Cole Jonathan J, Carpenter Stephen R, Pace Michael L, Van de Bogert Matthew C, Kitchell James L, Hodgson James R
Ecol Lett. 2006 May;9(5):558-68. doi: 10.1111/j.1461-0248.2006.00898.x.
Organic carbon inputs from outside of ecosystem boundaries potentially subsidize recipient food webs. Four whole-lake additions of dissolved inorganic 13C were made to reveal the pathways of subsidies to lakes from terrestrial dissolved organic carbon (t-DOC), terrestrial particulate organic carbon (t-POC) and terrestrial prey items. Terrestrial DOC, the largest input, was a major subsidy of pelagic bacterial respiration, but little of this bacterial C was passed up the food web. Zooplankton received <2% of their C from the t-DOC to bacteria pathway. Terrestrial POC significantly subsidized the production of both zooplankton and benthic invertebrates, and was passed up the food web to Chaoborus and fishes. This route supplied 33-73% of carbon flow to zooplankton and 20-50% to fishes in non-fertilized lakes. Terrestrial prey, by far the smallest input, provided some fishes with >20% of their carbon. The results show that impacts of cross-ecosystem subsidies depend on characteristics of the imported material, the route of entry into the food web, the types of consumers present, and the productivity of the recipient system.
来自生态系统边界之外的有机碳输入可能会为受援食物网提供补贴。进行了四次向整个湖泊添加溶解态无机¹³C的实验，以揭示陆地溶解有机碳（t-DOC）、陆地颗粒有机碳（t-POC）和陆地猎物对湖泊的补贴途径。陆地溶解有机碳是最大的输入量，是浮游细菌呼吸的主要补贴来源，但这种细菌碳很少通过食物网向上传递。浮游动物从t-DOC到细菌的途径中获得的碳不到其碳总量的2%。陆地颗粒有机碳显著补贴了浮游动物和底栖无脊椎动物的生产，并通过食物网向上传递给摇蚊幼虫和鱼类。在未施肥的湖泊中，这条途径为浮游动物提供了33%-73%的碳流，为鱼类提供了20%-50%的碳流。陆地猎物是迄今为止最小的输入量，为一些鱼类提供了超过20%的碳。结果表明，跨生态系统补贴的影响取决于输入物质的特性、进入食物网的途径、现存消费者的类型以及受援系统的生产力。
