The continental shelf benthic ecosystem: current status, agents for change and future prospects

摘要

Continental shelf benthic ecosystems play an important role in the economy of many coastal states through the provision of food, non-living resources and through control of climate. Changes in the status of these ecosystems, through either natural or human-induced environmental drivers can be expected to have important economic and social consequences. Agents that could induce change include climate and oceanography, hydrology (river discharge), land-use and waste disposal practices, fishing, aquaculture and extraction of non-living resources. Trends in all of these drivers, particularly those under human influence, suggest that shelf systems will come under increasing pressure. Attempts to predict the future state of any ecological system are fraught with difficulty, particularly over decadal time-frames. This is, perhaps, especially true for continental shelf ecosystems where data on current status are poor and our understanding of many of the drivers of change somewhat rudimentary. What can be said for certain, however, is that change will occur and, in the short term, many of the signs point towards deterioration in the ecological condition of many shelf systems, but particularly those of developing countries. Trends in land-use practices, with consequences for nutrient, sediment and freshwater input to coastal seas appear to be particularly worrying, but the poor state of many demersal fisheries systems must also be acknowledged. In contrast to the developing world, although challenges undoubtedly remain, particularly with respect to atmospheric inputs resulting from energy production, current trends in environmental management suggest that pressures imposed by land use, waste disposal and fishing will probably decline over the coming decades on the shelves of many developed countries. At the global scale, therefore, the key driver for sustainable use of our continental shelf ecosystems would appear to be intimately linked to the social and economic well-being of poorer nations.