Research Highlights

Unlocking the Climate Archives

Podcasts

Listen to or download the podcast to learn more about how NRMRL research helps to support the protection of human health and the environment.

 

Within our continent’s aquifers lie archives of long-term climate changes documenting precipitation recharge in watersheds. Aquifers act as filters that smooth out short-term climate fluctuations and record continental climate signals. Past temperature signals (paleotemperatures) are stored with dissolved noble (inert) gases in ground water. Using noble gases as proxies, NRMRL hydrologists are sampling paleotemperatures in the Elwha watershed on the Olympic Peninsula in Washington state. The goal is to record paleotemperatures in the region in an effort to forecast the range of future shifts in recharge. Changing recharge patterns can result in severe consequences for many habitats, most notably the salmon habitats of the Pacific Northwest. The Elwha watershed is the centerpiece of widespread efforts at salmon habitat restoration on behalf of tribal communities and declining regional fisheries.*

Background

Sampling the upper catchments in the Elwha watershed, Washington.

While no wells exist, nor can be drilled, in Olympic National Park itself, the abundant springs and seeps in the area provide samples that are linked chemically and isotopically to recharge from the Olympic Mountains. When sampled for certain parameters, these springs provide a window into the regional aquifer’s recharge history. Recent advances in sampling technology allow micro-volume extractions from watershed sites and expedite the transport of dissolved gases for laboratory analysis.

To provide a basis for paleotemperature estimates, researchers combine noble gas spectrometry with known solubility equilibrium constants for neon, argon, krypton and xenon. These inert gases dissolve in precipitation, infiltrating to the water table where, until air saturation is reached, they are dependent on temperature. A noble-gas temperature (NGT) is therefore a measure of the temperature at which ground water equilibrated with the atmosphere during infiltration, and it commonly corresponds to the mean air temperature. Measurement of the composition of each noble gas in a ground water sample provides respective independent estimates of that recharge temperature. Solubility of each heavier noble gas is increasingly more sensitive to changes in temperature.

Recharge temperatures are derived by extraction of air from the analyzed neon, argon, krypton and xenon gas concentrations of ground water samples. The key assumption is that the ground water system has remained closed since its recharge. Isotopes of these noble gases are measured to decipher whether significant mixing, dispersion, or atmospheric contamination have occurred during their residence time. (Note that the present water temperature, such as at a hot or cold spring, does not disguise the recorded temperature of a dissolved noble gas entrapped since recharge.)

A total of 63 springs or seeps have been sampled thus far in the Elwha watershed. In 13 of those samples, the recharge air temperatures varied from 8.2 degrees C to 12.4 degrees C over an interval of 900 years before the present. While cooler air temperatures prevailed, the present mean recharge air temperature was exceeded by much warmer air about 750 years ago. As more detailed maps of recharge air temperature changes are developed for younger and older recharged waters, scaled modeling of hydrologic impacts for salmon-spawning habitats will be forecasted.

While many elements influence the decline of salmon runs, climate change and its relationship to stream temperatures are recognized as significant potential influences in the restoration of salmon populations in the Northwestern states.

*In 2007, the governors of Washington, Oregon and California asked for federal disaster relief after a regional salmon fishery cancelled the commercial fishing season because of a critical decline in salmon populations.

Contact

Jane Ice, NRMRL Office of Public Affairs (513) 569-7311

Hot Off the Presses—NRMRL Publications

Journal Articles

Baruwati, B., M. N. Nadagouda, and R. S. Varma. (2008). “Bulk Synthesis of Monodisperse Ferrite Nanoparticles at Water-Organic Interfaces Under Conventional and Microwave Hydrothermal Treatment and Their Surface Functionalization.” G. C. Schatz (ed.), Journal of Physical Chemistry. American Chemical Society, Washington, DC, 112(47):18399–18404.

Forshay, K. J., P. T. Johnson, M. Stock, C. Peñalva, and S. I. Dodson. (2008). “Festering Food: Chytridiomycete Pathogen Reduces Quality of Daphnia Host as a Food Resource.” Ecology, Ecological Society of America, Ithaca, NY, 89(10):2692–2699.

Grandesso, E., S. Ryan, B. Gullett, A. Touati, E. Collina, M. Lasagni, and D. Pitea. (2008). “Kinetic Modeling of Polychlorinated Dibenzo-p-dioxin and Dibenzofuran Formation Based on Carbon Degradation Reactions.” Environmental Science and Technology, American Chemical Society, Washington, DC, 42(19):7218–7224.

Gibbs, S., M. C. Meckes*, M. Ortiz, C. F. Green, and P. V. Scarpino. (2008). “Evaluation of the Inhibition of Culturable Enterococcus faecium, Escherichia coli, or Aeromonas hydrophilia by an Existing Drinking Water Biofilm.” Journal of Environmental Engineering and Science, NRC Research Press, Ottawa, Canada, 7(6):559–568.

Williamson, J. M. and H. W. Thurston. (2008). “Valuing Acid Mine Drainage Remediation in West Virginia: A Hedonic Modeling Approach.” 10.1007/s00168-007-0 Johansson, Kim, Stough (ed.), The Annals of Regional Science, Springer Science Business Media B.V, Dordrecht, Netherlands, 42(4):987–999.

Paper in Non-EPA Proceeding

Smith Jr., J. E. (2008). “Meeting Regulatory Requirements and Moving to Class A.” In Proceedings, 81st Annual Water Environment Federation Technical Exhibition and Conference: Pre-Conference Workshop, Chicago, IL, October 18–22.

EPA Published Reports

US EPA. (2008). Jordan, D. “Mine Waste Technology Program: Electrochemical Tailings Cover (PDF).” (62 pp, 1.39 MB) EPA/600/R-08/095 | Abstract | NTIS PB2009-100862.

US EPA. (2008). Jordan, D. “Mine Waste Technology Program: Passive Treatment for Reducing Metal Loading (PDF).” (37 pp, 415 KB) EPA/600/R-08/097 | Abstract | NTIS PB2009-100863.

US EPA. (2008). Nordwick, S. “Mine Waste Technology Program: In Situ Source Control of Acid Generation Using Sulfate-Reducing Bacteria (PDF).” (77 pp, 655 KB) EPA/600/R-08/096 | Abstract | NTIS PB2009-102096.

US EPA. (2008).Thurston, H. W., A. Roy, W. D. Shuster, H. Cabezas, M. A. Morrison, and M. A. Taylor. “Using Economic Incentives to Manage Stormwater Runoff in the Shepherd Creek Watershed, Part I (PDF).” (66 pp, 3.55 MB) EPA/600/R-08/129 | Abstract.

US EPA. (2008). Wilmoth, R. C., L. Drees, J. R. Kominsky, G. M. Shaul, D. Cox, D. Eppler, W. M. Barrett, F. D. Hall, and J. A. Wagner. “Comparison of the Alternative Asbestos Control Method and the NESHAP Method for Demolition of Asbestos-Containing Buildings (PDF).” (229 pp, 8.46 MB) EPA/600/R-08/094 | Abstract | NTIS PB2009-102095.

US EPA. (2008). Wilson, J. T., K. Banks, R. C. Earle, Y. He, T. Kuder, and C. J. Adair. “Natural Attenuation of the Lead Scavengers 1,2-Dibromoethane (EDB) and 1.2-Dichloroethane (1,2-DCA) at Motor Fuel Release Sites and Implications for Risk Management (PDF).” (74 pp, 2.11 MB) EPA/600/R-08/107 | Abstract

You will need Adobe Reader to view some of the files on this page.
See EPA's PDF page to learn more.