Accumulation of phosphorus in coastal marine sediments: relationship to benthic and diffusive fluxes

摘要

Sedimentary phosphorus was characterized in sediment cores from 3 coastal ecosystems of the Gulf of Cadiz High spatial variability was observed in total phosphorus (from 445 to 20291 mu g g sed (1)) and in the other phosphorus phases studied This variability correlates with the proximity of the 10 sampling stations to sources of urban and/or industrial effluent in the zone The benthic and diffusive fluxes were measured concurrently with sediment collection at these stations The measured values of benthic fluxes range between -14 and 6 mmol m (2) d (1) Generally stations that showed increased interstitial phosphate concentrations with increasing depth were characterized by positive values in phosphate benthic fluxes and by high percent ages of reactive forms of sedimentary phosphorus Negative benthic fluxes were associated with stations receiving more anthropogenic matter which showed progressively decreasing phosphate concentrations in the interstitial water with depth In these anthropogenic areas the non reactive forms of phosphorus (those associated with ferric oxyhydroxide and authigenic carbonate fluorapatite) are abundant and reach values exceeding 75% of total phosphorus in sediment