Crustal Geophysics and Geochemistry Science Center

Isotope and chemical methods for mineral and geoenvironmental assessments

Reimbursable investigations with Ecosystems mission area, Water mission area, and OFA scientists

Task Objectives

The processes that occur throughout the life cycle of mineral resources are fundamentally the same as those that occur in the lithosphere, hydrosphere, and atmosphere and can be traced by the same stable isotope and geochemical techniques that have been successfully used in the study of mineral resources. Increasingly, scientists in the USGS Ecosystems scientific mission area in particular are realizing that stable isotopes are powerful tools in the study of ecosystems. Such studies offer the unprecedented opportunity to develop the frontier of integrated earth and life science studies particularly with regard to the study of ecosystems. Furthermore this task addresses directly the vision outlined by the USGS Science Strategy Team to leverage its talents and skills to undertake comprehensive and integrated studies that examine the Earth as a system including atmosphere, biosphere, hydrosphere, and lithosphere.

One of the great opportunities in science today is the integration of earth and life sciences in the studies of ecosystems. The task seeks to transfer stable isotope technology to the Ecosystems mission area and actively develop the scientific infrastructure for the coming generation of integrated earth and life science studies between the USGS scientific mission area scientists.

Statement of Work

The following projects fall under the technology transfer task:

  1. Importance of marine-derived nutrients in the Kenai River watershed, Kenai Peninsula, Alaska: Submit fitness-related effects of marine derived nutrients manuscript to a peer-reviewed journal.
  2. Nutritional ecology of polar bears in the Chukchi-Bering Seas. This project provides stable isotope support and interpretation for ongoing studies of the Chukchi polar bear population that is jointly managed with Russia via a treaty agreement. We are also conducting controlled feeding studies on captive brown bears at Washington State University under the direction of Dr. Charlie Robbins.
  3. Use of stable isotopes to differentiate Dunlin subspecies breeding in Beringia. There are five subspecies of Dunlin (Calidris alpina) that breed in the Beringia region. How these subspecies distribute during the winter is unknown, but has large ramifications due to the potential exposure to high pathogenic avian influenza viruses. Isotopic analysis of feathers is being used to infer summer and wintering ground locations.
  4. Mercury-food web dynamics in Missouri Ozark streams: Complete and submit manuscript on the trophic relations of mercury transfer in Ozark stream food webs.
  5. The population and ecological history of an endangered seabird. We will continue to analyze newly acquired feather and muscle samples. However, our efforts will be largely directed at developing a methodology for the hydrogen isotopic analysis of bone collagen. These data will be used to make inferences about the biogeography and ecology of petrel colonies prior to human colonization of the Hawaiian archipelago more than 1000 years ago.
  6. Methylmercury cycling and export from agricultural and natural wetlands in the Yolo Bypass: Presentation on the biogeochemistry of sulfur in agricultural wetlands.
  7. Captive feeding trial on Alaskan Stellar sea lions: Complete collation of isotopic data, disseminate to collaborators, and synthesize results for application to the ADF&G funded study of Stellar sea lions.
  8. Trophic and nutritional status of Alaskan Stellar sea lions: Complete isotope analyses of vibrissae samples, prepare draft manuscript related to regional assessment of milk nutritional quality.
  9. Improving geochemical methods for assessing the impacts of anthropogenic landscape changes on wildlife: Analyze and synthesize isotopic data; prepare two draft manuscripts related to i) the concept of an isoscape and niche variation, and ii) geographic origins of wind turbine-killed bats.
  10. Importance of hurricane-derived offshore, marine sediments to Gulf of Mexico coastal wetlands: a geochemical proxy-based proof of concept study: Complete analyses of core stratigraphy for trace metals, C isotopes, and Sr isotopes; synthesize data and prepare draft manuscript.
  11. Determining the effects and consequences of global climate change on white-tailed ptarmigan: Initiate field studies on the Rocky Mountain National Park population of ptarmigan; analyze the genetic and isotopic composition of historical and modern birds; compare data from this population with the Mt. Evans population.



  • Cryan, P.M., C.A. Stricker, and M.B. Wunder, Migratory structure and geographic origins of hoary bats (Lasiurus cinereus) inferred from stable isotope analysis: American Society of Mammologists.
  • Cryan, P.M., C.A. Stricker, and M.B. Wunder, Migratory structure and geographic origins of hoary bats (Lasiurus cinereus) inferred from stable isotope analysis: International Bat Meeting, Prague.
  • Goldhaber, M.B., C.T. Mills, C.A. Stricker, J.W. Labaugh, D. Mushet, and N.H. Euliss, Modeling the dynamic geochemistry of prairie pothole wetlands: USGS.
  • Rinella, D.J., M.S. Wipfli, C.A. Stricker, and R. Heintz , The relationship between spawning salmon abundance and the fitness of stream-dwelling fishes: American Fisheries Society Western Division Annual Meeting.
  • Schmitt, C.J., C.A. Stricker, and W.G. Brumbaugh, Factors influencing mercury bioavailability and accumulation in Ozark stream ecosystems: USGS.
  • Stricker, C.A., B.A. Murry, D. Clapp, and D.G. Uzarski, Historical food web changes in Lake Michigan inferred from isotopic analysis of archived yellow perch scales.
  • Wiley, A., P.H. Ostrom, H. James, C.A. Stricker, and H. Gandhi, Utilizing feathers in isotope studies of avian ecology: sampling strategies and considerations: American Ornithologist's Union.


  • Adams, L.G., Farley, S.D., Stricker, C.A., Demma, D.J., Roffler, G.H., Miller, D.C., and Rye, R.O., 2010, Are inland wolf/ungulate communities in Alaska influenced by marine subsidies of Pacific salmon?: Ecological Applications 20(1): 251-262.
  • Barros, N.B., Ostrom, P.H., Stricker, C.A., and Wells, R.S., 2010, Stable isotopes differentiate bottlenose dolphins off west-central Florida: Marine Mammal Science 26(2): 324-336.
  • Wiley, A., Ostrom, P., Stricker, C.A., James, H., and Gandhi, H., 2010, Isotopic characterization of flight feathers in two pelagic seabirds: Sampling strategies for ecological studies: Condor 112(2): 337-346.
  • Wunder, M.B., Hobson, K.A., Kelly, J., Marra, P.P., Wassenaar, L.I., Stricker, C.A., and Doucett, R.R., 2009, Does a lack of design and repeatability compromise scientific criticism? A response to Smith et al:. The Auk 126(4): 922-926.

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