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Integrative Foraging in Complex Landscapes: Nutrient acquisition and mixing across food patches at the primary producer-Daphnia interface

复杂景观中的综合觅食：初级生产者与水蚤界面处食物斑块间的养分获取和混合

基本信息

批准号：
240744106
负责人：
Professor Dr. Alexander Wacker
金额：
--
依托单位：
Professur für Tierökologie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2013
资助国家：
德国
起止时间：
2012-12-31 至 2016-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/240744106?language=en
关键词：
Integrative Foraging Complex Landscapes Nutrient

项目摘要

Consumers such as the keystone aquatic herbivore Daphnia, continuously experience spatial and temporal variability in their food availability and quality. Depending on the observational scale, this variability is driven by various factors such as successions in algal species, variation of abiotic factors (light, nutrients) and/or to movements between food patches of different quality. As a result, the uptake of limiting nutrients by Daphnia is temporally fluctuating and in the case of co-limiting nutrients the uptake might even be decoupled. In such complex nutritional environments, it is difficult to predict Daphnia responses only based on lab nutrition studies were food quality is kept constant and on punctual (and usually very distant) estimates of seston nutritional quality. Predicting Daphnia responses, requires understanding (a) how the resources fluctuate at temporal scales which are relevant to Daphnia, and (b) how Daphnia integrate such spatio-temporally heterogeneous resources into long-term fitness i.e. how nutrients acquired in different patches are be taken up, stored, mixed and used for growth and reproduction. This project aims to characterise the natural variability of the nutritional quality (in terms of Phosphorus, essential fatty acids and sterol contents) of seston at the poorly studied, but relevant to Daphnia, hourly and daily scale. Additionally, through a series of life table experiments, we aim to understand how fluctuation and decoupling in the uptake of co-limiting nutrients affect Daphnia growth rates, fecundity and nutrient assimilation efficiency. Finally, this project also aims to increase the very limited knowledge on Daphnia digestive enzyme physiology, which might potentially be their most important tool for optimizing the acquisition of various nutrients from a continuously fluctuating diet. We expect that outcomes of the project will improve our understanding of the scale at which temporal and/or spatial heterogeneity in resource quality matters for zooplankton. Moreover knowledge will be gained on how such heterogeneity should be averaged to obtain estimates of the overall habitat quality for zooplankton which is essential for accurate model building.

消费者，如Keystone水生食草动物Daphnia，不断体验其食物供应和质量的时空变异性。根据观测规模的不同，这种差异是由各种因素驱动的，例如藻类物种的演替、非生物因素(光、营养物质)的变化和/或不同质量的食物斑块之间的移动。因此，水蚤对限制性营养物质的吸收是在时间上波动的，在共同限制营养物质的情况下，吸收甚至可能是分离的。在如此复杂的营养环境中，仅基于实验室营养研究很难预测水蚤的反应，因为食物质量保持不变，并对Seston营养质量进行准时(通常是非常遥远的)估计。为了预测水蚤的反应，需要了解(A)与水蚤相关的资源在时间尺度上如何波动，以及(B)水蚤如何将这种时空上不同的资源整合到长期适宜性中，即不同斑块中获取的营养如何被吸收、储存、混合和用于生长和繁殖。该项目旨在描述Seston的营养质量(磷、必需脂肪酸和甾醇含量)的自然变异性，研究较少，但与水蚤、每小时和每天的规模相关。此外，通过一系列生命表实验，我们的目的是了解摄取共限制营养物质的波动和解耦如何影响水蚤的生长速度、繁殖力和养分同化效率。最后，这个项目还旨在增加关于大型水蚤消化酶生理学的非常有限的知识，这可能是他们从不断波动的饮食中优化各种营养获取的最重要工具。我们预计，该项目的成果将提高我们对浮游动物资源质量的时间和/或空间异质性在多大程度上的理解。此外，还将了解如何对这种异质性进行平均，以获得对浮游动物总体栖息地质量的估计，这对准确建立模型至关重要。