Moore N.,Zhejiang University |
Moore N.,Michigan State University |
Alagarswamy G.,Michigan State University |
Pijanowski B.,Purdue University |
And 6 more authors.
Climatic Change | Year: 2012
Climate change impacts food production systems, particularly in locations with large, vulnerable populations. Elevated greenhouse gases (GHG), as well as land cover/land use change (LCLUC), can influence regional climate dynamics. Biophysical factors such as topography, soil type, and seasonal rainfall can strongly affect crop yields. We used a regional climate model derived from the Regional Atmospheric Modeling System (RAMS) to compare the effects of projected future GHG and future LCLUC on spatial variability of crop yields in East Africa. Crop yields were estimated with a process-based simulation model. The results suggest that: (1) GHG-influenced and LCLUC-influenced yield changes are highly heterogeneous across this region; (2) LCLUC effects are significant drivers of yield change; and (3) high spatial variability in yield is indicated for several key agricultural sub-regions of East Africa. Food production risk when considered at the household scale is largely dependent on the occurrence of extremes, so mean yield in some cases may be an incomplete predictor of risk. The broad range of projected crop yields reflects enormous variability in key parameters that underlie regional food security; hence, donor institutions' strategies and investments might benefit from considering the spatial distribution around mean impacts for a given region. Ultimately, global assessments of food security risk would benefit from including regional and local assessments of climate impacts on food production. This may be less of a consideration in other regions. This study supports the concept that LCLUC is a first-order factor in assessing food production risk. © 2011 The Author(s). Source
He C.,Western Michigan University |
He C.,Lanzhou University |
Zhang L.,Lanzhou University |
DeMarchi C.,Case Western Reserve University |
Croley T.E.,Great Lakes Environmental Research Laboratory
Journal of Great Lakes Research | Year: 2014
Databases of point sources including combined sewer overflows (CSOs) were acquired from the governmental agencies to map the occurrences and magnitude of the CSOs. Multiple databases of land use, topography, hydrography, soils, and agricultural statistics were used to estimate nonpoint source loading potential in the Saginaw Bay Basin, Michigan. Animal manure production was computed from tabulations of animals by 5-digit zip code area for the census years of 1987, 1992, 1997, and 2002. Fertilizer applications for both urban and agricultural land uses were calculated from county fertilizer estimates for the same periods. Results indicate that point sources from municipalities, industrial sectors and business entities contribute approximately 25% of the total phosphorus load to Saginaw Bay, with the remainder being accounted for by nonpoint source contributions. While the total amount of nutrients (N and P) from animal manure and fertilizer applications and atmospheric deposition declined in the Saginaw Bay Basin, fertilizer applications in non-farmland increased significantly. Estimation of nutrient loading potential at 5-digit zip code level reveals more detailed spatial variation and critical areas of nutrient loading than county level data for implementation of targeted water quality programs. © 2014 Elsevier B.V. Source
Hawley N.,Great Lakes Environmental Research Laboratory |
Redder T.,Limno Technology |
Beletsky R.,University of Michigan |
Verhamme E.,Limno Technology |
And 2 more authors.
Journal of Great Lakes Research | Year: 2014
An integrated hydrodynamic and sediment transport model was applied to Saginaw Bay for the ice-free portions of 2009 and 2010. Observations of surface waves and suspended sediment concentration made during the spring of both years were used to constrain the model and to validate the model output. The results show that sediment resuspension in both the inner and outer bay is due almost entirely to surface wave action, and that the bulk of the resuspension events occur during the fall of each year. Although the model accurately predicted the occurrence of resuspension events, it did not always accurately simulate the amount of material resuspended. Because resuspension mixes bottom sediment into the water column and makes it and associated nutrients available to the biota, the effects of sediment resuspension need to be accounted for in any water quality model of the bay. Better specification of both the surface waves and the initial specification of the bottom sediment would probably improve the performance of the model. © 2013. Source
However, most of the expected declines in Lake Erie will not be as extreme as some experts have predicted, according to the food-web study by the University of Michigan's Hongyan Zhang and colleagues from other American and Canadian research institutions. A few fish species, including smallmouth bass, would likely increase. The study is the first to use a food-web model to examine the likely impacts of bighead and silver carp in Lake Erie. These plankton-eating Asian carp are established in watersheds close to the Great Lakes but not in the lakes themselves. The invasive carp would likely affect Lake Erie's food web in two main ways: They would likely compete with native fish by eating their food, and juvenile Asian carp would likely become food for fish-eating fish. According to the study, walleye, rainbow trout, gizzard shad and emerald shiners could all decline, with declines in emerald shiner of up to 37 percent. Smallmouth bass stood to gain the most, with increases of up to 16 percent. A paper summarizing the findings was published online Dec. 30, 2015 in the journal Transactions of the American Fisheries Society. The model results suggest that Asian carp could eventually account for up to 34 percent of the total fish weight in the lake, said Zhang, assistant research