Dynamics of grazing protozoa follow that of microalgae in natural biofilm communities
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This study investigates the dynamics of protozoan community in biofilms formed on inert artificial surfaces suspended in various freshwater environments. The results also test the hypothesis that the dynamics of protozoan and microalgal communities in biofilms are interdependent because the latter form one of the major food items of benthic protozoa. Cleaned glass slides were suspended in surface waters at four sampling locations to collect biofilm communities. The glass slides after retrieval were observed under a microscope for diatom and protozoan density and their generic composition. Members of protozoa belonging to phylum Sarcomastigophora dominated the protozoan community followed by phylum Ciliophora in all sampling locations. The variation of protozoan feeding groups showed an initial abundance of autotrophs/holophytes which gave way to heterotrophs, predators, and bacterivores towards the end of the study. The density and generic composition of protozoa varied significantly with the age of biofilm and sampling location. The density variation of protozoa followed that of diatoms in all four sampling locations and this has resulted in a significant positive correlation between diatom and protozoan densities. This suggests the dependency and/or food web connectedness of these two communities in natural biofilms.
KeywordsBiofilm protozoa Lentic system Natural biofilms Diatoms Water quality
This work was supported by Lakehead University Research Development Fund. Undergraduate students Diane Mitchell and Katelyn Weel helped in data collection.
- Characklis, W. G., G. A. McFeters & K. C. Marshall, 1990. Physiological ecology in biofilm systems. In Characklis, W. G. & K. C. Marshall (eds), Biofilms. Wiley, New York.Google Scholar
- Curds, C. R., A. Cockburn & J. M. Vandyke, 1968. An experimental study of the role of the ciliated protozoa in the activated sludge process. Water Pollution Control 67: 312–329.Google Scholar
- Eaton, A. D., L. S. Clesceri, E. W. Rice & A. E. Greenberg (eds), 2005. Standard Methods for the Examination of Water and Wastewater, Centennial edition. American Public Health Association, Washington, DC.Google Scholar
- Kanavillil N., M. Thorn & S. Kurissery, 2012. Characterization of natural biofilms in temperate inland waters. Journal of Great Lakes Research. doi: 10.1016/j.jglr.2012.06.014.
- Lake Simcoe Environmental Management Strategy (LSEMS), 2003. State of the Lake Simcoe Watershed 2003. Lake Simcoe Region Conservation Authority, New Market, ON.Google Scholar
- Lamb, L. A. & R. L. Lowe, 1987. Effects of current velocity on the physical structuring of diatom (Bacillariophyceae) communities. Ohio Journal of Science 87: 72–78.Google Scholar
- Lee, J. J., S. H. Hunter & E. C. Bovee, 1985. An Illustrated Guide to the Protozoa. Society of Protozoologists, Lawrence: 615.Google Scholar
- Lee, J. J., G. F. Keedale & P. Bradbury, 2000. An Illustrated Guide to the Protozoa, Vols. I & II, 2nd ed. Society of Protozoologists, Lawrence: 1425 pp.Google Scholar
- Lower Colorado River Authority (LCRA), 2011. Water quality indicators. Key measures provide a snapshot of conditions. http://www.lcra.org/water/quality/crwn/indicators.html.
- Prescott, G. W., 1978. How to Know Freshwater Algae. W.C. Brown, Dubuque.Google Scholar
- Ricklefs, R. E., 2001. The Economy of Nature. W.H. Freeman and Company, New York.Google Scholar
- Round, F. E., R. M. Crawford & D. G. Mann, 1990. Diatoms: Biology and Morphology of the Genera. Cambridge University Press, New York.Google Scholar
- Verity, P. G., 1985. Grazing, respiration, excretion and growth rates of tintinnids. Limnology and Oceanography 33: 245–255.Google Scholar