Growth of red algae at McKinley Park pond raises safety concerns
A growing rust-red layer of algal muck has spread steadily throughout the McKinley Park pond in East Sacramento.
The muck, which resembles algae or another type of water bacteria, has drawn the concern of a pond activist over the potential effects a poisonous algal organism could have on the animals that inhabit the pond in East Sacramento’s prized park. Now the city of Sacramento and the California Water Board have said they will examine the ominous algal globs.
“They need to flush all this out,” said Judy McClaver, a self-described waterfowl activist and volunteer pond cleaner.
McClaver first noticed the muck on the eastern side of the pond Tuesday. By Friday morning, McClaver could point out how the algae-like substance had spread along the edges of the pond.
In the midday sunlight, the floating sludge gleamed.
McClever said she worried the muck could be poisonous cyanobacteria, an algal that can poison animals that interact with the water. She also fears increasing temperatures in the pond water can create toxins that lead to botulism, a toxin-induced condition that can paralyze animals.
She said the pond serves as a habitat for ducks, geese and mosquito fish, a type of fish McCklever said limits the mosquito population and thus reduces the risk of West Nile Virus. Dogs, too, approach the pond during walks.
“It’s unlikely that it’s cyanobacteria,” said Benjamin Chen, an aquatic biologist for SOLitude Lake Management, a contractor that manages the pond. “But we need to put it under a microscope.”
Chen told The Bee that the substance could be any number of algae or bacteria that resemble the dangerous cyanobacteria.
SOLitude will test the pond water for the city in a lab as early as Monday to determine if the muck poses a risk to humans or animals. Results will arrive later in the week, according to Chen.
The California Water Board’s Freshwater Harmful Algae Bloom program will conduct its own test beginning Monday.
McClever said she believes the pond is in need of more oxygen circulation through its aerators, a pond equipment piece she said the city’s Parks Department has begun to turn off during the day to prevent overheating.
Grace Nunez, a spokesperson for the city of Sacramento, said in an email the city “is considering extending the length of time aerators operate to increase water flow and help oxygenate the pool.”
Summer conditions in Sacramento are optimal for algal organisms like algae and other water bacteria, Chen said. The increase in temperatures and sunlight from the region’s Mediterranean climate often warms still water like that of the park pond.
The region’s abundant sunlight also allows algae to photosynthesize and grow at a steady rate.
At park ponds, natural and man-made runoff, such as animal feces and fertilizers, create muck at the bottom of the pond, increasing the amount of phosphate and nitrogen in the pond and providing ample nutrients for the algae or algae-like bacteria.
To diminish the favorable conditions for algae at the pond, Chen said, pond phosphate levels must be kept down either through increased use of aerators. The aerators increase the amount of oxygen in the pond or by increasing the amount of bacteria that break down the muck that accumulates at the bottom of the pond.
