Skip to main content
Advanced Search

Filters: Tags: nutrient cycles (X)

7 results (24ms)   

View Results as: JSON ATOM CSV
thumbnail
Southern Nevada Water Authority will add new modeling and analytical capabilities to tools developed as part of a previous WaterSMART Climate Analysis Tools Grant that assessed impacts of climate change on water quality and sediment transport in Lake Mead. Project results are intended to increase an understanding of how water quality characteristics and nutrient levels in Lake Mead may be affected by climate change.
thumbnail
Southern Nevada Water Authority will add new modeling and analytical capabilities to tools developed as part of a previous WaterSMART Climate Analysis Tools Grant that assessed impacts of climate change on water quality and sediment transport in Lake Mead. Project results are intended to increase an understanding of how water quality characteristics and nutrient levels in Lake Mead may be affected by climate change.
Soil surface growths dominated by cyanobacteria and the lichen Collema in southeastern Utah are shown to be associated with greater tissue content of several bio-essential elements in two co-occurring seed plants (Festuca octoflora, Poaceae, and Mentzelia multiflora, Loasaceae). The elements N, P, K, Ca, Mg, and Fe were present in significantly greater concentrations in Festuca growing on soils heavily encrusted with cyanobacteria and cyanolichens than in plants on the same soil where foot traffic had destroyed the cryptobiotic crusts. With Mentzelia, N, Mg, and Fe were present in significantly greater concentrations in plants from sites with encrusted soil surfaces than on blow-sand sites. The cryptobiota appeared...
Transitions between atmosphere and soil, and between soil and roots, are two examples of small-scale boundaries across which the nutrient, water, and gas dynamics of ecosystems are modulated. Most atmospheric inputs to ecosystems have to pass through the soil; thus, the atmosphere?soil boundary influences the type and amount of materials and energy entering the soil. Belowground plant inputs occur through the rhizosphere, the zone of soil immediately adjacent to the root. This soil boundary layer affects root inputs to soil and root extraction of water and nutrients from soil. We discuss how water, carbon, nitrogen, and oxygen dynamics are affected by atmosphere?soil and soil?root boundaries and how light, soil...
thumbnail
c) We examined effects of flooding on supply rates of 14 nutrients in floodplain areas invaded by Phalaris arundinacea (reed canarygrass), areas restored to young successional forests (browsed by white-tailed deer and unbrowsed), and remnant mature forests in the Upper Mississippi River floodplain. Plant Root Simulator ion-exchange probes were deployed for four separate 28-day periods. The first deployment occurred during flooded conditions, while the three subsequent deployments were conducted during progressively drier periods. Time after flooding corresponded with increases in NO3--N, K+ and Zn+2, decreases in H2PO4--P, Fe+3, Mn+2, and B(OH)4-B, a decrease followed by an increase in NH4+-N, Ca+2, Mg+2 and Al+3,...
thumbnail
ELCOM and CAEDYM are three-dimensional finite-difference codes; they were used to simulate three-dimensional transport and the interactions of flow, physics, biology, and chemistry in the reservoir. The study indicated that the hydrodynamic flow patterns within Boulder Basin are mainly driven by the Colorado River inflow, the Hoover Dam outflow, and meteorological parameters. However, the water quality of Boulder Basin is also affected by the load of nutrients from the Las Vegas Wash, which carries the treated wastewater effluents from municipal wastewater treatment plants, surface runoff, and groundwater discharges into the basin.The goal of this proposed project is to assess the potential for changes in water...
thumbnail
Invasion of the exotic annual grass Bromus tectorum into stands of the native perennial grass Hilaria jamesii significantly reduced the abundance of soil biota, especially microarthropods and nematodes. Effects of invasion on active and total bacterial and fungal biomass were variable, although populations generally increased after 50+ years of invasion. The invasion of Bromus also resulted in a decrease in richness and a species shift in plants, microarthropods, fungi, and nematodes. However, despite the depauperate soil fauna at the invaded sites, no effects were seen on cellulose decomposition rates, nitrogen mineralization rates, or vascular plant growth. When Hilaria was planted into soils from not-invaded,...
    map background search result map search result map Soil Biota Can Change after Exotic Plant Invasion: Does This Affect Ecosystem Processes? A Study of Climate Change Impacts on Water Quality and Internal Nutrient Recycling in Lake Mead, Arizona-Nevada WKBT Soils and Floodplain Nutrients data Final Report BOR R13AP80034 FY13: (A Study of Climate Change Impacts on Water Quality and Internal Nutrient Recycling in Lake Mead, Arizona-Nevada) Presentation: Three-dimensional Hydrodynamic and Water Quality Model for Lake Mead WKBT Soils and Floodplain Nutrients data Soil Biota Can Change after Exotic Plant Invasion: Does This Affect Ecosystem Processes? A Study of Climate Change Impacts on Water Quality and Internal Nutrient Recycling in Lake Mead, Arizona-Nevada Final Report BOR R13AP80034 FY13: (A Study of Climate Change Impacts on Water Quality and Internal Nutrient Recycling in Lake Mead, Arizona-Nevada) Presentation: Three-dimensional Hydrodynamic and Water Quality Model for Lake Mead