洱海湖心区沉积柱芯营养盐垂向分布及时间演化特征

发布时间：2018-04-22 04:23

本文选题：沉积柱芯 + 营养盐　；参考：《生态环境学报》2016年10期

【摘要】：连续的沉积物记录为研究湖泊富营养化的长期过程提供了可能。分析了洱海湖中心沉积柱的营养盐浓度垂向分布和沉积物年代记录,并结合湖心水质变化情况,研究了洱海沉积物营养盐的时间演化特征及生态意义。结果显示:Cal.AD 1960年以前,洱海沉积物营养盐稳定在较低水平,总有机碳(TOC)平均质量分数为1.45%,总氮(TN)平均质量分数为0.20%,总磷(TP)质量分数低于1 000 mg·kg~(-1);Cal.AD 1960年以后,TOC和TN质量分数均急剧升高,尤其在1990年之后呈直线上升态势,最高值分别为5.8%和0.84%,TP质量分数从1 000 mg·kg~(-1)。左右直线上升至1 345 mg·kg~(-1),反映了洱海近几十年来的人为富营养化加剧过程。沉积物TP与TOC、TN呈极显著正相关(P=0.001),TOC与TN的Pearson相关系数最大。洱海沉积物的TOC/TN比值总体比较稳定,数值在5.8~11.5之间波动,反映出这3种营养物质的藻类同源性。沉积物的营养物累积过程伴随水质变化呈不断恶化趋势,1990年后沉积物营养盐的时间演变规律与湖心区水质随时间的变化趋势基本一致。洱海表层沉积物TN、TP浓度明显高于东部平原湖区的湖泊,其营养盐内源负荷不容忽视。与同地区湖泊相比,沉积物TN浓度水平与抚仙湖和滇池相当,而TP浓度明显低于这两个湖泊,说明洱海沉积物对P仍具有较强的吸附容量及潜在缓冲能力。
[Abstract]:Continuous sediment records make it possible to study the long-term process of lake eutrophication. The vertical distribution of nutrient concentration and chronological record of sediment in the center of Erhai Lake were analyzed. The temporal evolution characteristics and ecological significance of nutrient salt in the sediment of Erhai Lake were studied in combination with the changes of water quality in the center of the lake. The results showed that before 1960, nutrients in Erhai Lake sediments were stable at a relatively low level. The average mass fraction of total organic carbon (TOC) and total nitrogen (TNN) were 1.45 and 0.20, respectively. The total phosphorus content of TOC and TN increased sharply after 1960, especially after 1990. The highest values of TP were 5. 8% and 0. 84% respectively from 1 000 mg 路kg ~ (-1) to 1 ~ (-1) mg 路kg ~ (-1) 路L ~ (-1). The linear rise from left to right to 1 345 mg 路kg ~ (-1) ~ (-1) reflects the increasing process of anthropogenic eutrophication in Erhai Lake in recent decades. The Pearson correlation coefficient between TP and TOC was the highest. The TOC/TN ratio of Erhai Lake sediment was stable and fluctuated between 5.8 and 11.5, reflecting the algae homology of the three nutrients. The accumulation of nutrients in sediments was accompanied by the change of water quality, and the temporal evolution of nutrients in sediments after 1990 was basically consistent with the trend of water quality in the center of the lake with time. The concentration of TNT in the surface sediments of Erhai Lake is obviously higher than that in the lakes of the eastern plain lake area, and the endogenous load of nutrients should not be ignored. Compared with the lake in the same area, the TN concentration of sediment is similar to that of Fuxian Lake and Dianchi Lake, but TP concentration is obviously lower than that of these two lakes, which indicates that the sediment of Erhai Lake still has strong adsorption capacity and potential buffer capacity for P.
【作者单位】：上海市环境科学研究院;华东师范大学河口海岸学国家重点实验室;中国科学院地球化学研究所环境地球化学国家重点实验室;
【基金】：国家水专项项目(2009ZX07106-001-006)
【分类号】：X524

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