Temperature plays a fundamental role in determining phytoplankton community structure, distribution, and abundance. With climate models predicting increases in ocean surface temperatures of up to 3.2°C by 2100, there is a genuine need to acquire data on the phenotypic plasticity, and thus performance, of phytoplankton in relation to temperature. We investigated the effects of temperature (14–28°C) on the growth, morphology, productivity, silicification and macromolecular composition of the marine diatom Thalassiosira pseudonana. Optimum growth rate and maximum P:R ratio were obtained around 21°C. Cell volume and chlorophyll a increased with temperature, as did lipids and proteins. One of the strongest temperature-induced shifts was the higher silicification rates at low temperature. Our results reveal temperature-driven responses in physiological, morphological and biochemical traits in T. pseudonana; whereby at supra-optimal temperatures cells grew slower, were larger, had higher chlorophyll and protein content but reduced silicification, while those exposed to sub-optimal temperatures were smaller, heavily silicified with lower lipid and chlorophyll content. If these conserved across species, our findings indicate that as oceans warm, we may see shifts in diatom phenotypes and community structure, with potential biogeochemical consequences of higher remineralisation and declines in carbon and silicon export to the ocean interior.

中文翻译：

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高于热最佳温度会减少细胞生长和二氧化硅的产生，同时增加硅藻 Thalassiosira pseudonana 中的细胞体积和蛋白质含量

温度在决定浮游植物群落结构、分布和丰度方面起着重要作用。由于气候模型预测到 2100 年海洋表面温度将升高 3.2°C，因此真正需要获取有关浮游植物与温度相关的表型可塑性以及性能的数据。我们研究了温度 (14–28°C) 对海洋硅藻 Thalassiosira pseudonana 的生长、形态、生产力、硅化和大分子组成的影响。最佳生长速度和最大 P:R 比是在 21°C 左右获得的。细胞体积和叶绿素 a 随温度升高而增加，脂质和蛋白质也是如此。最强的温度引起的变化之一是低温下较高的硅化率。我们的结果揭示了生理中温度驱动的反应，T. pseudonana 的形态和生化特征；因此，在超最佳温度下，细胞生长更慢，更大，具有更高的叶绿素和蛋白质含量，但硅化降低，而暴露在次优温度下的细胞更小，严重硅化，脂质和叶绿素含量较低。如果这些在不同物种中都是保守的，我们的研究结果表明，随着海洋变暖，我们可能会看到硅藻表型和群落结构的变化，这可能会导致再矿化程度提高以及向海洋内部的碳和硅出口减少的潜在生物地球化学后果。高度硅化，脂质和叶绿素含量较低。如果这些在不同物种中都是保守的，我们的研究结果表明，随着海洋变暖，我们可能会看到硅藻表型和群落结构的变化，这可能会导致再矿化程度提高以及向海洋内部的碳和硅出口减少的潜在生物地球化学后果。高度硅化，脂质和叶绿素含量较低。如果这些在不同物种中都是保守的，我们的研究结果表明，随着海洋变暖，我们可能会看到硅藻表型和群落结构的变化，这可能会导致再矿化程度提高以及向海洋内部的碳和硅出口减少的潜在生物地球化学后果。