仙桃地区关键带生态演化与碳埋藏

发布时间：2018-08-28 08:05

【摘要】：仙桃地区湖群不断萎缩,水体富营养化水平和湿地沉积物重金属含量持续升高,江汉湖群生态系统日益脆弱,加强对该地区生态环境演化研究、分析人类活动和富营养化对湖泊生态系统的影响、探究该地区不同沉积环境的碳埋藏规律等显得尤为重要.在对江汉平原重点地区(仙桃彭场镇幅和脉旺咀幅)第四纪地质调查的基础上,选取研究区大型渔场、小型鱼塘、沟滩、湖泊、水稻田、泄洪道、旱地、汉水阶地8种不同沉积环境的16个关键带点位,分别测定了其表层及浅层钻孔沉积物的色素、TOC(total organic carbon,总有机碳)与TN(total nitrogen,总氮).表层沉积物TOC含量反映了研究区南部多湖泊区域有机碳埋藏量较高,而北部冲、洪积成因环境相对较低,与色素、TN所指示的人类活动强度和富营养化水平相吻合.湿地浅层钻孔沉积物碳埋藏速率变化整体表现为升高趋势,与色素所指示的湖泊富营养化的趋势相吻合;不同沉积环境碳埋藏速率差异较大,最高为大型渔场77.71g·m~(-2)·a~(-1)、最低为汉水阶地3.61g·m~(-2)·a~(-1).研究结果表明,受到人类活动影响,湖相沉积物中碳埋藏量相对较高,湖泊碳汇功能不断增强,这对江汉平原关键带碳循环研究具有重要意义.
[Abstract]:The lake group in Xiantao area is shrinking, the eutrophication level of water body and the heavy metal content in wetland sediment are increasing, and the ecosystem of Jianghan Lake Group is becoming more and more fragile, so the study on the evolution of ecological environment in this area is strengthened. It is particularly important to analyze the effects of human activities and eutrophication on the lake ecosystem and to explore the carbon burial rules of different sedimentary environments in this area. Based on the Quaternary geological survey of the key areas of Jianghan Plain (Xiantao Pengchang Town and Sui Wangzui), large fishing grounds, small fish ponds, gully beaches, lakes, rice paddies, spillways, drylands in the study area were selected. The total organic carbon (TOC (total organic carbon,) and total nitrogen (TN (total nitrogen,) of the surface and shallow borehole sediments were determined at 16 critical zones of 8 different sedimentary environments in the Hanshui terrace. The TOC content of surface sediments reflects the high buried amount of organic carbon in many lakes in the southern part of the study area, while the alluvial environment in the north is relatively low, which is consistent with the intensity of human activity and eutrophication level indicated by pigment TN. The carbon burial rate of shallow drilled sediments in wetland showed an increasing trend, which coincided with the eutrophication trend of lakes indicated by pigments, and the carbon burial rates varied greatly in different sedimentary environments. The maximum was 77.71 g m-2 a ~ (-1) and the lowest was 3.61 g m-2 ~ (-1) a ~ (-1) in the Hanshui terrace. The results show that, under the influence of human activities, the carbon burial in lake sediments is relatively high, and the function of lake carbon sinks is increasing, which is of great significance to the study of the carbon cycle in the key zone of Jianghan Plain.
【作者单位】：中国地质大学地球科学学院;中国地质大学生物地质与环境地质国家重点实验室;中国地质大学湿地演化与生态恢复湖北省重点实验室;中国地质大学环境学院;
【基金】：中国地质调查局项目(No.12120114069301)
【分类号】：X171;X524

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