By measuring and comparing δD, δ18O, and 3H values of different sections in Lhasa River, we can trace its water resource and water environment. We have concluded that the upper reaches of the Lhasa River are mainly ...By measuring and comparing δD, δ18O, and 3H values of different sections in Lhasa River, we can trace its water resource and water environment. We have concluded that the upper reaches of the Lhasa River are mainly supplied by melt-water (with lower 3H value and mineralization degree) and underground water (with lower 3H value and higher mineralization degree). The middle reaches are mainly supplied by rainwater (with higher 3H value and mineralization degree).展开更多
Stable oxygen and hydrogen isotopic compositions （δ18O and δD） of soil water and shallow groundwater of a riparian forest, an artificial shrub forest, and Gobi of the lower reaches of the Heihe River Basin are use...Stable oxygen and hydrogen isotopic compositions （δ18O and δD） of soil water and shallow groundwater of a riparian forest, an artificial shrub forest, and Gobi of the lower reaches of the Heihe River Basin are used to study the recharge water sources of those ecosystems. IsoSource software is used to determine the δ180 values for root water of Populous euphratica and Tamarix ramosissima in the riparian forest ecosystem, Haloxylon ammodendron in the artificial shrub forest, and Reaumuria soongorica in the Gobi, as well as for local soil water and groundwater, and precipitation in the upper reaches of the Heihe River Basin. Our results showed that soil water and shallow groundwater of the riparian forest and the artificial shrub forest were recharged by river water which originated from precipitation in the upper reaches, and strong evaporation occurred in the artificial shrub forest. Soil water of the Gobi was not affected by Heihe River water due to this area being far away from the river channel. The main water sources of Populous euphratica were from 40-60-cm soil water and groundwater, and of Tamarix ramosissima were from 40-80-cm soil water in the riparian forest ecosystem. In the artificial forest, Haloxylon ammodendron used 200-cm saturated-layer soil water and shallow groundwater. The Reaumuria soongorica mainly used soil water from the 175-200-cm depth in the Gobi. Therefore, soil water and groundwater are the main water sources which maintain survival and growth of the plants in the extremely arid regions of the lower reaches of the Heihe River Basin.展开更多
To assess the effects of river damming on dissolved inorganic carbon in the Jialing River, a total of 40 water samples, including inflow, outflow, and stratified water in four cascade reservoirs(Tingzikou, Xinzheng,Do...To assess the effects of river damming on dissolved inorganic carbon in the Jialing River, a total of 40 water samples, including inflow, outflow, and stratified water in four cascade reservoirs(Tingzikou, Xinzheng,Dongxiguan, Caojie) were collected in January and July,2016. The major cations, anions, and δ^(13)C_(DIC) values were analyzed. It was found that the dissolved compositions are dominated by carbonate weathering, while sulfuric acids may play a relatively important role during carbonate weathering and increasing DIC concentration. Different reservoirs had variable characteristics of water physiochemical stratification. The DIC concentrations of reservoir water were lower in summer than those in winter due to the dilute effects and intensive aquatic photosynthesis, as well as imported tributaries. The δ^(13)C_(DIC) values in Tingzikou Reservoir were higher during summer than those in winter,which indicated that intensive photosynthesis increased the δ^(13)C_(DIC) values in residual water, but a similar trend was not obvious in other reservoirs. Except for in Xinzheng Reservoir, the δ^(13)C_(DIC) values in inflow and outflow reservoir water were lower than those in the surface water of stratified sampling in summer. For stratified sampling, it could be found that, in summer, the Tingzikou Reservoir δ^(13)C_(DIC) values significantly decreased with water depthdue to the anaerobic breakdown of organic matter. The significant correlation(p<0.01 or 0.05) between the DIC concentrations, the δ^(13)C_(DIC) values and anthropogenic species(Na^++K^+, Cl~–, SO_4^(2-) and NO_3^-) showed that the isotope composition of DIC can be a useful tracer of contaminants. In total, Tingzikou Reservoir showed lacustrine features, Xinzheng Reservoir and Dongxiguan Reservoir had "transitional'' features, and Caojie Reservoir had a total of "fluvial'' features. Generally, cascade reservoirs in the Jialing River exhibited natural river features rather than typical lake features due to characteristics of reservoir water in physiochemical stratification, spatiotemporal variations of DIC concentrations and isotopic compositions. It is evident that the dissolved inorganic carbon dynamics of natural rivers had been partly remolded by dam building.展开更多
文摘By measuring and comparing δD, δ18O, and 3H values of different sections in Lhasa River, we can trace its water resource and water environment. We have concluded that the upper reaches of the Lhasa River are mainly supplied by melt-water (with lower 3H value and mineralization degree) and underground water (with lower 3H value and higher mineralization degree). The middle reaches are mainly supplied by rainwater (with higher 3H value and mineralization degree).
