@article{fdi:010071322,
  title = {{O}xidation of {N}i-{R}ich mangrove sediments after isolation from the sea ({D}umbea {B}ay, {N}ew {C}aledonia) : {F}e and {N}i behavior and environmental implications},
  author = {{N}oel, {V}. and {J}uillot, {F}arid and {M}orin, {G}. and {M}archand, {C}yril and {O}na-{N}guema, {G}. and {V}iollier, {E}. and {P}revot, {F}. and {D}ublet, {G}. and {M}aillot, {F}. and {D}elbes, {L}. and {M}arakovic, {G}. and {B}argar, {J}. {R}. and {B}rown, {G}. {E}.},
  editor = {},
  language = {{ENG}},
  abstract = {{F}ormation of {F}e-sulfides in anoxic horizons of mangrove sediments makes this ecosystem a potential long-term sink for metal contaminants in the intertropical region. {I}ncreasing anthropogenic pressure on coastal areas can alter the physicochemical of mangrove sediments by modifying their redox state, affecting directly the rate of {F}e-sulfides that mediate accumulation of metal contaminant. {H}ere, we show that isolation from the sea, due to land use planning, directly modify the redox state of mangrove sediments from reducing condition to oxidizing condition, affecting the stability of {N}i-accumulating {F}e-sulfides. {U}nusual suboxic/oxic conditions are indeed observed at intermediate depths in these mangrove sediments and favor the oxidative dissolution of {N}i-pyrite ({F}e1-x{N}ix{S}2) that initially formed under anoxic/suboxic conditions. {T}his reaction leads to a significant release of aqueous {HS}-, {F}e2+ and {N}i2+ at the redox boundary. {HS}- and {F}e2+ oxidize into {SO}42- and {F}e3+ and precipitate as schwertmannite ({F}e8{O}8({OH})(6){SO}4), leading to acidification of the pore-waters. {M}eanwhile, aqueous {N}i2+ is mostly leached downward in the underlying anoxic layers of the sediment where it sorbs at the surface of pyrite and/or incorporates in the structure of newly formed pyrites. {T}hese results emphasize the potential of {F}e-sulfides for mitigating the impact of the oxidation of former {N}i-rich mangrove sediments, as long as the anoxic conditions are preserved at depth. {T}his assumption can be expanded to other divalent metals and should be applicable to a larger set of mangrove ecosystems worldwide.},
  keywords = {{M}angrove sediments ; oxidation processes ; iron and nickel ; {X}-ray ; absorption spectroscopy ; anthropogenic pressure ; pyrite ; {NOUVELLE} {CALEDONIE} ; {DUMBEA} {BAIE}},
  booktitle = {},
  journal = {{ACS} {E}arth and {S}pace {C}hemistry},
  volume = {1},
  numero = {8},
  pages = {455--464},
  ISSN = {2472-3452},
  year = {2017},
  DOI = {10.1021/acsearthspacechem.7b00005},
  URL = {https://www.documentation.ird.fr/hor/fdi:010071322},
}