Hydrogeologic Setting and Ground-Water Flow Simulations of the Eastern High Plains Regional Study Area, Nebraska

The transport of anthropogenic and natural contaminants to public-supply wells was evaluated in a part of the High Plains aquifer near York, Nebraska, as part of the U.S. Geological Survey National Water-Quality Assessment Program. The aquifer in the Eastern High Plains regional study area is composed of Quaternary alluvial deposits typical of the High Plains aquifer in eastern Nebraska and Kansas, is an important water source for agricultural irrigation and public water supply, and is susceptible and vulnerable to contamination. A six-layer, steady-state ground-water flow model of the High Plains aquifer near York, Nebraska, was constructed and calibrated to average conditions for the time period from 1997 to 2001. The calibrated model and advective particle-tracking simulations were used to compute areas contributing recharge and travel times from recharge areas to selected public-supply wells. Model results indicate recharge from agricultural irrigation return flow and precipitation (about 89 percent of inflow) provides most of the ground-water inflow, whereas the majority of ground-water discharge is to pumping wells (about 78 percent of outflow). Particle-tracking results indicate areas contributing recharge to public-supply wells extend northwest because of the natural ground-water gradient from the northwest to the southeast across the study area. Particle-tracking simulations indicate most ground-water travel times from areas contributing recharge range from 20 to more than 100 years but that some ground water, especially that in the lower confined unit, originates at the upgradient model boundary instead of at the water table in the study area and has travel times of thousands of years.

Solar Forcing of Gulf of California Climate During The Past 2000 Yr Suggested by Diatoms and Silicoflagellates

High-resolution records of the past 2000 yr are compared in a north–south transect (28° N to 24° N) of three cores from the eastern slopes of the Guaymas, Carmen, and Pescadero Basins of the Gulf of California (hereafter referred to as the “Gulf”). Evenly-spaced samples from the varved sediments in each core allow sample resolution ranging from ∼ 16 to ∼ 37 yr. Diatoms and silicoflagellates capture the seasonal variation between a late fall to early spring period of high biosiliceous productivity, that is driven by northwest winds, and a summer period of warmer, more stratified waters during which these winds slacken and/or reverse direction (monsoonal flow). As these winds decrease, tropical waters enter the Gulf and spread northward. Individual samples represent a composite of 7 to 23 yr of deposition and are assumed to record the relative dominance of the winter vs. summer floral components. Intervals of enhanced summer incursion of tropical waters, alternating with periods of increased late fall to early spring biosiliceous productivity are recorded in all three cores. Regularly spaced cycles (∼ 100 yr duration) of Octactis pulchra, a silicoflagellate proxy for lower SST and high productivity, and Azpeitia nodulifera, a tropical diatom, occur between ∼ A.D. 400 and ∼ 1700 in the more nearshore Carmen Basin core, NH01-21 (26.3° N), suggesting a possible solar influence on coastal upwelling. Cores BAM80 E-17 (27.9° N) and NH01-26 (24.3° N) contain longer-duration cycles of diatoms and silicoflagellates. The early part of Medieval Climate Anomaly (∼ A.D. 900 to 1200) is characterized by two periods of reduced productivity (warmer SST) with an intervening high productivity (cool) interval centered at ∼ A.D. 1050. Reduced productivity and higher SST also characterize the record of the last ∼ 100 to 200 yr in these cores. Solar variability appears to be driving productivity cycles, as intervals of increased radiocarbon production (sunspot minima) correlate with intervals of enhanced productivity. It is proposed that increased winter cooling of the atmosphere above southwest U.S. during sunspot minima causes intensification of the northwest winds that blow down the Gulf during the late fall to early spring, leading to intensified overturn of surface waters and enhanced productivity. A new silicoflagellate species, Dictyocha franshepardii Bukry, is described and illustrated.

