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Wedelineated natural and oil-field salinity sources that degrade water qualityin the upper Colorado River (west Texas) andPetronila Creek (Texascoast) by combining multifrequency airborne EM measurements of apparent groundconductivity with chemical analyses of surface water at key streamlocations. To reduce the cost of high-resolution airborne surveying oversuch large areas, we first flew along the stream axesand then examined preliminary results in the field to identifylikely salinized stream segments. We then flew more detailed surveysover these areas rather than over the entire basin. Stream-axisEM data also helped identify water-sampling locations upstream and downstreamfrom each salinized segment. We used these...
The upper Colorado River system is the habitat of several endangered fish: Kendall Warm Springs dace, Colorado squawfish, humpback chub, and bonytail chub. The single most important factor contributing to the decline of these species has been the construction and operation of dams and reservoirs, which have effected flow, temperature, chemistry, biota, and migration routes. Water depletion amounting to about 25% of the total has also had similar effects, particularly by eliminating the backwater nursery areas. A predicted decrease in agricultural use and increase in energy development use would decrease the amount of used irrigation water percolating back into the groundwater and streams. In addition, water allocated...
IS PURE SHEAR STIMULATION ALWAYS THE MECHANISM OF STIMULATION IN EGS?, credited to McClure, M, published in 2013. Published in PROCEEDINGS, Thirty-Eighth Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, California, February 11-13, 2013, in 2013.
Carbon allocation and N acquisition by plants following defoliation may be linked through plant-microbe interactions in the rhizosphere. Feedbacks between herbivory and plant-microbe interactions may also be affected by increasing atmospheric CO2, through plant responses to changes in carbon and nitrogen availability. We studied Bouteloua gracilis (C4) and Pascopyrum smithii (C3), two widespread perennial grasses native to rangelands of western North America to examine the hypotheses that (1) defoliation-induced enhancement of rhizodeposition would change prokaryotic community composition in the rhizosphere and (2) defoliation-induced enhancement of rhizodeposition would increase under elevated CO2, thus increasing...
Natural and mining-related dissolved-constituent concentrations need to be distinguished in a water- shed affected by abandoned mines to prioritize subbasins for remediation and to assist with the establish- ment of water-quality standards. The oxygen isotopes of dissolved sulfate can be used to distinguish betweennaturalandmining-relatedsourcesofdissolvedconstituents. Severalmethodsemployingtheoxy- gen isotopes of dissolved sulfate can be used to determine the relative amounts of natural and mining- related dissolved constituents in water: (1) the isotope-dilution equation for simple mixing zones (two sources and one receiving stream); (2) the isotope mass-balance equation for streams receiving dissolved sulfate...
Modeling Impacts of Mesoscale Eddies on Iron Cycle and Biogeochemical Processes in the Gulf of Alaska, credited to Chao, Y, published in 2010. Published in American Geophysical Union Fall Meeting, in 2010.
Studies of brittle fault populations over the past decade have revealed that large extensional faults grow by the lengthening, interaction and physical linkage of en echelon fault segments. However, the temporal evolution of displacement accumulation during segment interaction and linkage is difficult to unravel due to a lack of direct observation during each stage in the fault array development. The process of profile re-adjustment prevents reconstruction of the growth history of a fault from its final configuration, and as a result, several models for the growth trajectory of a fault array undergoing linkage are possible. Observational data with which to constrain the relative timing and mode of displacement accumulation...
Ceratoides lanata (Rydb.) J.T. Howell, common winterfat, is valued for its nutrient content and palatability to livestock; however, the subspecies Ceratoides lanata var. subspinosa (Rydb.) J.T. Howell, (‘subspinosa’) is considered unpalatable. Curiously, observations of ‘subspinosa’ revealed several populations in central New Mexico that were heavily grazed. Volatile terpene profiles are associated with differences in palatability in many plant species. To determine whether differences in volatile profiles between ‘subspinosa’ populations would correlate with apparent differences in palatability, plants from 13 populations of ‘subspinosa’ were collected. Volatile analysis of shoot samples identified 33 compounds....
The Rocky Mountains and Southwestern United States, essentially the Colorado River Basin, have been the focus of a wide range of research efforts to learn more about the effects of natural and human induced disturbances on the functioning, processes, and components of the regions?s ecosystems. Watershed research, spearheaded by the USDA Forest Service and its cooperators, leads to a better understanding of the regions?s ecology, and to the formulation of management guidelines to meet the increasing needs of people living in these regions and throughout the Western United States. This paper presents pertinent details of watershed research that has been accomplished in the Colorado River Basin two regions and to provides...
