title: Yearly variation of bacterial production in the Arraial do Cabo protection area (Cabo Frio upwelling region): an evidence of anthropogenic pressure.
abstract: 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 emissions. 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 different natural (upwelling and cold fronts) and anthropogenic pressures. During 2006, we sampled surface 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 different 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 μM, 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 of fronts should not be neglected since it had consequences in the auto-heterotrophic coupling, increasing the concentrations of non fluorescent particles and POM. Stations clustered in function of natural and anthropogenic pressures degrees and both determined the temporal-spatial variability.
authors.affiliation: Departamento de Biotecnologia Marinha, Instituto de Ciências do Mar Almirante Paulo Moreira, Arraial do Cabo, RJ, Brazil. ; Universidade de Santo Amaro, São Paulo, SP, Brazil. ; Laboratório de Traçadores, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Sérgio A
authors.initials: SA
authors.lastname: Coelho-Souza
authors.affiliation: Instituto Alberto Luiz Coimbra de Pós-Graduação e Pesquisa de Engenharia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Gilberto C
authors.initials: GC
authors.lastname: Pereira
authors.affiliation: Departamento de Biotecnologia Marinha, Instituto de Ciências do Mar Almirante Paulo Moreira, Arraial do Cabo, RJ, Brazil.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Coutinho
authors.affiliation: Laboratório de Traçadores, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Jean R D
authors.initials: JR
authors.lastname: Guimarães
mesh_terms: D001419:Bacteria / Q000254:growth & development*; D001938:Brazil; D052836:Heterotrophic Processes; D012623:Seawater / Q000382:microbiology*; D062211:Spatio-Temporal Analysis
keywords: bacterioplankton; extractive reserve; heterotrophic activity; impacted area; upwelling system