Pico and nanoplankton abundance and carbon stocks along the Brazilian Bight

PeerJ

article

Adriana Lopes dos Santos¹  Dominique Marie¹  Vivian Helena Pellizari²  Frederico Pereira Brandini²  Daniel Vaulot¹  Catherine Gérikas Ribeiro² 

[1] Sorbonne Universités, UPMC Université Paris 06, CNRS, UMR 7144, Station Biologique de Roscoff;Departamento de Oceanografia Biológica, Instituto Oceanográfico, Universidade de São Paulo

关键词: Picoplankton;    Nanoplankton;    Prochlorococcus;    Synechococcus;    Heterotrophic bacteria;    Flow cytometry;    Southwest Atlantic Ocean off Brazil;   

DOI  :  10.7717/peerj.2587

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

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°S to 31°S and 39°W to 49°W. Heterotrophic bacteria (including archaea, maximum of 1.5 × 106 cells mL−1) were most abundant in Coastal and Tropical Water whereas Prochlorococcus was most abundant in open-ocean oligotrophic waters (maximum of 300 × 103 cells mL−1). Synechococcus(up to 81 × 103 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 × 103 cells mL−1 and 5 × 103 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.

【 授权许可】

CC BY