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Maize (Zea mays) was a primary food crop for aboriginal societies of the arid American Southwest. Water used for maize production in these arid zones could have come from precipitation and runoff during the summer monsoon, from perennial streams and springs, or from stored soil water fed by snowmelt. The oxygen stable isotope ratio (?18O) of summer and winter precipitation on the Colorado Plateau naturally differ by more than 10? providing a powerful tool for distinguishing winter- from summer-derived water sources used in cultivation of maize. We investigated whether variation in ?18O of potential source waters is preserved in the ?18O of cellulose (?18Ocellulose) of maize cobs by growing four aboriginal and one...
In many ecosystems, seasonal shifts in temperature and precipitation induce pulses of primary productivity that vary in phenology, abundance, and nutritional quality. Variation in these resource pulses could strongly influence community composition and ecosystem function, because these pervasive bottom-up forces play a primary role in determining the biomass, life cycles, and interactions of organisms across trophic levels. The focus of this research is to understand how consumers across trophic levels alter resource use and assimilation over seasonal and interannual timescales in response to climatically driven changes in pulses of primary productivity. We measured the carbon isotope ratios (delta(13)C) of plant,...
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We analyzed tissue δ13C, δ15N, and δ34S of animals associated with hydrocarbon seeps on the lower continental slope of the Gulf of Mexico. We made discrete collections of fauna associated with four dominant chemosymbiotic seep fauna: vestimentiferan tubeworms, bathymodiolin mussels, vesicomyid clams, and Sclerolinum sp. (another siboglinid worm related to vestimentiferans). These collections were conducted in 2006 and 2007 using the manned submersible Alvin and the remotely operated vehicle Jason II, both operated by Woods Hole Oceanographic Institute. The purpose of this study was to use stable isotopes to explore potential nutritional sources and trophic interactions in these seep communities, especially those...
Sugar cane cropping for biofuel production reduces water discharge from a northern Indian basin and threatens downstream communities. Regulators want to partition blame between climate change—induced declines in mountain snowpack and excessive evaporation from poorly managed fields. In the same basin, a tiger is found shot. Is it the nuisance animal that has been tormenting local communities, or is it a different animal poached from the upland forests?
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This dataset includes total phosphorus (TP), total nitrogen (TN), and total carbon (TC) concentrations as well as δ15N and δ13C composition, and overall C:N:P stoichiometry for adult emergent Diptera from the Colorado River, Grand Canyon, AZ. The samples were collected before and after a fire and subsequent storm occurred in the Shinumo Watershed, a tributary to the Colorado River in Northern Arizona. Diptera specimens were collected via light traps placed on the banks of the Colorado River 25 miles above and 25 miles below Shinumo Creek (river miles 85-135) between 2013 and 2015. This data series contains Diptera TP concentrations (in mg P per mg Diptera) for 44 samples from 11 location/date combinations. We also...
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These data were compiled for a manuscript that examines the riverine food-web structure of the Colorado River below Glen Canyon dam to its confluence with Lake Mead. Tissue from primary producers (vascular plants and algae) and consumers (aquatic invertebrates and fish) were collected before and after monsoon floods in 2006 along the 388 kilometer segment of the Colorado River in the Southwest US. Tissue samples were dried, ground, and analyzed for δ13C, δ15N, and δ2H stable isotope signatures and percent carbon and nitrogen. Analysis of these data focused on determining the proportion of terrestrial (allochthonous) vs. aquatic (autochthonous) organic matter sources at the base of the food web, trophic diversity...
Semiarid areas in the US have realized extensive and persistent exotic plant invasions. Exotics may succeed in arid regions by extracting soil water at different times or from different depths than native plants, but little data is available to test this hypothesis. Using estimates of root mass, gravimetric soil water, soil-water potential, and stable isotope ratios in soil and plant tissues, we determined water-use patterns of exotic and native plant species in exotic- and native-dominated communities in Washington State, USA. Exotic and native communities both extracted 12 � 2 cm of water from the top 120 cm of soil during the growing season. Exotic communities, however, shifted the timing of water use by extracting...


    map background search result map search result map Stable isotope compositions of animal tissues in Gulf of Mexico lower slope seep communities. Food Web Data, Colorado River Corridor, Grand Canyon, Arizona, 2006 Carbon, nitrogen, and phosphorus content of adult emergent Diptera before and after a fire-storm sequence in the Colorado River near Shinumo Creek, Grand Canyon, AZ Food Web Data, Colorado River Corridor, Grand Canyon, Arizona, 2006 Carbon, nitrogen, and phosphorus content of adult emergent Diptera before and after a fire-storm sequence in the Colorado River near Shinumo Creek, Grand Canyon, AZ Stable isotope compositions of animal tissues in Gulf of Mexico lower slope seep communities.