Department of Limnology and Oceanography, University of Vienna, Vienna, Austria.
Department of Organismic Biology, University of Salzburg, Salzburg, Austria.
ISME J. 2014 Jun;8(6):1346-51. doi: 10.1038/ismej.2013.241. Epub 2014 Jan 16.
Trophic cascade effects occur when a food web is disrupted by loss or significant reduction of one or more of its members. In East African Rift Valley lakes, the Lesser Flamingo is on top of a short food chain. At irregular intervals, the dominance of their most important food source, the cyanobacterium Arthrospira fusiformis, is interrupted. Bacteriophages are known as potentially controlling photoautotrophic bacterioplankton. In Lake Nakuru (Kenya), we found the highest abundance of suspended viruses ever recorded in a natural aquatic system. We document that cyanophage infection and the related breakdown of A. fusiformis biomass led to a dramatic reduction in flamingo abundance. This documents that virus infection at the very base of a food chain can affect, in a bottom-up cascade, the distribution of end consumers. We anticipate this as an important example for virus-mediated cascading effects, potentially occurring also in various other aquatic food webs.
当食物网因一个或多个成员的缺失或大量减少而被打乱时，就会发生营养级联效应。在东非大裂谷的湖泊中，小火烈鸟处于短食物链的顶端。它们最重要的食物来源——蓝细菌束丝藻的优势会时不时地被打断。噬菌体作为潜在的控制光自养细菌浮游生物的物质而被人们所熟知。在内罗毕湖（肯尼亚），我们发现了有记录以来在自然水生系统中存在的最高丰度的悬浮病毒。我们记录到蓝藻噬菌体感染以及相关的束丝藻生物量的崩溃，导致了火烈鸟数量的急剧减少。这证明了食物链最底层的病毒感染可以通过自下而上的级联反应，影响终级消费者的分布。我们预计这将是一个重要的病毒介导级联效应的例子，这种效应可能也会在各种其他水生食物网中发生。
