Direct and indirect effects of temperature on the population dynamics and ecosystem functioning of aquatic microbial ecosystems
Article first published online: 13 AUG 2010
© 2010 The Authors. Journal compilation © 2010 British Ecological Society
Journal of Animal Ecology
Volume 79, Issue 6, pages 1324–1331, November 2010
How to Cite
Beveridge, O. S., Petchey, O. L. and Humphries, S. (2010), Direct and indirect effects of temperature on the population dynamics and ecosystem functioning of aquatic microbial ecosystems. Journal of Animal Ecology, 79: 1324–1331. doi: 10.1111/j.1365-2656.2010.01741.x
- Issue published online: 19 OCT 2010
- Article first published online: 13 AUG 2010
- Received 8 February 2010; accepted 21 July 2010 Handling Editor: Ben Woodcock
- Colpidium striatum;
- Didinium nasutum;
- ecosystem functioning;
- indirect and direct temperature effects;
- trophic interactions;
1. While much is known about the direct effect that temperature can have on aquatic communities, less is known about its indirect effect via the temperature dependence of viscosity and temperature-dependent trophic interactions.
2. We manipulated the temperature (5–20 °C) and the viscosity (equivalent to 5–20 °C) of water in laboratory-based bacteria–protist communities. Communities contained food chains with one, two or three trophic levels. Responses measured were population dynamics (consumer carrying capacity and growth rate, average species population density, and the coefficient of variation of population density through time) and ecosystem function (decomposition).
3. Temperature, viscosity and food chain length produced significant responses in population dynamics. Temperature-dependent viscosity had a significant effect on the carrying capacity and growth rates of consumers, as well as the average density of the top predator. Overall, indirect effects of temperature via changes in viscosity were subtle in comparison to the indirect effect of temperature via trophic interactions.
4. Our results highlight the importance of direct and indirect effects of temperature, mediated through trophic interactions and physical changes in the environment, both for population dynamics and ecosystem processes. Future mechanistic modelling of effects of environmental change on species will benefit from distinguishing the different mechanisms of the overall effect of temperature.