2022 Early Hearing Detection & Intervention Virtual Conference
March 13 - 15, 2022
5/25/2021 | 2:00 PM - 3:30 PM | NUISANCE PROLIFERATIONS OF THICK BENTHIC DIATOM MATS IN OLIGOTROPHIC LAKES: A NEW PROBLEM WITH CHALLENGES FOR IDENTIFYING THE CAUSES | Virtual Platform
NUISANCE PROLIFERATIONS OF THICK BENTHIC DIATOM MATS IN OLIGOTROPHIC LAKES: A NEW PROBLEM WITH CHALLENGES FOR IDENTIFYING THE CAUSES
Watershed groups for high quality lakes (TP less than 10 ug\L) in the northern region of Michigan’s lower peninsula have observed increases in thick, nuisance-level benthic diatom mats in the last 1-2 decades. Stakeholders and I developed a list of potential hypotheses for causes of what stakeholders call golden brown algae (GBA). Groundwater contamination by nutrients was deemed the most likely hypothesis, but we also consider many more. Spatial patterns in GBA are poorly related to land use and streams around lakes, as we would expect for groundwater or surface water contamination. However nearshore waters are enriched with P, which likely comes from P-enriched groundwater. Experiments and nutrient concentrations show that GBA growth is highly limited by low P supply, more than low N. GBA mats are dominated by diatom species adapted to the extremely low nutrient supply in control treatments of my experiment. In addition, historical diatom assemblages reported in regional paleolimnological studies indicate at least one low nutrient taxon was not listed. Therefore, incomplete and often contradictory results prevent identifying the causes of GBA with enough certainty to guide management. Studies continue to reach that goal.
- Contaminants
- Global change
- Land use
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Presenters/Authors
R. Jan Stevenson
(), Michigan State University, rjstev@msu.edu;
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