| 淀山湖百年营养演化历史及营养物基准的建立 |
| 摘要点击 2701 全文点击 1201 投稿时间：2011-12-15 修订日期：2012-02-28 |
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| 中文关键词 硅藻 总磷 营养本底 湖泊沉积物 淀山湖 |
| 英文关键词 diatom total phosphorus nutrient baseline lake sediment Dianshan Lake |
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| 中文摘要 |
| 富营养湖泊生态系统的修复必须建立在历史营养演化过程、营养本底状况认识的基础之上. 对上海市郊淀山湖不同湖区的4个沉积钻孔进行了210Pb/137 Cs放射性年代、含水量、烧失量、沉积物总磷、总氮、总有机碳、沉积硅藻等古湖沼学分析,各指标均具有较好的一致性,反映了淀山湖相对稳定的沉积环境. 过去百年来沉积硅藻群落发生了显著的变化,随着人类干扰的加强,硅藻由贫营养的属种如Cyclotella bodanica、C.ocelata、附生种Achnanthes minutissima、Cocconeis placentula var lineate、Cymbella sp.及底栖种Fragilaria piñata、F. brevistrata、F. construens var venter等占优的组合过渡到近年来的以富营养的浮游类型属种 Cyclotella meneghinena、Aulacoseria alpigena、C. atomus、Stephanodiscus hantzschi、Thalassiosira visurgis等为主的组合,揭示出明显的富营养化过程. 利用区域硅藻-总磷转换函数结果,重建了淀山湖过去近100年来的湖水总磷变化的历史. 已有的监测数据与硅藻重建的总磷值对比结果表明硅藻-总磷转换函数能较准确地描述水体总磷浓度的变化趋势,是一种有效的水体总磷重建手段. 根据淀山湖多个沉积柱对比研究及重建的硅藻-水体总磷浓度结果,提出淀山湖治理的营养物基准水体总磷值为 50~60 μg·L-1,而沉积物中 N、P浓度的基准值为 500 mg·kg-1和550 mg·kg-1. |
| 英文摘要 |
| The restoration of eutrophic lakes requires a good knowledge on the history and baseline of nutrients in the lakes. This work conducted an analysis on210Pb/137 Cs, water content, loss-on-ignition, sedimentary total phosphorus (TP), total nitrogen (TN), total organic carbon (TOC) and diatoms in the four sediment cores from Dianshan Lake (near Shanghai City). Good coherence in palaeoproxies between the cores indicates a relatively stable sedimentary environment. With increasing human impact, diatom communities shifted from oligo-trophic species Cyclotella bodanica, C. ocelata, Achnanthes minutissima, Cocconeis placentula var lineate, Cymbella sp., Fragilaria piñata, F. brevistrata, F. construens var venter to recent eutrophic species including Cyclostephanos dubius, C. atomus, Stephanodiscus minitulus, S. hantzschi, Aulacoseria alpigena. The epilimnetic TP over the past 100 years reconstructed using an established diatom-TP transfer function matches well with the monitoring TP where exists. Based on the sedimentary nutrient characteristics and diatom-reconstructed nutrient dynamics, we proposed that the nutrient baseline for Dianshan Lake is 50-60 μg·L-1, 500 mg·kg-1 and 550 mg·kg-1 for water TP concentration, sedimentary TP and TN, respectively. |
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