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Hydrodynamics, Aquatic ecology -- Research -- United States, Environmental monitoring -- Pacific Northwest, Lakes Oregon


Even though we are managing lakes to decrease algal blooms overall, harmful algal blooms seem to be showing up more and more frequently. Although the word “blooms” connotes dominance and rapid growth, dangerous accumulations of cyanobacteria can occur because of combinations of physiological advantages and particular weather and hydrodynamic conditions. I am particularly interested in specific conditions that might favor Aphanizomenon versus those that might favor Microcystis in Upper Klamath and Agency Lakes. Aphanizomenon is a nuisance and large blooms can lead to oxygen depletion and fish deaths. Microcystis can both be a nuisance and is toxic. The comparison of the physiologies of these two cyanobacterial strains could lead to an understanding of both short term adaptation and mitigation tactics as well as long term lake restoration strategies. Ideally, we would like to employ lake restoration strategies and see constant improvement leading to safer and cleaner water. However, either because of threshold effects or ineffective lake management approaches, we might have to take short-term manipulations that can reduce local accumulations of cyanobacteria to protect the health of humans and other species. These short term tactics must have three characteristics: First, we need to find mitigation techniques that might knock down or stall a bloom of algae from occurring. Second, we have to have ways to model and monitor these manipulations over relevant time and space scales. Third, any short-term techniques we employ should not substantial interfere with the long term goals of lake restoration, i.e. the quick fix shouldn’t undermine the solving the problem. I will present several potential short-term solutions based algal physiology and hydrodynamics. Then I will describe how we have used temperature datalogging (10 minute intervals) and high-resolution transects (1 meter spatial resolution) to understand impacts on accumulation processes. Then finally, I will describe a framework for supporting fast and cheap methods to adapt to cyanobacteria accumulations that don’t result in unintended consequences or interfere with lake restoration efforts.


Presented at the Oregon Lakes Association. Oct. 14, 2016. The Dalles, OR.

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