ice

A global compilation of dissolved iron measurements: focus on distributions and processes in the Southern Ocean

Natural iron enrichment around the Antarctic Peninsula in the Southern Ocean

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