Raven L. Bier

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Mountaintop mining is the dominant form of coal mining and the largest driver of land cover change in the central Appalachians. The waste rock from these surface mines is disposed of in the adjacent river valleys, leading to a burial of headwater streams and dramatic increases in salinity and trace metal concentrations immediately downstream. In this(More)
The biologically active properties of many nanomaterials, coupled with their rapidly expanding production and use, has generated concern that certain types of nanoparticles could have unintended impacts when released into natural ecosystems. In the present study, the authors report the results of an experiment in which they grew three common species of(More)
Microbial community composition and diversity change along chemical gradients, leading to the expectation that microbial community information might provide new gradient characterizations. Here we examine stream bacteria composition and diversity along a strong chemical gradient in Central Appalachian streams. Coal mining in the region generates alkaline(More)
A major goal of microbial ecology is to identify links between microbial community structure and microbial processes. Although this objective seems straightforward, there are conceptual and methodological challenges to designing studies that explicitly evaluate this link. Here, we analyzed literature documenting structure and process responses to(More)
We examined how TiO2 nanoparticles (nTiO2) impact the growth and metabolism of three species of freshwater green algae (Scenedesmus quadricauda, Chlamydomonas moewusii, and Chlorella vulgaris) that are widespread throughout North America. We exposed laboratory cultures to five initial concentrations of nTiO2 (0, 50, 100, 200, and 300 ppm) and measured(More)
Affiliations: Colorado State University, Fort Collins CO (ed.hall@colostate.edu, claudia.boot@colostate.edu, matt.wallenstein@colostate.edu) Duke University, Durham, N.C. (ebernhar@duke.edu, ebgraham2@colorado.edu, diana.nemergut@duke.edu) Yale University, New Haven, CT (mark.bradford.yale@gmail.com) University of Minnesota, Saint Paul, MN(More)
Background: Mesocosm experiments have become increasingly popular in climate change research as they bridge the gap between small‐scale, less realistic, microcosm experiments, and large‐scale, more complex, natural systems. Characteristics of aquatic mesocosm designs (e.g., mesocosm volume, study duration, and replication) vary widely, potentially affecting(More)
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