@article{PAR00005958,
  title = {{I}n vitro simulation of oxic/suboxic diagenesis in an estuarine fluid mud subjected to redox oscillations},
  author = {{A}bril, {G}wena{\¨e}l and {C}ommarieu, {M}. {V}. and {E}tcheber, {H}. and {D}eborde, {J}. and {D}eflandre, {B}. and {Z}ivadinovic, {M}. {K}. and {C}haillou, {G}. and {A}nschutz, {P}.},
  editor = {},
  language = {{ENG}},
  abstract = {{E}stuarine turbidity maxima ({ETM}s) are sites of intense mineralisation of land-derived particulate organic matter ({OM}), which occurs under oxic/suboxic oscillating conditions owing to repetitive sedimentation and resuspension cycles at tidal and neap-spring time scales. {T}o investigate the biogeochemical processes involved in {OM} mineralisation in {ETM}s, an experimental set up was developed to simulate in vitro oxic/anoxic oscillations in turbid waters and to follow the short timescale changes in oxygen, carbon, nitrogen, and manganese concentration and speciation. {W}e present here the results of a 27-day experiment (three oxic periods and two anoxic periods) with an estuarine fluid mud from the {G}ironde estuary. {T}ime courses of chemical species throughout the experiment evidenced the occurrence of four distinct characteristic periods with very different properties. {S}teady oxic conditions were characterised by oxygen consumption rates between 10 and 40 mu mol {L}-1 h(-1), dissolved inorganic carbon ({DIC}) production of 9-12 mu mol {L}-1 h(-1), very low {NE}4+ and {M}n2+ concentrations, and constant {NO}3 production rates (0.4 - 0.7 mu mol {L}-1 h(-1)) due to coupled ammonification and nitrification. {T}he beginning of anoxic periods (24 h following oxic to anoxic switches) showed {DIC} production rates of 2.5-8.6 mu mol {L}-1 h(-1) and very fast {NO} consumption (5.6-6.3 mu mol {L}-1 h(-1)) and {NH}4+ production (1.4-1.5 mu mol {L}-1 h(-1)). {T}he latter rates were positively correlated to {NO} concentration and were apparently caused by the predominance of denitrification and dissimilatory nitrate reduction to ammonia. {S}teady anoxic periods were characterised by constant and low {NO}3- concentrations and {DIG} and {NH}4+ productions of less than 1.3 and 0.1 mu mol {L}-1 h(-1), respectively. {M}n2+ and {CH}4 were produced at constant rates (respectively 0.3 and 0.015 mu mol {L}-1 h(-1)) throughout the whole anoxic periods and in the presence of nitrate. {F}inally, reoxidation periods (24-36 h following anoxic to oxic switches) showed rapid {NH}4+ and {M}n2+ decreases to zero (1.6 and 0.8-2 mu mol {L}-1 h(-1), respectively) and very fast {NO} production (3 mu mol {L}-1 h(-1)). {T}his {NO}3- production, together with marked transient peaks of dissolved organic carbon a few hours after anoxic to oxic switches, suggested that particulate {OM} mineralisation was enhanced during these transient reoxidation periods. {A}n analysis based on {C} and {N} mass balance suggested that redox oscillation on short time scales (day to week) enhanced {OM} mineralisation relative to both steady oxic and steady anoxic conditions, making {ETM}s efficient biogeochemical reactors for the mineralisation of refractory terrestrial {OM} at the land-sea interface.},
  keywords = {{OM} mineralisation ; redox oscillations ; estuarine turbidity maximum},
  booktitle = {},
  journal = {{E}stuarine {C}oastal and {S}helf {S}cience},
  volume = {88},
  numero = {2},
  pages = {279--291},
  ISSN = {0272-7714},
  year = {2010},
  DOI = {10.1016/j.ecss.2010.04.003},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00005958},
}