skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Iron Isotope Fractionation during Fe(II) Oxidation Mediated by the Oxygen-Producing Marine Cyanobacterium Synechococcus PCC 7002

Journal Article · · Environmental Science and Technology
ORCiD logo [1];  [2];  [3];  [4];  [2];  [2];  [5];  [2]; ORCiD logo [2];  [2];  [2]
  1. Iowa State Univ., Ames, IA (United States)
  2. Univ. of Tuebingen (Germany)
  3. Univ. of Tuebingen (Germany); Chinese Academy of Sciences, Guiyang (China)
  4. Univ. of Bayreuth (Germany)
  5. Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

In this study, we couple iron isotope analysis to microscopic and mineralogical investigation of iron speciation during circumneutral Fe(II) oxidation and Fe(III) precipitation with photosynthetically produced oxygen. In the presence of the cyanobacterium Synechococcus PCC 7002, aqueous Fe(II) (Fe(II)aq) is oxidized and precipitated as amorphous Fe(III) oxyhydroxide minerals (iron precipitates, Feppt), with distinct isotopic fractionation (ε56Fe) values determined from fitting the δ56Fe(II)aq (1.79‰ and 2.15‰) and the δ56Feppt (2.44‰ and 2.98‰) data trends from two replicate experiments. Additional Fe(II) and Fe(III) phases were detected using microscopy and chemical extractions and likely represent Fe(II) and Fe(III) sorbed to minerals and cells. The iron desorbed with sodium acetate (FeNaAc) yielded heavier δ56Fe compositions than Fe(II)aq. Modeling of the fractionation during Fe(III) sorption to cells and Fe(II) sorption to Feppt, combined with equilibration of sorbed iron and with Fe(II)aq using published fractionation factors, is consistent with our resulting δ56FeNaAc. The δ56Feppt data trend is inconsistent with complete equilibrium exchange with Fe(II)aq. Because of this and our detection of microbially excreted organics (e.g., exopolysaccharides) coating Feppt in our microscopic analysis, we suggest that electron and atom exchange is partially suppressed in this system by biologically produced organics. These results indicate that cyanobacteria influence the fate and composition of iron in sunlit environments via their role in Fe(II) oxidation through O2 production, the capacity of their cell surfaces to sorb iron, and the interaction of secreted organics with Fe(III) minerals.

Research Organization:
Argonne National Laboratory (ANL), Argonne, IL (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)
Grant/Contract Number:
AC02-06CH11357
OSTI ID:
1372246
Journal Information:
Environmental Science and Technology, Vol. 51, Issue 9; ISSN 0013-936X
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
ENGLISH
Citation Metrics:
Cited by: 27 works
Citation information provided by
Web of Science

References (59)

