Pink Salmon induce a trophic cascade in plankton populations in the southern Bering Sea and around the Aleutian Islands
Pink Salmon induce a trophic cascade in plankton populations in the southern Bering Sea and around the Aleutian Islands
复制标题
DOI：
10.1111/fog.12276
复制
发表时间：
2018-11-01
影响因子：
2.6
通讯作者：
Ortiz, Ivonne
中科院分区：
文献类型：
--
作者：
Batten, Sonia Dawn;Ruggerone, Gregory T.;Ortiz, Ivonne
我们利用连续浮游生物记录仪在夏季采集的浮游生物种群15年时间序列（2000 - 2014年），检验了阿留申群岛周围和白令海南部浮游生物种群自上而下（捕食者）控制的假说。我们的分析揭示了大型浮游植物和桡足类丰度的两年交替模式。这种模式可能是由两年一次大量出现的东堪察加粉红鲑鱼对桡足类的捕食压力导致的营养级联效应引起的。在奇数年，粉红鲑鱼数量极多，大型桡足类数量少，被桡足类摄食的大型硅藻数量多。此外，大型桡足类数量与粉红鲑鱼数量呈负相关，硅藻数量与粉红鲑鱼数量呈正相关。除了影响硅藻和大型桡足类的数量外，我们还报告了对浮游植物分类组成的影响。我们发现这些影响的表现存在区域差异，奇/偶年交替模式在白令海南部中部和阿留申群岛东部最强，在阿留申群岛西部减弱或不存在。当2013年粉红鲑鱼数量意外偏低时，浮游生物种群随之发生变化，大型桡足类和微型浮游动物（有硬壳的纤毛虫）在时间序列中出现了有记录以来的最高数量。这些发现强调了捕食者数量的变化及其对整个生态系统的影响的重要性，在这种情况下，这种影响大于海洋物理变化的影响。
We examined the hypothesis of top-down (predator) control of plankton populations around the Aleutian Islands and in the southern Bering Sea using a 15year time series (2000-2014) of plankton populations sampled during summer by Continuous Plankton Recorders. Our analyses reveal opposing biennial patterns in abundances of large phytoplankton and copepods. This pattern is likely caused by the predation pressure on copepods from biennially abundant eastern Kamchatka Pink Salmon that results in a trophic cascade. In odd years, Pink Salmon are exceptionally abundant, large copepod abundance is low, and abundance of large diatoms grazed by copepods is high. Furthermore, large copepod abundance was inversely correlated, and diatom abundance was positively correlated, with Pink Salmon abundance. In addition to influencing the abundance of diatoms and large copepods we also report an effect on phytoplankton taxonomic composition. We find regional differences in the expression of these effects with alternating odd/even year patterns being strongest in the central Southern Bering Sea and eastern Aleutians and reduced, or absent, in the western Aleutians. When the abundance of 2013 Pink Salmon was unexpectedly low, there were consequent changes in the plankton populations, with highest recorded numbers in the time series of large copepods and microzooplankton (hard-shelled ciliates). These findings emphasise the importance of variability in predator abundance and its effect across the ecosystem, which in this case was greater than physical oceanographic variability.