Research Projects
Convergence
BRIDGING KNOWLEDGE SYSTEMS AND EXPERTISE FOR UNDERSTANDING THE DYNAMICS OF A CONTAMINATED TRIBAL LANDSCAPE SYSTEM – This recently initiated project brings natural and social sciences researchers together with tribal community partners in the Upper Peninsula (U.P.) of Michigan to better understand toxic contamination and climate-related changes across the water-rich landscape. The team will map the extent of the region’s mercury and PCBs contamination in inland lakes, and concurrently, map tribal harvesting practices, valued resources, and climate-related changes across the landscape to categorize lakes as low, moderate or high risk. This research also aims to explore specific management and outreach decisions to minimize contaminant risks and support human-environment relationships that promote the health and wellbeing of the U.P. environment and its communities.
Mercury and other trace metals in the regions waters and soils come not only from long-range atmospheric transport and deposition but also from regional mining. Impacts of mining are being evaluated in this project through mapping of metal concentrations and fluxes in streams throughout the local area. Findings to date are summarized in the Mercury and Copper in Torch Lake story map. Results demonstrate both local hot spots of contamination as well as the regionally elevated concentrations.
Lake Superior
MEASUREMENT AND MODELING OF PROCESSES CONTROLLING ACIDIFICATION IN THE GREAT LAKES - This 3-yr, $1.4M project funded by NOAA’s Ocean Acidification Program will demonstrate how high-quality data can be collected and modeled to determine what factors regulate the carbon system on daily, seasonal, and interannual scales in the Great Lakes. Moorings will be installed in lakes Superior and Erie in optimal locations to provide two years of high precision measurement of dissolved carbon dioxide and pH, two important parameters for measuring the carbon system. Ancillary information on chemical and biological processes that also can influence acidification will be gather as well to provide a more complete understanding. A coupled hydrodynamic-biogeochemical model and model experiments will be used to determine how temperature change, vertical mixing of the water column, biological processes, air-water exchange, or changes in pools of dissolved organic and inorganic carbon control the carbon system and potential acidification. PIs on the project include Urban, Hayden Henderson, Trista Vick-Majors, and Pengfei Xue from Michigan Tech and Reagan Errera from NOAA- GLERL.
KEWEENAW INTERDISCIPLINARY TRANSPORT EXPERIMENT IN SUPERIOR (KITES) - This 5-year, $5.4 million, multi-university study, funded by NSF-NOAA, explored the role of thermal fronts and longshore currents in mediating the transport of chemically- and biologically-important materials across the coastal margin of Lake Superior. Applied here as a freshwater analogue to coastal ocean processes, the effort explored the fate of materials discharged to (watershed inputs) and generated within (primary and secondary production) the lake's nearshore waters and the importance of those materials in driving ecosystem dynamics in pelagic regions. Urban’s group focused on carbon and copper cycling, rates of sediment resuspension and focusing, and the lability of phosphorus. Selected publications include:
- Urban, NR, MT Auer, SA Green, D Apul, L Bub, KD Powers, X Lu, 2005, Carbon cycling in L. Superior, J. Geophys. Res., 110(C6): doi: 10.1029/2003JC002230 C06S90
- Chai, Y, NR Urban, 2004, 210Po and 210Pb distributions and disequilibria in the near-shore region of Lake Superior, J. Geophys. Res., 109(C10), doi:10.1029/2003JC002081, C10S07
- Russ, ME, Ostrom, NE, Ostrom, PH, Gandhi, H, Urban, NR, 2004, Temporal and spatial variations in R:P ratios in Lake Superior, an oligotrophic freshwater environment, J. Geophys. Res., 109(C10), DOI:10.1029/2003JC001890, C10S12
- Urban, NR, Apul, D.S., Auer, MT, 2004, Planktonic Respiration Rates in Lake Superior, J. Great Lakes Res., 30(Suppl. 1):230-244.
- Urban, NR, Y Chai, J Jeong, 2004, The benthic nepheloid layer (BNL) north of the Keweenaw Peninsula in Lake Superior: composition, dynamics, and role in sediment transport, J. Great Lakes Research 30(Suppl. 1):133-146.
