Press Release: Feb. 26, 2014
Contact: Jim Erickson, (734) 647-1842, firstname.lastname@example.org
EDITORS: High-resolution map of major Lake Erie tributaries available
Ambitious new pollution targets needed to protect Lake Erie from massive 'dead zone'
ANN ARBOR—Reducing the size of the Lake Erie "dead zone" to acceptable levels will require cutting nutrient pollution nearly in half in coming decades, at a time when climate change is expected to make such reductions more difficult.
That's one of the main conclusions of a comprehensive new study that documents recent trends in Lake Erie's health. It offers science-based guidance to policymakers seeking to reduce the size of toxic algae blooms and oxygen-starved regions called hypoxic zones, or dead zones—two related water-quality problems that have seen a resurgence in the lake since the mid-1990s.
The report from the multi-institution EcoFore-Lake Erie project states that a 46 percent reduction in the amount, or load, of phosphorus pollution would be needed to shrink Lake Erie's Central Basin hypoxic zone to a size last seen in the mid-1990s—a time that coincided with the recovery of several recreational and commercial fisheries in the lake's west and central basins.
Phosphorus is a nutrient used in crop fertilizers. Excess phosphorus washes off croplands during rainstorms and flows downstream in rivers that feed the Great Lakes. Once in the lakes, phosphorus can trigger algae blooms. When the algae die and sink to the lake bottom, oxygen-consuming bacteria feed on them and create hypoxic zones in the process. Many fish shun these oxygen-starved waters, which significantly reduce the amount of suitable habitat available to the fish.
The study, accepted for publication in a forthcoming edition of the Journal of Great Lakes Research, calls for Central Basin phosphorus reductions considerably higher than other recent recommendations, including a proposal issued last year by the Ohio Lake Erie Phosphorus Task Force aimed at avoiding Western Basin toxic algae blooms. The new report is a synthesis of the major findings from the EcoFore-Lake Erie project, created in 2005 and supported by the U.S. National Oceanic and Atmospheric Administration's Center for Sponsored Coastal Ocean Research.
"The new target is very ambitious but is achievable if the region agrees to adopt agricultural practices that help reduce the amount of phosphorus-bearing fertilizer washing off fields," said aquatic ecologist Donald Scavia, director of the University of Michigan's Graham Sustainability Institute and EcoFore-Lake Erie principal investigator. "We believe this EcoFore synthesis report provides important input to the U.S. and Canadian teams charged with setting new phosphorus load targets for Lake Erie."
The EcoFore recommendations are aimed at policymakers who will update the binational Great Lakes Water Quality Agreement. A 2012 protocol amending the 1972 agreement commits the United States and Canada to revising phosphorus targets for open waters and near-shore areas of each Great Lake and taking actions to reduce phosphorus levels that contribute to harmful algae.
Lake Erie, once declared dead and then recovered, began showing signs of distress again in the mid-1990s, with large algae blooms and dead zones becoming more common. EcoFore-Lake Erie scientists created, tested and applied computer models to forecast how nutrient pollution and climate change are likely to influence the formation and growth of hypoxia in Lake Erie's largest basin, the Central Basin.
They also assessed the likely ecological impacts with an emphasis on fish production, because Central Basin hypoxia has a high potential to harm valued Lake Erie fisheries.
The researchers found that while the total amount of phosphorus washing into Lake Erie from several key watersheds (including the Maumee and Sandusky rivers) has been nearly constant since the mid-1990s, the percentage of a special type of phosphorus called dissolved reactive phosphorus, or DRP, more than doubled from 11 percent to 24 percent during that time.
"DRP is extremely bioavailable to algae, meaning the algae can readily absorb this nutrient and use it to fuel explosive growth," said EcoFore team member Joseph DePinto of LimnoTech in Ann Arbor.
Changes in farming practices in the region since the mid-1990s and an increased frequency of severe spring rainstorms likely worked together to boost the levels of DRP entering Lake Erie, according to the EcoFore researchers. Practices such as fall fertilizer broadcast application and no-till farming tend to leave lots of phosphorus in surface soils, where heavy rains can wash it away.
The observed precipitation trends are expected to continue in the coming decades. At the same time, Lake Erie's problems will be compounded by warming lake temperatures, the EcoFore scientists concluded. To explore various phosphorus-runoff scenarios, team members used previously published climate models that project spring precipitation increases in the region of 11 and 29 percent by the end of the century, along with summer temperature increases of 7.2 and 12.6 degrees Fahrenheit.
"Potential impacts of climate change need to be taken into consideration for effective action," said team member Nathan Bosch of Grace College in Winona Lake, Ind. "Most indications suggest that climate change will not only exacerbate existing problems but also make reducing phosphorus loads more difficult."
As Lake Erie warms, its fish will likely feel the squeeze from above and below.
"Climate warming can cause preferred habitat to be squeezed both from above by warmer temperatures and from below via increased hypoxia," said EcoFore team member Tomas Höök of Purdue University.
In fact, warming water temperatures "may have a stronger effect on fish habitat quality than nutrient loading," the EcoFore report states. "Under a warmer climate, we may need to reduce (phosphorus) loading levels even more dramatically to have meaningful positive effects on habitat quality and Lake Erie fish stocks."
