Publications

Populations of Atlantic white cedar (Chamaecyparis thyoides (L.) B.S.P.) growing at the extreme western range of the species are in danger of being lost, and information on the ecology of these populations is limited. Seeds and seedlings ("wildlings") were collected near Vancleave, MS. The wildlings were transplanted to bay-head sites on Bogue Chitto National Wildlife Refuge where canopy...

The U.S. Geological Survey (USGS) Nonindigenous Aquatic Species (NAS) Program has tracked the distribution of introduced species for more than 20 years. This effort began with foreign fishes in Florida and later expanded to include aquatic nuisance species nationwide. The tracking database contains locational and temporal data for introductions and spread. This data is generally derived...

Surface-water sampling protocols of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program specify samples for most properties and constituents to be collected manually in equal-width increments across a stream channel and composited for analysis. Single-point sampling with an automated sampler (autosampler) during storms was proposed in the upper part of the South...

The South Florida Ecosystem Program is a collaborative effort by Federal agencies, working with State and local agencies, to help resolve land-use demands and water-supply issues in south Florida. The role of the U.S. Geological Survey in the program is to provide scientific insight into south Florida's hydrology and geology, which are an integral part of the fragile ecosystems of the...

An inventory of public water-supply systems in Tennessee in 1995 indicated that 530 public water-supply systems supplied water to 4.42 million people, or 84 percent of Tennessee's population. Public-supply water withdrawals totaled 779 million gallons per day, 64 percent (500 million gallons per day) of which was from surface-water sources. All of the surface-water withdrawals for public...

No abstract available.

No abstract available.

In Texas, the Rio Grande forms the international boundary between Mexico and the United States and extends about 2,000 kilometers from El Paso to the mouth of the Rio Grande just south of Brownsville, where the river flows into the Gulf of Mexico (fig. 1). The North American Free Trade Agreement (NAFTA) has resulted in increased industrialization and population growth on both sides of...

The U.S. Geological Survey (USGS) operates a network of streamflow-gaging stations in Texas that provides discharge data used for water-management decisions and various other purposes. Operating stations at all locations where discharge data are needed is not feasible, but the statistical characteristics of the network station data can be used to estimate discharge characteristics at...

A comprehensive set of soil characteristics were examined to determine the effect of soil on the transport of agrichemicals to ground water. This paper examines the relation of local soil characteristics to concentrations and occurrence of nitrate, atrazine (2-chloro-4 ethylamino-6-isopropylamino-s-trazine), and atrazine residue [atrazine + deethylatrazine (2-amino-4-chloro-6...

Ideally, general ecological relationships may be used to predict responses of natural communities to environmental change, but few attempts have been made to determine the reliability of predictions based on descriptive data. Using a previously published structural equation model (SEM) of descriptive data from a coastal marsh landscape, we compared these predictions against observed...

In PLHC-1 hepatoma cells, benzo[a]pyrene (B[a]P) caused a maximum induction of cytochrome P4501A (CYP1A) activity, measured as ethoxyresorufin O-deethylation (EROD), after 4 to 8 h of exposure, depending on the B[a]P concentration. The decline of EROD activity at longer exposure times was probably caused by the rapid metabolism of B[a]P in this system (57% metabolism within 4 h...