Pico and nanoplankton abundance and carbon stocks along the Brazilian Bight

Ribeiro, Catherine Gerikas; dos Santos, Adriana Lopes; Marie, Dominique; Pellizari, Vivian Helena; Brandini, Frederico Pereira; Vaulot, Daniel

Abstract

Pico and nanoplankton communities from the Southwest Atlantic Ocean along the Brazilian Bight are poorly described. The hydrography in this region is dominated by a complex system of layered water masses, which includes the warm and oligotrophic Tropical Water (TW), the cold and nutrient rich South Atlantic Central Water (SACW) and the Coastal Water (CW), which have highly variable properties. In order to assess how pico-and nanoplankton communities are distributed in these different water masses, we determined by flow cytometry the abundance of heterotrophic bacteria, Prochlorococcus, Synechococcus and autotrophic pico and nanoeukaryotes along three transects, extending from 23 degrees S to 31 degrees S and 39 degrees W to 49 degrees W. Heterotrophic bacteria (including archaea, maximum of 1.5 x 10(6) cells mL(-1)) were most abundant in Coastal and Tropical Water whereas Prochlorococcus was most abundant in open-ocean oligotrophic waters (maximum of 300 x 10(3) cells mL(-1)). Synechococcus (up to 81 x 10(3) cells mL(-1)), as well as autotrophic pico and nanoeukaryotes seemed to benefit from the influx of nutrient-rich waters near the continental slope. Autotrophic pico and nanoeukaryotes were also abundant in deep chlorophyll maximum (DCM) layers from offshore waters, and their highest abundances were 20 x 10(3) cells mL(-1) and 5 x 10(3) cells mL(-1), respectively. These data are consistent with previous observations in other marine areas where Synechococcus and autotrophic eukaryotes dominate mesotrophic waters, whereas Prochlorococcus dominate in more oligotrophic areas. Regardless of the microbial community structure near the surface, the carbon stock dominance by autotrophic picoeukaryotes near the DCM is possibly linked to vertical mixing of oligotrophic surface waters with the nutrient-rich SACW and their tolerance to lower light levels.

Más información

Título según WOS: ID WOS:000388082300001 Not found in local WOS DB
Título de la Revista: PEERJ
Volumen: 4
Editorial: PEERJ INC
Fecha de publicación: 2016
DOI:

10.7717/peerj.2587

Notas: ISI