Publications

The Sacramento metropolitan (SacMetro) study unit covers approximately 3,250 square kilometers of the Central Valley along the eastern edge of the northern and southern ends of the San Joaquin and Sacramento Valleys, respectively. Groundwater withdrawals supply a significant portion of the water-resource needs of the region. In the southern portion of the study unit, groundwater accounts...

Numerous studies have established strong linkages between acid deposition, soil and surface-water acidification, and toxicity to aquatic biota. Little is known however, about the effects of acidification on fish assemblages in headwater streams because they are highly variable, and pre-acidification data are often lacking. The primary purpose of this study was to describe spatial and...

A basic understanding of how the landscape impedes, or creates resistance to, the dispersal of organisms and hence gene flow is paramount for successful conservation science and management. Spatially structured ecological networks are often used to represent spatial landscape‐genetic relationships, where nodes represent individuals or populations and resistance to movement is represented...

The relative importance of nitrogen (N) deposition as a stressor to global forests is likely to increase in the future, as N deposition increases in Asia and Africa, and as sulfur declines more than nitrogen in Europe, the US, and Canada. Even so, it appears that decreased N deposition may not be sufficient to induce recovery, suggesting that management interventions may be necessary to...

To better understand the effects of climate change on streamflow, the hydrologic response to both temperature and precipitation needs to be examined at the mesoscale. New York State provides a hydrologically diverse mesoscale region, where sub-regional clusters of watersheds may respond differently to changes in temperature and in seasonal precipitation rates. Connections between...

High natural variability in the condition of fish communities in headwater streams complicates detection of long-term responses to changes in water quality. As a result, little is known about the impacts and recovery of fishes from acid deposition in streams of New York. Twenty-one fish metrics from annual electrofishing surveys at 13 streams sites in the Catskill and Adirondack...

The sustainability of ground-source geothermal systems can be severely impacted by microbially mediated clogging processes. Biofouling of water wells by hydrous ferric oxide is a widespread problem. Although the mechanisms and critical environmental factors associated with clogging development are widely recognized, effects of mixing processes within the wells and time scales for...

Trapa natans, characterized by four-horned fruits, has been recognized as an introduced species in the northeastern United States since the 1920′s. However, in 2014 a two-horned morphotype of Trapa was discovered in the Potomac River in Virginia. As such, we hypothesize the two-horned variety represents a cryptic introduction of a Trapa taxon distinct from the four-horned T. natans...

A case study of groundwater contamination is a detailed study of a single site contaminated with a chemical or mixture that is known to be a problem at many sites. The goal of case studies is to provide insights into the physical, chemical, and biological processes controlling migration, natural attenuation, or remediation of common groundwater contaminants. Ideally, processes occurring...

Over the last decade, studies at the Shale Hills Critical Zone Observatory (Shale Hills) have greatly expanded knowledge of weathering in previously understudied, shale-mantled terrains, as well as Earth's Critical Zone as a whole. Among the many discoveries made was the importance of redistribution and losses of micron-sized particles during development of shale-derived soils. A...

The Precipitation-Runoff Modeling System (PRMS) is widely used to simulate the effects of climate, topography, land cover, and soils on landscape-level hydrologic responses and streamflow. The U.S. Geological Survey (USGS), in cooperation with the New Mexico Department of Homeland Security and Emergency Management, developed procedures to apply the PRMS model to simulate the effects of...

The quantity and character of dissolved organic matter (DOM) can change rapidly during storm events, affecting key biogeochemical processes, carbon bioavailability, metal pollutant transport, and disinfection byproduct formation during drinking water treatment. We used in situ ultraviolet–visible spectrophotometers to concurrently measure dissolved organic carbon (DOC) concentration and...