The effects of diel cycles and temperature on size distributions of pico- and nanophytoplankton in the subtropical and tropical Pacific Ocean
The effects of diel cycles and temperature on size distributions of pico- and nanophytoplankton in the subtropical and tropical Pacific Ocean
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DOI：
10.3800/pbr.10.26
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发表时间：
2015-03
影响因子：
0.6
通讯作者：
Mitsuhide Sato;T. Kodama;F. Hashihama;K. Furuya
中科院分区：
文献类型：
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作者：
Mitsuhide Sato;T. Kodama;F. Hashihama;K. Furuya
为了阐明是什么决定了亚热带和热带海洋中的浮游生物群落结构，在整个北太平洋和南太平洋广泛测量pico和nanophytoplankton的细胞大小分布。三个不同的群体，聚球藻，纳米尺寸的蓝藻，真核生物的平均细胞大小，显示出明确的昼夜周期的高峰在下午晚些时候。通过拟合正弦曲线减去昼夜变化的影响后，三个种群的平均细胞大小对温度和营养浓度进行回归。多元回归分析表明，真核生物的细胞大小和温度之间的正相关性是唯一显着的参数。大小直方图表明，在温暖的沃茨，pico大小的真核生物的总浮游植物生物量的贡献是相对较小的，这与原绿球藻的数量优势相结合，造成整个pico和nanophytoplankton社区的大小谱的双极化。这些结果表明，常用的海洋地球化学模型需要修正，以考虑到海表温度的增加只会导致较小的浮游植物的流行。为了揭示温度对整个食物网的影响，在未来的研究中需要对浮游动物群落结构进行广泛的调查。
To elucidate what determines plankton community structures in subtropical and tropical oceans, cell size distributions of picoand nanophytoplankton were extensively measured throughout the North and South Pacific Ocean. Mean cell sizes of three different populations, Synechococcus, nano-sized cyanobacteria, and eukaryotes, showed a clear diel cycle with a peak in the late afternoon. After subtracting the effect of the diel variation by fitting sine curves, the mean cell sizes of the three populations were regressed against temperature and nutrient concentrations. The multiple regression analyses revealed that a positive correlation between the cell size of eukaryotes and temperature was the only significant parameter. Size histograms demonstrated that in the warm waters, the contribution of pico-sized eukaryotes to total phytoplankton biomass was relatively small, which in combination with the numerical dominance of Prochlorococcus caused bipolarization of the size spectrum of the entire picoand nanophytoplankton community. These results demonstrate that commonly used biogeochemical models require amendment to account for the fact that an increase in sea surface temperature will simply lead to a prevalence of smaller phytoplankton. To reveal the effect of temperature on the entire food web, extensive surveys of zooplankton community structures will be required in future studies.