Relative importance of natural and human perturbtion factors on the nitrogen cycle and dynamics of toxic algal blooms of coastal watersheds

超过65%的人口居住在海岸带100公里以内，预计这一比例在世纪将大幅增加。沿海地区为全世界人类社区提供了必不可少的生境、资源和服务。在国家一级，加拿大国内生产总值约三分之一直接或间接与沿海区活动有关。人口规模的增加和工业活动的加强，以及气候多变性等自然因素，都有助于改变沿海生态系统的健康状况。由此造成的水质和可再生资源生产力的下降预计将对全球和国家人类社会的财富产生负面影响。

Over 65% of the human population lives within 100 km of coastal zones, and this fraction is expected to increase greatly during the 21st century. Coastal zones provide habitat, resources and services essential to human communities worldwide. At the national level, about one-third of Canada's GDP is directly or indirectly related to coastal zone activities. Increasing population size and intensifying industrial activities contribute to alter the health of coastal ecosystems, as do natural factors such as climatic variability. Resulting declines in water quality and productivity of renewable resources are expected to have negative impacts on the wealth of human societies, both globally and nationally.