在长江中下游的洪湖、太湖、巢湖采集了沉积柱样,测定了总有机碳、总氮、磷,并采用^210Pb和^137Cs定年。洪湖1950年以来沉积物中营养元素急剧增加,巢湖在20世纪70年代以来营养元素开始增加,而在太湖中则为80年代。结果表明草型湖中有机质增加比藻型湖迅速,洪湖湖泊沉积物有机质迅速增加与围垦活动开始时间一致。沉积物中总磷的变化不如总有机碳、总氮的变化规律性明显。洪湖两钻孔总磷背景值为0.7~0.8g/kg,太湖钻孔其总磷本底为0.6g/kg,梅梁湾大量钻孔表明总磷本底在0.5g/kg;巢湖的则更低。对比湖泊类型来看,目前为藻型湖的沉积本底磷偏低,而目前为草型湖的沉积本底磷偏高,这可能与不同生态类型湖泊营养元素的生物地球化学循环与积累的方式有关。
Sedimentary cores named HN, HS, THS, and CH were collected from the Honghu Lake, the Lake Taihu, and the Chaohu Lake. The total organic carbon, total nitrogen, phosphorus were analyzed. Combing with ^137Cs or ^210pb dating, nutrient evolution succession of historical period can be constructed. There was an obvious increase of organic production since the 1950s at the Honghu Lake, while the 1970s for the Chaohu Lake and the 1980s for the Lake Taihu. The onset time of rapid enrichment of organic matter accorded with that of cultivation at the Honghu Lake. Comparison of nutrients of these cores indicates that difference does exist due to different kinds of lake ecosystem and organic matter in macrophytic lake increases faster than that in algae lake. In general total phosphorus in sediment varied complicatedly. Background value of total phosphorus in Honghu Lake cores is about 0.7 - 0. 8g/kg, while 0.6g/kg at THS core. Analysis of muhi-cores in Meiliang Bay shows that background value of total phosphorus is 0.5g/kg. The lowest background value of total phosphorus was found in Chaohu Lake sediments. Background value of phosphorus is higher in macrophytic lake than that of algae lake. This may be the difference of biogeochemistry recycle of phosphorus in different kinds of lakes.