Estación de Fotobiología Playa Unión, Casilla de Correos 15, 9103, Rawson, Chubut, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
Centro de Investigación Mariña da Universidade de Vigo (CIM-UVigo), Illa de Toralla s/n, 36331, Vigo, Spain; Departamento de Ecología y Biología Animal, Universidade de Vigo, Facultad de Ciencias del Mar, Campus Lagoas Marcosende s/n, 36310, Vigo, Spain.
Mar Environ Res. 2021 Jan;163:105235. doi: 10.1016/j.marenvres.2020.105235. Epub 2020 Dec 7.
Rainfall events bring both, terrigenous materials (including DOM) and nutrients to the aquatic system (e.g., via riverine runoff) having potential effects on the structure and metabolism of the phytoplankton communities. As extreme rainfall events in Patagonia occurred more frequently in the last decade (2010-2019) as compared to the previous ones (1972-2009), we exposed winter and summer phytoplankton communities (using microcosms) to solar radiation, simulating two rainfall conditions - a single extreme vs. intermittent i.e., with gradual inputs, and we assessed their photosynthetic and growth rates responses and taxonomic changes. Rainfall scenarios significantly increased growth of both communities, mainly of small nanoplanktonic species, as compared to the control. Small nanoplanktonic centric diatoms increased and dominated in both rainfall scenarios, as compared to the control, during winter and summer, with significantly smaller cells during summer as compared to winter. Photosynthetic efficiency increased in both rainfall scenarios at the end of the experiment as compared to the control. Overall, the change towards small cells (associated to rainfall events) that can use more effectively solar radiation and nutrients (as compared to large cells) may have a significant impact on the trophic webs of the South West Atlantic Ocean by favoring grazing pressure by microzooplankton, especially during summer.
降雨事件将陆源物质（包括 DOM）和营养物质带入水生系统（例如，通过河流径流），对浮游植物群落的结构和代谢产生潜在影响。由于与前一个十年（1972-2009 年）相比，巴塔哥尼亚的极端降雨事件在过去十年（2010-2019 年）更为频繁，我们使用微宇宙将冬季和夏季浮游植物群落暴露在太阳辐射下，模拟两种降雨条件——单一极端与间歇性，即逐渐输入，然后评估它们的光合作用和生长速率响应和分类变化。与对照相比，降雨情景显著增加了两个群落的生长，主要是小型纳米浮游植物物种。与对照相比，冬季和夏季的小型纳米中心硅藻在两种降雨情景中均增加并占主导地位，夏季的细胞明显小于冬季。与对照相比，实验结束时两种降雨情景下的光合作用效率都有所提高。总的来说，向可以更有效地利用太阳辐射和营养物质的小细胞（与降雨事件相关）的转变（与大细胞相比）可能会对西南大西洋的营养网产生重大影响，特别是在夏季，通过促进微浮游动物的摄食压力。
