First report of the ectomycorrhizal status of boletes on the Northern Yucatan Peninsula, Mexico determined using isotopic methods

Despite their prominent role for tree growth, few studies have examined the occurrence of ectomycorrhizal fungi in lowland, seasonally dry tropical forests (SDTF). Although fruiting bodies of boletes have been observed in a dry tropical forest on the Northern Yucatan Peninsula, Mexico, their occurrence is rare and their mycorrhizal status is uncertain. To determine the trophic status (mycorrhizal vs. saprotrophic) of these boletes, fruiting bodies were collected and isotopically compared to known saprotrophic fungi, foliage, and soil from the same site. Mean δ15N and δ13C values differed significantly between boletes and saprotrophic fungi, with boletes 8.0‰ enriched and 2.5‰ depleted in 15N and 13C, respectively relative to saprotrophic fungi. Foliage was depleted in 13C relative to both boletes and saprotrophic fungi. Foliar δ15N values, on the other hand, were similar to saprotrophic fungi, yet were considerably lower relative to bolete fruiting bodies. Results from this study provide the first isotopic evidence of ectomycorrhizal fungi in lowland SDTF and emphasize the need for further research to better understand the diversity and ecological importance of ectomycorrhizal fungi in these forested ecosystems

Limited Occurrence of Denitrification in Four Shallow Aquifers in Agricultural Areas of the United States

The ability of natural attenuation to mitigate agricultural nitrate contamination in recharging aquifers was investigated in four important agricultural settings in the United States. The study used laboratory analyses, field measurements, and flow and transport modeling for monitoring well transects (0.5 to 2.5 km in length) in the San Joaquin watershed, California, the Elkhorn watershed, Nebraska, the Yakima watershed, Washington, and the Chester watershed, Maryland. Ground water analyses included major ion chemistry, dissolved gases, nitrogen and oxygen stable isotopes, and estimates of recharge date. Sediment analyses included potential electron donors and stable nitrogen and carbon isotopes. Within each site and among aquifer-based medians, dissolved oxygen decreases with ground water age, and excess N2 from denitrification increases with age. Stable isotopes and excess N2 imply minimal denitrifying activity at the Maryland and Washington sites, partial denitrification at the California site, and total denitrification across portions of the Nebraska site. At all sites, recharging electron donor concentrations are not sufficient to account for the losses of dissolved oxygen and nitrate, implying that relict, solid phase electron donors drive redox reactions. Zero-order rates of denitrification range from 0 to 0.14 μmol N L−1d−1, comparable to observations of other studies using the same methods. Many values reported in the literature are, however, orders of magnitude higher, which is attributed to a combination of method limitations and bias for selection of sites with rapid denitrification. In the shallow aquifers below these agricultural fields, denitrification is limited in extent and will require residence times of decades or longer to mitigate modern nitrate contamination

Interview no. 166

Speech given at UTEP on Indian/white relations and the aims of the AIM; biographical comments

United States Bureau of Mines Report 7775

Report issued by the Bureau of Mines discussing the geology and oil-yield of the Green River in the Washakie Basin, Wyoming. Evaluations of the geology and oil-shale resources of the area are presented. This report includes tables, maps, illustrations, and photographs

United States Bureau of Mines Report 7357

Report issued by the Bureau of Mines discussing the oil-shale formations of the Green River in the Piceance Creek Basin. Detailed descriptions of oil-shale samples taken from the Green River formation are presented. This report includes tables, maps, illustrations, and a photograph

Oil yields of sections of Green River oil shale in Colorado, 1957-63 /

Chiefly tables."December 1967"--Cover.Bibliography: p. 9.Mode of access: Internet

VIDEO: Opening Session: Welcome and Introductions, Opening Reflections, Evening Tributes, and Closing Tribute

VIDEO: 5:30 p.m. - 6:45 p.m. OPENING SESSION Welcome and Introductions: Sarah Krakoff, Professor of Law, University of Colorado Law School; Phil Weiser, Dean, University of Colorado Law School Opening Reflections: Michael Connor, Deputy Secretary, United States Department of the Interior Evening Tributes: Moderator: Phil Weiser, Dean, University of Colorado Law School Speakers: Richard Trudell, Executive Director, American Indian Resources Institute Monte Mills, Assistant Professor & Co-Director, Margery Hunter Brown Indian Law Clinic, Alexander Blewett III School of Law, University of Montana John Leshy, Professor of Law, University of California at Hastings John Echohawk, Executive Director, Native American Rights Fund Michael Connor, Deputy Secretary, United States Department of the Interior Closing Tribute: Ann Marks Getches, GWC Advisory Counci

VIDEO: Opening Session: Welcome and Introductions, Opening Reflections, Evening Tributes, and Closing Tribute

VIDEO: 5:30 p.m. - 6:45 p.m. OPENING SESSION Welcome and Introductions: Sarah Krakoff, Professor of Law, University of Colorado Law School; Phil Weiser, Dean, University of Colorado Law School Opening Reflections: Michael Connor, Deputy Secretary, United States Department of the Interior Evening Tributes: Moderator: Phil Weiser, Dean, University of Colorado Law School Speakers: Richard Trudell, Executive Director, American Indian Resources Institute Monte Mills, Assistant Professor & Co-Director, Margery Hunter Brown Indian Law Clinic, Alexander Blewett III School of Law, University of Montana John Leshy, Professor of Law, University of California at Hastings John Echohawk, Executive Director, Native American Rights Fund Michael Connor, Deputy Secretary, United States Department of the Interior Closing Tribute: Ann Marks Getches, GWC Advisory Counci