CYCLING OF CARBON IN LAKE SUPERIOR (CyCleS) – This NSF-funded collaborative project with researchers from UW-Madison explored the physical and biogeochemical controls on Lake Superior’s carbon cycle using data (Atilla et al., 2011, Desai et al. 2009), and models (Bennington et al. 2010, McDonald et al. 2012, Bennington et al. 2012). The impacts of the lake on estimation of terrestrial carbon fluxes were quantified (Vasys et al., 2011), and biogeochemical retrievals from ocean color satellites were improved (Mouw et al. 2012). A major contributor to the contributor to the previous carbon imbalance was found to be inadequate spatial sampling (Bennington et al. 2012).
- Atilla, N., McKinley, G.A., Bennington, V., Baehr, M., Urban, N.R., DeGrandpre, M., Desai, A.R., Wu, C. 2010, Observed Variability of Lake Superior pCO2, Limnol. Oceanogr., 56(3):775-786.
- Bennington, V, McKinley G, McDonald CP, Urban NR, 2012. Can spatial heterogeneity explain the perceived imbalance in Lake Superior’s carbon budget: a modeling study. J. Geophys. Res. – Biogeosciences, 117: G03020, DOI 10.1029/2011JG001895RR.
- McDonald, CP, Bennington V, Urban NR, McKinley GA, 2012. 1-D test-bed calibration of a 3-D Lake Superior biogeochemical model, Ecological Modeling 225(1):115-126.
- Phillips, J.C., G.A. McKinley, V. Bennington, H.A. Bootsma, D.J. Pilcher, R.W. Sterner, and N.R. Urban. 2015. The potential for CO2-induced acidification in freshwater: A Great Lakes case study. Oceanography 28(2):136–145, http://dx.doi.org/10.5670/oceanog.2015.37.
Mining Legacies and Remediation
SEDIMENTATION IN TORCH LAKE – Funded by the Michigan Dept. of Environmental Quality, this project measured the sedimentation rate in Torch Lake in order to determine the time that would be required for natural attenuation to bury the metal-rich stamp sands in the bottom of the lake. Results indicated that lake recovery might take as long as 800 years.
- McDonald, C.P., Urban, NR, Barkach, JH, McCauley, D. 2009, Copper profiles in the sediments of a mining-impacted lake, Journal Soils and Sediments, 10(3):343-349.
- McDonald, CP, Urban, NR, 2007, Sediment Radioisotope Dating across a stratigraphic discontinuity in a Mining-Impacted Lake, J. Environ. Rad. 92(2): 80-95.
- Kerfoot, W.C., Urban, N.R., McDonald, C.P., Rossman, R., and Huanxin Zhang, 2016. Legacy Mercury Releases during Copper Mining near Lake Superior, J. Great Lakes Res., 42(1):12
INTEGRATED ASSESSMENT OF TORCH LAKE – Michigan Sea Grant funded this integrated assessment of Torch Lake to document the history, the existing data, and the knowledge gaps that were preventing a more complete remediation of this site.
- Urban, NR, MacLennan, CA, Perlinger, JA. 2018. An Integrated Assessment of Torch Lake Area of Concern: Summary. (16 pp.)
- Urban, NR, MacLennan, CA, Perlinger, JA. 2018. An Integrated Assessment of Torch Lake Area of Concern. (262 pp.)
ASSESSMENT OF MERCURY SOURCES TO TORCH LAKE - More than 30 years after Torch Lake was listed as a Superfund Site and more than 17 years after it was delisted, the source of mercury causing elevated concentrations in fish remains unknown This ongoing project seeks to determine the major source(s) of methyl mercury that cause elevated concentrations and consumption advisories for the fish in Torch Lake. Tributaries and lake waters will be sampled for one year, a mass balance on total and methyl mercury inputs will be constructed, and modeling of the bioaccumulation of methylmercury in walleye will be modeled. Results will show whether methyl mercury is generated primarily in the lake or in wetlands in the catchment, and which tributaries contribute the largest inputs to the lake.
Regional to Global Biogeochemistry
MANAGING IMPACTS OF GLOBAL TRANSPORT OF ATMOSPHERE-SURFACE EXCHANGEABLE POLLUTANTS IN THE CONTEXT OF GLOBAL CHANGE (ASEPS) - Investigators at Michigan Tech and three participating institutions, Massachusetts Institute of Technology, Desert Research Institute, and University of Massachusetts Boston, conducted a research and education project related to the Dynamically Coupled Human-Natural Atmosphere-Surface Exchangeable Pollutants (ASEP) System with funding from the National Science Foundation Geosciences Division. With input from project partners and stakeholders, the investigators simulated features of the Dynamically Coupled Human-Natural ASEP system and how it is evolving under global change as well as identified gaps in and means to improve effectiveness of ASEP governance at multijurisdictional scales focused in the Laurentian Great Lakes.