The EcoFore team recommends that policymakers set separate targets for reducing both total phosphorus and DRP loading to Lake Erie. A 78 percent reduction in DRP annual load would be needed to reach a Central Basin hypoxia goal of 780 square miles. That's an area larger than Los Angeles and is roughly the size of the Central Basin dead zone that existed in the early 1990s.
Nutrient-reduction efforts, in the form of agricultural best management practices, should focus on the sites within watersheds that release the most phosphorus into rivers, according to the researchers.
"Importantly, while agricultural BMPs might be less effective under future climates, higher BMP implementation rates could still substantially offset anticipated increases in sediment and nutrient yields," Bosch said.
The report's U-M authors are from the Graham Sustainability Institute, School of Natural Resources and Environment, Cooperative Institute for Limnology and Ecosystems Research, Water Center and Department of Civil and Environmental Engineering.
In addition, the study's 28 authors include researchers at the Ohio Department of Natural Resources, Grace College, Ohio State University, LimnoTech, Purdue University, Heidelberg University, University of Wisconsin-Green Bay, University of Wisconsin-Madison, Korea Environment Institute, NOAA's Great Lakes Environmental Research Laboratory, the U.S. Geological Survey, Oregon State University, Cardno ENTRIX, and the Carnegie Institution for Science.
Funding for the project was provided by NOAA, the National Science Foundation and a Federal Aid in Sport Fish Restoration grant from the U.S. Fish and Wildlife Service and the Ohio Division of Wildlife. The title of the paper is "Assessing and addressing the re-eutrophication of Lake Erie: Central Basin Hypoxia."
Study and other information about the EcoFore-Lake Erie project: http://ecofore.org
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Check out more about the project Stu Ludsin and his colleagues are working on: http://lakeerieceap.com/
For more about Stu's work, peruse his research interests and projects.
Description: Drs. Jay F. Martin and Stuart A. Ludsin have 2 years of support for a Post-doctoral Scientist to contribute to an ongoing biophysical modeling project that is focused on Lake Erie and its watershed.
The incumbent will lead a major modeling effort in support of a funded 4-year NSF Combined Human and Natural Systems project that is investigating linkages among climate change, ecology, and human behavior (e.g., farmers, decision-makers) in the largely agricultural Maumee River watershed, which is a primary source of sediments and nutrients to western Lake Erie. The Post-doc’s primary responsibilities will be two-fold: 1) predict how climate and watershed land use interact to affect downstream (Lake Erie) ecosystem attributes (e.g., water clarity, harmful algal blooms, fisheries production) by integrating an existing SWAT watershed model that is driven by climate and land use/management with established statistical models from western Lake Erie; and 2) to determine if changes in human behavior across the watershed can offset the expected impacts of climate change on Lake Erie ecosystem services. This latter objective will be achieved by modeling ecosystem scenarios in which a regional climate model is used to drive linked, spatially-explicit models of public policy, farmer behavior, land management change, and the biophysical system. Because the SWAT model has been calibrated and validated, the successful candidate can immediately begin performing management and climate scenarios, as well as publishing results.
The Post-doc will be co-supervised by Drs. Martin and Ludsin and work closely with an interdisciplinary team of Ohio State faculty, researchers, and students that includes social scientists, economists and communication specialists.
The Post-doc is expected to write manuscripts, present scientific papers, and help mentor students that are conducting related field, laboratory, and modeling research. Opportunities, if interested, would exist to participate in field and lab work, gain university teaching experience, attend training workshops, and write research grants. Support to attend scientific meetings will be provided annually.
Location: The incumbent would join a dynamic, interactive group of faculty, post-docs, and students at the Aquatic Ecology Laboratory (AEL; www.ael.osu.edu/), which is housed within the Department of Evolution, Ecology, and Organismal Biology (www.eeob.osu.edu/), or the Ecological Engineering Program, which is located within the department of Food, Agricultural & Biological Engineering (www.fabe.osu.edu/fabe/). Office space would be provided on Ohio State’s main campus in Columbus.
Qualifications: A successful applicant will be creative, motivated, and capable of working both independently and cooperatively within an interdisciplinary group. Minimum qualifications include a PhD in ecology, engineering, aquatic sciences, biostatistics, or a related field. Strong quantitative and communication skills are required. Ideal candidates will have extensive experience using SWAT models to analyze watershed hydrology and nutrient transport. Additional experience in ecological engineering, aquatic ecology and familiarity with GIS is desired.
How to apply: Electronically submit a cover letter, CV, and names/contact information of three references to Stuart Ludsin at email@example.com and Jay Martin at firstname.lastname@example.org (please put “NSF-CHNS Post-Doc” in the subject line). We have begun reviewing applications and will continue until a suitable candidate is found. An ideal start date would be March 2014. Feel free to direct questions to Drs. Ludsin and Martin.
Maura O'Brien is joining us as a Research Assistant for Conor Keitzer, a post-doc for Stu Ludsin. She's joining the AEL to help with a project assessing the impacts of best management practices along lotic ecosystems on downstream habitats. For more information on the project, visit the CEAP webpage.
Last week, Dr. Peter Sale, a world-renowned coral reef ecologist and climate change advocate, visited the AEL. He spent his two-day visit meeting with graduate students, giving an EEOB seminar, and providing a well-attended public lecture on climate change.
Thank you for visiting, Dr. Sale!
For more about Peter Sale's impressive career, visit his Institute for Water, Environment, and Health webpage. You can also read his blog, which he updates with new information on the climate change crisis.
Dr. Stuart Ludsin