The headwaters of the San Juan River begin on the western slope of the Rocky Mountains in southwestern Colorado. The headwaters, located at over 14,000 feet in ele­vation, are the beginning of what down­ stream is to become the second largest tribu­tary to the Colorado River (San Juan River Basin Recovery Implementation Program, 1992). The San Juan River is located within the San Juan River Basin (Fig. 1) which drains approximately 38,000 square miles of south­ western Colorado, northwestern New Mexi­co, southeastern Utah, and northeastern Arizona. Many tributaries add to the San Juan with the largest being the Animas river. The San Juan River flows approximately 360 miles from headwaters in Colorado to the...
Hanging garden plant communities form at seeps on cliffs. A given community may include common riparian species, disjunct populations, and species endemic to hanging gardens. What structures hanging harden communities, and how they respond to disturbance are poorly understood. In 1989, fireworks ignited a hanging garden in Knowles Cañon, destroying aboveground vegetation. Permanent plots were established in July 1993 to monitor changes in vegetation and soil biota. Revegetation of the garden has been limited to grasses, forbs, and ferns where water was present at the soil surface, and shrubs and trees sprouting from surviving rootstocks. Water drips from the overhanging cliff in the central area, where plant cover...
Hanging garden plant communities form at seeps on cliffs. A given community may include common riparian species, disjunct populations, and species endemic to hanging gardens. What structures hanging harden communities, and how they respond to disturbance are poorly understood. In 1989, fireworks ignited a hanging garden in Knowles Cañon, destroying aboveground vegetation. Permanent plots were established in July 1993 to monitor changes in vegetation and soil biota. Revegetation of the garden has been limited to grasses, forbs, and ferns where water was present at the soil surface, and shrubs and trees sprouting from surviving rootstocks. Water drips from the overhanging cliff in the central area, where plant cover...
Stream thermal regimes and aquatic ecosystems in a changing climate, credited to Luce, Charles H., published in 2009. Published in Western Watersheds and Climate Change Workshop. Boulder, CO. November 17 – 19., in 2009.
A Carex aguatilis daninated fen in the Peru Creek drainage, Colorado Rocky Mountains has been impacted by drainage from the Pennsylvania Mine. Metal concentrations in leaves, roots and standing dead leaves were analyzed and it was determined that Zn, Cu, and Al were probably the leading cause of poor plant health. Published in Wetland and Riparian Ecosystems of the American West: Proceedings of the Eight Annual Meeting of the Society of Wetland Scientists, on pages 26 - 29, in 1987.
Development of the best available seamless intertidal DEM from multiple sources for the Yaquina River estuary, credited to Saarinen, J. A., published in 2010. Published in Central Coast GIS User’s Group, November 10, in 2010.
Differences in anatomical characteristics of blackbrush (Coleogyne ramosissima Torr.) leaves were quantitatively investigated along an elevational gradient in Lee Canyon of the Spring Mountains in southern Nevada. Three elevational sites were selected: a lower blackbrush ecotone, a nearly monospecific stand in the middle of the gradient, and an upper blackbrush ecotone. Stomatal density was significantly greater and palisade parenchyma was significantly shorter in the lower ecotone compared to the upper ecotone. Vessel diameters and areas were significantly smaller, while vessel density was higher with increasing aridity. Blackbrush shrubs exhibited upper and lower elevational ecotypes at the anatomical level in...
Instream flow and climate modeling research in the upper Columbia River Basin, credited to Muhlfeld, C., published in 2010. Published in Flathead Hydrologic Modeling Workshop, Flathead Community College, Kalispell, Montana, January 26, 2010, in 2010.
The desert tortoise, Gopherus agassizii, and its habitats in the western Mojave Desert and elsewhere are negatively affected by off-road vehicles (ORVs). Data from a study conducted at the Desert Tortoise Research Natural Area during 1992 provide insights into why ORVs are likely to affect tortoises. To determine habitat use and food preferences, 18 large immature and adult tortoises were observed. The study site contained four subhabitats or strata: washes (comprising 7.9% of the area), washlets (2.4%), hills (42.3%), and flats (47.4%). The tortoises used the four habitat strata differentially, spending significantly more time (92%) in washes, washlets, and hills throughout spring than in the flats (8%). They were...
A remote-sensing/GIS application for analysis of sea surface temperature off the western coast of North America, credited to Reusser, D.A., published in 2010. Published in AGU Ocean Sciences Meeting, February 22-26, in 2010.
Past and Future Effects of Climate Change on Stream Thermal Regimes, credited to Luce, Charles H., published in 2010. Published in USFS Region 1 and 6 annual meetings. Vancouver, Washington and Missoula, MT., in 2010.
map background search result map search result map The Knowles Cañon Hanging Garden, Glen Canyon National Recreation Area, Five Years after Burning: Vegetation and Soil Biota Patterns