Abstract
To predict future effects of climate change, a comprehensive mechanistic understanding is essential. In marine ecosystems, a mismatch between oxygen demand and oxygen supply to tissues was shown to be the first mechanism to restrict survival at thermal extremes. Here I propose a study on climate-driven oxygen limitation in freshwater stream inverte-brates. Stream invertebrates display a range of adaptations related to respiration and oxygen is a key factor structuring species assemblages. Therefore, oxygen limitation likely plays a role. First I will assess if thermal limits of species arise due to oxygen limitation. In laboratory experiments I will test the prediction that a species? thermal window expands under higher oxygen concentrations. In a field study I will asses if species occupy different thermal niches under high and low oxygen conditions. Secondly, I will assess if and how differences in a species? thermal vulnerability can be predicted from their morphological and physiological traits that are related to oxygen supply and demand. I propose experimental work to characterize the oxygen demand (metabolic rate) of species and relate these to their observed thermal limits. The proposed research combines physiological measurements with an ecological field study to rigorously test the oxygen limitation hypothesis in streams.
Netherlands