SEDIMENTARY RECORD OF NUTRIENT ACCUMULATION RATES IN CORE ZS FROM TAIHU LAKE FOR RECENT 50 YEARS
-
摘要: 通过对太湖北部竺山湾沉积物(ZS孔)钻探,测试ZS孔沉积物210Pb、137Cs、总有机碳(TOC)、总氮(TN)、总磷(TP)和粒度,研究近代太湖湖泊沉积物营养盐沉积通量变化。结果表明,ZS孔中137Cs比活度较低(137Cs 1963年时标得到平均沉积速率为0.32cm/a,与应用210Pb的CRS模式获得的近50年来平均沉积速率一致,利用210Pb的CRS模式计算出近50年来沉积通量为0.13~0.75g·cm-2·a-1),结合沉积物中的TOC、TN和TP浓度,获取了营养盐沉积通量在垂向上的变化,结果显示,自20世纪80年代初以来,营养盐沉积通量明显增加,该变化趋势与20世纪60年代以来的观测资料相符,有机磷的影响和人类活动被认为是造成近20年来TP沉积通量增加的原因。Abstract: The Taihu Lake drainage basin is an economically developed area among the highest population densities in China. The lake has been deteriorated due to ecological destruction and eutrophication. Core ZS dated by 210Pb or 137Cs method from Zhushan Bay of Taihu Lake were collected. Nutrients including TOC (total organic carbon), TN (total nitrogen), and TP (total phosphorous) were analyzed for the purpose of understanding nutrient change. 137Cs activities were low (less than 15 Bq/kg) in core ZS. The sedimentation accumulation rates ranged from 0.13 to 0.75 g/cm2/a at core ZS based on CRS model. A remarkable increase in nutrient accumulation rates since the early 1980s occurred in the core. The historical change of nutrient accumulation rates observed in cores concoined with monitoring data for surface sediment since 1960s. TP flux after early 1980s was 0.91 times higher than rates calculated between 1950s and 1970s in core ZS. It was concluded that higher TP accumulation rates in very recent deposits of Taihu Lake resulted from both diagenetic factors and human activities.
-
Key words:
- 210Pb /
- 137Cs /
- nutrient accumulation rate /
- ZS core of Taihu Lake
-
-
计量
- 文章访问数: 906
- PDF下载数: 7
- 施引文献: 0
下载: