RUI: The Importance of Clays and Dissolved Organic Matter to the Trophic Base of Turbid Lake Ecosystems

粘土浊度抑制浮游植物生产 湖泊. 这项研究将探讨补偿作用， 粘土交替营养途径。 它是假设 溶解性有机物（DOM）更容易被高浓度的有机物所利用。 营养水平通过粘土颗粒的浓度。 具体而言：（1）粘土颗粒吸附大量 DOM（其营养价值随来源而异）， 促进细菌生产;（2）由于细菌 表面生长，粘粒与吸附DOM团聚体成 更大的颗粒。 该研究将研究以下方面的相对重要性： 自养和异养，以及粘土的机制 颗粒在湖泊食物网中很重要。 该项目回答 四个问题：（1）粘土浊度的多少影响 细菌的绝对数量和相对数量 生产和浮游植物生产？ (2)数量是否 粘土浊度影响细菌利用浮游植物分泌物？ (3)粘土的吸附或聚集能力是否不同 与DOM的性质（异地与本地）？ (4)细菌在聚集体上的生长是否会影响 粘土-有机-细菌聚集体 查帕拉湖的可预测的空间和时间梯度 悬浮粘土浓度允许结合实验室 和实地实验来验证假设 答案将 允许新的营养模式适合湖泊和水库 粘土浊度高。 管理人员可以更换 管理措施（水质和渔业）， 传统模式。 这种替代途径尤其是 因为常年温暖的沃茨 使细菌活性始终保持在较高水平。 该项目由RUI倡议资助。 是 独特的是，它的本科生参与实地工作， 热带地区，并通过国际合作者的使用。

Clay turbidity inhibits the phytoplankton production of lakes. This research will investigate a compensatory role for clays in an alternate trophic pathway. It is hypothesized that dissolved organic matter (DOM) is more available to higher trophic levels through concentration on clay particles. Specifically: (1) clay particles adsorb significant quantities of DOM (the nutritional value of which varies with the source) to facilitate bacterial production; and (2) as a result of bacterial surface growth, clay particles with adsorbed DOM aggregate into larger particles. The research will examine the relative importance of autotrophy and heterotrophy, and the mechanisms by which clay particles are important in lake food webs. The project answers four questions: (1) Does the quantity of clay turbidity affect the absolute as well as the relative amounts of bacterial production and phytoplankton production? (2) Does the quantity of clay turbidity affect bacterial use of phytoplankton exudates? (3) Does the sorptive or aggregative capacity of the clays vary with the nature of the DOM (allochthonous vs. autochthonous)? (4) Does bacterial growth on aggregates affect the size of the clay-organic-bacteria aggregates? Lake Chapala's predictable spatial and temporal gradients of suspended clay concentrations allows a combination of laboratory and field experimentation to test hypotheses. Answers will permit a new trophic model appropriate to lakes and reservoirs with high clay turbidity. Managers may be able to replace management practices (water quality and fisheries) based on traditional models. This alternate pathway is especially important in tropical lakes because year-around warm waters enable consistently high bacterial activity. This project is funded under the RUI initiative. It is unique in its involvement of undergraduates in field work in the tropics and through its use of international collaborators.