Fe(II) stability in seawater

Abstract. The speciation of dissolved iron (DFe) in the ocean is widely assumed to consist exclusively of Fe(III)-ligand complexes. Yet in most aqueous environments a poorly defined fraction of DFe also exists as Fe(II). Here we deploy flow injection analysis to measure in-situ Fe(II) concentrations during a series of mesocosm/microcosm experiments in coastal environments in addition to the decay rate of this Fe(II) when moved into the dark. During 5 mesocosm/microcosm experiments in Svalbard and Patagonia, where dissolved (0.2 µm) Fe and Fe(II) were quantified simultaneously, Fe(II) constituted 24–65 % of DFe suggesting that Fe(II) was a large fraction of the DFe pool. When this Fe(II) was allowed to decay in the dark, the vast majority of measured oxidation rate constants were retarded relative to calculated constants derived from ambient temperature, salinity, pH and dissolved O2. The oxidation rates of Fe(II) spikes added to Atlantic seawater more closely matched calculated rate constants. The difference between observed and theoretical decay rates in Svalbard and Patagonia was most pronounced at Fe(II) concentrations

[1]  U. Riebesell,et al.  Plankton Community Respiration and ETS Activity Under Variable CO2 and Nutrient Fertilization During a Mesocosm Study in the Subtropical North Atlantic , 2018, Front. Mar. Sci..

[2]  E. Achterberg,et al.  Trace chemical species in marine incubation experiments, part A. Experiment design and bacterial abundance control extracellular H2O2 concentrations , 2018 .

[3]  M. González‐Dávila,et al.  Effect of Organic Fe-Ligands, Released by Emiliania huxleyi, on Fe(II) Oxidation Rate in Seawater Under Simulated Ocean Acidification Conditions: A Modeling Approach , 2018, Front. Mar. Sci..

[4]  J. Santana-Casiano,et al.  Impact on the Fe redox cycling of organic ligands released by Synechococcus PCC 7002, under different iron fertilization scenarios. Modeling approach , 2018, Journal of Marine Systems.

[5]  E. Achterberg,et al.  Photochemical vs. Bacterial Control of H2O2 Concentration Across a pCO2 Gradient Mesocosm Experiment in the Subtropical North Atlantic , 2018, Front. Mar. Sci..

[6]  Toru Watanabe,et al.  Importance of allochthonous and autochthonous dissolved organic matter in Fe(II) oxidation: A case study in Shizugawa Bay watershed, Japan. , 2017, Chemosphere.

[7]  E. Achterberg,et al.  A Comparison between Four Analytical Methods for the Measurement of Fe(II) at Nanomolar Concentrations in Coastal Seawater , 2017, Front. Mar. Sci..

[8]  K. Johnson,et al.  The integral role of iron in ocean biogeochemistry , 2017, Nature.

[9]  Kai Sørensen,et al.  FerryBox-assisted monitoring of mixed layer pH in the Norwegian Coastal Current , 2016 .

[10]  E. Achterberg,et al.  Volcanic ash as an oceanic iron source and sink , 2016 .

[11]  E. Galbraith,et al.  How well do global ocean biogeochemistry models simulate dissolved iron distributions? , 2016 .

[12]  Martin Frank,et al.  The GEOTRACES Intermediate Data Product 2017 , 2018, Chemical Geology.

[13]  William J. Jenkins,et al.  Basin-scale transport of hydrothermal dissolved metals across the South Pacific Ocean , 2015, Nature.

[14]  M. Lohan,et al.  Alkaline phosphatase activity in the subtropical ocean: insights from nutrient, dust and trace metal addition experiments , 2014, Front. Mar. Sci..

[15]  S. John,et al.  Quantification of dissolved iron sources to the North Atlantic Ocean , 2014, Nature.

[16]  M. González‐Dávila,et al.  Effect of Dunaliella tertiolecta organic exudates on the Fe(II) oxidation kinetics in seawater. , 2014, Environmental science & technology.

[17]  B. Twining,et al.  The regeneration of highly bioavailable iron by meso‐ and microzooplankton , 2014 .

[18]  M. González‐Dávila,et al.  Characterization of phenolic exudates from Phaeodactylum tricornutum and their effects on the chemistry of Fe(II)–Fe(III) , 2014 .

[19]  J. Egge,et al.  Elemental stoichiometry of marine particulate matter measured by wavelength dispersive X-ray fluorescence (WDXRF) spectroscopy , 2013, Journal of the Marine Biological Association of the United Kingdom.

[20]  M. Ardelan,et al.  Assessing the micro-phytoplankton response to nitrate in Comau Fjord (42°S) in Patagonia (Chile), using a microcosms approach , 2013, Environmental Monitoring and Assessment.

[21]  U. Riebesell,et al.  Technical Note: A mobile sea-going mesocosm system – new opportunities for ocean change research , 2013 .

[22]  S. Baines,et al.  The trace metal composition of marine phytoplankton. , 2013, Annual review of marine science.

[23]  P. Statham,et al.  The measurement of organically complexed FeII in natural waters using competitive ligand reverse titration. , 2012, Analytica chimica acta.

[24]  K. Bruland,et al.  Rapid and noncontaminating sampling system for trace elements in global ocean surveys , 2012 .

[25]  Y. Shaked,et al.  Disassembling Iron Availability to Phytoplankton , 2012, Front. Microbio..

[26]  M. Wells,et al.  Evidence for regulation of Fe(II) oxidation by organic complexing ligands in the Eastern Subarctic Pacific , 2011 .

