Saving Lake Erie
By Terri Carroll
Walking toward the shores of Lake Erie during the summer, it is easy to imagine visiting a sparkling tropical ocean. The turquoise water glimmers in the sun as gentle waves lap at the white beach. A capricious breeze carries the animated sounds of birds chirping among the reeds and grasses.
Upon closer approach, however, it becomes clear that all may not be as sublime as first envisioned. Lake Erie water should be a deep, dark blue – the turquoise hue is actually the result of toxic blue-green algae blooms. The white beach is the result of invasive zebra mussel shells that litter Lake Erie shores. The aggressive flowering rush and other invaders are overtaking native reeds and grasses, home to hundreds of bird species.
Lake Erie is the 12th largest lake in the world and the most biologically productive of the five Great Lakes, which contain 20 percent of the planet’s surface freshwater and supply drinking water to more than 35 million people. Additionally, Lake Erie is a driving force in Ohio’s tourism industry, accounting for more than $10.7 billion in revenue and employing 119,100 residents. Birding is an increasingly important tourism component that generated $26 million in revenue last year. However, ongoing threats from invasive species, toxins and pollution pose serious dangers to the lakes, their fragile ecosystems and local economies.
Teams of BGSU faculty and students are tackling the complex problems facing Lake Erie and in so doing have created a living laboratory for scientific inquiry and investigation. In the process, they not only are making discoveries with potential global implications, but are also infusing classroom and laboratory lessons with the kind of energy that only exists when passion, resources and knowledge intersect.
With Lake Erie just a short drive from BGSU campuses, students can read about invasive species or water toxins and then explore these environmental phenomena firsthand. Students gain mastery of complex scientific and technical skills as well as a lifelong enthusiasm for asking questions and seeking answers.
The research projects are also excellent examples of multidisciplinary science at work. Cooperation among its academic departments strengthens the University’s research capabilities and scope while teaching students the importance of collaboration as they unravel problems that require more than one scientific discipline to solve.
One important area of multidisciplinary research is the investigation of blue-green algae. It wasn’t long ago that the algae could only be seen in the middle of the lake; now it washes up on the beaches along the entire coastline. Last year the western basin experienced the worst toxic algae bloom in recorded history – worse than when the lake was declared “dead” in the 1960s.
The blue-green algae thicken the water with a foul-smelling sludge that is full of the cyanobacterial species, Microcystis spp., which produces a toxin called microcystin. The toxin irritates the skin and can cause liver damage. These blue-green algae also produce compounds that impart an unpleasant odor to drinking water and are increasingly linked to a growing list of health problems, such as Parkinson’s disease, Lou Gehrig’s disease and other disorders of the human nervous system. Additionally, upon decay of the cyanobacteria, oxygen becomes depleted in the water, resulting in massive “dead zones.”
Upon decay of the cyanobacteria, oxygen becomes depleted in the water, resulting in massive “dead zones.”Blue-green algae prosper when there is an abundance of phosphorus in the water. The blooms subsided after the 1970s, when regulations and improvements in agriculture, reductions of phosphates in detergents, and sewage treatment limited the amount of phosphorus that reached the lake.
However, the blooms have returned with a vengeance.
It is one thing to see these harmful cyanobacteria algae blooms from the coastline or a boat, but one BGSU faculty member wanted a better view. A vantage point above Earth’s atmosphere allowed Dr. Robert Vincent to consider the extent of the problem through his project, “Monitoring Lake Erie Water Quality.“
Vincent is a professor of geology, co-founder of Blue Water Satellite Inc., and one of the country’s leading experts in remote sensing. He has obtained more than $4 million in funding from the National Aeronautics and Space Administration and National Oceanic and Atmospheric Administration for remote satellite monitoring of cyanobacterial blooms in
Vincent’s satellite images show most of Lake Erie as a broad and serene blue. But within the algae bloom areas, blue shading gives way to extensive areas of red, which indicates high blooms of cyanobacteria. The images, captured from satellites 370 miles above Earth’s surface, show that at one point last summer, the blooms extended across almost the entire western basin and into the central basin, and in some places were up to two feet thick.
Rather than detecting cyanobacteria directly, the remote sensing method was devised to observe phycocyanin, which is a light-harvesting pigment associated with cyanobacteria, giving them their blue-green color. It is the presence of phycocyanin that is being measured in this project.
“Detecting cyanobacteria, its location, its concentrations, its sources and its history in Lake Erie are critical to stopping the deadly spread of toxins that they can produce,” said Vincent.
While Vincent and his team are surveying the cyanobacteria algae blooms from space, three BGSU biologists are analyzing the problem at the microbial level. Drs. George Bullerjahn, Michael McKay and Paul Morris’s study of the Great Lakes and dead zones in Lake Erie was chosen for support this year by the U.S. Department of Energy’s Joint Genomic Institute.
