Leopold A., Marchand Cyril, Deborde J., Chaduteau C., Allenbach M. (2013). Influence of mangrove zonation on CO2 fluxes at the sediment-air interface (New Caledonia). Geoderma, 202, p. 62-70. ISSN 0016-7061.
Titre du document
Influence of mangrove zonation on CO2 fluxes at the sediment-air interface (New Caledonia)
Leopold A., Marchand Cyril, Deborde J., Chaduteau C., Allenbach M.
Source
Geoderma, 2013,
202, p. 62-70 ISSN 0016-7061
Mangroves are the major ecosystems of tropical and subtropical coastlines. They are considered as a sink for atmospheric CO2 because they are characterized both by high net primary production, and by low rates of organic matter decomposition. However, a recent reassessment of the global mangrove budget suggests that organic carbon sinks have been underestimated, notably CO2 efflux from sediments and creek waters, and tidal export of dissolved inorganic carbon. Our objective was to understand the influence of mangrove zonation on the magnitude of CO2 fluxes at the sediment-air interface. Transparent and opaque dynamic closed chamber systems, coupled with an infra-red gas analyzer were used to measure CO2 fluxes. In addition, the physico-chemical properties (salinity, redox potential) of pore waters were determined, as well as the carbon content and the origin of surface sediments (Chlorophyll-a and delta C-13). Depending on the type of measurement (in the dark with or without biofilm, in the light with biofilm) and mangrove stand (saltflat, Avicennia sp., or Rhizophora spp.), mean surface sediment CO2 fluxes ranged between 40 +/- 56 and 199 +/- 95 mmol.m(-2).d(-1). We suggest that these differences mainly result both from the organic content and the redox conditions of the sediments, which are influenced by the physiological activities of the root system, and by the position and the elevation of the stand in the intertidal zone. In addition, the quality and abundance of biofilm, which also vary with the mangrove stand, also appear to strongly affect sediment CO2 fluxes as a result of chemical (metabolism) and also physical (barrier) processes.
Plan de classement
Ecologie, systèmes aquatiques [036]
;
Géologie et formations superficielles [064]
;
Etudes, transformation, conservation du milieu naturel [082]