scientist at U-M's Cooperative Institute for Limnology and Ecosystems Research in the School of Natural Resources and Environment. "Fortunately, the percentage would not be as high as it is today in the Illinois River, where Asian carp have caused large changes in the ecosystem and have affected human use of the river," she said. Previous predictions of Asian carp impacts in the Great Lakes have ranged widely. Some experts say Asian carp could decimate Great Lakes fisheries and food webs, while others suggest the effects would likely be minor because much of the Great Lakes is not a suitable habitat for Asian carp. >Results of the new study fall somewhere between the two extremes. "This study goes beyond previous efforts in two significant ways. It focuses on the food webs and—where model input data were not available—it includes uncertainty estimates from experts," said co-author Ed Rutherford, a fisheries biologist at the Great Lakes Environmental Research Laboratory (GLERL) in Ann Arbor, a U.S. National Oceanic and Atmospheric Administration facility. To include uncertainty in model predictions, team members interviewed 11 leading experts on Asian carp biology and Great Lakes ecology and fisheries, then incorporated the experts' estimates into the model. The experts were also asked to indicate the level of uncertainty associated with each statement they provided. "We don't know how these two Asian carp species are going to do in Lake Erie, so we have to incorporate that uncertainty into our model projections," said co-author Doran Mason, a research ecologist at GLERL. "It's like using computer models to predict a hurricane's path and intensity and including the margin of error in the forecast." The team has shared its Lake Erie results with Great Lakes resource managers to help inform decisions related to Asian carp. Of the Great Lakes, Erie may be most vulnerable to Asian carp invasion due to its proximity to waters where Asian carp exist, the presence of adequate food, and the availability of suitable spawning habitat. The same research team is now working on modeling studies to predict Asian carp impacts in lakes Michigan, Huron and Ontario, as well as a study of the regional economic impacts associated with Asian carp in Lake Erie.
News Article | April 2, 2016
If the old pipelines under the Straits of Makinac burst, more than 700 miles of the Great Lakes shoreline are at at risk for oil spills, a University of Michigan study has revealed. The computer-modeling study conducted by hydrodynamics expert David Schwab included 840 oil spill simulations from the Enbridge Line 5 pipeline that lies underneath the Mackinac strait. The simulation, under the support of National Wildlife Federation, found more than 245 kilometers (152 miles) of Huron and Michigan lakes shoreline could be greatly affected by a single oil spill. Once all 840 simulated spills were plotted, the researchers found that about 1,162 kilometers (720 miles) of U.S. and Canadian shorelines would become vulnerable to the spills. Those with the highest risk include Bois Blanc and Mackinac islands, as well as areas that are directly west and east of Mackinaw City. Beaver Island, Harbor Springs, Cross Village, Cheboygan and other communities along the Huron and Michigan lakes' shoreline would also be greatly affected. The report is, by far, the only study that detailed the length and speed in case an oil spill occurs. Schwab's study provides a very good material the government can use when planning for a spill-response. Mike Shriberg, National Widlife Federation's Great Lakes Regional Center regional executive director, believes that the study is an important component of assessing Line 5's risk to the Great Lakes. "Michigan public officials have an important decision to make about how to protect our communities, economy, wildlife and Great Lakes from an oil spill disaster," Shriberg said. Using a high-resolution hydrodynamic model developed by Schwab ad Eric Anderson of the National Oceanic and Atmospheric Administration's (NOAA) Great Lakes Environmental Research Laboratory, the researchers were able to do simulations that incorporated approximations in case an oil spill occurs at the halfway point of the 5-mile wide Straits of Mackinac. The study also showed several significant findings including that in one of the 840 simulations, the open waters of Lake Huron and Lake Michigan would have 60 percent and 15 percent of visible oil, respectively. The open water, at risk, is 44,405 square kilometres (17,318 square miles), almost equal to the combined surface areas of lakes Ontario and Erie. A single hypothetical spill covers a maximum open water area of 1,600 square kilometres (624 square miles), which is bigger than Lake St. Clair. The simulation also noted that visible surface oil can arrive at the shore in just 2.5 hours. The whole Mackinac Island could be severely affected in just nine hours and can reach Cheboygan in 30 hours. The extent of the oil spill is due to the volume of oil that passes through Enbridge Line 5 pipeline under the Straits of Mackenzie. About 20 million gallons of light synthetic crude oil, light crude oil, and natural gas liquids pass through the pipes each day. In case of a 25,000 barrel spill scenario, Schwab said a cleanup of Mackinac Island is 90 percent probable. It is important to note that the study simulation did not include a containment action to stop the oil spill at the Straits of Mackinac. The present study complements Schwab's 2014 study, which only used two computer simulations, and aims to help Michigan officials to decide on the old pipeline before an oil spill happens and a beach cleanup becomes necessary. A previous study by marine scientists from University of Georgia who lab-simulated an oil spill, which released 172 million gallons of oil in the Gulf of Mexico, revealed that chemical dispersants used to remove oil from the water were not able to fully degrade it and even hurt the oil-degrading microbes present in the water.