Harmful algal blooms reported at Saratoga Lake for fifth year

For yet another year, Saratoga Lake has been added to the list of lakes and reservoirs where dangerous cyanobacteria blooms have been found. Advisories of harmful algal blooms—also known as blue-green algae—have previously been issued for the lake beginning in 2019.

What are harmful algal blooms and why do they seem to keep happening every year?

Tiny organism,

big impacts

“Lake water has many different types of microscopic organisms and some of them—many different types of algae and cyanobacteria—are plants or bacteria that can perform photosynthesis,” said Sarah Michelle Collins, an assistant professor at the University of Wyoming’s Department of Zoology and Physiology. “Even though algae and cyanobacteria aren’t closely related to each other in the tree of life, both of them can make lakes turn green when they are growing quickly and cause water quality problems.”

The water quality problems is what has lead both the Wyoming Department of Health and the Wyoming Livestock Board to issue the following recommendations:

Avoid contact with water in the vicinity of the bloom, especially in areas where cyanobacteria are dense and form scums.

Do not ingest water from the bloom. Boiling, filtrating and/or other treatments will not remove toxins.

Rinse fish with clean water and eat only the filet portion.

Avoid water spray from the bloom.

Do not allow pets or livestock to drink water near the bloom, eat bloom material or lick fur after contact.

If people, pets or livestock come into contact with a bloom, rinse off with clean water and contact a doctor or veterinarian.

According to the Centers for Disease Control and Prevention, the symptoms related to exposure to a harmful algal bloom depends on the type of contact made with cyanobacteria. Those who come into contact by touching or swimming in contaminated water, or by breathing in droplets of contaminated water, may experience irritation of the skin, eyes, nose, throat and lungs. Those who have consumed contaminated food or swallowed contaminated food may experience symptoms such as stomach pain, headache, dizziness, muscle weakness or vomiting.

Researching Blooms

Collins and her lab have been monitoring cyanobacterial blooms throughout Wyoming and researching the frequency of blooms in the past using satellite records.

“It’s not clear whether blooms have never occurred in the past are starting to get worse, or whether we haven’t noticed them in the past and people are becoming more aware of blooms,” said Collins. “It’s likely that both of these are contributing to what appears to be a big increase in blooms.”

According to Collins, the analysis conducted by her lab appears to suggest that Wyoming lakes haven’t become greener over the past 40 years. Though, that suggestion comes with a caveat.

“Those are estimates based on data from the center of lakes and a lot of blooms are reported or observed along the lakeshore on beaches where we can’t get good satellite data,” said Collins.

While looking at data from Wyoming’s lakes, additional research has been done by looking at other places in the United States which experience harmful algal blooms. According to Collins, in the upper Midwest—which has a lot of agricultural activity—a major contributing factor to blooms is an increased input of nutrients from fertilizer and animals. Those nutrients include nitrogen and phosphorus.

“We also know that warm temperatures, high winds and inputs of water from big precipitation events can promote bloom development,” said Collins. “Wyoming is a really different environment from other regions where these ideas were developed, so we need to do more research to figure out what climate and nutrient conditions are promoting blooms here.”

According to Collins, warmer temperatures and more extreme weather events may be a strong influence on the development of harmful algal blooms and their duration. Specific predictions as to whether blooms will happen earlier in the summer or last longer are difficult to make, she said, because “there are some really complex interactions between climate and nutrient inputs that lead to blooms” along with a lot of variability between different summers.

What about the fish?

Earlier this year, Saratoga Lake was restocked with new trout species. The restocking came after the Wyoming Game and Fish had drained the lake and applied rotenone last fall, an action taken in response to the illegal introduction of yellow perch. According to Collins, it’s unclear whether the harmful algal blooms will have a negative impact on the new trout inventory or how it might impact the population.

“Cyanobacteria and algae are the bottom of the food web and a bloom might influence the abundance or types of zooplankton—the next step up in the food web—which could influence energy available to fish,” said Collins. “The toxins produced by a bloom could also negatively affect fish. One of the graduate students on our harmful bloom project is specifically examining how the blooms in Saratoga Lake influence zooplankton and fish feeding.”

The results of that study, said Collins, are still pending.

Saratoga Lake is currently one of seven lakes or reservoirs which has had an advisory issued regarding harmful toxins from algal blooms. It is also one of 29 to have a harmful algal bloom advisory. Blooms were previously reported in 2019, 2020, 2021 and 2022 while toxin advisories were issued in 2021 and 2022.