Interhabitat Transport of Nutrients by Detritivorous Fish: Impacts on Phytoplankton Communities

小行星9318452 这项研究试图了解反食鱼是如何通过充当“营养泵”来影响湖泊浮游植物群落的。“通过以底栖碎屑为食并将营养物质（氮和磷）排泄到湖沼生境中，这些鱼类有效地将营养物质从底栖生境泵到湖沼生境，营养物质可以刺激浮游植物生长并改变浮游植物群落结构。动物可以以多种方式影响群落，众所周知，在北方湖泊，鱼类可以通过食物链相互作用对浮游植物群落产生强烈影响。这里提出，在暖水湖泊和水库，鱼类影响浮游植物主要是通过营养泵机制，而不是通过传统的食物链相互作用。具体目标是量化的湖泊浮游植物群落水平的影响，食饵性鱼类。有待检验的假设包括：1）食鱼通过营养泵机制影响浮游植物，2）营养泵机制的影响取决于鱼类种群结构和碎屑营养物含量，3）食鱼是小水库流入量低时浮游植物营养物的主要来源。这些假设将使用一系列的经验观察，现场和实验室实验进行测试。 这项研究将推进我们对食物网调控的认识，自上而下与自下而上控制群落，以及底栖-湖沼耦合。虽然该项目侧重于社区影响，但它整合了从个人到生态系统的组织层次。此外，由于营养泵可能会影响蓝绿藻水华的频率和强度，因此该研究对水质管理具有影响。 ***

9318452 Vanni This research seeks to understand how detritivorous fish affect lake phytoplankton communities by acting as "nutrient pumps." By feeding on benthic detritus and excreting nutrients (nitrogen and phosphorus) into the limnetic habitat, these fish effectively pump nutrients from benthic to limnetic habitats, where nutrients can stimulate phytoplankton growth and alter phytoplankton community structure. Animals can affect communities in many ways and it is well known that in northern lakes fish can have strong effects on phytoplankton communities through food chain interactions. It is proposed here that in warm-water lakes and reservoirs, fish affect phytoplankton primarily through the nutrient pump mechanism rather than through conventional food chain interactions. The specific objectives are to quantify the community level effects of detritivorous fish on lake phytoplankton communities. Hypotheses to be tested include: 1) detritivorous fish affect phytoplankton via the nutrient pump mechanism, 2) the effects of the nutrient pump mechanism is dependent on fish population structure, and detrital nutrient content, and 3) detritivorous fish are a major source of nutrients to phytoplankton in small reservoirs during times with stream inflows are low. These hypotheses will be tested using a series of empirical observations, field and laboratory experiments. %%% This research will advance our knowledge of food web regulation, top down versus bottom up controls on communities, and benthic-limnetic coupling. Although this project focuses on community effects, it integrates levels of organization from individual to ecosystem. In addition, because nutrient pumps may have effects on the frequency and intensity of nuisance blooms of blue-green algae, the research has implications for water quality management. ***