Harmful Algal Blooms: A threat to freshwater lakes
The residents of Whatcom County frequent freshwater lakes for recreational amenities and rely on lakes like Lake Whatcom, Lake Samish, and Cain Lake as a drinking water source. With increasing development and population growth rates in the county (30% over the next 20 years), our freshwater lakes are vulnerable to pollution. With a changing climate, our lakes are also vulnerable to disturbance due to warming temperatures and more severe rainfall events. This can lead to harmful algal blooms, impacting our freshwater lake’s vital ecosystem functions and threaten public health.
Harmful algal blooms are caused by an excess of nutrients, specifically nitrogen and phosphorus, which enter lakes from stormwater runoff and wastewater effluent. Stormwater can contain harmful detergents, pesticides, and fertilizers and wastewater effluent can enter lakes from leaking septic tanks and sewage pipes. The increase of available nutrients in the water column creates an ideal environment for algae to grow. Algae are aquatic organisms that live in the water column and on the surface of the water. They photosynthesize rapidly and their growth on the surface of the water blocks sunlight from reaching aquatic plants and depletes dissolved oxygen as the algae decomposes. This can lead to “dead zones” where fish and other aquatic organisms can’t survive. Algal blooms are also a threat to the public and our pets, ranging from moderate irritations like skin rashes and gastrointestinal issues to neurological effects and even death in wildlife and domestic animals. As the potential for harmful algal blooms increases with development and runoff pollution, it is vital to monitor our lakes for early signs, and to protect Whatcom County residents and pets from harm.
Project Overview
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 in collaboration with Whatcom County Health and Human Services and Western Washington University’s Institute for Watershed Studies (WWU IWS). The lakes were selected because they are used as drinking water or have high recreational usage like swimming, boating, and fishing.
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. If any algal blooms are observed on the surface or in the water column, samples are collected for microscopic identification.
Project Spotlight: Lake Padden
Lake Padden is located at Lake Padden Park in Whatcom County and is a popular fishing spot for its kokanee, coastal cutthroat trout, rainbow trout, and largemouth bass. The area is well known for its recreational activities and amenities like the golf course and dog park. In the past, Lake Padden has had occasional algal blooms. These can occur naturally in freshwater lakes but further investigation is underway to determine any outside nutrient sources that are being deposited into the water. Understanding the changing conditions of the lake and any external influences contributing to algal blooms is critical to assessing the lake’s ecosystem health and protecting its recreational value to the public. RE Sources is doing paired sampling with WWU IWS at Lake Padden. Nutrient samples are being collected from the top and bottom of the lake as well as the two inlets, to help identify the source of the nutrients feeding the algae. Lake Padden will be sampled all year round as it has more frequent blooms in the off season.