From The Colorado Springs Gazette (Rachel Riley):
Steamy temperatures, a lack of shady trees and stagnant, shallow waters make the pond [Duckwood Pond in Fountain Creek Regional Park ] a breeding ground for the green algae, which thrives on warmth and sunlight. Another ingredient for the algae’s success, nitrogen, is added by the resident flock of Canada geese, with each bird producing about a pound of nutrient-rich feces each day…
The photosynthetic, plant-like organisms are found in practically every…body of water, from ponds to reservoirs, and can multiply rapidly under the right conditions to create algae blooms. Luckily, there are no negative effects on the body of water’s aquatic ecosystem – only its aesthetic value, Salamon said.
But it’s often hard to distinguish regular algae with its much less innocuous counterpart: cyanobacteria, also known as blue-green algae. For reasons scientists haven’t nailed down, cyanobacteria blooms can sometimes produce toxins that threaten nearby flora and fauna.
Of the 150 lakes across the state sampled routinely by the Colorado Department of Public Health and Environment, about 30 have tested positive for blue-green algae, including 10 to 15 that regularly produce blue-green algae blooms, according to the department.
And while officials have not observed any negative consequences for wildlife connected to the presence of cyanobacteria, state agencies are taking precautions.
The department has developed an in-house testing method to determine if the blue-green algae is producing harmful toxins, what the toxins are and how concentrated they are, said Sarah Wheeler, a researcher at the state’s Water Quality Control Division…
According to Colorado Parks and Wildlife, areas where cyanobacteria blooms have occurred include Stagecoach State Park, Barr Lake State Park, and Cherry Creek State Park and De Weese Reservoir.
The cyanobacteria blooms most often occur in urban areas and agricultural regions the eastern plains that experience a lot of runoff from fertilizers – the same places that are hotspots for regular algae blooms, Wheeler said.
“Cyanobacteria do really well with high nutrients and lots of sunlight – they form when conditions are right, so when the temperatures are really hot in the summer, the water temperatures increase and you also have high nitrogen,” she said.
Unlike most other contaminants, cyanobacteria and the toxins they produce are not regulated by the Environmental Protection Agency, so it’s up to state officials to decide how to monitor its presence in recreational and drinking water sources. In June 2015, the EPA issued a drinking-water health advisory for two contaminants sometimes produced by cyanobacteria: microcystins and cylindrospermopsin.
Research has associated high levels of drinking water containing the toxins with stomach flu, liver and kidney damage. People swimming in lakes where cyanobacteria was present have reported stomachaches, allergic reactions and skin rashes. For wildlife, long-term exposure may also lead to liver and kidney damage, according to the EPA advisory.
While officials have observed some drinking-water sources that have cyanobacteria blooms, none has tested positively for levels of above-recommended levels of microcystins and cylindrospermopsin specified in the EPA’s health advisory, said David Dani, who oversees coaching and training for the Colorado Safe Drinking Water Program…
In 2014, the agency formed the Algal Toxin Team, consisting of park, district, area and deputy regional managers, as well as public information officers. Last spring, Parks and Wildlife met with environmental epidemiology officials from the health and environment department to determine at what toxin level warning or caution signs should be posted at bodies of water containing cyanobacteria blooms.
The guidelines also help park officials identify the blooms, [Mindi May] said.
One method is the stick test: If you run a stick through the water and strings of the algae cling to the stick, it’s filamentous algae, not cyanobacteria. Another is the bottle test: If you scoop up some of the water and the algae sinks to the bottom of the container, it’s probably regular algae and not cyanobacteria, which would float or remain suspended in the water.
When park officials identify a cyanobacteria bloom, there is often little they can do besides wait for the bloom to subside, which can happen within days, May said.