Contrasting size evolution in marine and freshwater diatoms
Contrasting size evolution in marine and freshwater diatoms
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DOI：
10.1073/pnas.0810891106
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发表时间：
2009-02-24
影响因子：
11.1
通讯作者：
Yoshiyama, K.
中科院分区：
文献类型：
--
作者：
Litchman, E.;Klausmeier, C. A.;Yoshiyama, K.
硅藻是全球碳循环和大多数水生生态系统的关键参与者。它们的细胞大小影响碳封存和能量转移到更高的营养水平。我们报告的海洋和淡水硅藻的大小分布的根本差异，海洋硅藻显着大于淡水物种。进化博弈理论模型与经验异速生长和养分吸收表明，这些差异可以解释为氮磷限制，养分波动和混合层深度的差异。恒定和脉冲磷供应选择小尺寸，恒定氮供应也是如此。相比之下，海洋中常见的中频氮脉冲选择大尺寸或大尺寸和小尺寸的进化稳定共存。尺寸相关的下沉与混合层深度（MLD）相互作用，以进一步调节最佳尺寸，通过强下沉和浅MLD选择较小的尺寸。在淡水中，广泛的磷限制，加上强大的下沉和浅MLD产生较小的范围，平均值和上限值的大小分布，与海洋相比。营养限制和混合模式的变化可能会改变硅藻的大小分布，影响全球碳循环以及水生生态系统的结构和功能。
Diatoms are key players in the global carbon cycle and most aquatic ecosystems. Their cell sizes impact carbon sequestration and energy transfer to higher trophic levels. We report fundamental differences in size distributions of marine and freshwater diatoms, with marine diatoms significantly larger than freshwater species. An evolutionary game theoretical model with empirical allometries of growth and nutrient uptake shows that these differences can be explained by nitrogen versus phosphorus limitation, nutrient fluctuations and mixed layer depth differences. Constant and pulsed phosphorus supply select for small sizes, as does constant nitrogen supply. In contrast, intermediate frequency nitrogen pulses common in the ocean select for large sizes or the evolutionarily stable coexistence of large and small sizes. Size-dependent sinking interacts with mixed layer depth (MLD) to further modulate optimal sizes, with smaller sizes selected for by strong sinking and shallow MLD. In freshwaters, widespread phosphorus limitation, together with strong sinking and shallow MLD produce size distributions with smaller range, means and upper values, compared with the ocean. Shifting patterns of nutrient limitation and mixing may alter diatom size distributions, affecting global carbon cycle and the structure and functioning of aquatic ecosystems.