Selenium is a naturally occurring trace element that can become concentrated and released by industrial, agricultural, petrochemical and mining activities. At concentrated levels it is toxic and has polluted ecosystems around the world. This book will serve as a comprehensive practical handbook for everyone dealing with selenium in aquatic environments. It offers field-tested approaches and methods for assessment and water quality management. Using his twenty-year experience, the author discusses the effects of selenium on fish and bird populations and presents guidelines for identifying sources of pollution, interpreting selenium concentrations, assessing hazardous conditions, setting water quality criteria and ecosystem loading limits (TMDLs). He also includes a procedure for setting environmentally safe limits that ensure compliance with EPA regulations. Selenium Assessment in Aquatic Ecosystems will interest field scientists, natural resource managers, risk assessors and environmental planners.
This book is the outcome of a NATO Advanced Research Workshop on "The Eastern Mediterranean as a laboratory basin for the assessment of contrasting ecosystems" that was held in Kiev, Ukraine, March 23-27, 1998. The scientific rationale of the workshop can be summarized as follows. The Eastern Mediterranean is the most nutrient impoverished and oligotrophic large water body known. There is a well-defined eastward trend in nutrient ratios over the entire Mediterranean that starts at the Gibraltar Straits and, through the western basin, proceeds to the Ionian and Levantine Seas. Supply of nutrients to the entire Mediterranean is limited by inputs from the North Atlantic and various river systems along the sea. The unique feature of the Mediterranean is the presence of an eastward longitudinal trend in available nitrate/phosphate ratios. This apparently induces a west-to-east variation in the structure of the pelagic food web and trophic interactions. In this context the Mediterranean, and in particular its Eastern basin, provides probably a unique platform to explore the hypotheses related to the suggested phosphate-limitation on production and to the shift between "microbial" and "classical" modes of operation of the photic food web. The major exception of the overall oligotrophic nature of the Eastern Mediterranean is the highly eutrophic system of the Northern Adriatic Sea. Here, during the last two decades the discharges of the northern rivers (especially of the Po), together with municipal sewage, have led to a very marked increase of nutrients and subsequent imponent eutrophication events.
This book focuses on fluxes of energy, carbon dioxide and matter in and above a Central European spruce forest. The transition from a forest affected by acid rain into a heterogeneous forest occurred as a result of wind throw, bark beetles and climate change. Scientific results obtained over the last 20 years at the FLUXNET site DE-Bay (Waldstein-Weidenbrunnen) are shown together with methods developed at the site, including the application of footprint models for data-quality analysis, the coupling between the trunk space and the atmosphere, the importance of the Damkohler number for trace gas studies, and the turbulent conditions at a forest edge. In addition to the many experimental studies, the book also applies model studies such as higher-order closure models, Large-Eddy Simulations, and runoff models for the catchment and compares them with the experimental data. Moreover, by highlighting processes in the atmosphere it offers insights into the functioning of the ecosystem as a whole. It is of interest to ecologists, micrometeorologists and ecosystem modelers.
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