Temperature and light play a crucial role in regulating phytoplankton blooms in the Ocean. To assess the importance of these two parameters experimentally, microcosms were conducted on seven picoplankton communities sampled in December, March, June and September 2015 and 2016 in the North Western Mediterranean Sea. Each community was exposed to 4 realistic seasonal conditions (December, March, June and September). Metabarcoding was used to investigate the eukaryotic diversity in the 56 microcosms experiments in parallel to high-frequency monitoring of environmental diversity in the sea. The three major lineages identified were the Stramenopiles, Alveolata and Archaeplastida. Overall, the five-day incubations were not sufficient to reshape the initial microbial communities completely. The microcosm outcome was strongly influenced by the dynamics of phytoplankton starting communities. In pre-bloom conditions, phytoplanktonic species were the most sensitive to temperature and light conditions. During a bloom, species belonging to diatoms or Chlorodendrophyceae usually did not respond to light and temperature in microcosms and continued to bloom independently of the applied seasonal condition. Together, these results suggest that light and temperature seasonal conditions play a crucial role in regulating phytoplankton dynamics in pre-bloom conditions and biotic interactions may be preponderant in bloom and post-bloom conditions.

中文翻译：

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原位群落动力学影响季节性浮游植物的温度和光照依赖性演替

温度和光在调节海洋浮游植物的开花中起着至关重要的作用。为了通过实验评估这两个参数的重要性，对2015年12月，3月，6月和9月以及2015年2016年12月，7月在西北地中海采样的七个浮游生物群落进行了缩影。每个社区都受到4种现实季节条件的影响（12月，3月，6月和9月）。在对海洋环境多样性进行高频监测的同时，使用元条形码技术在56个微观世界实验中研究了真核生物多样性。确定的三个主要谱系是Stramenopiles，Alveolata和Archaeplastida。总体而言，为期五天的培养不足以完全重塑最初的微生物群落。浮游植物起始群落的动力学强烈影响缩影的结局。在开花前的条件下，浮游植物对温度和光照条件最敏感。在开花期间，属于硅藻或绿萝科的物种通常在微观环境中对光和温度没有响应，并且继续开花，与所施加的季节条件无关。总之，这些结果表明，光照和温度的季节性条件在开花前的条件下在调节浮游植物的动态中起着至关重要的作用，而在开花和开花后的条件下，生物相互作用可能是主要的。属于硅藻或绿藻科的物种通常在微观世界中对光和温度无响应，并且会继续开花，而与所施加的季节条件无关。总之，这些结果表明，光照和温度的季节性条件在开花前的条件下在调节浮游植物的动态中起着至关重要的作用，而在开花和开花后的条件下，生物相互作用可能是主要的。属于硅藻或绿藻科的物种通常在微观世界中对光和温度无响应，并且会继续开花，而与所施加的季节条件无关。总之，这些结果表明，光照和温度的季节性条件在开花前的条件下在调节浮游植物的动态中起着至关重要的作用，而在开花和开花后的条件下，生物相互作用可能是主要的。