This day the Lake was different. My husband Jeff and I are water quality monitors for the Clean Lakes Alliance (CLA, not-for-profit organization dedicated to the improvement and protection of the lakes, streams and wetlands in the Yahara River) on Lake Mendota. At 3:32 pm we received an email from Paul Dearlove, CLA Sr Director of Watershed Initiatives, “Be aware that we are experiencing major blue-green algae blooms on Lake Mendota today (mostly W and SW portions).” He urged all monitors to continue reporting for the rest of the day. We rushed back to Spring Harbor and were shocked at the scene on Lake Mendota. The putrid bluegreen cyanobacteria bloom was as thick as guacamole and smelled of sewage. From our vantage point, we could see that the bloom extended halfway across Lake Mendota, and from Marshall Park to the UW Lakeshore Nature Preserve. We saw a family of Mallard Ducks with 8 tiny ducklings foraging in the foul crud. People continued to zip along in their speedboats and jet skis though the sloshing scum. I saw a kayaker and a family of 3 in a rowboat with a young child rowing to their sailboat through the active bloom. There were workers installing docks in the toxic bloom. I grabbed my cameras to document scene. Workers in the area came up to me, asking “What’s happening? This looks horrible!”
In this review, I will discuss the what, where, when and why of the two massive cyanobacteria blooms of June 7th and June 27th in Lake Mendota and the Yahara Lakes., as well as efforts of community groups and government agencies to address the issue of these bloegreen blooms. I believe the health of the Preserve, and of Madison, cannot be viewed separately from the health of Lake Mendota and the Yahara Lakes Watershed.
Lake Mendota-PlanetScope-Massive Scums(in reddish color) cyanobacteria Bloom, June 7, 2018
Permission Team Cyanotracker.Cyanotracker – Computer Science Department at University of Georgia – Cyanotracker Project.
What causes the growth of cyanobacteria? John Magnuson, Professor Emeritus and Director Emeritus UW Department of Limnology, stated “It was a bluegreen bloom. Bluegreen are photosynthetic cyanobacteria. Bluegreen stay in the sunlight—they need light for photosynthesis—with gas vacuoles for flotation. If it is calm they float to the surface, if there is a slight breeze they tend to accumulate on the downwind side of a lake. When the cells age their membranes breakdown and the water turns into a bluegreen paint-pot appearance from the release of their photosynthetic pigments. The grey you saw,” Magnuson said, is bacterial cells decomposing, producing the foul smells we experienced in University Bay.
Not all cyanobacteria have toxins. There is a diverse set of these species living in Lake Mendota. When the water has warmed and there is plenty of sun and little wind, and when the nutrients pour in with heavy rain events, typically between June and September, a bloom can develop within a few hours.
Steve Carpenter, Professor Emeritus and Director Emeritus UW Department of Limnology, states in Yahara 2070, “One organism, exploding in population, thrives at the expense of others in its ecosystem. That’s essentially what happens in a toxic algae bloom.” In the June 7th and June 23rd Lake Mendota blooms, this organism was cyanobacteria, commonly called blue-green algae. Carpenter says, “Elements like nitrogen and phosphorus that cyanobacteria require, in addition to favorable weather conditions, occur naturally in the environment, but usually not in quantities that support a massive bloom. That issue is becoming more common though, as humans provide massive extra helpings of those nutrients, mostly in the runoff from farms.” He states, “The amount of phosphorus in the Yahara water shed has increased by a factor of ten since urban settlement and rural agriculture transformed the region in the 1840’s and 1850’s…Manure production has gone up…which is rich in phosphorus. The intensity of precipitation has increased—the rain that we are getting is coming in bigger storms.” Carpenter states, “A heavy rainstorm can push a lot of phosphorus into lakes and streams all at once”. Carpenter considers this climate change’s biggest contribution to the toxic cyanobacteria problem, driving average temperatures upward as well as increasing the likelihood of extreme rainfalls.
June 27. Female Mallard Duck & Duckling Foraging in Cyanobacteria Bloom. Spring Harbor Beach. “Microcystin level was greater than 75 ppb.” PHMDC
Why are some cyanobacteria blooms dangerous? Some cyanobacteria can produce toxins called microcystins. These toxins build up inside the cyanobacteria cell and are released in the water once the bacteria die. But not all cyanobacteria produce toxins and researchers have not yet found a way to predict what percentage of cells in a bloom will be toxic. Testing for toxicity is crucial, and in case of doubt taking precautions is the best response for the public.
