2022 Early Hearing Detection & Intervention Virtual Conference
March 13 - 15, 2022
6/06/2017 | 9:45 AM - 10:00 AM | CHRONIC NITRATE CONCENTRATIONS ALTER THE STRUCTURE AND FUNCTION OF RIVER BIOFILMS | 306A
CHRONIC NITRATE CONCENTRATIONS ALTER THE STRUCTURE AND FUNCTION OF RIVER BIOFILMS
We tested the effects increased nutrient availability on the composition and function of river biofilms using laboratory mesocosms. Early and mature stage biofilms from two rivers were incubated in for three weeks at four nitrate loads (0, 0.5, 5 and 25 mg L-1). Early stage biofilms increased growth rates in response to elevated nitrate, but growth of mature biofilms were less responsive to added elevated nitrate. In terms of nutrient acquisition, cell specific maximum uptake rates declined with elevated nitrate treatments, resulting in an essentially constant rate of uptake per unit photosynthesis across a wide range of nitrate concentrations. Nutrient recycling within the biofilm was driven by the level of biofilm development, as biofilms became more self-reliant on internal N cycling with increasing size. Early stage biofilms shifted from a diatom dominated community to a community dominated by green algae and cyanobacteria with increasing nitrate treatment levels. Our results indicate that nitrate loading alters biofilm structure and function and provides a set of mechanisms to explain for the efficacy loss pattern seen in field studies.
- C01 Algae
- C04 Microbial Ecology
- C10 Biogeochemistry
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Presenters/Authors
Jonathan O'Brien
(), Canisius College, obrien46@canisius.edu;
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David Kerling
(), Canisius College, kerling1@canisius.edu;
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