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）和养分同时带入水生系统（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。由于过去10年（2010-2019年）与先前（1972-2009年）相比，巴塔哥尼亚的极端降雨事件发生的频率更高，我们模拟了两种降雨条件，将冬季和夏季的浮游植物群落（使用缩影）暴露在太阳辐射下-单个极端条件与间歇条件，即逐步输入，我们评估了它们的光合作用和生长速率响应以及分类学变化。与对照相比，降雨情景显着增加了两个群落的增长，主要是小型纳米浮游生物。与降雨相比，在冬季和夏季，小型纳米浮游生物中心的硅藻在两种降雨情况下均增加并占主导地位，夏季与冬季相比，细胞明显较小。与对照组相比，实验结束时两种降雨情景下的光合效率均得到提高。总体而言，向小细胞（与降雨事件相关）的转变（可以与大细胞相比）可以更有效地利用太阳辐射和养分，这可能会通过有利于微带浮游生物的放牧压力而对西南大西洋的营养网产生重大影响。 ，尤其是在夏天。与对照组相比，实验结束时两种降雨情景下的光合效率均得到提高。总体而言，向小细胞（与降雨事件相关）的转变（可以与大细胞相比）可以更有效地利用太阳辐射和养分，这可能会通过有利于微带浮游生物的放牧压力而对西南大西洋的营养网产生重大影响。 ，尤其是在夏天。与对照组相比，实验结束时两种降雨情景下的光合效率均得到提高。总体而言，向小细胞（与降雨事件相关）的转变（可以与大细胞相比）可以更有效地利用太阳辐射和养分，这可能会通过有利于微带浮游生物的放牧压力而对西南大西洋的营养网产生重大影响。 ，尤其是在夏天。