Cal State East Bay Professor, Grad Student Look into Toxic Algae Blooms Invading Local Lakes
This toxic blue-green algae bloom has closed swimming at Lake Temescal in Oakland.
- August 19, 2015
California State University, East Bay’s Department of Earth & Environmental Sciences is investigating the causes of recent toxic blue-green algae blooms, resulting in closures of Lake Temescal in Oakland and Quarry Lakes in Fremont. Dr. Jean Moran, associate professor and chair of the department, is conducting the investigation along with Faithe Lovelace, a graduate student in geology. Together, they are collaborating with East Bay Regional Parks & Recreation to determine the source of the blooms, which are highly toxic and can be deadly to humans and animals.
Toxic blue-green algae blooms are a type of cyanobacteria that grows when an excess of nitrogen and phosphorus is present in a body of water. They typically occur in stagnant or slow-moving water during periods of warm weather, producing a pea green soup-like substance on the surface. Last year, several dogs died after swimming in Lake Chabot during an algae bloom, most likely due to ingesting water or licking their wet fur. In 2012, approximately 30 otters are thought to have died when agricultural runoff from Pinto Lake brought algae toxins to Monterey Bay.
While nitrogen and phosphorus occur naturally in lake water, they can cause toxic blooms if they grow unchecked. “There are many ways that these nutrients can enter the lake,” says Moran. “Because Lake Temescal is on the Hayward Fault, the ground is under a constant shear stress. Sewer lines can fracture and leak, bringing phosphorus from detergents and other nutrients into the water column. That’s the focus of our research, to determine how these nutrients are getting to the lake. Direct runoff from lawns and nurseries can contain fertilizers, pet waste and other chemicals that can add to water quality problems for the lake.”
Climate change may also play a role in bloom growth, explains Moran. “Warmer water temperatures can provide ideal conditions for blooms. Rising temperatures and the California drought have made blue-green algae grow at a faster rate. And climate change is also causing blooms at higher latitudes and higher altitudes. We’re even seeing them in colder areas like Canada.”
To determine whether excess nutrients are coming from natural or unnatural sources, Moran and Lovelace are using radon and other isotopes to analyze samples. “If there is a high amount of radon in a sample, it tells you that groundwater is entering the lake near the sampling point; if the sample contains high phosphate, then it’s likely that nutrients are entering the lake via groundwater,” says Lovelace.
Other than controlling nutrient sources, there aren’t any reliable ways of preventing toxic algae blooms in the long term, and even short-term solutions are considered “band-aids.” One method is to target phosphates and make them solid so they sink to the bottom of the lake. “It’s only a temporary fix because, even though you remove it from the water column, it’s still in the sediment,” explains Moran. “Water gets mixed every year as it turns over, so phosphates may be re-suspended in the water column.” The park district wants to find a long-term solution, but first the main source of phosphorus needs to be identified.
“Faithe and Dr. Moran are performing an intensive characterization of surface water and ground water interactions in the Temescal Watershed,” said Pamela Beitz, a CSUEB graduate who now works for the EBRPD. “Investigations of anthropogenic (human impact on the environment) and geologic nutrient sources will provide the East Bay Regional Park District with essential data that will guide the future management of this historic swimming spot in the Oakland hills.”
Blue-green algae blooms will eventually dissipate as temperatures decrease, but that process can take weeks or even months. Though park officials regularly monitor them and announce beach closures on the East Bay Regional Parks website, extreme caution should still be taken. Pets should be kept away from these areas and swimming in them should be avoided at all costs.
For further information about the research project on toxic blue-green algae blooms, contact Dr. Jean Moran via email at jean.moran@csueastbay.edu. For park information, call 1-888-EBPARKS or email help@regionalparksfoundation.org.