Transient exposure to novel high temperatures reshapes coastal phytoplankton communities
Transient exposure to novel high temperatures reshapes coastal phytoplankton communities
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DOI：
10.1038/s41396-019-0525-6
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发表时间：
2019-10
期刊：
影响因子：
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通讯作者：
Joshua D. Kling;Michael D. Lee;Feixue Fu;Megan D. Phan;Xinwei Wang;Ping-Ping Qu-Ping;D. Hutchins
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文献类型：
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作者：
Joshua D. Kling;Michael D. Lee;Feixue Fu;Megan D. Phan;Xinwei Wang;Ping-Ping Qu-Ping;D. Hutchins
预计本世纪平均海面温度将上升4°，海洋浮游植物和细菌群落的组成、海洋地球化学速率和营养相互作用都将在未来更温暖的海洋中发生变化。热实验通常使用恒定的温度;然而，天气和水文学导致海洋温度在昼夜周期和多天内波动。我们孵化自然群落的浮游植物收集从加州沿海沃茨在春季，夏季和秋季在现今和未来的平均温度下，使用热处理，要么是恒定的或波动的48小时的周期。通过标记基因测序分析，除了培养温度超过10年本地热数据集记录的最高温度外，每个季节内出现的微生物群落是一致的。当温度处理超过10年的最大浮游植物群落转移，成为占主导地位的硅藻扩增子序列变异体（ASVs）没有看到在较低的温度。当平均温度高于10年最高值时，恒定和波动制度分别为不同的ASV选择。这些发现表明，沿海微生物群落在很大程度上适应了它们所经历的当前温度范围。他们还提出了一个一般性的假设，即多年的温度上限可能代表阈值，超过阈值可能会发生大的社区重组。现在，不可避免的未来温度上升超过这些环境阈值，即使是暂时的，也可能从根本上重塑海洋微生物群落，从而重塑它们所介导的生物地球化学循环。
Average sea surface temperatures are expected to rise 4° this century, and marine phytoplankton and bacterial community composition, biogeochemical rates, and trophic interactions are all expected to change in a future warmer ocean. Thermal experiments typically use constant temperatures; however, weather and hydrography cause marine temperatures to fluctuate on diel cycles and over multiple days. We incubated natural communities of phytoplankton collected from California coastal waters during spring, summer, and fall under present-day and future mean temperatures, using thermal treatments that were either constant or fluctuated on a 48 h cycle. As assayed by marker-gene sequencing, the emergent microbial communities were consistent within each season, except when culture temperatures exceeded the highest temperature recorded in a 10-year local thermal dataset. When temperature treatments exceeded the 10-year maximum the phytoplankton community shifted, becoming dominated by diatom amplicon sequence variants (ASVs) not seen at lower temperatures. When mean temperatures were above the 10-year maximum, constant and fluctuating regimes each selected for different ASVs. These findings suggest coastal microbial communities are largely adapted to the current range of temperatures they experience. They also suggest a general hypothesis whereby multiyear upper temperature limits may represent thresholds, beyond which large community restructurings may occur. Now inevitable future temperature increases that exceed these environmental thresholds, even temporarily, may fundamentally reshape marine microbial communities and therefore the biogeochemical cycles that they mediate.