我国淡水藻华长期变动特征综合分析

An integrated analysis of dynamic characteristics of harmful algal bloom in fresh water in China

水体富营养化与淡水藻华(水华)是全球普遍现象,我国是一个高氮磷投入的国家,在人类活动和全球气候变化背景条件下,河流湖库富营养化问题日益突出。文章收集了近30年来我国水华事件的相关文献资料,基于综合研究和统计学分析,回顾性评估了我国水华发生的基本特征、变动规律和成因。数据表明,自上世纪80年代以来,水华发生频率从上世纪80年代每年1～2次上升到2000年以后的每年近10次(不完全统计),总体呈现上升趋势;水华从湖泊向河流库区扩展,从点到面蔓延,且主要集中在人口密集、污染严重的长江中下游地区和东部沿海地区;在我国化肥施用、畜禽养殖、电站大坝建设等人类活动以及气候变暖的叠加影响下,河流湖库的氮磷浓度上升、氮磷比值下降,水体水化学和生态环境的长期变动加大了水华发生的风险。文章认为,在流域海域综合管理框架下进行氮磷污染的联合控制,以及多学科交叉开展特定水体的水华过程和机理研究是今后藻华防控的根本要求。

Eutrophication and harmful algal bloom（HAB） is a global issue.Fresh water in reservoirs and lakes in China has experienced critical eutrophication due to human activities and global warming.To indentify the HAB characteristics,dynamics and potential causes,an integrated analysis was conducted using a comprehensive database of reported HAB events.The results showed that occurrence of HAB in China expanded both spatially and temporally during 1985-2009.The underestimated HAB occurrence increased from 1-2 to about 10 times each year from 1980s to 2000s.HAB events mostly occurred in populated area（i.e.lakes and reservoirs in lower Yangtze River and coastal region） where great nutrients were loaded.Interactive effect of human activities（e.g.,fertilizer application,animal feeding,hydropower station construction） and climate warming has substantially resulted in change of hydrogeochemical conditions（nutrient enrichment,N：P ratio decline）,which resulted in the risk of HAB forming in reservoirs and lakes.The control of eutrophication will likely require integrated basin-marine reductions in both N and P,and interdisciplinary understanding of the key physical,chemical and biological factors that determine the HAB process in target aquatic systems.