Laboratório de Estudos dos Oceanos e Clima (LEOC), Instituto de Oceanografia, Universidade Federal do Rio Grande - FURG, Rio Grande, RS, 96203-900, Brazil.
Laboratório de Estudos dos Oceanos e Clima (LEOC), Instituto de Oceanografia, Universidade Federal do Rio Grande - FURG, Rio Grande, RS, 96203-900, Brazil; Laboratório de Fitoplâncton e Microorganismos Marinhos, Instituto de Oceanografia, Universidade Federal do Rio Grande (FURG), Av. Itália km 8, Rio Grande, 96203-900, RS, Brazil.
Mar Environ Res. 2019 Feb;144:154-165. doi: 10.1016/j.marenvres.2018.12.003. Epub 2018 Dec 21.
This study describes the pigment-based phytoplankton community within three South Atlantic anticyclonic eddies (at different ages) shed from the Agulhas Current retroflection crossing the South Atlantic Ocean. Seawater samples were collected over these mesoscale structures in June-July 2015 during the Following Ocean Rings in the South Atlantic (FORSA) cruise. Data on phytoplankton pigments, measured with high-performance liquid chromatography (HPLC), were processed using a chemical taxonomy (CHEMTAX) tool to determine and quantify phytoplankton taxonomic groups. In addition, physical (water column structure) and chemical (macronutrient) parameters were determined and related to the biological data. Our results showed that, in general, the community was composed mostly of small flagellates (haptophytes) and prokaryotes (Prochlorococcus) and that pelagophytes were prominent in the younger eddy. This ring, located in the eastern basin of the South Atlantic Ocean, represented a younger and stronger structure, with no evident deep chlorophyll maximum (DCM) depth and an evenly distributed biomass over a well-mixed upper layer, revealing a more diverse phytoplankton community. The weakened structures of the older western eddies presented a pronounced DCM depth below 100 m and similar phytoplankton community composition patterns marked by enhanced Prochlorococcus contributions but also the important occurrences of haptophytes at the DCM depth and Synechococcus and chlorophytes at the surface. The community distributions in all three structures were associated with the distribution of nutrients and acclimation to light conditions. This study contributes to a better understanding of the phytoplankton distribution and its association with the presence of mesoscale anticyclonic eddies in an undersampled and complex region of the South Atlantic Ocean.
本研究描述了南大西洋反气旋涡旋（处于不同年龄阶段）中的色素浮游植物群落，这些涡旋是从穿越南大西洋的阿古拉斯 Current 折返处分离出来的。在 2015 年 6 月至 7 月的 Following Ocean Rings in the South Atlantic（FORSA）考察期间，在这些中尺度结构上采集了海水样本。使用高效液相色谱法（HPLC）测量的浮游植物色素数据，通过化学分类学（CHEMTAX）工具进行处理，以确定和量化浮游植物分类群。此外，还测定了物理（水柱结构）和化学（大量营养物）参数，并将其与生物数据相关联。我们的结果表明，一般来说，该群落主要由小型鞭毛藻（甲藻）和原核生物（聚球藻）组成，而在较年轻的涡旋中，浮游植物更为突出。这个位于南大西洋东部盆地的环，代表了一个较年轻和较强的结构，没有明显的深层叶绿素最大值（DCM）深度，并且在一个充分混合的上层中均匀分布的生物量，显示出一个更加多样化的浮游植物群落。较老的西部环的结构较弱，在 100m 以下出现明显的 DCM 深度，并且浮游植物群落组成模式相似，表现为聚球藻的贡献增强，但也在 DCM 深度出现重要的甲藻和在表面出现的蓝藻和绿藻。所有三个结构中的群落分布与营养物质的分布以及对光条件的适应有关。本研究有助于更好地了解浮游植物的分布及其与南大西洋未充分采样和复杂区域中中尺度反气旋涡旋的存在的关联。
