DGS staff member Scott Andres along with Bill Ullman and Tye Pettay from the College of Earth, Ocean, and Environment, and Chris Main of the Department of Natural Resources and Environmental Control had an article “Hydrophysical and Hydrochemical Controls of Cyanobacterial Blooms in Coursey Pond, Delaware” published in the Journal of Environmental Quality (doi:10.2134/jeq2018.03.0108). Cyanobacteria are primitive microscopic single-celled organisms that are found nearly everywhere but can take over ponds, lakes, estuaries, and coastal oceans when plant nutrients (nitrogen and phosphorus) are too abundant. Some forms of cyanobacteria can produce toxins that are harmful to aquatic life or to animals and people that contact or ingest them. Work at Coursey Pond is an offshoot of the NEWRNet project (https://www.dgs.udel.edu/projects/newrnet-north-east-water-resources-ne…).

Cyanobacteria blooms are common in many small flow-through ponds in the mid-Atlantic Coastal Plain and this study used off-the-shelf biogeochemical sensors to characterize bloom onset, intensity, and dissipation. The work had several key findings. Water residence time in the pond, temperature, and nitrate concentration are robust predictors of bloom onset. Storms temporarily disrupt blooms by flushing, but blooms re-establish once stormflow ceases. Irrigation within the watershed increases pond residence time, thus promoting blooms.

This project and publication fill the Survey’s mission to explore and to advise, inform, and educate Delawareans about the State’s water resources. For additional information, contact the Survey at (302) 831-2833 or via email at delgeosurvey@udel.edu.