基金supported by the National Natural Science Foundation of China (Grant Nos. 91325102, 91025016 and 91125025)the National Science & Technology Support Project (No. 2011BAC07B05)
文摘Stable oxygen and hydrogen isotopic compositions （δ18O and δD） of soil water and shallow groundwater of a riparian forest, an artificial shrub forest, and Gobi of the lower reaches of the Heihe River Basin are used to study the recharge water sources of those ecosystems. IsoSource software is used to determine the δ180 values for root water of Populous euphratica and Tamarix ramosissima in the riparian forest ecosystem, Haloxylon ammodendron in the artificial shrub forest, and Reaumuria soongorica in the Gobi, as well as for local soil water and groundwater, and precipitation in the upper reaches of the Heihe River Basin. Our results showed that soil water and shallow groundwater of the riparian forest and the artificial shrub forest were recharged by river water which originated from precipitation in the upper reaches, and strong evaporation occurred in the artificial shrub forest. Soil water of the Gobi was not affected by Heihe River water due to this area being far away from the river channel. The main water sources of Populous euphratica were from 40-60-cm soil water and groundwater, and of Tamarix ramosissima were from 40-80-cm soil water in the riparian forest ecosystem. In the artificial forest, Haloxylon ammodendron used 200-cm saturated-layer soil water and shallow groundwater. The Reaumuria soongorica mainly used soil water from the 175-200-cm depth in the Gobi. Therefore, soil water and groundwater are the main water sources which maintain survival and growth of the plants in the extremely arid regions of the lower reaches of the Heihe River Basin.
基金financially supported by the National Key Research and Development Program of China(2016YFA0601000)the National Natural Science Foundation of China(Grant No.41373136)
文摘To assess the effects of river damming on dissolved inorganic carbon in the Jialing River, a total of 40 water samples, including inflow, outflow, and stratified water in four cascade reservoirs(Tingzikou, Xinzheng,Dongxiguan, Caojie) were collected in January and July,2016. The major cations, anions, and δ^(13)C_(DIC) values were analyzed. It was found that the dissolved compositions are dominated by carbonate weathering, while sulfuric acids may play a relatively important role during carbonate weathering and increasing DIC concentration. Different reservoirs had variable characteristics of water physiochemical stratification. The DIC concentrations of reservoir water were lower in summer than those in winter due to the dilute effects and intensive aquatic photosynthesis, as well as imported tributaries. The δ^(13)C_(DIC) values in Tingzikou Reservoir were higher during summer than those in winter,which indicated that intensive photosynthesis increased the δ^(13)C_(DIC) values in residual water, but a similar trend was not obvious in other reservoirs. Except for in Xinzheng Reservoir, the δ^(13)C_(DIC) values in inflow and outflow reservoir water were lower than those in the surface water of stratified sampling in summer. For stratified sampling, it could be found that, in summer, the Tingzikou Reservoir δ^(13)C_(DIC) values significantly decreased with water depthdue to the anaerobic breakdown of organic matter. The significant correlation(p<0.01 or 0.05) between the DIC concentrations, the δ^(13)C_(DIC) values and anthropogenic species(Na^++K^+, Cl~–, SO_4^(2-) and NO_3^-) showed that the isotope composition of DIC can be a useful tracer of contaminants. In total, Tingzikou Reservoir showed lacustrine features, Xinzheng Reservoir and Dongxiguan Reservoir had "transitional'' features, and Caojie Reservoir had a total of "fluvial'' features. Generally, cascade reservoirs in the Jialing River exhibited natural river features rather than typical lake features due to characteristics of reservoir water in physiochemical stratification, spatiotemporal variations of DIC concentrations and isotopic compositions. It is evident that the dissolved inorganic carbon dynamics of natural rivers had been partly remolded by dam building.
