[目的]河流筑坝对有机碳具有重要的拦截作用,影响内陆水体碳循环.目前,河道型水库沉积物有机碳空间分布特征和自生有机碳埋藏通量仍不明确.[方法]采用沉积物柱芯法、沉积物物理化学参数和碳同位素二元混合模型,对河道型水库(银盘水库)沉积物有机碳埋藏开展了调研.[结果]结果显示:银盘水库沉积物有机碳含量变化范围为0.99％～1.32％,库中和坝前沉积柱有机碳含量均值分别为1.12％和1.16％;内源有机碳与总磷呈现显著正相关;有机碳埋藏速率变化范围为98.7～348.9 g C·m-2·a-1,平均值为223.8 g C·m-2·a-1,有机碳埋藏通量和内源有机碳埋藏通量分别为2.5×109 g C·a-1和1.8×109 g C·a-1;内源有机碳对沉积物总有机碳的贡献比例为69.0％～75.2％,平均值为71.5％.[结论]结果表明:河道型水库沉积柱有机碳含量从库中到坝前没有明显变化;水库内源有机质的生成与营养盐输入和水体滞留时间密切相关;银盘水库有机碳埋藏通量相当于全球水库有机碳埋藏通量的0.04‰,河道型水库是个重要的潜在碳汇.研究结果能够为河道型水库碳埋藏研究和水电清洁型评估提供参考依据.
Abstract
[Objective]River damming plays an important role in intercepting organic carbon(OC),which affects carbon cycles of inland waters.Nowadays,the spatial variation of sedimentary OC and the magnitude of autochthonous OC burial flux in the channel-type reservoir are still uncertain.[Methods]The OC burial in the channel-type reservoir(Yinpan Reservoir)was investi-hated,by using sediment cores,physicochemical data of sediment and a two-end-member mixing model of carbon isotope values.[Results]The result showed that the sedimentary organic carbon of Yinpan Reservoir varied from 0.99％to 1.32％.The mean val-ue of OC of sediment core in the middle of reservoir and the front of the dam was 1.12％and 1.16％,respectively.There was a sig-nificant positive relationship between autochthonous OC and TP(total phosphorus).The OC burial rate(OCBR)of the Yinpan Reservoir ranged from 98.7 g C·m-2·a-1 to 348.9 g C·m-2·a-1,with a mean value of 223.8 g C·m-2·a-1,and the burial flux of OC and autochthonous organic carbon in the Yinpan Reservoir was 2.5×109 g C·a-1 and 1.8×109 g C·a-1,respectively.The contribution of autochthonous organic carbon to total organic carbon in Yinpan Reservoir varied from 69.0％to 75.2％,with an average of 71.5％.[Conclusion]The OC concentration of sediment cores in the channel-type reservoir didn't change significantly from the middle of reservoir area to the front of the dam.The autochthonous OC generated within the reservoir was closely associated with nutrient input and hydraulic retention time.The OC burial flux of the Yinpan Reservoir accounted for 0.04‰ of OC burial flux of global reservoirs,indicating that channel-type reservoir is an important potential carbon sink.The research findings provide a reference basis for the study of OC burial in the channel-type reservoirs and the cleanliness assessment of hydropower.
维普
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