According to the Clean Lakes Alliance, “people and pets are urged to stay out of the water during blue-green algae or cyanobacteria blooms. The UW Center for Limnology warned that “the toxins can cause issues such as upset stomach, rashes and respiratory problems. Such blooms can also lead to fish kills if the bacteria sinks to the bottom”. The Ecotoxicology Program of the California EPA states “Upon ingestion, toxic microcystins are actively absorbed by fish, birds and mammals. Microcystin primarily affects the liver, causing minor to widespread damage, depending on the amount of toxin absorbed. People swimming, waterskiing, or boating in contaminated water can be exposed to microcystins. Microcystins may also accumulate in fish that are caught and eaten by people. Finally, pets and livestock have died after drinking water contaminated with microcystins.” The most serious problems are caused by ingestion of the contaminated water e.g. a child may drink the water while swimming. Dogs frequently drink lake water. Water skiers and boaters may inhale aerosolized microcystins.
Soup- Cyanobacteria Bloom
Close-up. Note the green paint pot appearance and grey bacterial growth.
What is done to protect the public? Between Memorial Day and Labor Day, Public Health Madison & Dane County (PHMDC) tests water at local swimming beaches for bacteria and blue-green algae to determine if the lake water is safe for swimming and recreation, and to reduce the risk of illness. Sarah Mattes, Public Health Madison & Dane County, states, “Water is tested at the beaches weekly, and if a test shows concerning results, PHMDC will close the beach by posting signs and updating the PHMDC website. Water is then checked each weekday until levels of bacteria and blue-green algae return to acceptable levels.”
Bihm Nimgade of PHMDC stated ”The bloom on June 7th on Lake Mendota was massive. Fortunately it cleared fast this time. We measured high levels of microcystin toxin at Spring Harbor (microcystin at 62.5 µg/L, 22,703 microcystin gene copies) and Marshall (microcystin at >125 µg/L 26.151 microcystin gene copies) beaches.” On June 7th, PHMDC estimated levels of Microcystin >125 ppb estimated throughout the bloom. On June 28th, Jennifer Levander Braun of PHMDC reported the following high values for Madison beaches. This level is considered to be a high probability for adverse health effects for humans. Goodland >125 ppb microcystin Esther >125 ppb microcystin Olin >125 ppb microcystin BB Clarke >125 ppb microcystin Marshall >125 ppb microcystin Warner >125 ppb microcystin Brittingham >125 ppb microcystin.
Kirsti Sorsa confirmed that PHMDCis only testing the public beaches. Regarding Picnic Point, she stated that “UW Health has previously brought samples to us from Picnic Point. However, my understanding is that it is no longer considered as a beach because of vandalism occurring in the area.”
June 27, Picnic Point Shoreline, University Bay, UW Lakeshore Nature Preserve.
What is being done about the cyanobacteria problem? The current high values of microcystin measured during blooms on the Yahara Lakes clearly pose a risk for the public as well as other organisms in the lake that has to be addressed through efforts to reduce blooms and through effective warnings systems.
1. Clean Lake Alliance Plan 2020 Clean Lakes Alliance has developed a road map for achieving cleaner lakes and has adopted Plan 2020: A Clear Path Forward–2018 Priorities Update. Accordingto the Clean Lakes Alliance, 30% of the phosphorus runoff to our lakes comes from urban area and 70% is from agricultural areas. CLA focuses on phosphorus actions for the year 2020. The Yahara CLEAN Strategic Action Plan for Reducing Phosphorus enumerates fourteen specific actions with clear, achievable phosphorus reduction goals to clean the lakes. The actions promote proven, cost-effective urban and rural practices to address phosphorus pollution now. The goal of the plan is to produce dramatic improvements in lake water quality by achieving a 50% reduction in the average annual phosphorus load from direct drainage sources in the Yahara chain of lakes.
Through the combination of urban and rural actions, we will reduce phosphorus loads into Lake Mendota by 53%, Lake Monona by 26%, Lake Waubesa by 50%, and Lake Kegonsa by 56%. Phosphorus reductions in the Lake Mendota watershed will provide additional benefits to the rest of the lakes since phosphorus from Mendota flows to each of the downstream lakes via the Yahara River. CLA is collaborating with and supporting efforts of Dane County leadership, Metropolitan Sewage District, City of Madison, and importantly Yahara Pride farms, the farmer-led agricultural partner of CLA.
