Inorganic carbon fluxes at the water–sediment interface in five littoral systems in Spain (southern Europe)

The benthic fluxes of dissolved inorganic carbon have been measured in five different littoral ecosystems in Spain (Southern Europe). The values measured by means of benthic chambers ranged between 30 and 378 mmol m−2 d−1 and may be considered relatively high. They were linearly correlated with the organic carbon content in surface sediments. The concentration of dissolved inorganic carbon in interstitial water presents a strong vertical gradient (30 mM at 25 cm), with diffusive fluxes between 0.1 and 14.1 mmol m−2 d−1. The comparison between diffusive fluxes and benthic chamber (in situ) fluxes shows the important role of the benthic macrofauna irrigation processes in relation to species exchange across the sediment-water interface.