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Advances have been made recently in assessing accumulation and effects of coal combustion residues (CCR). I provide a brief review of recent advancements, provide a tabulated summary of results of recent work, and put forth recommendations for future studies. One advancement is that mercury accumulation has begun to receive (limited) attention, whereas it had rarely been considered in the past. Additionally, some constituents of CCR have been shown to be accumulated by adults and transferred to offspring, sometimes compromising offspring health. Studies have demonstrated that amphibians, possessing complex life cycles, may accumulate and transfer some contaminants to terrestrial systems. Some study has been given to molecular and cellular effects of CCR exposure, although these studies have been limited to invertebrates. Population models have also been applied to CCR affected systems and have shown that CCR may affect animal populations under some conditions. In light of these advancements, there are several topics that require further assessment. First, more attention to Hg and its dynamics in CCR affected systems is warranted. Hg can be highly accumulative and toxic under some conditions and may interact with other components of CCR (notably Se), perhaps altering accumulation and effects of the contaminant mixtures. Second, further investigation of maternal transfer and effects of CCR contaminants need to be conducted. These studies could benefit from incorporation of quantitative models to project impacts on populations. Finally, more attention to the organic constituents of CCR (PAHs) is required, as a focus on inorganic compounds only may restrict our knowledge of contaminant dynamics and effects as a whole. While further studies will shed light on some chemical and biological nuances of exposure and effect, information available to date from numerous study sites implicates CCR as a bulk effluent that presents risks of bioaccumulation and effects on organisms in aquatic systems. © 2014. Source

Secor D.H.,University of Maryland Center for Environmental science
Environmental Biology of Fishes

Publications focused on fish otolith applications grew exponentially from 1981-2000 but have subsequently stabilized, suggesting maturation of otolith applications. Over the past 30 years >3,500 primary journal publications were identified prompting the question, how have otoliths fundamentally changed our understanding of fishes and their environment? Has otolith science in this way been transformative? I use Harden Jones' 1968 Fish Migration as a benchmark of fish migration concepts prior to Pannella's 1971 breakthrough paper on otolith microstructure. For case study species I highlight how otolith science has informed migration concepts including, (1) parent stream theory (Atlantic bluefin tuna), (2) adoptive homing (Atlantic herring), and (3) partial migration (European eel). Harden Jones' overall conclusion that life cycle closure leads to population structure (also known as the migration triangle) is a first principle in fisheries science, but in recent years has been challenged by otolith science. In particular, a transformative discovery attributable to otoliths is that life cycles vary substantially within populations. New avenues of otolith science are now exploring the causes and consequences of this life cycle diversity, and large advances are expected through integration of otolith approaches with electronic tagging, genetics, field manipulations, and modeling that will permit migration concepts to be tested at multiple ecological scales. © 2010 Springer Science+Business Media B.V. Source

Bernhardt E.S.,Duke University | Palmer M.A.,University of Maryland Center for Environmental science
Annals of the New York Academy of Sciences

Southern Appalachian forests are recognized as a biodiversity hot spot of global significance, particularly for endemic aquatic salamanders and mussels. The dominant driver of land-cover and land-use change in this region is surface mining, with an ever-increasing proportion occurring as mountaintop mining with valley fill operations (MTVF). In MTVF, seams of coal are exposed using explosives, and the resulting noncoal overburden is pushed into adjacent valleys to facilitate coal extraction. To date, MTVF throughout the Appalachians have converted 1.1 million hectares of forest to surface mines and buried more than 2,000 km of stream channel beneath mining overburden. The impacts of these lost forests and buried streams are propagated throughout the river networks of the region as the resulting sediment and chemical pollutants are transmitted downstream. There is, to date, no evidence to suggest that the extensive chemical and hydrologic alterations of streams by MTVF can be offset or reversed by currently required reclamation and mitigation practices. © 2011 New York Academy of Sciences. Source

Frisk M.G.,State University of New York at Stony Brook | Jordaan A.,University of Massachusetts Amherst | Miller T.J.,University of Maryland Center for Environmental science
Fish and Fisheries

During the past century, the field of fisheries oceanography has dominated the study of population connectivity in marine environments. The influence of physical and biological processes and their relationship to transport and retention of early life history stages has been central in providing insight into population structuring and connectivity. However, the focus on dispersive early life history stages has meant that the role of adults has received less attention and is not fully understood or appreciated. We argue that adults play a vital role in population connectivity for a wide range of marine taxa and hypothesize that adult-mediated population connectivity commonly results in a diverse array of population structuring. Two case-studies on winter skate, Leucoraja ocellata, and winter flounder, Pseudopleuronectes americanus, are presented to illustrate the role adults play in marine connectivity at both broad and fine scales, respectively. Indeed, if adults are important for population connectivity, we argue that the role of larval processes is conditional on adult choice and only management and research pursuits that integrate the full life cycle of species will capture the full dynamics of metapopulation connectivity. Failure to include the roles of adults can lead to misinterpretation of the causes and consequences of changes in ecosystem structure and fisheries productivity. © 2013 John Wiley & Sons Ltd. Source

Nelson D.M.,University of Maryland Center for Environmental science
New Phytologist

There is limited evidence on how shifts in plant physiological performance influence vegetation variations in the paleorecord. To evaluate δ13C of pollen from C3 plants as an indicator of community-level physiology, small quantities (10-30 grains) of untreated pollen and sporopollenin from herbarium specimens of Ambrosia (A. tomentosa and A. psilostachya) and Artemisia (A. frigida, A. ludoviciana and A. dracunculus), genera abundant in grassland pollen profiles, were isolated by micromanipulation. Their δ13C values were measured using a spooling-wire microcombustion device interfaced with an isotope-ratio mass spectrometer. Leaf δ13C was also measured. Carbon isotope discrimination (Δ) for untreated pollen, sporopollenin and leaves was compared with historic records of seasonal precipitation amount, vapor pressure deficit and the Palmer Drought Severity Index (PDSI). Each species showed positive correlations between Δ of untreated pollen and sporopollenin. Sporopollenin Δ was most strongly correlated with PDSI. Correlations among leaf Δ and moisture indicators were stronger for Ambrosia than Artemisia. These results suggest that sporopollenin Δ indicates the level of moisture stress in C3 plants. Therefore, δ13C analysis of pollen promises to help address important paleoecological questions, such as how community-level physiology contributes to shifts in vegetation composition. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust. Source

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