Iron biogeochemistry across marine systems – progress from the past decade

Biogeosciences (Impact Factor: 3.98). 03/2010; DOI: 10.5194/bg-7-1075-2010
Source: DOAJ


Based on an international workshop (Gothenburg, 14–16 May 2008), this review article aims to combine interdisciplinary knowledge from coastal and open ocean research on iron biogeochemistry. The major scientific findings of the past decade are structured into sections on natural and artificial iron fertilization, iron inputs into coastal and estuarine systems, colloidal iron and organic matter, and biological processes. Potential effects of global climate change, particularly ocean acidification, on iron biogeochemistry are discussed. The findings are synthesized into recommendations for future research areas.

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    • "During the 2010–2011 exploration season of the E/V Nautilus we studied the deep benthic environment of the Levantine basin, the most oligotrophic part of the Mediterranean Sea [23]. The contrast between the high iron demand for required for nitrogen fixation [24] and the low iron availability in the surface waters [25] may explain the low nitrogen fixation rates in this area [26]. The paradigm of Fe-rich dust supply to surface waters as the dominant iron source includes Levantine basin [27]. "
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    ABSTRACT: During the 2010-2011 E/V Nautilus exploration of the Levantine basin's sediments at the depth of 300-1300 m, densely patched orange-yellow flocculent mats were observed at various locations along the continental margin of Israel. Cores from the mat and the control locations were collected by remotely operated vehicle system (ROV) operated by the E/V Nautilus team. Microscopic observation and phylogenetic analysis of microbial 16S and 23S rRNA gene sequences indicated the presence of zetaproteobacterial stalk forming Mariprofundus spp. - like prokaryotes in the mats. Bacterial tag-encoded FLX amplicon pyrosequencing determined that zetaproteobacterial populations were a dominant fraction of microbial community in the biofilm. We show for the first time that zetaproteobacterial may thrive at the continental margins, regardless of crustal iron supply, indicating significant fluxes of ferrous iron to the sediment-water interface. In light of this discovery, we discuss the potential bioavailability of sediment-water interface iron for organisms in the overlying water column.
    PLoS ONE 03/2014; 9(3):e91456. DOI:10.1371/journal.pone.0091456 · 3.23 Impact Factor
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    • "Iron limitation controls biological productivity in 30 % of the world's oceans (Ardelan and Steinnes 2010); therefore, assessing the potential effects of OA on iron biogeochemistry is crucial. Millero et al. (2009) showed that a decrease in pH from 8.1 to 7.4 will increase the solubility of Fe(III) by approximately 40 %, whilst Breitbarth et al. (2010) showed a similar pH decrease could cause a 10-fold increase in the half-life of Fe(II). In comparison, other studies have suggested that the bioavailability of iron will decrease under acidified conditions (Martin and Fitzwater 1988; Shi et al. 2010). "
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    ABSTRACT: Research into the effects of ocean acidification (OA) on marine organisms has greatly increased during the past decade, as realization of the potential dramatic impacts has grown. Studies have revealed the multifarious respon-ses of organisms to OA conditions, indicating a high level of intra-and interspecific variation in species' ability to accommodate these alterations. If we are to provide policy makers with sound, scientific input regarding the expected consequences of OA, we need a broader understanding of these predicted changes. As a group of 20 multi-disci-plinary postgraduate students from around the globe, with a study focus on OA, we are a strong representation of 'next generation' scientists in this field. In this unique cumulative paper, we review knowledge gaps in terms of assessing the biological impacts of OA, outlining directions for future research.
    Marine Biology 08/2013; 160:1789-1805. DOI:10.1007/s00227-012-2033-3 · 2.39 Impact Factor
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    • "In addition, terrestrially derived humic substances apparently play a major role as chelators for iron and other trace metals (Laglera and van den Berg 2009) in the marine environment. This holds true especially for high nutrient low chlorophyll (HNLC) areas where iron limits primary production (Breitbarth et al. 2010). The Tanner Moor, a pristine submountainous raised peat bog in Lower Austria, releases water with elevated NOM and iron content (Krachler et al. 2005). "
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    ABSTRACT: Samples from a pristine raised peat bog runoff in Austria, the Tannermoor creek, were analysed for their iron linked to natural organic matter (NOM) content. Dissolved organic carbon < 0.45 μm (DOC) was 41-64 mg L(-1), iron 4.4-5.5 mg L(-1). Samples were analysed applying asymmetric field flow fractionation (AsFlFFF) coupled to UV-vis absorption, fluorescence and inductively coupled plasma mass spectrometry (ICP-MS). The samples showed an iron peak associated with the NOM peak, one sample exhibiting a second peak of iron independent from the NOM peak. As highland peat bogs with similar climatic conditions and vegetation to the Tanner Moor are found throughout the world, including areas adjacent to the sea, we examined the behaviour of NOM and iron in samples brought to euhaline (35‰) conditions with artificial sea salt. The enhanced ionic strength reduced NOM by 53% and iron by 82%. Size exclusion chromatography (SEC) of the samples at sea-like salinity revealed two major fractions of NOM associated with different iron concentrations. The larger one, eluting sharply after the upper exclusion limits of 4000-5000 g mol(-1), seems to be most important for iron chelating. The results outline the global importance of sub-mountainous and mountainous raised peat bogs as a source of iron chelators to the marine environment at sites where such peat bogs release their run-offs into the sea.
    Limnologica - Ecology and Management of Inland Waters 06/2013; 43(4):239-244. DOI:10.1016/j.limno.2012.09.006 · 1.80 Impact Factor
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