人类活动影响下营养盐向河口/近海的输出和模型研究

人类活动（人口增长和经济发展所带来的对粮食和能源的需求和消费等）已经大大改变了地表圈层（土壤圈-水圈-大气圈）营养盐（主要是氮、磷、硅）的生物地球化学循环,结果是许多陆地、淡水和海洋生态系统受到显著影响并导致了严重的环境质量退化。本文对2002²005年由联合国教科文组织（UNESCO）和美国国家自然科学基金委员会资助的“全球营养盐输出和模型”（Global NEWS）项目进行了总结。

Summary of human activities on global nutrient export from watersheds to estuaries and coastal water: biogeochemical cycles and modeling

Having been invited as a member of the project of global nutrient export from watersheds(Global NEWS) by UNESCO-IOC (2002-2005),the author summarizes progresses of human activities on global nutrient export from watersheds.Human activities,such as production and consumption of food and energy to supply the increasing demands of the human population,have markedly altered the Earth's N,P,C and Si cycles.Consequently,many terrestrial,freshwater and marine ecosystems are being significantly altered.Nutrient inputs to coastal ecosystems are not evenly distributed globally.The uneven spatial pattern,in part,the result of the global distribution of human population,and activities associated with the production and consumption of food to feed those people and support their energy needs,has made nutrient enrichment contribute to increased algal growth,loss of seagrass habitats,increases in anoxic water,harmful algal blooms,coral reef degradation,and increased anthropogenic emissions of CO_(2),N_(2)O and CH_(4) among other effects.Marked increases in human population are predicted over the next 50 years in certain world regions(e.g.,S.and E.Asia,S.America,and Africa).Industrialization is also predicted in many of these same regions.Both will undoubtedly lead to increased export of N and P to coastal ecosystems,as well as changes in the ratio of N:P:Si exported.The purpose of the project is to develop spatially explicit global models to hindcast,nowcast and forecast under a range of potential scenarios the export of N,P,C and Si to coastal ecosystems as a function human activities and natural processes in watersheds.Dissolved inorganic N,P and Si;dissolved organic N,P;and particulates N,P and Si are being explicitly modeled.Progress in the development of these model systems will be presented.