中国太湖1950年以来主要环境的变化和迅速富营养化的开始

太湖是我国第三大淡水湖，面积２３５０ｋｍ＾２，位于长江三角洲（面积３５０００ｋｍ＾２）的中部，自６０００年前太湖形成以来，湖泊经历了几个主要变化，１９５０年以前太湖最明显的变化发生在海侵和湖盆大小，海侵是太湖形成的主要原因。太湖形成后，在不同的干燥和湿润时期，湖盆经历了由一系列的小湖或统一湖盆之间的波动，但一般来说，近２０００年以来，湖盆的大小在增大，然而１９５０年以后，为适应人口的增长，许多浅水

MAJOR ENVIRONMENTAL CHANGES SINCE 1950 AND THE ONSET OF ACCELERATED EUTROPHICATION IN TAIHU LAKE,CHINA

Taihu I.ake is t he t hir(l larch'~t frcshwat"r lake ill Chilla, covering an area t)f 2:350 kmZ and ail ualccl in lhccelller of the:{5 BOO. kelp yanglys I{ivcr Della.Taillu I.akc has undergone coveral major change'~since its ortllation al out six;tilt)us;lntl years ag(7.The luost noticeal)lc changes in Taihu I.ake prior to 1 950 involved sealevel I rallsgression an(l lake size. Sea Icvcl transgrcssi')11 was a primary mccllitnism leading to tileormation ofTaihu l.akc.Th('lake and ifs basill have 'flu('luatctl l)ctween a cluslcr of small lakes and a single large lakesince its format ion, reflecting dry an(j wet regiollfll clinlale Pcrio(Is, but lake size 11as generally increased during the last 2 ()()() years. Sillal tile 1 )5(Js, however,sllallow areas of the lake 11ave been converted to farmlandfor rice cult urn and to poncl culttlr('to sul)I)orl 1ilo increase(l I)ol)ulation. Increased use of the lake and ifs watcrsllcd since foe 1 f)5()s have led in challges in 1lie lake. The major changes in Taillu l.ake during this periodhave been: (l) (lain consl ruction all,I littoral conversion, whicll have had a major lull)acl on water drainage analon the ccology and trol)hic dynamics of Taihu I.akt' an'I (2) remarkal)lc illcrcascs beginning in 1 983/ 1 984 Int he level of cul rol)hicat ion.Tile l)rinlilry nlccllanisms font rihLli ills to 1 he aCceleraiccl cutrol)hicat ion arc he increased loadillg of Unt realed cfflucnl s fronl ed)allsion in indusl ry,agricull urn and un)anization ill t 11e lakebasin. The large anllual inpuls of nutricllts to the lake 11ave 11ad a major iml)acon culrol)hi('ation conditions inthe lake,in Particular bluring foe low water period.