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Weekly Highlights for 10-06-2009

I. Departmental/Bureau News

A. Upcoming Events

USGS Science at GSA Annual Meeting
USGS Alaska Science Center research will be presented at the annual Geological Society of America Meeting to be held in Portland, OR October 18-21. A talk entitled "USGS-NPS Joint Effort to Create Digital Geologic Data for Alaska National Parks" will describe a USGS-NPS effort to provide USGS digital data to all Alaska National Parks in a Park Service designed digital format. Our available digital data is much richer than the NPS data structure was designed for and a significant part of the effort involves both restructuring as well as addenda to the NPS data structure to accept the additional data.
Contact: Nancy Norvell Anchorage, AK, (907) 786-7029

B. Current

Climate Change and Ocean Carrying Capacity Examined in Recent Publication on Pacific Salmon Growth and Survival
USGS Alaska Science Center Biologist Jennifer Nielsen is the lead author of a study in “Pacific Salmon Environmental and Life History Models,” American Fisheries Society Symposium 71, titled "Climate Change and a Dynamic Ocean Carrying Capacity: Growth and Survival of Pacific Salmon at Sea." The study explores key questions on whether competition with other salmon translates into reduced growth and survival of salmon at-sea (‘density-dependence’) and whether changes in ocean regimes can alter this relationship. The researchers conclude that salmon growth and survival responses to oceanic changes can vary with season and life stage, and that density-dependent growth at-sea is an important, yet often elusive, mechanism affecting salmon survival. Thus, as life history models of Pacific salmon are developed to include dynamic ocean and climatic conditions, they should also include density-dependence at-sea in factors of growth, survival, and abundance.
Contact: Jennifer Nielsen Anchorage, AK, (907) 786-7062

New Publication Links Channel Incision and Water-Table Decline
USGS Alaska Science Center investigator Edward G. Neal is author of a newly published paper entitled "Channel incision and water-table decline along a recently formed proglacial stream, Mendenhall Valley, southeastern Alaska." Retreat of the Mendenhall Glacier, in southeastern Alaska, resulted in the formation of Mendenhall Lake, which has reduced the supply of coarse sediment to the proglacial Mendenhall River. Channel incision in the Mendenhall River is believed to be the result of a combination of factors resulting from localized and region-wide glacial retreat. This study suggests channel incision can rapidly lower water-table elevations for large distances in the adjacent aquifer, potentially modifying the hydrology to a degree capable of influencing adjacent surface-water features, such as off-channel wetlands and flood-plain side channels. Channel incision followed by lowering of the adjacent water table is likely to have wide-reaching implications in the maintenance and recovery of salmonid habitat throughout the Pacific Northwest. Findings presented here provide resource scientists and managers evidence linking small-scale channel incision to reduced groundwater levels, as well as methods for developing long-term monitoring of the linkage between channel incision and groundwater levels. This research is one of the papers included in the USGS professional paper "Studies by U.S. Geological Survey in Alaska, 2007" and is available online at http://pubs.usgs.gov/pp/1760/e/.
Contact: Edward Neal Juneau, AK, (907) 586-7216 x33

Fault System in Lake Clark National Park May Be Extensive
Work in the vicinity of Lake Clark National Park this summer provided data for a theory that suggests the Castle Mountain fault system is much more extensive than previously thought and has an order of magnitude more strike-slip offset than is commonly accepted. Results included the location of a number of suggestive geomorphic and kinematic features supporting the theory and collection of a number of samples to test aspects of the theory. Additional fieldwork is anticipated in the future. This work is important in elucidating the tectonics of Alaska and may yield information useful in identification of petroleum and mineral deposits.
Contact: Chad Hults Anchorage, AK, (907) 786-7417

II. Press Inquiries/Media

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