2. Dane County’s “Suck the Muck” Initiative In summer 2018, Dane County initiated the “Suck the Muck” lake clean-up project that will remove 870,000 pounds of phosphorus from 33 miles of tributary streams feeding Madison's lakes. County Executive Joe Parisi explained that these “waterways are feeders of phosphorus into the chain of lakes. Until the muck under the water flowing above is free and clear of pollutants, the streams will continue to release phosphorus, responsible for creating algae, into the lakes. This project will provide a benefit by returning these stream bottoms to the way they were back in 1890, allowing for new fisheries and healthy habitats for wildlife.” See a summary of various lake clean-up approaches in Dane County at From "Suck the Muck" to Bubble Barriers at Madison.com, with numerous links. 3. Communicating with the Public Public Health Agencies Public Health Madison and Dane County test some of the beaches and lake access point for microcystin and e. coli and communicates results to Clean Lakes Alliance and through their website. Warning signs are posted at beaches to alert the public. The State is now requiring medical personal to report illnesses related to algae bloom. The Public Health Department will use these data to gain a better understanding of the effect of water conditions and to raise public awareness--See Steven Verburg's report on Madison.com.
Real time information and forecasts of water quality and beaches for Madison lakes The public can access information on current lake conditions and forecasts at http://lakeforecast.org/. This webpage is maintained by Clean Lakes Association.
June 27 Spring Harbor Beach Closed. Microcystin >125 ppb
Warning Sign from New York State Department of Health
UW-Madison The Environmental and Occupational Health (EOH, a unit of University Health Services) is responsible for 3.5 miles of lakeshore from the Memorial Union to Shorewood. Lake water is sampled at the Memorial Union Pier and Hoofer’s Pier, and results are communicated to UW students and faculty, City of Madison, Clean Lakes Alliance, and warning or closure signs are posted. Previous swimming areas that are no longer open along the UW Lakeshore (i.e. Picnic Point and Willow Creek Beach) have large “No Swimming” signs posted to deter use. “These areas are not open for recreational swimming,” according to Jeffrey Steele, Environmental Health Specialist.
Jeffrey Steele, in a recent follow-up, reports that as of this August "Environmental and Occupational Health (EOH) has conducted a comprehensive review of our blue-green algae policy and two changes have been made. One change is that we will now be posting educational signage along the lakeshore about blue-green algae (what it looks like, what its health effects are, what to do if exposed, etc.). The other change is how we relay closures of the Memorial Union swimming pier and Hoofer's pier to our campus partners. UHS will now be posting updates on their website homepage regarding closures. Also, UHS has streamlined how it disseminates closures to UW Communications to be posted on social media platforms. This will reduce any "lag" in reporting."
This positive change in university policy addresses the fact people do enter the lake from those beaches as well as peers. A warning and informational poster at the Picnic Point entrance kiosk and the public boat landing will help educate the public about the risks associated with cyanobacteria blooms. An example of an effective Warning Sign is shown above.
Friends of the Lakeshore Nature Preserve Our Friends President, currently Doris Dubielzig, was not directly informed of the June 7 and June 27th blooms. In the future, the President of the Friends should be contacted directly by the university’s Environmental and Occupational Health about future cyanobacteria blooms in Lake Mendota. Our members could then be made aware of the toxic conditions and health alerts.
To sum up, I saw many people recreating in the June 7th and June 27th Lake Mendota cyanobacteria blooms. There are people who wish to ignore heath alerts. However, it is apparent that many were not aware of the toxic conditions. It would be a good idea to post attention getting warning signs at access points to Lake Mendota. I think the Picnic Point, Raymer’s Cove and Frautschi Point entrances to the Preserve should have warning signs, like this one:
“It’s perhaps a little known fact that 48 percent or 28 miles of all the land surrounding our five big lakes is publicly owned. Our lakes are truly OUR lakes-and it’s our job to protect them in every way possible…..Healthy lakes, healthy community” James Tye, Executive Director, Lloyd Egan, Chair, Clean Lakes Alliance.
June 7. Massive Cyanobacteria Bloom, Spring Harbor with Eagle Heights Woods in background. Bloom extends to middle of Lake Mendota. Grey Areas are bacterial growth.
Friends of the Lakeshore Nature Preserve P.O. Box 5534 Madison, WI 53705