A5022422079- Hydrology and Watershed Management Studies
- Soil and Water Nutrient Dynamics
- Soil Carbon and Nitrogen Dynamics
- Rangeland and Wildlife Management
- Cryospheric studies and observations
- Groundwater and Isotope Geochemistry
- Fire effects on ecosystems
- Climate change and permafrost
- Plant Water Relations and Carbon Dynamics
- Soil erosion and sediment transport
- Microbial Community Ecology and Physiology
- Peatlands and Wetlands Ecology
- Atmospheric and Environmental Gas Dynamics
- Urban Stormwater Management Solutions
- Geology and Paleoclimatology Research
- Ecology and Vegetation Dynamics Studies
- Soil Geostatistics and Mapping
- Flood Risk Assessment and Management
- Hydrology and Sediment Transport Processes
- Soil and Unsaturated Flow
- Groundwater flow and contamination studies
- Landslides and related hazards
- Land Use and Ecosystem Services
- Climate variability and models
- Biocrusts and Microbial Ecology
Idaho State University
2015-2024
University of Arizona
2008-2014
University of California, Berkeley
2005-2008
Arizona State University
2005-2008
Stanford University
2002
Soil profiles are rarely homogeneous. Resource availability and microbial abundances typically decrease with soil depth, but microbes found in deeper horizons still important components of terrestrial ecosystems. By studying 20 across the United States, we documented consistent changes bacterial archaeal communities depth. Deeper soils harbored distinct from those more commonly studied surface horizons. Most notably, that candidate phylum Dormibacteraeota (formerly AD3) was often dominant...
Here we review the fundamental interactions between hydrology and cycling of carbon (C) nitrogen (N) in terrestrial stream ecosystems. We organize this around five commonly studied environments: land-atmosphere interface, soil, groundwater, streams, headwater catchments. Common among all environments is that hydrological transitions, either episodic changes water availability or hydrologic transport reactants, result disproportionately high rates C N cycling. Two major research challenges...
To understand the hydrologic and biogeochemical controls on age recalcitrance of dissolved organic matter (DOM) found in stream waters, we combined hydrometric monitoring along a topographic gradient from ridge to channel with isotopic ( 13 C 14 C) spectroscopic (UV nuclear magnetic resonance) analyses soil water samples small coastal watershed California. With increasing discharge, carbon concentrations increased 2.2 10.9 mg L −1 , Δ values −125 +120‰, δ decreased −24 −29‰, C:N ratios 6.5...
Abstract. The critical zone (CZ), the dynamic living skin of Earth, extends from top vegetative canopy through soil and down to fresh bedrock bottom groundwater. All humans live in depend on CZ. This has three co-evolving surfaces: canopy, ground surface, a deep subsurface below which Earth's materials are unweathered. network nine CZ observatories supported by US National Science Foundation made advances broad areas research relating surfaces. First, monitoring revealed how natural...
The structure of the critical zone (CZ) is a result tectonic, lithogenic, and climatic forcings that shape landscape across geologic time scales. CZ can be probed to measure contemporary rates regolith production hillslope evolution, its fluids solids sampled determine how affects function as living filter for hydrologic biogeochemical cycles. Substantial uncertainty remains regarding variability in climate lithology influence both short (e.g., event) long evolution) We are addressing this...
Soil thickness is a fundamental variable in many earth science disciplines due to its critical role hydrological and ecological processes, but it difficult predict. Here we show strong linear relationship (r2 = 0.87, RMSE 0.19 m) between soil hillslope curvature across both convergent divergent parts of the landscape at field site Idaho. We find similar relationships diverse landscapes (n 6) with slopes these varying as function standard deviation catchment curvatures. This...
Runoff pathways strongly influence hydrologic and biogeochemical losses landscape evolution. On an evolving landscape, soil development may alter properties thereby change through time the relative importance of various pathways. Here we report in situ water retention, unsaturated saturated hydraulic conductivity, flow path characteristics a 300 year old Andisol 4.1 million Oxisol, located at extreme ends substrate age gradient across Hawaiian Islands. The two soils contrasted depth texture;...
[1] Feedbacks among vegetation dynamics, pedogenesis, and topographic development affect the "critical zone"—the living filter for Earth's hydrologic, biogeochemical, rock/sediment cycles. Assessing importance of such feedbacks, which may be particularly pronounced in water-limited systems, remains a fundamental interdisciplinary challenge. The sky islands southern Arizona offer an unusually well-defined natural experiment involving feedbacks because mean annual precipitation varies by...
Abstract In mountains with seasonal snow cover, the effects of climate change on snowpack will be constrained by landscape‐vegetation interactions atmosphere. Airborne lidar surveys used to estimate depth, topography, and vegetation were coupled reanalysis products quantify these highlight potential sensitivities across western U.S. at Rocky Mountain (RM), Northern Basin Range (NBR), Sierra Nevada (SNV) sites. forest shrub areas, elevation captured greatest amount variability in depth...
Urban watersheds are often sources of nitrogen (N) to downstream systems, contributing poor water quality. However, it is unknown which components (e.g., land cover and stormwater infrastructure type) urban contribute N export may be sites retention. In this study we investigated watershed characteristics control sourcing, biogeochemical processing nitrate (NO3-) during storms, the amount rainfall that retained within watersheds. We used triple isotopes NO3- (δ15N, δ18O, Δ17O) identify...
Abstract Large uncertainties in global carbon (C) budgets stem from soil estimates and associated challenges distributing organic (SOC) at local to landscape scales owing lack of information on thickness controls SOC storage. Here we show that 94% the fine-scale variation total profile within a 1.8 km 2 semi-arid catchment Idaho, U.S.A. can be explained as function aspect hillslope curvature when entire vertical dimension is measured fine-resolution (3 m) digital elevation models are...
Abstract Chemical stabilization of microbial-derived products such as extracellular enzymes (EE) onto mineral surfaces has gained attention a possibly important mechanism leading to the persistence soil organic carbon (SOC). While controls on EE activities and their in surface are reasonably well-understood, how these change with depth diverge from those at due distinct physical, chemical, biotic conditions remains unclear. We assessed activity 1 m (10 cm increments) 19 profiles across...
Langridge, R., J. Christian-Smith, and K. A. Lohse. 2006. Access resilience: analyzing the construction of social resilience to threat water scarcity. Ecology Society 11(2): 18. https://doi.org/10.5751/ES-01825-110218
Wet tropical forests growing on highly weathered soil, depleted in rock-derived nutrients, yet rich nitrogen (N), may respond quite differently to anthropogenic N inputs than those younger soils low N. We evaluated the effects of first-time and long-term additions pattern regulation hydrologic losses from wet located at extreme ends a soil age fertility gradient Hawaiian Islands. In contrast our expectations that N-limited forest 300-year-old would initially retain inputs, both forests,...
Abstract Despite a multitude of small catchment studies, we lack deep understanding how variations in critical zone architecture lead to hydrologic states and fluxes. This study characterizes dynamics 15 catchments the U.S. Critical Zone Observatory (CZO) network where hypothesized that our subsurface structure would illuminate patterns partitioning. The CZOs collect data sets characterize physical, chemical, biological subsurface, while also monitoring fluxes such as streamflow,...