@article{fdi:010076622,
  title = {{N}ickel and iron partitioning between clay minerals, {F}e-oxides and {F}e-sulfides in lagoon sediments from {N}ew {C}aledonia},
  author = {{M}errot, {P}. and {J}uillot, {F}arid and {N}oel, {V}. and {L}efebvre, {P}. and {B}rest, {J}. and {M}enguy, {N}. and {G}uigner, {J}. {M}. and {B}londeau, {M}. and {V}iollier, {E}. and {F}ernandez, {J}. {M}. and {M}oreton, {B}. and {B}argar, {J}. {R}. and {M}orin, {G}.},
  editor = {},
  language = {{ENG}},
  abstract = {{I}n the tropics, continental weathering and erosion are major sources of trace metals towards estuaries and lagoons, where early diagenesis of sediments may influence their mobility and bioavailability. {D}etermining trace metals speciation in tropical sedimentary settings is thus needed to assess their long-term fate and potential threat to fragile coastal ecosystems. {I}n this study, we determined {F}e, {N}i and {S} speciation across a shore-to-reef gradient in sediments from the {N}ew {C}aledonia lagoon that receive mixed contribution from lateritic (iron-oxyhydroxides and clay minerals), volcano-sedimentary (silicates) and marine (carbonate) sources. {S}ulfur {K}edge {XANES} data indicated a major contribution of pyrite ({F}e{S}2) to {S} speciation close to the shore. {H}owever, this contribution was found to dramatically decrease across the shore-to-reef gradient, {S} mainly occurring as sulfate close to the coral reef. {I}n contrast, {F}e and {N}i {K}-edge {XANES} and {EXAFS} data indicated a minor contribution of pyrite to {F}e and {N}i speciation, and this contribution could be evidenced only close to the shore. {T}he major fractions of {F}e and {N}i across the shore-to-reef gradient were found to occur as {N}i- and {F}e-bearing clay minerals consisting of smectite (similar to nontronite), glauconite and two types of serpentines (chrysotile and greenalite/berthierine). {A}mong these clay minerals, greenalite/berthierine, glauconite and possibly smectite, were considered as authigenic. {T}he low contribution of pyrite to trace metals speciation compared to clay minerals is interpreted as a result of (1) a reduced formation rate due to the low amounts of organic carbon compared to the {F}e pool and (2) repeated re-oxidation events upon re-suspension of the sediments top layers due to the specific context of shallow lagoon waters. {T}his study thus suggests that green clay authigenesis could represent a key process in the biogeochemical cycling or trace metals that are delivered to lagoon ecosystems upon continental erosion and weathering.},
  keywords = {{L}agoon sediments ; {T}race metals ; {S}peciation ; {G}reen clays ; {TEM} ; {XAS} ; {NOUVELLE} {CALEDONIE}},
  booktitle = {},
  journal = {{S}cience of the {T}otal {E}nvironment},
  volume = {689},
  numero = {},
  pages = {1212--1227},
  ISSN = {0048-9697},
  year = {2019},
  DOI = {10.1016/j.scitotenv.2019.06.274},
  URL = {https://www.documentation.ird.fr/hor/fdi:010076622},
}