Neill, W. E. University of British Columbia, neill@zoology.ubc.ca
, . E. ,

 
LESSONS FROM 20 YEARS OF MESOCOSM STUDIES OF PLANKTON DYNAMICS IN OLIGOTROPHIC LAKES
 
Enclosed mesocosms capture only a limited portion of the diverse physical, chemical and biotic processes that function in open lakes. To the extent that experimental field tests of hypotheses depend on which of these background processes have been [intentionally or inadvertantly] included or excluded, manipulations in mesocosms may under- or over-estimate the general significance of specific mechanisms. Using several examples from my own and student's mesocosm studies in oligotrophic lakes over the past 20 years, I shall illustrate the varying sensitivity of tests of mechanistic hypotheses to (1) mesocosm size, productivity, and mixing regime, (2) experiment duration, and (3) food web structure and taxonomic resolution of the analysis. Strategies for coping with and exploiting these effects will be indicated. I will conclude with some general inferences about the utility of mesocosm approaches to testing direct and indirect effects of species' interactions in lakes.
 
Day: Thursday, Feb. 4
Time: 09:00 - 09:15am
Location: Eldorado Hotel
 
Code: SS51TH0900E