Environmental future of estuaries.

Background Estuaries rank among the most productive and valuable aquatic ecosystems on Earth (Alongi, 1998). Because of rapid development in coastal watersheds and increasing commercial and recreational use of estuaries, anthropogenic impacts threaten the long-term viability and health of these important ecotones (Kennish 1992, 2001, 2002). Trends of population growth and development in the coastal zone indicate that anthropogenic activities and impacts on estuaries will likely become more pervasive and persistent throughout the world during the next 25 years.