流域不同地质生态环境中水体碳酸酐酶活性特征——以桂江流域为例

在对桂江流域进行考察时,选取了流域地质类型不同、人类活动程度不一的6条支流以及干流的水体为研究对象,研究比较了流域不同生态环境下水体中的碳酸酐酶(CA)活性、游离CO2浓度和HCO3-浓度,并对比了流域内部分区域的归一化植被指数(NDVI)数据,获得如下结果:(1)证实水体中具有CA活性,且其活性与游离CO2浓度呈负相关,与HCO3-浓度呈正相关；(2)大量的人类活动加剧流域生态环境恶化,造成植被覆盖率降低,使河流水体中的CA活性降低,HCO3-浓度降低,表明CA对岩溶作用具有不可忽视的影响；(3)流域地质类型会影响水体中CA活性,在人类活动程度相似的情况下,岩溶区水体中的CA活性高于非岩溶区.总之,在进行流域碳汇潜力调查研究时,必须综合考虑人类活动、生态环境和地质类型等因素的影响,进行科学分段调查研究与计算.CA所引起的生物岩溶作用不容忽视,其对流域碳汇的潜在贡献值得深入研究.

Carbonic anhydrase activity of the water-body in different eco-environments of river basins: A case study in the Guijiang river basin

The water-bodies in six tributaries and mainstream, which have different geologic types and different degrees of human activities, are chosen as the research object during investigating the Guijiang river basin. The carbonic anhydrase (CA) activity, free CO2 and HCO3- concentration of the water-bodies under different ecological environments are compared. The data of normalized difference vegetation index (NDVI) among some areas within the river basin are also compared. The following results are obtained :( 1) It is confirmed that the water has CA activity. Its activity is negatively correlated with free CO2 concentration and positively correlated with HCO3- concentrations; (2)Large number of human activities exacerbate the deterioration of the ecological environment in the river basin and result in vegetation cover reduction, so that the CA activity and HCO3- concentration of the water-bodies in the river decreases, indicating that the influence of CA on karst carbon sinks cannot be ignored; (3)The geological type in the river basin would affect CA activity of the water-bodies. Under the condition of similar degrees of human activity, the CA activity of the water-bodies in the karst area is higher than that in the non-karst areas. In summary, to investigate the carbon sink potential in the river basin, the impacts of human activities, eco-environments and geologic types should be comprehensively considered, and scientific segment research and calculation should be conducted. Furthermore, the biological karstification induced by CA cannot be ignored, and its contribution to the carbon sink potential deserves research.