Yearly variation of bacterial production in the Arraial do Cabo protection area (Cabo Frio upwelling region): An evidence of anthropogenic pressure

Arraial do Cabo is where upwelling occurs more intensively on the Brazilian coast. Although it is a protection area it suffers anthropogenic pressure such as harbor activities and sporadic sewage emis-sions. Short-time studies showed a high variability of bacterial production (BP) in this region but none of them evaluated BP during long periods in a large spatial scale including stations under differ-ent natural (upwelling and cold fronts) and anthropogenic pressures. During 2006, we sampled sur-face waters 10 times (5 in upwelling and 5 in subsidence periods) in 8 stations and we measured BP, temperature as well as the concentrations of inorganic nutrients, pigments and particulate organic matter (POM). BP was up to 400 times higher when sewage emissions were observed visually and it had a positive correlation with ammonia concentrations. Therefore, in 2007, we did two samples (each during upwelling and subsidence periods) during sewage emissions in five stations under dif-ferent anthropogenic pressure and we also measured particles abundance by flow cytometry. The 12 samples in the most impacted area confirmed that BP was highest when ammonia was higher than 2 M, also reporting the highest concentrations of chlorophyll a and suspended particles. However, considering all measured variables, upwelling was the main disturbing factor but the pressure o