The influence of long emersion on biota, ammonium fluxes and nitrification in intertidal sediments of Marennes-Oléron Bay, France.

摘要: A comparative study between waterlogged and reflooded intertidal sediments was undertaken in March June 1999 through statistical analysis of selected sediment parameters (biota, salinity, O2, Eh), pool sizes benthic fluxes nutrients (NH4+, NO2−, NO3−) nitrification rates. In samples, absence polychaetes oligochaetes from upper horizons were due to erosional events sweeping away surface sediments. Presence richer annelid assemblages samples indicated more stable hydrodynamic conditions that favoured the development microalgae biofilms. Dewatering during a 3-day emersion period promoted salinity rise on top layers, migration pore water ions towards surface, created fissures accelerated exchange reflooding. Reflooded systems comparable with respect release NH4+ overlying but different Sediment-water higher (P=0.011) (3.3 mmol m−2 day−1) compared (1.4 macrofauna biomasses lower concentrations samples. Potential rates (range 19 60 NO3− not statistically June. thinner oxic layer reflects decrease O2 diffusion into at high salinities which resulted fall actual (P<0.05). Our data suggest long term dessication may depress process ecosystem level.