Quagga mussels feed on a variety of algae types in Lake Havasu, filtering the water for nutrients as they continue their invasion of the lake. But what’s bad for once species is almost certainly good for another.
And a potentially toxic algae-like substance is cashing in on the Quaggas’ distaste for it, flourishing into full-blown algae blooms for the past few years as regular algae is kept at bay, according to local scientists.
“We’ve seen the outbreaks now for about three years and some of them have been pretty heavy,” Bureau of Land Management Biologist Doug Adams said.
Cyanobacteria Microcystis potentially carries toxins – although not always and at different levels – and the organism has caused the death of wildlife as their toxins move up the food chain, Adams said. An algal bloom in Lake Eerie resulted in a “do not drink” advisory for more than 400,000 people in Toledo, Ohio in August.
Doyle Wilson, Havasu’s water resource coordinator, said he has seen the blooms throughout the lake this year. He sent a sample of the organism to a University of Arizona scientist, who can analyze the specific type of species and whether it carries toxins. Wilson is still waiting for the results.
Cheri Engels, who has lived in Havasu for 14 years, was on the lake at the beginning of November with family when they came across a sticky, bright green substance as they waded to a beach across the lake from Site Six. She said he had never seen algal blooms that looked like that before and that it was closer to lime green and stickier than the algae she is used to.
“It was really kind of weird,” Engels said. “It was thick and it was gross.” She said the substance was spread across the cove they had pulled their boat into and lapping up to the shores.
Adams and Wilson both said the description Engels provided of her sighting was consistent with what they have seen in the field.
If the blooms are toxic, they could harm species on the lower end of the food chain that feed on algal nutrients and move their way up the chain. Adams said the toxins in fish were credited with the death of raccoons near infested lakes in the eastern United States.
Local scientists are still working on getting their hands around the extent of the algal blooms and impact on the lake’s ecosystem, but they say there are no signs that it has had a negative impact on fisheries.
“This is still a lot of new stuff…” Adams said. “In general, we haven’t seen anything yet, but reading the literature, we should anticipate changes.”
He said if the blooms continue at their current pace they could harm the lake’s fish populations. There could even be a level of growth that would force the lake to be closed, he said. “I will be getting into concern when the whole lake is blooming,” he said.
Russ Engel, a fish biologist with Arizona Game and Fish, recently conducted a survey of fish populations and composition in the lake. Although the data is still being processed, he said, anecdotally fish seem to be thriving at Lake Havasu.
“At this point, we don’t think there is any impact from (the blooms),” Engel said. “Just anecdotally, things look great, just fantastic.”
View original article at: Scientists test for toxins in algae-like substance growing in Lake Havasu