Busca avançada
Ano de início
Entree


Anomalous trend of chlorophyll-a as a response to mesoscale phenomena in a Brazilian ria

Texto completo
Autor(es):
Berbel, G. B. B. ; Chiozzini, V. G. ; Jovane, L. ; Braga, E. S.
Número total de Autores: 4
Tipo de documento: Artigo Científico
Fonte: CONTINENTAL SHELF RESEARCH; v. 269, p. 12-pg., 2023-11-14.
Resumo

Saco do Mamangu ' a is a tropical Brazilian ria characterized by low nutrient availability and subject to seasonal thermocline, which is mainly influenced by the intrusion of South Atlantic Central Water (SACW) on the continental shelf. Sampling was performed in summer (2014, 2015) and spring (2017). The dissolved inorganic and organic nutrients (nitrogen [N] and phosphorus [P]), along with chlorophyll-a (Chl-a), were evaluated to characterize this area. As a result, the general trophic condition of Saco do Mamangu ' a is a meso-oligotrophic ria with low Chl-a concentrations. Due to the presence of an atmospheric phenomena that causes an extremely dry period during the summer of 2014, a strong thermocline was observed in the water column which was associated with high Chl-a concentrations (median of 6.14 mg m-3). These values were much higher than those observed during the summer of 2015 and in the spring of 2017 (median of 1.03 mg m-3). The dissolved inorganic nutrients presented low values in all studied periods with concentrations of nitrate (0.00-0.20 mu mol L-1) and phosphate (0.00-0.20 mu mol L-1). A wide range of dissolved organic compounds were also observed, as shown by the presence of dissolved organic carbon (DOC), which varied from 63 to 212 mu mol L-1; dissolved organic nitrogen (DON), which varied from 2.97 to 12.92 mu mol L-1; and dissolved organic phosphorus (DOP), which reached a maximum value of 0.63 mu mol L-1. DON and DOP represented at least 50% total dissolved N and P. In this region, the biogeochemical cycles of N and P could ensure the availability of regenerated nutrients from organic sources to support primary production of phytoplankton. (AU)

Processo FAPESP: 11/22018-3 - Avaliação da produtividade primária marinha através do estudo das bactérias magnetotáticas em sedimentos
Beneficiário:Luigi Jovane
Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Jovens Pesquisadores