Toxic Algae Making Itself at Home in Oregon & Elsewhere

Blue green algae blooms were responsible for the closing of ten lakes, ponds, and other public swimming areas in Oregon in 2014, including a portion of the Willamette River. A new study has shown that the algae is able to alter the chemical balance in bodies of water to make them more conducive to the algae’s growth.

It Ain’t Easy Being Blue Green

Researchers from Dartmouth College recently discovered that the blue green algae, also known as cyanobacteria, that appears in Oregon waters is able to manipulate natural chemical cycles to create more hospitable conditions. This process occurs most often in nutrient-poor lakes, despite their natural resistance to algae blooms.

The blue green algae manipulates the waters’ biogeochemical cycling, a naturally occurring process in which living organisms exchange nutrients with air, land, or water. Specifically, the algae affects the levels of nitrogen and phosphorus, two nutrients critical to its survival. Once the biogeochemical cycling process has been altered, it tends to stay that way, with, in this case, nitrogen and phosphorous levels becoming higher and higher over time, therefore making the water that much more conducive to algae growth.

Bloomin' blue green algae.

Bloomin’ blue green algae.

“Human Manipulations” the Main Culprit

According to Kathryn Cottingham, a Dartmouth professor and lead author of the study, recently published in Ecosphere, the team’s research revealed a key cause of the algae infestation. “We usually think of cyanobacteria as responders to human manipulations of watersheds that increase nutrient loading, but our findings show they can also be drivers of nitrogen and phosphorous cycling in lakes,” a statement from Cottingham read, in part.

Ongoing human-caused changes to their environment will allow cyanobacteria blooms to thrive as the effect on the nutrient cycle grows stronger. This is especially true in “clear-water, low-nutrient lakes that are so important for drinking water, fisheries, and recreation,” Cottingham wrote.

The Dartmouth researchers hope their findings will positively affect land-use decisions, leading to reduce human-caused pollution in Oregon’s waterways. Said Cottingham, “The cyanobacteria are showing up […] in response to our human activities. We’re sort of cracking the door, and what this paper is saying is they’re at slamming it open once they get in.”

Photo credit: Wisconsin Department of Natural Resources / Foter / CC BY-ND