The project, which includes dozens of undergraduate and graduate students, involves sampling at the site of a National
Oceanic and Atmospheric Administration buoy that continuously monitors oxygen and temperature through the water column during summer and fall. Research partners at Environment Canada collect surface water every two weeks as well as samples from the hypolimnion, the densest bottom layer of lake water, before and after the onset of the low oxygen conditions caused by the cyanobacteria algae blooms.
The Department of Energy’s massive-scale genetic sequencing and data analysis capabilities will enable BGSU researchers and students to better understand the interplay between climate, ecosystem and organism. “If you pull up a bucket of water, there are several thousands of organisms living in a complex community structure. We want to know who’s doing what,” said Bullerjahn, professor of biological sciences.
The samples collected in the summer are being used to complement the team’s intensive research conducted during the winter months. “While the blue-green algae are most visible in the summer, we speculate that activity at the microbial level in winter may contribute to and exacerbate the summer blooms,” said McKay, the Pat and Debra Ryan Professor of Biological Sciences.
Curiosity about winter algae activity was piqued when Canadian Coast Guard icebreaker deck hands described ice that was no longer clear, but brown. At first, the brown color was attributed to sediment churned up from the lake’s bottom. However, laboratory analysis revealed water teeming with algae and a level of photosynthesis that rivaled summer levels.
“This was an astonishing discovery,” said McKay. “It was long assumed that algae were dormant in the winter due to the cold temperatures.” With unique access to Lake Erie and Coast Guard icebreaker vessels, and funding from the Ohio Sea Grant College Program, the Lake Erie Protection Fund and the National Science Foundation, the team has gained international recognition for discovering that algae grows throughout the winter, producing sufficient biomass that, when decomposed during summer, consumes oxygen, which contributes to the dead zones.
The data generated by the genetic analysis of both winter and summer sampling are expected to unleash a virtual tsunami of information that will be usable for years to come by the BGSU team and scientists worldwide studying greenhouse gases and lake ecosystems.
The team is working to make sure there are tools in place to effectively interpret this genetic analysis. “We get billions of bits of DNA information from each sample analysis,” said Morris, professor of biological sciences. “Genetic sequencing is often compared to a blueprint, but it is more like a parts list. For example, if you were building a jet, just having the parts list wouldn’t get you very far. You need to know how everything fits together. Similarly, we are working to not just create a list of organisms, but to understand their creation and function within the lake community.”
In a review of BGSU’s efforts, The National Science Foundation stated, “The kinds of tools they have begun to develop are among the tools that will move us into a new age of marine biochemistry and biogeochemistry.”
Dr. Hans Wildschutte, assistant professor of biology, complements the genome project with his efforts to isolate the bacteria found in each sample. “Within each water sample of water, there is a lot of activity and perhaps symbiotic relationships, but we can’t analyze individual genes and proteins until we isolate the bacteria,” he said. One hypothesis is that some of these bacteria enable algae to attach to the underside of ice, allowing access to light and contributing to the winter algae/dead zone link Bullerjahn, McKay and Morris are exploring.
In the same way blue-green algae smother Lake Erie’s aquatic life, the flowering rush plants overwhelm the region’s native plants. The rush plants are lovely, but pretty as it is, the flowering rush is an unwanted and uninvited lodger in Ohio waterways, displacing native species used by area fish and wildlife. An interdisciplinary BGSU team is developing a method of identifying the invader from satellite images in order to identify where it has new colonies, in hopes of thwarting its spread.
Funded by the U.S. Fish and Wildlife Service, a group of graduate and undergraduate students led by Dr. Helen Michaels, associate professor of biological sciences, braved the summer’s high heat and humidity to find and map the plant in Lake Erie waters of the Ottawa National Wildlife Refuge.
“We use a global positioning system to precisely locate pre-selected sampling locations and ourselves in relation to those locations, and then mark off a one-meter by one-meter quadrant,” explained Arisca Droog ’10, a master’s student in geology. “We score the quadrant with marks for the rushes and the other plants. The biology students can identify them, and then we move on to another quadrant.”
This “ground truthing” component is in preparation for gathering the “spectral signature” — the wavelength of light emitted — for the flowering rush and its neighboring plants, by which they can be identified in high-resolution images from aerial photography provided by the refuge, U.S. Fish and Wildlife Service, and, eventually, the LandSat satellite.
Because flowering rush spreads so easily, it is extremely difficult to control, said Michaels. “If we can locate the flowering rush based on its spectral signature before it gets further out of control, we can mitigate its harmful effects.”
Not only do the algae and flowering rush damage the water and aquatic life, they also disrupt the delicate balance that makes Lake Erie a haven for North American migratory birds. Located at the junction of two major migratory flyways, millions of colorful migrating songbirds, shorebirds, waterfowl and raptors utilize the area’s varied habitats for food, cover and roosting areas.
