Testing the Sensitivity of Phytoplankton Communities to Changes in Water Temperature and Nutrient Load, in a Temperate Lake
- 1.2k Downloads
Freshwater lakes are biologically sensitive to changes in the surrounding environment and the impacts that such changes have on their water quality are of considerable ecological, recreational and economic importance. In this study the phytoplankton community model, PROTECH, was used to experiment with the effects of elevated temperatures and increased nutrient load on phytoplankton succession and productivity. The response of a phytoplankton community to combined incremental changes in these drivers was analysed, in order to elucidate the resulting ecological changes. Annual mean phytoplankton biomass increased with increases in temperature and nutrient loading, although the latter had the larger effect. The phenology of the dominant phytoplankton taxa changed with increasing water temperature; the three spring blooming species all peaked earlier in the year. The simulated summer bloom of Anabaena became earlier in the year and the Chlorella bloom later. The increased phytoplankton biomass was largely dominated by the cyanobacterium Anabaena, which was especially prevalent during the summer bloom. This resulted in a progressive loss of phytoplankton biodiversity with increasing water temperature and nutrient supply. Model experimentation showed that whilst both factors greatly affected the community, the changes to nutrient loading generally had the greater effect and that at low nutrient levels the effect of water temperature change was reduced considerably. Finally, the model predicted that cyanobacteria have the potential to dominate the phytoplankton community, with clear consequences for water quality, and that this dominance was at its greatest when high water temperatures were combined with high nutrient loads.
Keywordsbiodiversity cyanobacteria phenology PROTECH
Unable to display preview. Download preview PDF.
- Elliott, J. A., Thackeray, S. J., Huntingford, C., Jones, R. 2005Combining a Regional Climate Model with a phytoplankton community model to predict future changes in phytoplankton in lakesFreshwater Biology5014041411Google Scholar
- Gerten, D., Adrian, R. 2000Climate-driven changes in spring plankton dynamics and the sensitivity of shallow polymictic lakes to the North Atlantic OscillationLimnology & Oceanography4510581066Google Scholar
- Harper, D. 1992Eutrophication of freshwaters: principles, problems and restorationChapman & HallLondonGoogle Scholar
- Lampert, W., Sommer, U. 1997Limnoecology: The Ecology of Lakes and StreamsOxford University PressNew YorkGoogle Scholar
- Ramsbottom, A. E., 1976. Depth charts of the Cumbrian lakes. Freshwater Biological Association.Google Scholar
- Reynolds, C. S. 1984The Ecology of Freshwater PhytoplanktonCambridge University PressCambridgeGoogle Scholar
- Reynolds, C. S. 1997bVegetation Processes in the Pelagic: A Model for Ecosystem TheoryEcology InstituteGermanyGoogle Scholar
- Shannon, C. E., Weaver, W. 1949The Mathematical Theory of CommunicationUniversity of IllinoisUrbanaGoogle Scholar
- Thackeray, S. J., S. C. Maberly & I. J Winfield, 2005. The Ecology of Bassenthwaite Lake. Freshwater Forum, 25 (in press).Google Scholar