2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
5/24/2021 | 8:30 AM - 10:30 AM | Experimental evidence for summertime nutrient limitation of phytoplankton in the lower Columbia River, USA. | Virtual Platform
Experimental evidence for summertime nutrient limitation of phytoplankton in the lower Columbia River, USA.
Multiple factors influence large river phytoplankton dynamics, however eutrophication brings urgency to understanding how riverine phytoplankton respond to variable nutrient availability. Based on suggestive preliminary data, from May-September 2018 we undertook monthly 5-day experiments with the natural lower Columbia River (CR) phytoplankton assemblage incubated with amended NO3, PO4 and SiO4 to test for nutrient limitation. Treatment and non-amended control bottles were sampled daily for nutrients and chl a levels, as well as for assessment of phytoplankton composition and biomass. Phytoplankton biomass was lowest in May, when ambient nutrient concentrations were highest, and highest in August, when ambient nutrients were lowest. Diatom biomass dominated in spring, but cyanobacteria biomass increased substantially in late summer. Significantly higher phytoplankton biomass was observed in nutrient-amended treatments in June, July and September, indicating nutrient limitation in the lower CR during those months. Statistical results showed these increases were significantly associated with amended PO4 and SiO4, and to a lesser degree amended NO3 and temperature. Thus, the lower CR may not be conducive to phytoplankton growth during summer, and such conditions may become more prevalent as temperature increases under climate change.
- Microbial ecology
- Nutrients
- Non-perennial rivers
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Presenters/Authors
Gretchen Rollwagen-Bollens
(), Washington State University, rollboll@wsu.edu;
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Stephen M. Bollens
(), Washington State University, sbollens@wsu.edu ;
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Kristin Connelly
(), Washington State University, kristin.connelly@wsu.edu;
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Julie Zimmerman
(), Washington State University Vancouver, juliezimmerman@wsu.edu;
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Alixandra Coker
(), Camas High School, Camas, WA, USA, alixandra.coker@camas.wednet.edu;
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