Lu Xiao-Xuan, Li Qiang, Jin Zhen-Jiang, Peng Wen-Jie, Fang Jun-Jia, Huang Bing-Hui, Song Ang
Key Laboratory of Karst Dynamics, Ministry of Land and Resources & Guangxi, Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin 541004, China.
Chongqing Key Laboratory of Karst Environment, School of Geographical Sciences, Southwest University, Chongqing 400715, China.
Huan Jing Ke Xue. 2018 May 8;39(5):2075-2085. doi: 10.13227/j.hjkx.201708032.
In recent years, scientists have focused on the karst carbon cycle. To better understand the hydrochemical characteristics and the physical-chemical properties of DOC in the wet season in karst areas, the water chemistry and DOC distribution characteristics in Wulixia reservoir were analyzed. The molecular weight of the water organic matter was analyzed based on the UV absorption spectrum. The results showed that the water chemistry of Wulixia reservoir was HCO-Ca ·Mg, the nutrient status of the water body was of the medium nutrient type, and the water maintained a good quality. The DOC mass concentration was lower in the wet season than in the dry season, and DOC was the main component of TOC. The DOC mass concentration tended to decrease from the surface to the bottom in a vertical direction. Chl-a and DIC were the main factors affecting the DOC vertical distribution. The organic matter in the reservoir area related to the absorption spectrum parameters of , , SUVA, and / showed that the water was dominated by constituents with small molecular weight, a high proportion of fulvic acid, low proportion of humic acid, and weak aroma. The results showed that the organic matter in the reservoir area was readily consumed by microbial bioactivity and that it played an active role in the carbon cycle of the reservoir. It also showed that the DOC endogenous characteristics of the reservoir were strong and provided a sufficient carbon source for heterotrophic microbes.
近年来，科学家们聚焦于喀斯特碳循环。为了更好地了解喀斯特地区雨季水体化学特征及溶解性有机碳（DOC）的理化性质，对五里峡水库的水化学及DOC分布特征进行了分析。基于紫外吸收光谱分析了水体有机质的分子量。结果表明，五里峡水库水化学类型为HCO-Ca·Mg型，水体营养状况为中营养型，水质良好。雨季DOC质量浓度低于旱季，且DOC是总有机碳（TOC）的主要组成部分。DOC质量浓度在垂向上呈现出从表层到底层逐渐降低的趋势。叶绿素a（Chl-a）和溶解性无机碳（DIC）是影响DOC垂向分布的主要因素。库区有机质与、、SUVA及/的吸收光谱参数关系表明，水体以小分子质量、富里酸比例高、腐殖酸比例低、芳香性弱的组分为主。结果表明，库区有机质易被微生物生物活性消耗，在水库碳循环中发挥着积极作用。同时也表明该水库DOC内源特征较强，为异养微生物提供了充足的碳源。
