Influence of an estuarine plume and marine sewage outfall on the dynamics of coastal bacterioplankton communities

摘要: Marine bacterioplankton in the coastal region off Aveiro (NW Portugal) develop under influence of plume a mesotrophic estuarine system (Ria de Aveiro) and, more recently, discharges marine sewage outfall (S. Jacinto). In an attempt to com- pare degree disturbance introduced by these 2 features abundance bacteria and heterotrophic activity natural bacterioplankton, water samples were collected at 10 offshore nearshore locations. Rates ectoenzymatic monomer incorporation deter- mined as proxies for potential bacterial communities. ATP chl concentrations used estimates total phytoplankton. Faecal coliforms colony counts indicators contamination. However, ATP, a, faecal coliforms, counts, aminopeptidase maximum rate leucine (leucine Vm) correlated negatively with linear distance mouth estuary, establishing importance source disturbance. Chl also outfall, but no significant impact on concentration could be detected. Compliance European Union Bathing Water Directive 76/160/EEC was achieved 97% samples. The ratio between β-glucosidase (polymer degradation) glucose (monomer uptake) increased from estuary increased. This indicates that, addition inputs nutrients, changes quality available organic substrates and/or sewage-related toxic effects may impose shift functioning communities this costal area.