Environmental control of diatom community size structure varies across aquatic ecosystems
Environmental control of diatom community size structure varies across aquatic ecosystems
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DOI：
10.1098/rspb.2008.1610
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发表时间：
2009-05-07
影响因子：
4.7
通讯作者：
Smol, John P.
中科院分区：
文献类型：
--
作者：
Finkel, Zoe V.;Vaillancourt, Colin Jacob;Smol, John P.
光自养生物大小结构的变化影响着食物网结构和碳的生物地球化学循环。随着气候变暖和水柱分层，在海洋的新生代和过去50年的太浩湖已经观察到群落中硅藻大小的中位数减小。由于海洋系统和大型分层湖泊中限制性营养物质的浓度降低，经常观察到较大浮游生物的比例下降。相比之下，我们发现在一组中等大小的碱性湖泊中，浮游硅藻的中值大小随着营养物质浓度的升高而减小。气候引起的水柱分层频率、持续时间和强度的增加可能会选择海洋和较大湖泊中较小的浮游生物物种，因为营养物的可用性和下沉速率减少，而营养物富营养化和高叶绿素浓度刺激的光照限制可能会选择群落内较小的物种，因为它们的光吸收效率高，下沉速率较低。不同的生理和生态速率和过程对群落大小结构的相对重要性在不同的水生系统中是不同的，这是由于不同的非生物和生物限制的组合。
Changes in the size structure of photoautotrophs influence food web structure and the biogeochemical cycling of carbon. Decreases in the median size of diatoms within communities, in concert with climate warming and water column stratification, have been observed over the Cenozoic in the ocean and over the last 50 years in Lake Tahoe. Decreases in the proportion of larger plankton are frequently observed in response to reduced concentrations of limiting nutrients in marine systems and large stratified lakes. By contrast, we show a decrease in the median size of planktonic diatoms in response to higher nutrient concentrations in a set of intermediate-sized alkaline lakes. Climate-induced increases in the frequency, duration and strength of water column stratification may select smaller planktonic species in the ocean and larger lakes owing to a reduction in nutrient availability and sinking rates, while light limitation, stimulated by nutrient eutrophication and high chlorophyll concentrations, may select smaller species within a community owing to their high light absorption efficiencies and lower sinking rates. The relative importance of different physiological and ecological rates and processes on the size structure of communities varies in different aquatic systems owing to varying combinations of abiotic and biotic constraints.