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111.
112.
The New York Bight is perhaps one of the most used and abused coastal areas in the world as a consequence of urbanization and the disposal of the waste of some 20 million people who reside by its shores and surrounding bays and estuaries. A variety of sources, including those associated with sewage wastes, industrial wastes, contaminated dredged material, urban runoff, and atmospheric fallout contaminate these coastal waters. Many of the stresses of excess population and industrialization as measured by pollutant loadings and ecosystem impacts can be crudely quantified in terms of use impairments-use impairments that have measurable social and economic relevance. Five broad categories of impairment attributed to pollution in the Bight that are causing significant losses of ecological, economic, or social values are: beach closures, unsafe seafoods, hazards to commercial and recreational navigation, loss of commercial and recreational fisheries, and declines in birds, mammals and turtles. These impairments are generally caused by floatable wastes, nutrients, toxicants, pathogens and habitat loss. Measures of such impairments are not standard, nor in many cases totally quantifiable. We have examined specific subsets of these impairments in terms of their spatial and temporal changes and as a first approximation determined the economic and social significance of these changes. the cost of these impaired uses of the Bight are measured in terms of billions of dollars annually for New York and New Jersey.  相似文献   
113.
Principles of probability survey design were applied to guide large-scale sampling of populations of stony corals and associated benthic taxa in the Florida Keys coral reef ecosystem. The survey employed a two-stage stratified random sampling design that partitioned the 251-km(2) domain by reef habitat types, geographic regions, and management zones. Estimates of the coefficient of variation (ratio of standard error to the mean) for stony coral population density and abundance ranged from 7% to 12% for four of six principal species. These levels of survey precision are among the highest reported for comparable surveys of marine species. Relatively precise estimates were also obtained for octocoral density, sponge frequency of occurrence, and benthic cover of algae and invertebrates. Probabilistic survey design techniques provided a robust framework for estimating population-level metrics and optimizing sampling efficiency.  相似文献   
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