By Dr. Kate Fickas
In a fitting end, the final week of the Utah Division of Water Quality’s 2019 recreational monitoring season was marked with below-freezing temperatures and storms that sprinkled our hills and mountains with snow and ice. For the past five months, DWQ’s Harmful Algal Bloom (HAB) Program has visited and analyzed data from 800 sites across 65 different water bodies to help the State’s Local Health Departments ensure recreators are safe when enjoying Utah’s waters. With the help of the public, health departments, and other partners, we detected HABs at 38 different water bodies this year; nearly 60 percent more than any other year of this program.
This year also marked a statewide shift in awareness about HABs. Over the summer, we received daily phone calls from concerned citizens and recreators as HABs became a top news story across the country for their role in the death and illness of pets and people. Closer to home, a well researched article by Sofia Jeremias for the Deseret News helped summarized the problem in Utah and around the country. Traffic to DEQ’s HABs website increased as Utahns checked to see if their favorite lake or reservoir was on advisory before heading out on a weekend trip.
Three questions consistently come up when discussing HABs: “Has this always been a problem?,” “Why is this happening?,” and “Is the problem getting worse?.” These are hard questions to answer with complicated and nuanced implications for management and safety. To start, HABs are not actually comprised of algae, they are formed from toxic cyanobacteria. With fossil records back to 3.5 billion years ago, the scientific community finds that cyanobacteria were one of the first forms of life on this planet and are partly responsible for our DNA structure, our diurnal sleep pattern, and the oxygen in Earth’s atmosphere. Not all cyanobacteria are toxic, but there are very few, if any, lake systems around the globe that do not have some form of cyanobacteria present.
This year, several peer-reviewed scientific studies were published to inform on these questions in Utah and across the globe. In her Ph.D. research at the University of Utah, Dr. Carly Hansen used satellite imagery to extend the period of investigatory record to the 1980s to estimate potential HAB presence across lake systems in Utah. In her article published in the Journal of Lake and Reservoir Management, she finds that, as detected through remote sensing, HABs have been present in Utah Lake for the past four decades. To get at ‘why?’, she notes that ‘the long-term remotely sensed record supports the suggestion that high winter/spring precipitation, high temperatures, and high runoff contribute to algal blooms in Utah Lake’. Exploring the question of a worsening phenomenon, Hansen found that the remotely sensed record shows peak HAB concentrations happening around 3 days earlier each year; expand that out for 35 years and you get a much earlier start to the HAB season. These findings have the potential to significantly impact water quality management, recreation, and safety across the state.
In her M.S. research at Brigham Young University, Shanae Tate also used remote sensing imagery back to 1984 to evaluate if there are consistent ‘hot spots’ for HABs on Utah Lake. In her study titled “Landsat Collections Reveal Long-Term Algal Bloom Hot Spots of Shallow, Eutrophic Utah Lake,” she found that some areas of the lake, such as Provo Bay, are intensifying and enduring hot spots for HABs. This finding and research has great potential to help inform managers and scientists towards targeting monitoring and potential remediation.
On a global scale, researchers from Stanford University and NASA also used satellite imagery to examine the spatial distribution of HABs across the planet over the past three decades. In an article published in Nature, researchers cite a widespread global increase in HABs, but they did not find a ‘silver bullet’ for the reason behind an increase in blooms globally. They did find, however, that lakes that did not warm as intensely over the past 35 years were less likely to see an increase in bloom intensity over time. This should help inform managers about the imperative need to account for shifting hydrologic conditions under global climate change.
While the recreation season is over and advisories will be lifted, we continue to see HABs in lakes and reservoirs across the state. Cyanobacteria are ancient organisms and have billions of years of adaptation mechanisms to shift towards surviving in extreme environments, including snow and ice. We ask that those of you who continue to recreate in waters between now and next summer keep an eye out for signs of HABs in order to keep yourself, your family, and your pets safe. Our partners in Utah’s Division of Drinking Water will continue to monitor finished drinking water for cyanotoxins.
In the off-season, we plan on expanding our outreach to public schools as well as developing a more efficient communication strategy with our cooperating agencies and stakeholders. We also continue to work closely with other states in the region and country affected by HABs to gain insight into new ways to monitor and protect. DWQ would like to thank all of our partners for their dedication to public safety and thank the public for their role as citizen scientists, helping us detect HABs in many new recreational lakes. Until next year, stay safe and enjoy Utah.