Seeing the photos from the record-breaking algal bloom on Lake Erie in 2011 was like déjà vu for me. I grew up in the Great Lakes region in the 1960s and 1970s and remember the days when Lake Erie was declared “dead.”
I later learned that the green scum that plagued the lake during summer months was a sign that the lake was actually overly alive. It gained its morbid reputation because when blooms of the tiny plant-like organisms die-off, the decomposition process consumes oxygen. In extreme cases, it creates an unpleasant, smelly mess and literally sucks the oxygen from the water.
With anoxic conditions like these, walleye pike and yellow perch alike turn belly-up and die or gasp for breath at the surface, unable to syphon oxygen from the water that flows through their gills.
Algae gets a bad rap sometimes, a reputation not always deserved. Many varieties of algae are beneficial to lakes, providing the basis of the food chain that supports the entire ecosystem. Other types, like cyanobacteria, produce toxins that are harmful to humans and can even cause death to animals that consume it. Large blooms, even non-toxic ones, affect ecosystem health.
Too much phosphorus, an essential element for plant growth, is the usual culprit in triggering algal blooms in lakes. It washes into lakes from agricultural runoff, sewage treatment plants, lawn fertilizer, water treatment plants, and septic systems. At the right water temperature, the more phosphorus there is in the water, the more algal growth you get.
Lake Erie suffered from toxic algae blooms in the 1970s, but with a major effort to reduce phosphorus loading, the blooms disappeared for nearly two decades. By the mid 1990s, conditions began to deteriorate again. When I sailed across the lake in late summer 2004, an algae bloom stretched from the Erie Islands to the western shore.
Agricultural and Meteorological Trends Cause Massive 2011 Bloom
A recent forensic-like study of the 2011 bloom, published in the Proceedings of the National Academy of Sciences, gives new insight about possible causes of these extreme events.
The National Science Foundation awarded a five-year grant to a team of researchers to study the effects of climate-change induced extreme events on water quality and ecology in the Great Lakes system. “It was a coincidence that the project began in January 2011, and this perfect case study popped up out of nowhere,” a researcher at the Carnegie Institution for Science and principal investigator for the study, Anna M. Michalak explained to me.
Using a holistic approach, the team brought together high-tech tools and sophisticated statistical analysis to assess whether the record-setting algal bloom in Lake Erie was driven by an unfortunate combination of circumstances or is a sign of things to come. They concluded that trends in agricultural practices, increased intensity of precipitation, weak lake circulation, and quiescent conditions conspired to yield the massive bloom.
The main cause of the massive bloom was the confluence of long-term trends in nutrient management practices on farms and a changing climate, including more frequent extreme precipitation events. They study says these “are consistent with expected future conditions.” This means that unless something is done to reduce the input of nutrients from agriculture and other obvious sources or to stop changes in climate already underway, nuisance algal blooms are likely to become more common in the future.
Michalak recommends that future management plans be guided by science like hers and her colleagues’ to mitigate impacts, but she doesn’t want her team’s findings to be misunderstood as placing the blame on farmers. “Farmers and land managers deserve due credit for implementing a variety of recommended conservation practices,” she told me, “and these have gone a long way to limiting soil erosion and reducing carbon loss.”
In 2011, severe spring rain events made it difficult for farmers to apply fertilizers without having the nutrients washed away immediately. Fertilizers are expensive. “It’s no more in a farmer’s interest to have fertilizers end up in the lake than it is for the environment,” said Michalak. She cited improved forecasting of spring storms to better guide the timing of fertilizer applications as one example where science and management could come together to address the problem.
As certain agricultural practices have increased in the region over the past ten years, so has the loading of “dissolved reactive phosphorus” (DRP), a form of “bioavailable” phosphorus that is readily available for uptake by plants, including nuisance algae. Although the total inputs of phosphorus have decreased since the 1970s, the loading of DRP from nonpoint sources has increased in recent years. Michalak says that reducing these loads will be key to restoring the lake again.
