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Communication at the NABS Annual meeting, Keystone, 2000
(48) MICROPHYTOBENTHOS IN TEMPERATE FLOODPLAIN LAKES: EXPERIMENTAL ANALYSIS OF SPECIES DISTRIBUTION IN ENVIRONMENTAL GRADIENTS.
E. Van Der Grinten, A. Janssen, C. Barranguet, and W. Admiraal. Department of Aquatic Ecology and Ecotoxicology, University of Amsterdam, Kruislaan 320, 1098 SM Amsterdam, The Netherlands
Benthic microalgae colonize all kinds of illuminated substrates in aquatic ecosystems. A large range of microphytobenthos consortia with distinct physiognomy and species composition can be found, depending on the environmental conditions. Lakes in floodplains of large rivers are highly diverse, presenting differences in connectivity and frequency of flooding by the river. Such lakes will have a range of sizes, depths, substrates and nutrient concentrations that will create diverse habitats for microphytobenthos. In this study, field observations and laboratory studies are combined to study the factors regulating interspecific competition and success of microphytobenthic consortia in the gradients of floodplain lakes. Field sites were sampled seasonally in the floodplain lakes of the river Rhine. Common algal species, some of them site or season specific, were isolated and cultured. Specific growth rates under a pre-determined set of conditions (temperature, light, nutrients) were studied. Optimum growth rates for temperature, light and nutrients were estimated for each species to assess the factors governing the natural abundance in the field. Multispecies experiments were developed to elucidate competition mechanisms among several microphytobenthic species. The importance of competition as a force structuring benthic algal assemblages is discussed with the information obtained with the experimental manipulation of temperature, light and nutrients.
Presented at 3:30 PM on Monday, May 29, 2000 in Wetlands and Lentic Ecology II
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