Publications

The occurrence of mercury in fish is well-known and often occurs at levels that warrant restricted consumption by sensitive human populations. Because of this, local wildlife and health agencies have developed monitoring programs to identify the magnitude of fish contamination and changes through time. Monitoring mercury levels in fish typically requires killing fish for removal of a...

"Super-blooms" of cyanobacteria that produce potent and environmentally persistent biotoxins (microcystins) are an emerging global health issue in freshwater habitats. Monitoring of the marine environment for secondary impacts has been minimal, although microcystin-contaminated freshwater is known to be entering marine ecosystems. Here we confirm deaths of marine mammals from microcystin

The purpose of this experiment was to use mallards (Anas platyrhynchos) tested under controlled conditions to determine how much harm to reproduction resulted from various concentrations of mercury in eggs. Breeding pairs of mallards were fed a control diet or diets containing 1, 2, 4, or 8 μg/g mercury, as methylmercury chloride. Mean concentrations of mercury in eggs laid by parents...

Observational data sets generated by complex processes are common in ecology. Traditionally these have been very challenging to analyze because of the limitations of available statistical tools. This seems to be changing, and these are exciting times to be involved with ecological statistics, not just because of the neo-Bayesian revival but also because of the proliferation of...

In 2004, spotted sandpipers (Actitis macularia) were studied on the Hudson River near Fort Edward south to New Baltimore, NY and on two river drainages that flow into the Hudson River. Concentrations of 28 organochlorine pesticides, 160 polychlorinated biphenyl (PCB) congeners, and 17 dioxin and furan (PCDD-F) congeners were quantified in eggs collected on and off the Hudson River. The...

The ideal study of the effects of methylmercury on the reproductive success of a species of bird would be one in which eggs contained mercury concentrations ranging from controls to very heavily contaminated, all at the same site. Such a study cannot be realized at a mercury contaminated area or under laboratory conditions, but could be achieved by introducing methylmercury into breeding...

Using respective strengths of the biological, physical, and social sciences, we are developing an online decision support tool, the Santa Cruz Watershed Ecosystem Portfolio Model (SCWEPM), to help promote the use of information relevant to water allocation and land management in a binational watershed along the U.S.-Mexico border. The SCWEPM will include an ES valuation system within a...

Voles and small passerine birds were live-captured near the Delong Mountain Regional Transportation System (DMTS) haul road in Cape Krusenstern National Monument in northwest Alaska to assess metals exposure and sub-lethal biological effects. Similar numbers of animals were captured from a reference site in southern Cape Krusenstern National Monument for comparison. Histopathological...

We examined methylmercury (MeHg) bioavailability in four of the most predominant wetland habitats in California's Central Valley agricultural region during the spring and summer: white rice, wild rice, permanent wetlands, and shallowly-flooded fallow fields. We sampled MeHg and total mercury (THg) concentrations in two aquatic macroinvertebrate taxa at the inlets, centers, and outlets of...

Atrazine, the widely used herbicide, has shown to affect the hypothalamus–pituitary–gonad axis in certain vertebrate species, but few studies have examined reproductive effects of this chemical on fish. Our study was designed to evaluate a population endpoint (egg production) in conjunction with histological (e.g., gonad development) and biochemical (e.g., hormone production) phenotypes...

This is the first part of a study that evaluates the influence of nonpoint-source contaminants on the sediment quality of five streams within the metropolitan Kansas City area, central United States. Surficial sediment was collected in 2003 from 29 sites along five streams with watersheds that extend from the core of the metropolitan area to its development fringe. Sediment was analyzed...

A capillary separation method that incorporates pH-mediated stacking is employed for the simultaneous determination of circulating steroid hormones in plasma from Perca flavescens (yellow perch) collected from natural aquatic environments. The method can be applied to separate eight steroid standards: progesterone, 17α,20β-dihydroxypregn-4-en-3-one, 17α-hydroxyprogesterone, testosterone...