Publications

The Potomac-Raritan-Magothy (PRM) aquifer system is an important sole-source ground-water supply in Camden and Gloucester Counties, N.J. Elevated iron concentrations are a persistent water-quality problem associated with ground water from the PRM. In Philadelphia, the PRM no longer is usable as a water supply because of highly elevated concentrations of iron (as high as 429 mg/L...

The precious metals commonly referred to as platinum-group metals (PGM) include iridium, osmium, palladium, platinum, rhodium and ruthenium. PGM are among the rarest of elements, and their market values — particularly for palladium, platinum and rhodium — are the highest of all precious metals.

In 1992, ground-water withdrawals from the unconfined and confined aquifers in the New Jersey Coastal Plain totaled about 300 million gallons per day, and about 70 percent (200 million galllons per day) of this water was pumped from confined aquifers. The withdrawals have created large cones of depression in several Coastal Plain aquifers near populated areas, particularly in Camden and...

Two major pulses of sea-level rise are thought to have taken place since the last glacial maximum — meltwater pulses (mwp) 1A (12 cal ka) and 1B (9.5 cal ka). Between mwp 1B and about 6 cal ka, many of the complex coastal ecosystems which ring the world’s oceans began to form. Here we report data for rhenium, carbon isotopes, total organic carbon, and fossil oysters from Chesapeake Bay...

Sediment cores as long as 20 m, dated by 14C, 210Pb, and 137Cs methods and pollen stratigraphy, provide a history of diatom productivity and sediment-accumulation rates in Chesapeake Bay. We calculated the flux of biogenic silica and total sediment for the past 1500 yr for two high-sedimentation-rate sites in the mesohaline section of the bay. The data show that biogenic silica flux to...

We examined the distribution and abundance of the Coastal Plain Swamp Sparrow (Melospiza georgiana nigrescens) at previously occupied sites and points within potential habitat. We found Swamp Sparrows throughout their formerly documented range except in southern Chesapeake Bay. Swamp Sparrows were most common in the Mullica River region of New Jersey where we detected individuals at 78%...

1. Fat reserves are stored energy that may help birds survive periods of harsh winter weather. This hypothesis predicts that annual apparent survival is higher for birds with large fat reserves than for birds with few or no fat reserves in winter. 2. Blackbirds (Turdus merula Linnaeus) were ringed in central Italy from 16 November to 20 February during 1990-2001. Fat scores were recorded...

1. We investigated linkages between fishes and fluvial geomorphology in 31 wadeable streams in the Etowah River basin in northern Georgia, U.S.A. Streams were stratified into three catchment sizes of approximately 15, 50 and 100 km2, and fishes and geomorphology were sampled at the reach scale (i.e. 20–40 times stream width). 2. Non-metric multidimensional scaling (NMDS) identified 85%...

Methylmercury has been suspected as a cause of impaired reproduction in wild birds, but the confounding effects of other environmental stressors has made it difficult to determine how much mercury in the eggs of these wild species is harmful. Even when a sample egg can be collected from the nest of a wild bird and the mercury concentration in that egg compared to the laboratory-derived...

Capture-mark-recapture studies provide a useful mechanism for estimating the components of the population dynamics of birds, especially survival. In such studies, it is important that the population being captured matches the population of interest. In many studies, transients are captured along with the population of interest (e.g. resident breeders). Ignoring that phenomenon produces

Acorns of bottomland red oaks (Quercus spp.) are an important food of North American wood ducks (Aix sponsa). Barras et al. (1996) demonstrated that female wood ducks selected willow oak (Q. phellos) acorns over other species. We measured true metabolizable energy (TME) derived by captive, wild-strain, adult female wood ducks from acorns of willow oak, water oak (Q. nigra), cherrybark...

Few species are likely to be so evident that they will always be detected when present. Failing to allow for the possibility that a target species was present, but undetected, at a site will lead to biased estimates of site occupancy, colonization, and local extinction probabilities. These population vital rates are often of interest in long-term monitoring programs and metapopulation...