1997 Black Lake Survey


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Aquatic Synthesis for Voyageurs National Park


Book Description

Voyageurs National Park (VOYA) in northern Minnesota contains significant aquatic resources including 30 lakes and numerous wetlands. This synthesis contains an integrated account of what is known about the aquatic resources of VOYA; compares VOYA resources to those of other areas; and identifies opportunities and needs for future studies and surveys. Surveys and studies in VOYA have identified fifty-four fish species from 16 families 820 vascular plant species and 7 amphibian and 3 reptile species (higher numbers probably occur). Estimates of relative abundance for phyto- and zooplankton vary among VOYA lakes and depths surveyed. The VOYA fish populations and communities have been the most intensively studied. Twenty-eight percent of VOYA wetlands are the result of beaver activity. Mercury contamination and its food-chain bioaccumulation in VOYA are of particular concern. An integrated monitoring plan is needed in VOYA to provide continuous data and information on the complex physical chemical, and biological factors that influence aquatic systems. Resource managers in VOYA will use this information to understand and explain observed changes and to predict the potential for future changes.




Geochemistry and Geophysics of Active Volcanic Lakes


Book Description

Volcanoes sometimes host a lake at the Earth's surface. These lakes are the surface expressions of a reservoir, often termed a hydrothermal system, in highly fractured, permeable and porous media where fluids circulate. They can become monitoring targets since they integrate the heat flux discharged by an underlying magma body and condense some volcanic gases. Since they trap volcanic heat and gases, they are excellent tools to provide additional information about the status of a volcano and volcanic lake-related hazards. This Special Publication comes at an exciting time for the volcanic lake community. It brings together scientific papers, which include studies of their structure, hydrogeological modelling, long-term multi-disciplinary monitoring efforts, as well as a number of innovative methods of sampling, data acquisition and in situ and laboratory experiments. Several papers challenge long-established paradigms and introduce new concepts and terminologies. This collection of papers will be a useful reference for researchers dealing with volcanic lakes and more generally with hydrothermal systems, phreatic/hydrothermal eruptions and wet volcanoes.