08/27/2026
The freshwater lakes that we frequent are vulnerable to harmful algal blooms that threaten ecosystem function and public health. RE Sources’ North Sound Waterkeeper and team currently monitor five lakes throughout the summer and fall seasons, when algal blooms are more likely to occur due to warmer temperatures. These lakes were selected because they are used as drinking water or have high recreational usage like swimming, boating, and fishing. This week, RE Sources’ Program Coordinator Zoe Fry and North Sound Waterkeeper Intern Sarah Guenther were out collecting water samples at Cain Lake. Regularly monitoring these lakes is crucial for informing the public and leading agencies to further assess these blooms.
�The Lake Monitoring process consists of visual observations and data collection on water quality parameters, which aids in detecting signs of algal blooms and nutrient pollution. Using a YSI multimeter, a water quality monitoring instrument, we measure parameters from the surface of the water to the bottom of the lake. In the RE Sources lab, the water samples are analyzed for the presence of phosphate and nitrate. Harmful algal blooms are caused by an excess of nutrients, specifically nitrogen and phosphorus, which enter lakes from stormwater runoff and wastewater effluent. If any algal blooms are observed on the surface or in the water column, samples are collected for microscopic identification.
One of the best ways to be informed about harmful algae blooms is signing up for ’s listserv, or visiting nwtoxicalgae.org. And, check out re-sources.org for tips and resources for staying safe while swimming and harvesting seafood this summer.