[27]  S. Speich,et al.  Labile Fe(II) concentrations in the Atlantic sector of the Southern Ocean along a transect from the subtropical domain to the Weddell Sea Gyre , 2011 .

[28]  T. Nielsen,et al.  Copepod guts as biogeochemical hotspots in the sea: Evidence from microelectrode profiling of Calanus spp , 2011 .

[29]  D. Hammond,et al.  The continental shelf benthic iron flux and its isotope composition , 2010 .

[30]  P. Boyd,et al.  Environmental control of open‐ocean phytoplankton groups: Now and in the future , 2010 .

[31]  M. Gehlen,et al.  Hydrothermal contribution to the oceanic dissolved iron inventory , 2010 .

[32]  E. Achterberg,et al.  Large-scale distribution of Atlantic nitrogen fixation controlled by iron availability , 2009 .

[33]  E. Pulido-Villena,et al.  Dust iron dissolution in seawater: Results from a one‐year time‐series in the Mediterranean Sea , 2008 .

[34]  K. Bruland,et al.  Elevated Fe(II) and dissolved Fe in hypoxic shelf waters off Oregon and Washington: an enhanced source of iron to coastal upwelling regimes. , 2008, Environmental science & technology.

[35]  P. Boyd,et al.  Iron-binding ligands and their role in the ocean biogeochemistry of iron , 2007 .

[36]  K. Furuya,et al.  Iron regeneration and organic iron(III)-binding ligand production during in situ zooplankton grazing experiment , 2007 .

[37]  P. Boyd,et al.  Spinning the “Ferrous Wheel”: The importance of the microbial community in an iron budget during the FeCycle experiment , 2005 .

[38]  N. Mahowald,et al.  Atmospheric global dust cycle and iron inputs to the ocean , 2005 .

[39]  T. Moutin,et al.  Re-examination of the MAGIC method to determine low orthophosphate concentration in seawater , 2005 .

[40]  K. Coale,et al.  The flux of iron from continental shelf sediments: A missing source for global budgets , 2004 .

[41]  T. Waite,et al.  Effect of dissolved natural organic matter on the kinetics of ferrous iron oxygenation in seawater. , 2003, Environmental science & technology.

[42]  P. Croot,et al.  Continuous shipboard determination of Fe(II) in polar waters using flow injection analysis with chemiluminescence detection , 2002 .

[43]  Maria Włodarska-Kowalczuk,et al.  The marine ecosystem of Kongsfjorden, Svalbard , 2002 .

[44]  D. Turner,et al.  The Biogeochemistry of Iron in Seawater , 2001 .

[45]  F. Millero,et al.  The effect of organic compounds in the oxidation kinetics of Fe(II) , 2000 .

[46]  D. King,et al.  Role of carbonate speciation on the oxidation of Fe(II) by H2O2 , 2000 .

[47]  Xuewu Liu,et al.  The solubility of iron hydroxide in sodium chloride solutions , 1999 .

[48]  D. Kirchman.  Microbial ferrous wheel , 1996, Nature.

[49]  C. V. D. Berg.  Evidence for organic complexation of iron in seawater , 1995 .

[50]  M. Gledhill,et al.  Measurement of the redox speciation of iron in seawater by catalytic cathodic stripping voltammetry , 1995 .

[51]  W. Sunda,et al.  Iron uptake and growth limitation in oceanic and coastal phytoplankton , 1995 .

[52]  K. Bruland,et al.  Complexation of iron(III) by natural organic ligands in the Central North Pacific as determined by a new competitive ligand equilibration/adsorptive cathodic stripping voltammetric method , 1995 .

[53]  F. Millero,et al.  Rates and Mechanism of Fe(II) Oxidation at Nanomolar Total Iron Concentrations. , 1995, Environmental science & technology.

[54]  N. Welschmeyer.  Fluorometric analysis of chlorophyll a in the presence of chlorophyll b and pheopigments , 1994 .

[55]  R. Geider,et al.  The role of iron in phytoplankton photosynthesis, and the potential for iron-limitation of primary productivity in the sea , 1994, Photosynthesis Research.

[56]  D. O’Sullivan,et al.  Measurement of Fe(II) in surface water of the equatorial Pacific , 1991 .

[57]  O. Donard,et al.  The photolysis of colloidal iron in the oceans , 1991, Nature.

[58]  W. Sunda,et al.  Low iron requirement for growth in oceanic phytoplankton , 1991, Nature.

[59]  S. Fitzwater,et al.  Iron deficiency limits phytoplankton growth in Antarctic waters , 1990 .

[60]  F. Millero,et al.  The oxidation of Fe(II) with H2O2 in seawater , 1989 .

[61]  F. Millero,et al.  The oxidation kinetics of Fe(II) in seawater , 1987 .

[62]  F. Millero,et al.  Oxidation of iron (II) nanomolar with H2O2 in seawater , 2005 .

[63]  P. Falkowski,et al.  Iron limitation of phytoplankton photosynthesis in the equatorial Pacific Ocean , 1994, Nature.

[64]  S. Fitzwater,et al.  Iron deficiency limits phytoplankton growth in the north-east Pacific subarctic , 1988, Nature.

[65]  K. Bruland,et al.  The contrasting biogeochemistry of iron and manganese in the Pacific Ocean , 1987 .

[66]  M. E. L C H O R G O N Z A Ä L E Z-D A Ä V I L A, † A N D.  Oxidation of Nanomolar Levels of Fe ( II ) with Oxygen in Natural Waters , 2022 .