In addition to providing a haven for both migratory and resident birds, Lake Erie attracts thousands of bird watchers annually. Bird watching contributes more than $26 million and 283 jobs to northern Ohio’s economy, according to Dr. Philip Xie, director of the School of Human Movement, Sport, and Leisure Studies. Until Xie’s study, supported by the Ohio Sea Grant College Program, nobody knew exactly how much money birders spent or what kind of economic impact they had on communities.
“Having solid numbers will help policymakers understand the financial impact of bird watching in terms of how much tax revenue and jobs it creates,” Xie said.
Dr. Jeff Miner, associate professor and chair of biological sciences, and Dr. John Farver, associate professor of geology, are also conducting research that assists wildlife managers and policymakers in planning for healthy waterways. Annually, 2 million steelhead trout are released into Lake Erie tributaries from hatcheries in Michigan, Ohio, Pennsylvania and New York. However, little information is available once they are released. Miner and Farver use the unique chemical fingerprint found in special fish bones called otoliths to track fish populations and migration.
“Otoliths are hard calcareous structures in the inner ear of fish that grow throughout their life. As they grow, fish incorporate chemical elements in the otoliths from their surrounding water,” said Farver. Since different areas of the lake and each hatchery have unique water chemistry, otolith chemistry can be used without artificially marking every individual fish.
Not only do the algae and flowering rush damage the water and aquatic life, they also disrupt the delicate balance that makes Lake Erie a haven for North American migratory birds.Farver, Miner and their students have shown that about 85 percent of adult steelhead trout stocked into Lake Erie tributaries migrate back to their original stocked river for spawning. However, in New York rivers, highly regarded for naturally reproduced steelhead trout, 75-80 percent of the adult steelhead trout come from Ohio and Pennsylvania stocking. Fishery and hatchery managers are using these findings to improve stocking practices and return rates of stocked fish.
This collaboration between an aquatic ecologist (Miner), and a geologist (Farver) goes far beyond trout. They are using this chemical fingerprinting technology to track heavy metal pollution in Swan Creek, a tributary of the Maumee River that drains into Lake Erie, by examining the calcium shells of clams residing in the river. Additionally, they have worked with a graduate student to detect the presence of cadmium, a dangerous heavy metal, in Lake Erie sediments and in the multitude of mayflies burrowing in lake sediments. They have extended this work to determine if invading mussels concentrate heavy metals in sediments around them and if these metals are transmitted up the food chain.
Miner and his students have also studied the effects of the round goby, an invasive fish from Europe that eats zebra mussels. A reduction in the zebra mussel and its cousin the quagga mussel may be a positive outcome of the round goby arrival. After all, these mussels decrease the amount of phytoplankton available for other organisms, threaten native mussel populations, cover beaches with sharp-edged shells, and damage intake pipes of water treatment and power plants. And round gobies, estimated at nine billion in the western basin of Lake Erie, are now the favorite food of important sport fish like walleye, yellow perch, and smallmouth bass.
Pursuit of these complex interactions between organisms and the environment also involves training of and participation by undergraduate and graduate students. For example, Miner and Michaels collaborated in summer 2012 with Alyssa Dietz, a senior Honors student in biological sciences and recipient of the prestigious SETGO summer research award funded through the National Science Foundation. Dietz is extending the flowering rush research through her own independent experiments. These include collecting macroinvertebrate samples, such as dragonfly larvae and diving beetles, in areas with and without the invasive flowering rush. “These larvae serve as food for fish, so it is important to measure their health and then, in turn, determine the effect on fish that use the wetlands as nursery habitat,” said Dietz.
Dr. Linda Cornell, associate professor of chemistry at BGSU Firelands, also provides students with field experiences that enhance their education while contributing to lake monitoring efforts. Cornell’s primary research focus involves the health of small streams that flow into Lake Erie. The college is in the heart of the Firelands Coastal Tributary Watershed so we have an unmatchable opportunity to monitor waterway health. Draining into Lake Erie, the streams directly affect the overall health and composition of the lake,” she said. Her students collect water samples from Sawmill Creek and then analyze levels of sediment, nutrients and other water quality indicators. Additionally, Cornell has secured funding for “Flow Rate Study for Three Small Lake Erie Streams” which is funded through the Ohio Lake Erie Commission and the Lake Erie Protection Fund.
So while thousands of visitors enjoy the lakes and beaches, the future of Lake Erie is by no means assured. Although harmful trends such as blue-green algae and invasive species are visible to the human eye, can’t be mitigated without understanding the complex physical, chemical and biological interactions between organisms within the lake’s ecosystems. Such advances require collaboration across departments and the expertise of many skilled scientists.
The mysteries being unraveled by the multidisciplinary efforts of BGSU faculty and students may be the key to preventing Lake Erie from slipping back to its darkest days as a dead lake. Indeed, the hope is that with the knowledge being generated at the University, Lake Erie will have clean waterways, healthy fish populations and an abundance of wildlife — where paradise is a reality, not just an illusion.
Updated: 06/13/2018 02:58PM