Bivalve Grazing Can Shape Phytoplankton Communities
Bivalve Grazing Can Shape Phytoplankton Communities
复制标题
双壳类动物的放牧可以塑造浮游植物群落
DOI：
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发表时间：
2016
影响因子：
3.7
通讯作者：
J. Koseff
中科院分区：
文献类型：
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作者：
L. V. Lucas;J. Cloern;Janet K. Thompson;M. Stacey;J. Koseff
双壳类滤食性动物限制浅水浮游植物生物量的能力已得到充分证明，但双壳类动物在形成浮游植物群落中的作用尚未得到充分证明。双壳类在沉积物-水界面的掠食和浮游植物细胞下沉到底滤带的耦合效应会影响下沉（硅藻）和非下沉浮游植物的相对生物量。伪二维数值模型的模拟表明，底栖生物滤食可以与下沉相互作用，改变硅藻与非硅藻的比例。硅藻生物量占比最小的是沉降速度最快和双壳类食草率最强的地区。水动力调节了沉降-放牧对浮游植物群落的耦合影响。例如，在持续分层的模拟中，非下沉形式积聚在远离底层食草动物的表层，而下沉形式则从表层向底层食草动物方向下降。潮汐尺度的分层也以相反的方式影响两组的垂直梯度。该模型被应用于suissun湾，这是旧金山湾系统的一个低盐度栖息地，通过引入外来蛤蜊amamocorbula amurensis而改变。该海湾的模拟结果与一般生境相似（但比一般生境更弱），表明P. amurensis放牧可能在其引入后造成不成比例的硅藻损失。我们的模型模拟表明，双壳类动物的放牧影响了浅水浮游植物的生物量和群落组成。我们认为这些结果是假设，需要用实验和更复杂的建模方法来检验。
The ability of bivalve filter feeders to limit phytoplankton biomass in shallow waters is well-documented, but the role of bivalves in shaping phytoplankton communities is not. The coupled effect of bivalve grazing at the sediment-water interface and sinking of phytoplankton cells to that bottom filtration zone could influence the relative biomass of sinking (diatoms) and non-sinking phytoplankton. Simulations with a pseudo-2D numerical model showed that benthic filter feeding can interact with sinking to alter diatom:non-diatom ratios. Cases with the smallest proportion of diatom biomass were those with the fastest sinking speeds and strongest bivalve grazing rates. Hydrodynamics modulated the coupled sinking-grazing influence on phytoplankton communities. For example, in simulations with persistent stratification, the non-sinking forms accumulated in the surface layer away from bottom grazers while the sinking forms dropped out of the surface layer toward bottom grazers. Tidal-scale stratification also influenced vertical gradients of the two groups in opposite ways. The model was applied to Suisun Bay, a low-salinity habitat of the San Francisco Bay system that was transformed by the introduction of the exotic clam Potamocorbula amurensis. Simulation results for this Bay were similar to (but more muted than) those for generic habitats, indicating that P. amurensis grazing could have caused a disproportionate loss of diatoms after its introduction. Our model simulations suggest bivalve grazing affects both phytoplankton biomass and community composition in shallow waters. We view these results as hypotheses to be tested with experiments and more complex modeling approaches.