Iron adsorption onto soil and aquatic bacteria: XAS structural study journal April 2014
Tracing the stepwise oxygenation of the Proterozoic ocean journal March 2008
The impact of ocean deoxygenation on iron release from continental margin sediments journal May 2014
Characterization of the physiology and cell-mineral interactions of the marine anoxygenic phototrophic Fe(II) oxidizer Rhodovulum iodosum - implications for Precambrian Fe(II) oxidation journal March 2014
Iron Isotope Constraints on the Archean and Paleoproterozoic Ocean Redox State journal February 2005
Physiology, Fe(II) oxidation, and Fe mineral formation by a marine planktonic cyanobacterium grown under ferruginous conditions journal October 2015
The effect of silica and natural organic matter on the Fe(II)-catalysed transformation and reactivity of Fe(III) minerals journal August 2009
Iron isotope fractionation between aqueous Fe(II) and goethite revisited: New insights based on a multi-direction approach to equilibrium and isotopic exchange rate modification journal August 2014
Stable Iron Isotope Fractionation Between Aqueous Fe(II) and Hydrous Ferric Oxide journal March 2011
Biogeochemistry of Fe(II) oxidation in a photosynthetic microbial mat: Implications for Precambrian Fe(II) oxidation journal October 2007
Fe Isotope Variations in the Modern and Ancient Earth and Other Planetary Bodies journal January 2004
Comparison of iron isotope variations in modern and Ordovician siliceous Fe oxyhydroxide deposits journal February 2014
Iron isotope fractionation and atom exchange during sorption of ferrous iron to mineral surfaces journal April 2009
An assessment of the accuracy of stable Fe isotope ratio measurements on samples with organic and inorganic matrices by high-resolution multicollector ICP-MS journal April 2005
Iron isotopes constrain biologic and abiologic processes in banded iron formation genesis journal January 2008
Iron isotope fractionation during Fe(II) and Fe(III) adsorption on cyanobacteria journal April 2015
Evidence for equilibrium iron isotope fractionation by nitrate-reducing iron(II)-oxidizing bacteria journal May 2010
The Iron Isotope Fingerprints of Redox and Biogeochemical Cycling in Modern and Ancient Earth journal May 2008
Iron isotopes in the early marine diagenetic iron cycle journal January 2006
Structural constraints of ferric (hydr)oxides on dissimilatory iron reduction and the fate of Fe(II) journal August 2004
Applying Stable Isotope Fractionation Theory to New Systems journal January 2004
Coupled Fe(II)−Fe(III) Electron and Atom Exchange as a Mechanism for Fe Isotope Fractionation during Dissimilatory Iron Oxide Reduction journal September 2005
Spectroscopic Evidence for Fe(II)−Fe(III) Electron Transfer at the Iron Oxide−Water Interface journal September 2004
Iron isotope fractionation during microbially stimulated Fe(II) oxidation and Fe(III) precipitation journal February 2006
Iron Isotope Biosignatures journal September 1999
Binding of heavy metal ions in aggregates of microbial cells, EPS and biogenic iron minerals measured in-situ using metal- and glycoconjugates-specific fluorophores journal May 2016
The interplay of microbially mediated and abiotic reactions in the biogeochemical Fe cycle journal October 2014
Evidence for free oxygen in the Neoarchean ocean based on coupled iron–molybdenum isotope fractionation journal June 2012
Late-Neoproterozoic Deep-Ocean Oxygenation and the Rise of Animal Life journal January 2007
Iron Isotope Characteristics of Hot Springs at Chocolate Pots, Yellowstone National Park journal November 2013
The role of reduction in iron uptake processes in a unicellular, planktonic cyanobacterium journal September 2011
Iron isotopes in an Archean ocean analogue journal May 2014
The mechanisms of iron isotope fractionation produced during dissimilatory Fe(III) reduction by Shewanella putrefaciens and Geobacter sulfurreducens journal June 2007
Quantification of dissolved iron sources to the North Atlantic Ocean journal July 2014
Expanding Oxygen-Minimum Zones in the Tropical Oceans journal May 2008
ScatterJ: An ImageJ plugin for the evaluation of analytical microscopy datasets journal December 2014
Ocean oxygenation in the wake of the Marinoan glaciation journal September 2012
Iron isotope fractionation by Fe(II)-oxidizing photoautotrophic bacteria 1 1Associate editor: D. E. Canfield journal March 2004
Manganese and Iron Oxidation During Benthic Oxygenic Photosynthesis journal December 1998
Modern iron isotope perspective on the benthic iron shuttle and the redox evolution of ancient oceans journal January 2008
Ferruginous Conditions: A Dominant Feature of the Ocean through Earth's History journal April 2011
Fractionation of Fe isotopes during Fe(II) oxidation by a marine photoferrotroph is controlled by the formation of organic Fe-complexes and colloidal Fe fractions journal September 2015
A Comparative Study of Iron Uptake Rates and Mechanisms amongst Marine and Fresh Water Cyanobacteria: Prevalence of Reductive Iron Uptake journal March 2015
Use of Superoxide as an Electron Shuttle for Iron Acquisition by the Marine Cyanobacterium Lyngbya majuscula journal April 2005
Iron isotope fractionation between aqueous ferrous iron and goethite journal June 2010
Experimental constraints on Fe isotope fractionation during magnetite and Fe carbonate formation coupled to dissimilatory hydrous ferric oxide reduction journal February 2005
Secondary mineralization pathways induced by dissimilatory iron reduction of ferrihydrite under advective flow journal August 2003
FeIIaq–FeIIIoxide electron transfer and Fe exchange: effect of organic carbon journal January 2015
The effect of pH on stable iron isotope exchange and fractionation between aqueous Fe(II) and goethite journal March 2015
Modulation of oxygen production in Archaean oceans by episodes of Fe(II) toxicity journal January 2015
Pelagic photoferrotrophy and iron cycling in a modern ferruginous basin journal September 2015
Ferrozine---a new spectrophotometric reagent for iron journal June 1970
An rhodamine-based fluorescence probe for iron(III) ion determination in aqueous solution journal March 2010
Tuning the Selectivity of Two Chemosensors to Fe(III) and Cr(III) journal September 2007
3-D analysis of bacterial cell-(iron)mineral aggregates formed during Fe(II) oxidation by the nitrate-reducing Acidovorax sp . strain BoFeN1 using complementary microscopy tomography approaches journal May 2014
Oxygenation of Ferrous Iron journal February 1961
Isolation and characterization of exopolysaccharide produced byVibrio harveyistrain VB23 journal November 2006
Kinetic and equilibrium Fe isotope fractionation between aqueous Fe(II) and Fe(III) journal November 2003
Iron isotope composition of some Archean and Proterozoic iron formations journal March 2012

Cited By (1)

Iron Isotope Fractionation during Bio- and Photodegradation of Organoferric Colloids in Boreal Humic Waters journal September 2019

Similar Records

Effect of Aqueous Fe(II) on Arsenate Sorption on Goethite and Hematite
Journal Article · Thu Nov 17 00:00:00 EST 2011 · Environmental Science and Technology · OSTI ID:1372246

Arsenic mobilization by the dissimilatory Fe(III)-reducing bacterium Shewanella alga BrY
Journal Article · Mon Mar 01 00:00:00 EST 1999 · Environmental Science and Technology · OSTI ID:1372246

Citrate Controls Fe(II)-Catalyzed Transformation of Ferrihydrite by Complexation of the Labile Fe(III) Intermediate
Journal Article · Tue Jun 16 00:00:00 EDT 2020 · Environmental Science & Technology · OSTI ID:1372246