The role of colloid chemistry in providing a source of iron to phytoplankton

Wells, Mark L.; Zorkin, Niko G.; Lewis, A.G.

doi:10.1357/002224083788520478

Cited by 107 publications

(55 citation statements)

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“…These results are valuable because diatoms form algal blooms in HNLC areas (Maher et al, 2010). However, growth rates decreased with aged ferrihydrite, and other iron minerals (goethite, haematite) have been found to be only poorly bioavailable (Wells et al, 1983;Rich and Morel, 1990), probably because of their lower solubilities and dissolution rates in seawater (Kuma and Matsunaga, 1995). Yoshida et al (2006) studied the effects of ferrihydrite aging on iron uptake by coastal diatoms.…”

Section: Discussionmentioning

confidence: 99%

The Iron Biogeochemical Cycle Past and Present

Raiswell¹,

Canfield²

2012

GeochemPersp

581

445

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Section: Discussionmentioning

confidence: 99%

The Iron Biogeochemical Cycle Past and Present

Raiswell¹,

Canfield²

2012

GeochemPersp

581

445

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“…The earlier hypotheses that algae have to assimilate, directly or indirectly, particulate iron (HARVEY, 1937a;GOLDBERG, 1952) had been dictated by the erratic data of those days, and have now been abandoned. Nevertheless, colloids and fine particles may still play arole (WELLS, 1990), serving as a source (through, e.g., photoreduction) of readily supplied dissolved iron, also as Fe(II), towards maintaining the truly dissolved free ionic activity (also of Fe(II)) required for steady growth (WELLS, ZORKIN and LEWIS, 1983;WAITE and MOREL, 1984;FINDEN, TIPPING, JAWORSKI and REYNOLDS, 1984;WELLS and MAYER, 1991a, b;WELLS, MAYER and GUILLARD, 1991). Dissolution of the aeolian input of continental dust may also be supplementing the pool of dissolved iron in some regions (MOORE, MILLEY and CHATr, 1984;DUEL, 1986;DUCE and TINDALE, 1991).…”

Section: Growth Response Of Individual Phytoplankton Speciesmentioning

confidence: 99%

von Liebig's law of the minimum and plankton ecology (1899–1991)

Baar

1994

Progress in Oceanography

237

132

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-The Law of the Minimum was originally formulated by Justus yon Liebig, as one of the 50 interlinked laws concerned with agriculture. The original writings ofJ. von Liebig often were misinterpreted by his successors. BRAt, rOT (1899) took this one law out of its context and proposed that limitation by nitrogen is a dominant factor in plankton ecology, far beyond its original application to agriculture. This was opposed by NAmANSOrn~ (1908) who suggested instead a dynamic balance of growth and loss terms. Towards validating, or eventually falsifying Brandt's hypothesis, Atkins, Harvey, Cooper and others developed the chemical methods necessary for re-defining ocean nutrient cycling and growth limitation. The major exception to these modem perspectives was the Antarctic Paradox of higla nutrients and low chlorophyll which inspired Gran, Atkins, Harvey and Cooper to pioneer the concept of iron limitation. An exhaustive overview is given of efforts to define Fe in seawater and its controlling effect on in situ plankton growth, for the 1920-1984 period. Somewhat parallel work in the laboratory on single species of algae in chelation-controlled mediahas provided much insight, but is sketched only briefly. Martin and contemporaries developed the chemical methods necessary for defming the ocean chemistry of Fe and its role for in situ growth. These developments are sketched for the 1982-1991 period. Once again the Law of the Minimum and associated bold hypotheses served, albeit briefly, to bring a nutrient element in the forefront of research. This, and the recent awareness of CO 2 as rate limiting factor, underline the conclusion that advances in sciences often hinge on advances in technology, confirming Kta-~ (1962). In this case the new analytical techniques developed by Atkins, Harvey, Cooper, Martin and their associates have proven revolutionary for plankton ecology. Some observations in plankton ecology may be reminiscent of the agricultural Law of the Minimum, but this would not warrant its direct application, beyond its original context and agriculture, to plankton ecology. Rather the net rate of increase ofphytoplankton is the dynamic balance of multiple growth and loss terms, together also determining the biomass at given time and space. 347

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“…Incubation studies have shown that while a limited number of cFe forms are highly bioavailable (such as exopolymeric saccharides, Hassler et al, 2011b), sFe is typically preferred and is taken into the cell much faster than cFe (Chen et al, 2003;Chen and Wang, 2001;Wang and Dei, 2003). Crystalline inorganic cFe (such as nanoparticulate Fe oxyhydroxide) is not directly available to marine phytoplankton at all (Rich and Morel, 1990;Wells et al, 1983),…”

Section: Introductionmentioning

confidence: 99%

The composition of dissolved iron in the dusty surface ocean: An exploration using size-fractionated iron-binding ligands

et al. 2015

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Abbreviations cFe-colloidal iron (10 kDa < cFe < 0.2 µm) CLE-ACSV-competitive ligand exchange adsorptive cathodic stripping voltammetry CFF-cross flow filtration dFe-dissolved iron (< 0.2 µm) Fe-iron ID-ICP-MS-isotope dilution inductively-coupled plasma mass spectrometry sFe-soluble iron (< 10 kDa ) AbstractThe size partitioning of dissolved iron and organic iron-binding ligands into soluble and colloidal phases was investigated in the upper 150 m of two stations along the GA03 U.S.GEOTRACES North Atlantic transect. The size fractionation was completed using cross-flow filtration methods, followed by analysis by isotope dilution inductively-coupled plasma mass spectrometry (ID-ICP-MS) for iron and competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-ACSV) for iron-binding ligands. On average, 80% of the 0.1-0.65 nM dissolved iron (<0.2 µm) was partitioned into the colloidal iron (cFe) size fraction (10 kDa < cFe < 0.2 µm), as expected for areas of the ocean underlying a dust plume. The 1.3-2.0 nM strong organic iron-binding ligands, however, overwhelmingly (75-77%) fell into the soluble size fraction (<10 kDa). As a result, modeling the dissolved iron size fractionation at equilibrium using the observed ligand partitioning did not accurately predict the iron partitioning into colloidal and soluble pools. This suggests that either a portion of colloidal ligands are missed by current electrochemical methods because they react with iron more slowly than the equilibration time of our CLE-ACSV method, or part of the observed colloidal iron is actually inorganic in composition and thus cannot be predicted by our model of unbound iron-binding ligands. This potentially contradicts the prevailing view that greater than 99% of dissolved iron in the ocean is organically complexed. Untangling the chemical form of iron in the upper ocean has important implications for surface ocean biogeochemistry and may affect iron uptake by phytoplankton.

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The role of colloid chemistry in providing a source of iron to phytoplankton

Cited by 107 publications

References 0 publications

The Iron Biogeochemical Cycle Past and Present

The Iron Biogeochemical Cycle Past and Present

von Liebig's law of the minimum and plankton ecology (1899–1991)

The composition of dissolved iron in the dusty surface ocean: An exploration using size-fractionated iron-binding ligands

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