L'impatto di una piena fluviale di elevata intensità su un ecosistema marino costiero:relazioni tra gli apporti di origine alloctona e l'attività microbica

The coastal systems act as receptors basin of nutrients and pollutants generated by human activities. Microbial communities play an important role in the biogeochemical processes and in the pollutant biodegradation. Surface water samples were analysed for physical, chemical and microbial properties during a high intensity flood event along three transects perpendicular to the PO river delta. Under these conditions this area was moderately affected by PAHs pollution and enriched in organi matter of allochtonous origin. Prokaryote biomass increased according to salinity whereas prokaryote C production rate was inversely correlated . These results together with the inverse relation observed between cell specific production and d13C, , suggested that the riverine input can stimulate microbial metabolism. In conclusion, a high intensity river flood can alter the C-flux between the organic matter and the microbial cells with potential implications for the coastal marine system.