Although not considered a major factor in the 2011 bloom, converting land to corn production for the biofuel industry has more recently become a trend in the Lake Erie watershed. This fertilizer-intensive crop could further exacerbate the problem of harmful algae blooms, Michalak told me.
Another more subtle change underway is the rising water temperatures in all of the Great Lakes. “As Lake Erie warms, it increases the likelihood that the water will be warm enough earlier in the season when most of the nutrients are delivered to the lake,” said Michalak. “It’s a timing game. If the nutrients are still available when the lake warms up, it could trigger an algae bloom.”
What is Being Done to Restore the Lake?
The International Joint Commission (IJC) is one of many agencies focused on the algae problems in Lake Erie once again. Under the Great Lakes Water Quality Agreement (GLWQA), first signed in 1972 and most recently updated in 2012, the IJC advises the U.S. and Canadian governments on how to protect the lakes.
Declining water quality in Lake Erie is one of four priorities for the IJC’s work for the next three years. The IJC’s Lake Erie Ecosystem Priority, or LEEP, is aptly named. “We’d like the lake to improve by leaps and bounds,” the project website states.
According to the updated GLWQA, the governments have five years to put plans into place for reducing phosphorus inputs to Lake Erie. But after seeing the major bloom two years ago, the IJC set a more ambitious goal for achieving measurable reductions by 2015, explained Raj Bejankiwar, a physical scientist and phosphorus expert at the IJC. They have commissioned a series of studies and convened experts to develop findings and recommendations. A draft report is due out by the end of May and public consultations are planned this summer.
The IJC plans to make the case for more urgent action on Lake Erie during Great Lakes Week in September. The Great Lakes Restoration Conference will be held in Milwaukee the same week.
“The LEEP project is not just pure science. We’re also looking at socio-economics and stakeholder concerns. We can only solve this problem by looking at the issue in a broader context,” said Bejankiwar.
The project will enhance efforts underway as part of the larger Great Lakes Restoration Initiative (GLRI) on the U.S. side and a pledged $16 million investment in nutrient management on the Canadian side.
“Now scientists are telling us to be prepared for further challenges linked to climate change,” Bejankiwar told me. Warmer water, less ice cover, more intense rain events, and changing land use patterns are just some of the variables that might complicate future restoration efforts. “For these reasons, the IJC is promoting an adaptive approach to management of the Great Lakes,” he says.
The Nature Conservancy (TNC), one of many groups working to protect the Great Lakes, is actively acquiring, restoring, and managing land throughout the Lake Erie basin. “TNC is trying to find practical solutions by working with farmers to implement agricultural best management practices while keeping an eye on the impacts of climate change,” said Patrick Doran, Director of Conservation for Michigan at The Nature Conservancy.
Lake Erie’s largest tributary, the Maumee River, is one of three GLRI priority areas for reducing harmful algae in the Great Lakes watershed. It empties into the shallow, western basin of the lake, the area most affected by harmful algae blooms. Much of TNC’s work in this area is focused in the Maumee and Grand River watersheds.
Toxic Algae Blooms Becoming a Global Concern
Unfortunately, the problem of harmful algal blooms is not unique to Lake Erie. As lakes become warmer and extreme precipitation events become more common with climate change, more lakes throughout the world are experiencing cyanobacteria blooms.
Lake Winnipeg in Canada was declared the most endangered lake in the world last year because of toxic algae blooms. Lake Zurich in Switzerland and Lake Taihu in China are among other notorious examples. Visit this National Geographic photo gallery to see more examples.
Those concerned with the health of lakes are searching for solutions to this nagging problem around the globe. This will be a topic of a future post, so stay tuned.
Lisa Borre is a lake conservationist, freelance writer and sailor based in Annapolis, Maryland. With her husband, she co-founded LakeNet, a world lakes network, and co-wrote a sailing guide called “The Black Sea” based on their voyage around the sea in 2010. A native of the Great Lakes region, she served as coordinator of the Lake Champlain Basin Program in the 1990s. She is now an active member of the Global Lake Ecological Observatory Network.