The Probe, Issue 210 – May/June 2000

NADCA Election in Progress Berryman Institute Announces 1999 Awards New Probe Editor to be Appointed: Larry Sullivan Ken Garner Retires Book Review: "Master Land Snaring: Canine and Coon Techniques, Effective in All Terrains." by Newt Sterling as told to Bob Noonan. 1999. 58 pages, illustrated. NPCA Gets New Name Lobster Plates: PETA (People for the Ethical Treatment of Animals) is fighting to prevent the return of the lobster to Maine's automobile license plates. Active Antis in the Northwest Animal Rights Violence on Increase Abstracts from the 6th Annual Conference of The Wildlife Society: Monitoring of Sin Nombre Hantavirus in deer mice of the Southwest, USA -- Robinson, Rhonda /., Kathryn D. Bennett, James R. Biggs, Timothy K. Haarmann, David C. Keller, and Mary E. Salisbury Predators in the classroom: A prickly paradigm for educators -- Rollins, Dale Trends in bat rabies in the U.S.: Shaping public health policy -- Rupprecht, Charles E., Sharon B. Messenger, and Jean S. Smith

Draft U.S. Pacific Marine Mammal Stock Assessments: 2009

Under the 1994 amendments to the Marine Mammal Protection Act (MMPA), the National Marine Fisheries Service (NMFS) and the U.S. Fish and Wildlife Service (USFWS) are required to publish Stock Assessment Reports for all stocks of marine mammals within U.S. waters, to review new information every year for strategic stocks and every three years for non-strategic stocks, and to update the stock assessment reports when significant new information becomes available. This report presents stock assessments for 13 Pacific marine mammal stocks under NMFS jurisdiction, including 8 “strategic” stocks and 5 “non-strategic” stocks (see summary table). A new stock assessment for humpback whales in American Samoa waters is included in the Pacific reports for the first time. New or revised abundance estimates are available for 9 stocks, including Eastern North Pacific blue whales, American Samoa humpback whales, five U.S. west coast harbor porpoise stocks, the Hawaiian monk seal, and southern resident killer whales. A change in the abundance estimate of Eastern North Pacific blue whales reflects a recommendation from the Pacific Scientific Review Group to utilize mark-recapture estimates for this population, which provide a better estimate of total population size than the average of recent line-transect and mark-recapture estimates. The ‘Northern Oregon/Washington Coast Stock’ harbor porpoise stock assessment includes a name change (‘Oregon’ is appended to ‘Northern Oregon’) to reflect recent stock boundary changes. Changes in abundance estimates for the two stocks of harbor porpoise that occur in Oregon waters are the result of these boundary changes, and do not reflect biological changes in the populations. Updated information on the three stocks of false killer whales in Hawaiian waters is also included in these reports. Information on the remaining 50 Pacific region stocks will be reprinted without revision in the final 2009 reports and currently appears in the 2008 reports (Carretta et al. 2009). Stock Assessments for Alaskan marine mammals are published by the National Marine Mammal Laboratory (NMML) in a separate report. Pacific region stock assessments include those studied by the Southwest Fisheries Science Center (SWFSC, La Jolla, California), the Pacific Islands Fisheries Science Center (PIFSC, Honolulu, Hawaii), the National Marine Mammal Laboratory (NMML, Seattle, Washington), and the Northwest Fisheries Science Center (NWFSC, Seattle, WA). Northwest Fisheries Science Center staff prepared the report on the Eastern North Pacific Southern Resident killer whale. National Marine Mammal Laboratory staff prepared the Northern Oregon/Washington coast harbor porpoise stock assessment. Pacific Islands Fisheries Science Center staff prepared the report on the Hawaiian monk seal. Southwest Fisheries Science Center staff prepared stock assessments for 9 stocks. The stock assessment for the American Samoa humpback whale was prepared by staff from the Center for Coastal Studies, Hawaiian Islands Humpback National Marine Sanctuary, the Smithsonian Institution, and the Southwest Fisheries Science Center. Draft versions of the stock assessment reports were reviewed by the Pacific Scientific Review Group at the November 2008, Maui meeting. The authors also wish to thank those who provided unpublished data, especially Robin Baird and Joseph Mobley, who provided valuable information on Hawaiian cetaceans. Any omissions or errors are the sole responsibility of the authors. This is a working document and individual stock assessment reports will be updated as new information on marine mammal stocks and fisheries becomes available. Background information and guidelines for preparing stock assessment reports are reviewed in Wade and Angliss (1997). The authors solicit any new information or comments which would improve future stock assessment reports. These Stock Assessment Reports summarize information from a wide range of sources and an extensive bibliography of all sources is given in each report. We strongly urge users of this document to refer to and cite original literature sources rather than citing this report or previous Stock Assessment Reports. If the original sources are not accessible, the citation should follow the format: [Original source], as cited in [this Stock Assessment Report citation].