Caister Academic Press

Responses of Aquatic Protozoans to Climate Change

Hartmut Arndt and Mar Monsonís Nomdedeu
from: Climate Change and Microbial Ecology: Current Research and Future Trends (Second Edition) (Edited by: Jürgen Marxsen). Caister Academic Press, U.K. (2020) Pages: 107-132.


Heterotrophic protists (protozoans) play a key role in marine as well as in freshwater microbial food webs. They influence the abundance and taxonomic composition as well as size structure of bacteria and archaeans and thus regulate nutrient and carbon transfer in aquatic systems. Interactions between the different trophic levels of protists and different metazoan trophic levels are much more complex than generally believed. Laboratory experiments indicated a high capacity of genetic and non-genetic adaptation of heterotrophic protists to local temperature variations. Global warming does not only increase metabolic activity of protists and their impact on other microbes but since sensitivity to temperatures is potentially very different for each protist population unforeseeable impacts of warming have to be expected. Even if only one species in a system is temperature sensitive, the whole community is affected due to a close network of interactions. Warming has also a lot of important indirect effects on protists. Most important are changes in vertical stratifications and mixing processes in freshwater as well as in marine systems with fundamental effects on microbial food webs. Some of the major effects of temperature increases on free-living heterotrophic protist communities will be summarized on the background of complex microbial interactions read more ...
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