Aquatic Ecosystems | |
Overview | | |
Aquatic ecosystems have been especially subjected to the environmental degradation that has occurred over the last century in this country. Nearly every activity that occurs on land ultimately affects the receiving waters in that drainage. Whether it's pesticides and herbicides applied to crops, silt washed away because of vegetation removal, or even atmospheric deposition, aquatic ecosystems are a product of all local disturbances regardless of where they occur. In addition, waterways have been used for numerous activities other than providing habitat to aquatic organisms. They have been altered for transportation, diverted for agricultural and municipal needs, dammed for energy, borrowed as an industrial coolant, and straightened for convenience. These abuses have taken their toll as evidenced by worldwide declines in fisheries, monumental floods, an ever-growing list of endangered aquatic species, and communities trying to deal with finite water supplies. |
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The traits that make aquatic ecosystems particularly vulnerable also make them useful for monitoring environmental quality. Water serves to integrate these impacts by distributing them among the elements within aquatic ecosystems. Although dilution is occurring, subtle changes can be detected in habitats or organisms over a much larger area that may be the result of a single point source. A clean aquatic ecosystem with a healthy biological community will be indicative of the condition of the terrestrial habitat in the watershed, whereas the reverse may not necessarily be true. |
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This section features accounts of the alterations of aquatic habitats and their impacts on the biota. Evidence is presented documenting habitat destroyed by dams or channelization (see this section, Bogan et al.; Wlosinski et al.; and Wiener et al.), contaminants affecting organism health (see Hesselberg and Gannon; Lerczak and Sparks), wetlands affected by water-level control (see Wilcox and Meeker), reduced water quality (see Charles and Kociolek), and introductions of exotic species (see Hansen and Peck; Wiener et al.). These kinds of changes have caused declining biodiversity in many groups of aquatic species ranging from freshwater mussels to waterfowl. |
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