- Perlinger, J.A., Gorman, H.S., Norman, E.S., Obrist, D., Selin, N.E., Urban, N.R., and S. Wu. 2016, Measurement and Modeling of Atmosphere-Surface Exchangeable Pollutants (ASEPs) To Better Understand their Environmental Cycling and Planetary Boundaries. Environ. Sci. Technol. DOI: 10.1021/acs.est.6b03447
- Kerfoot, W.C., Urban, N.R., McDonald, C.P., Zhang, H. Rossmann, R., Perlinger, J.A., Khan, T., Hendricks, A.N., Priyadarshini, M. and M. Bolstad. 2018. Mining Legacy Effects Across A Wetland Landscape: The Enigma Of High Mercury In Upper Peninsula (Michigan) Fish. Environmental Science: Processes & Impacts 20:708-733. DOI: 10.1039/C7EM00521K.
- Perlinger, J.A., Urban, N.R., Giang, A., Selin, N.E., Hendricks, A.N., Zhang, H., Kumar, A., Wu, S., Gagnon, V.S., Gorman, H.S., Norman E.S. 2018. Responses of Deposition and Bioaccumulation in the Great Lakes Region to Policy and Other Large-scale Drivers of Mercury Emissions, Environmental Science: Processes & Impacts 20:195-209, DOI: 10.1039/c7em00547d.
- Urban, N.R., Lin, H., Perlinger, J.A. 2020. Temporal and spatial variability of PCB concentrations in lake trout (Salvelinus namaycush) in Lake Superior from 1995 to 2016. Journal Great Lakes Research 46:391-401. https://doi.org/10.1016/j.jglr.2020.02.001.
CHEMICAL, PHYSICAL, AND RADIATIVE PROPERTIES OF NORTH ATLANTIC FREE TROPOSPHERIC AEROSOL AFTER LONG-RANGE TRANSPORT – Under the direction of PI L. Mazzoleni (MTU), this large, multi-investigator project determined compositions, radiative properties, age and source of atmospheric aerosols over the mid-Atlantic. Urban supervised the use of radioisotopes to determine atmospheric lifetimes of aerosols.
Small Lakes/Reservoirs
Multiple small grants including: Sulfur diagenesis: paleolimnological implications, NSF, with K. Kelts; Catskill-Delaware Reservoir System Modeling, N.Y.C. Dept. Environ. Protection, PI – S. Effler; Croton Reservoir System Dynamics & Modeling, N.Y.C. Dept. Environ. Protection, PI – S. Effler; Sedimentation in Schoharie Reservoir: Temporal Dynamics, N.Y.C. Dept. Environ. Protection, PI – S. Effler; Mercury accumulation in South Dakota Lakes, South Dakota Dept. Env. Natural Resources, PI – J. Stone;
- Squillace, M.K., Sieverding, H.L., Betemariam, H.H., Urban, N.R., Penn, M.R., DeSutter, T.M., Chipps, S.R., Stone, J. J. 2018. Historical sediment mercury deposition for select South Dakota, USA, lakes: implications for watershed transport and flooding. J. Soils and Sediments, DOI: 10.1007/s11368-018-2014-3.
- Chapra, S.C., Gawde, R.K., Auer, M.T., Gelda, R.K., Urban, N.R. 2015. Sed2K: Modeling lake sediment diagenesis in a management context. J. Environ. Engineering 141(3), doi: 10.1061/(ASCE)EE.1943-7870.0000897
- McDonald, CP, Urban, NR, 2010, Using a model selection criterion to identify appropriate complexity in aquatic biogeochemical models, Ecol. Modeling, 221(3): 428-432.
- Schultz, P., Urban NR, 2007, Effects of bacterial dynamics on organic matter decomposition and nutrient release from sediments: A modeling study, Ecol. Modeling, 210(1-2):1-14, doi:10.1016/j.ecolmodel. 2007.06.026
- Urban, NR, Monte, AE, 2001, Sulfur burial in and loss from the sediments of Little Rock Lake, Wisconsin, Can. J. Fish. Aquat. Sci. 58(7):1347-1355