Publications

No abstract available.

The effects of simplifying hydraulic property layering within an unconfined aquifer and the underlying confining unit were assessed. The hydraulic properties of lithologic units within the unconfined aquifer and confining unit were computed by analyzing the aquifer-test data using radial, axisymmetric two-dimensional (2D) flow. Time-varying recharge to the unconfined aquifer and pumping...

Biodegradation of chlorinated ethenes by naturally occurring or artificially enhanced processes is an important component of current site remediation strategies. At this writing, several microbial mechanisms for chlorinated ethene transformation and degradation have been identified. The purpose of this chapter is to briefly summarize the current understanding of those processes that lead...

When the first edition of Ecotoxicology of Amphibians and Reptiles was published in 2000, I reviewed the state of the literature from 1972 through 1998 (Sparling et al. 2000). That review covered 11 271 contaminant citations listed in Wildlife Review and Sports Fisheries Abstracts published by the US Fish and Wildlife Service. Among its findings, only 2.7% of the cited papers were on...

No abstract available.

Animals and plants that live in the ocean form skeletons and other hard parts by combining calcium ions and carbonate ions to create calcium carbonate. This process is called calcification. In tropical and subtropical oceans, the calcification of corals and other organisms creates reefs that protect islands, produce beautiful white-sand beaches, and create habitat for thousands of...

Information on the flow of rivers and streams is a vital national asset that safeguards lives, protects property, and ensures adequate water supplies for the future. The U.S. Geological Survey (USGS) operates a network of more than 9,000 streamgages nationwide with more than 500 in Texas.

No abstract available.

Genetic diversity within plant populations can influence plant community structure along environmental gradients. In wetland habitats, salinity and soil type are factors that can vary along gradients and therefore affect plant growth. To test for intraspecific growth variation in response to these factors, a greenhouse study was conducted using common plants that occur in northern Gulf...

Extreme storms can have a profound impact on coastal topography and thus on ecosystems and human-built structures within coastal regions. For instance, landfalls of several recent major hurricanes have caused significant changes to the U.S. coastline, particularly along the Gulf of Mexico. Some of these hurricanes (e.g., Ivan in 2004, Katrina and Rita in 2005, and Gustav and Ike in 2008)...

Using a long-term fisheries-independent data set, we tested the 'shark nursery area concept' proposed by Heupel et al. (2007) with the suggested working assumptions that a shark nursery habitat would: (1) have an abundance of immature sharks greater than the mean abundance across all habitats where they occur; (2) be used by sharks repeatedly through time (years); and (3) see immature...

The Rio Grande cichlid (Herichthys cyanoguttatus) has been established in the Greater New Orleans Metropolitan area for at least 20 years, and its effect on native fishes is unknown. Behavioral trials were performed to determine if aggressive interactions occur between invasive H. cyanoguttatus and native bluegill (Lepomis macrochirus). When defending a territory as the resident, L...