@article{fdi:010058816,
  title = {{E}xtreme iron isotope fractionation between colloids and particles of boreal and temperate organic-rich waters},
  author = {{I}lina, {S}. {M}. and {P}oitrasson, {F}ranck and {L}apitskiy, {S}. {A}. and {A}lekhin, {Y}. {V}. and {V}iers, {J}. and {P}okrovsky, {O}. {S}.},
  editor = {},
  language = {{ENG}},
  abstract = {{S}ignificant and systematic variations of iron isotopic composition in surface water sample fractions obtained by frontal cascade filtration and ultrafiltration have been recorded in (1) subarctic organic-rich boreal river and stream, mire, lake and soil solutions in northern taiga zone ({K}arelia, {NW} {R}ussia) and (2) temperate river and lake waters of the southern boreal zone ({C}entral {R}ussia). {W}ater samples were filtered in the field employing progressively decreasing pore size from 100 mu m to 1 k{D}a followed by iron isotope analysis. {I}n all river samples, there was a gradual increase of delta {F}e-57 relative to {IRMM}-14 with decreasing pore size, from +0.4 +/- 0.1 parts per thousand at 100 mu m up to +4.2 +/- 0.1 parts per thousand at 10 k{D}a fraction in the subarctic zone and from -0.024 +/- 0.2 parts per thousand at 100 mu m up to +1.2 +/- 0.2 parts per thousand at 10 k{D}a in the temperate zone. {I}n the series of filtrates/ultrafiltrates of subarctic and temperate streams and rivers, the delta {F}e-57 value decreases with increasing molar {F}e/{C}-org ratio. {T}herefore, small-size, {F}e-poor, {C}-rich colloids (1-10 k{D}a) and {L}ow {M}olecular {W}eight ({LMW}) fractions of oxygenated water exhibit strong enrichment in heavy isotope whereas {H}igh {M}olecular {W}eight {F}e-rich colloids (100 k{D}a-0.22 mu m) and particles (1-100 mu m) are isotopically lighter and closer to the continental crust {F}e isotope composition. {T}he relative enrichment of 1-10 k{D}a ultrafiltrates in heavy isotopes suggests that low molecular weight ligands bind {F}e more strongly ({F}e-{O}-{C} bonds) than {F}e({III})oxy(hydr)oxides ({F}e-{O}-{F}e bonds), in accord with quantum mechanics principles. {H}ighly positive delta {F}e-57 of the {LMW} fraction of labile and potentially bioavailable {F}e in small subarctic rivers may turn out to be a very important source of isotopically heavy {F}e in the {A}rctic {O}cean. {T}he mechanisms involved in the production of this isotopically heavy {F}e may lead this tracer to become a new indicator of environmental changes occurring in the boreal zone.},
  keywords = {{RUSSIE}},
  booktitle = {},
  journal = {{G}eochimica et {C}osmochimica {A}cta},
  volume = {101},
  numero = {},
  pages = {96--111},
  ISSN = {0016-7037},
  year = {2013},
  DOI = {10.1016/j.gca.2012.10.023},
  URL = {https://www.documentation.ird.fr/hor/fdi:010058816},
}