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The role of polyunsaturated fatty acids for the competition in herbivorous zooplankton

多不饱和脂肪酸在草食性浮游动物竞争中的作用

基本信息

批准号：
315474598
负责人：
Professor Dr. Eric von Elert, Ph.D.
金额：
--
依托单位：
Arbeitsgruppe Aquatische chemische Ökologie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2021-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/315474598?language=en
关键词：
role polyunsaturated fatty acids competition

项目摘要

A major factor determining the trophic transfer efficiency in limnic systems is the food quality of algae and cyanobacteria for Daphnia. Several correlative studies point at an in-situ limitation of Daphnia by a low content of the polyunsaturated fatty acid eicosapentaenoic acid (EPA, C20:5 n-3) in natural phytoplankton, and numerous experimental studies have demonstrated negative effects of EPA-limitation on somatic growth and reproduction of Daphnia. These negative effects of EPA-limitation were stronger at lower temperatures than at 20°C. This proposal aims at investigating, if the limiting resource EPA affects the compe-tition among Daphnia and how an EPA-limitation affects the clonal composition of a Daphnia community.Here it is proposed to investigate, if the EPA-demand differs (i) between clones of the same species and (ii) between Daphnia species that differ in their ability to perform Diel Vertical Mirgation (DVM). To achieve this, life-history experiments will be performed with each clone using food with a gradient of increasing EPA-content at two different temperatures. Monod-like saturation functions will be used to estimate threshold concentrations for EPA-limited growth. Bootstrapping will be used to estimate the variability of these threshold concentrations, so that threshold concentrations can be statistically compared among Daphnia genotypes. In order to understand the mechanisms causing differences in EPA-threshold concentrations, a follow-up experiments will be conducted to determine the resource-use efficiency for EPA of the different genotypes by comparing ingested and assimilated EPA amounts. Finally a competition experiment will be performed to investigate, how EPA limitation affects the genetic composition of communities of Daphnia genotypes with different EPA threshold concentrations. The overall aim is to investigate if differences in EPA threshold concentrations among Daphnia genotypes are so relevant that EPA-limitation is a mechanism that affects competition among Daphnia.

决定湖泊系统营养转移效率的一个主要因素是藻类和蓝藻对水蚤的食物质量。一些相关的研究指出，在原位限制水蚤的天然浮游植物中的多不饱和脂肪酸二十碳五烯酸（EPA，C20：5 n-3）的含量低，许多实验研究表明，EPA限制水蚤的体细胞生长和繁殖的负面影响。EPA限制的这些负面影响在较低温度下比在20°C下更强。本研究的目的是探讨EPA的限制性资源是否会影响水蚤之间的竞争以及EPA限制如何影响水蚤群落的克隆组成，即（i）同种克隆之间的EPA需求是否存在差异，（ii）不同种间的EPA需求是否存在差异。为了实现这一目标，将对每个克隆进行生活史实验，在两个不同的温度下使用具有渐增EPA含量梯度的食物。Monod样饱和函数将用于估计EPA限制生长的阈值浓度。将使用自助法来估计这些阈值浓度的变异性，以便阈值浓度可以在水蚤基因型之间进行统计比较。为了了解EPA阈值浓度差异的机制，将进行后续试验，通过比较摄入和同化EPA的量，以确定不同基因型EPA的资源利用效率。最后，通过竞争实验，研究EPA限制对不同EPA阈值浓度的水蚤基因型群落遗传组成的影响。总体目标是调查，如果EPA阈值浓度的差异水蚤基因型之间是如此相关的EPA限制是一种机制，影响水蚤之间的竞争。