The characteristics of seasalt deposition and its impact on acid soils in maritime regions are reviewed. It is pointed out that studies involving the impact of seasalt deposition on acid soils have been concentrated o...The characteristics of seasalt deposition and its impact on acid soils in maritime regions are reviewed. It is pointed out that studies involving the impact of seasalt deposition on acid soils have been concentrated on short-term effects on soil and water acidification. A deep consideration of long-term effects on soil acidification in maritime regions is still needed.展开更多
King George Island, situated in the South Shetland Islands archipelago, is one of the most visited sites in Antarctica. Antarctica attracts much attention because it is one of the most sensitive areas under the influe...King George Island, situated in the South Shetland Islands archipelago, is one of the most visited sites in Antarctica. Antarctica attracts much attention because it is one of the most sensitive areas under the influence of global warming. To understand its hydrochemistry characteristics, we collected various types of water samples, including samples from streams, meltwaters, ground waters, snow and ice from around the Great Wall Station, Fildes Peninsula, King George Island, from January to February, 2015. Major ions, alkalinities, silicate, pH, dissolved oxygen, temperature, and electric conductivities were measured. Several approaches were applied to identify processes that af fect the hydrochemistry on Fildes Peninsula, including ternary diagrams, principal components analysis and cluster analysis. Our data suggest that atmospheric seasalt deposition is the main factor controlling the hydrochemistry on Fildes Peninsula. After atmospheric influences were corrected for seasalt, we defined the weathering of local rocks to be another important factor on the Peninsula's hydrochemistry. Processes such as Ca dissolution from the Ca-bearing basalt, Si loss through secondary mineralization and biological uptake influence the chemical composition of runof fs on the peninsula. Cluster analysis identified 4 groups of streams based on their hydrochemical features, which reflect their original weathering characters under icecap and the combined effects with melt snow, biological activity and the anthropogenic input.展开更多
Sea salt particles containing NaCl are among the most abundant particulate masses in coastal atmosphere. Reactions involving sea salt particles potentially generate Cl radicals, which are released into coastal atmosph...Sea salt particles containing NaCl are among the most abundant particulate masses in coastal atmosphere. Reactions involving sea salt particles potentially generate Cl radicals, which are released into coastal atmosphere. Cl radicals play an important role in the nitrogen and O3 cycles, sulfitr chemistry and particle formation in the troposphere of the polluted coastal regions. This paper aimed at .the heterogeneous reaction between gaseous HNO3 .and solid NaCl. The mech.anis.m was in.vestigatedby density functional theory （DFT）. The results imply that water molecules induce the surface reconstruction, which is essential for the heterogeneous reaction. The surface reconstruction on the defective （710） surface has a barrier of 10.24 kcal.mol-1 and is endothermic by 9.69 kcal.mol-1, whereas the reconstruction on the clean （100） surface has a barrier of 18.46 kcal.mol-1 and isendothermic by 12.96 kcal.mol-1. The surface reconstruction involved in water-adsorbed （710） surface is more energetically favorable. In comparison, water molecules adsorbed on NaCl （100） surface likely undergo water diffusion or desorption. Further, it reveals that the coordination number of the Cl-out is reduced after the surface reconstruction, which assists Clout to accept the proton from HNO3. HCl is released from heterogeneous reactions between gaseous HNO3 and solid NaCl and can react with OH free radicals to produce atomic Cl radicals. The results will offer further insights into the impact of gaseous HNO3 on the air quality of the coastal areas.展开更多
文摘The characteristics of seasalt deposition and its impact on acid soils in maritime regions are reviewed. It is pointed out that studies involving the impact of seasalt deposition on acid soils have been concentrated on short-term effects on soil and water acidification. A deep consideration of long-term effects on soil acidification in maritime regions is still needed.
基金Supported by the Chinese Arctic and Antarctic Administration(No.2014GW08008)the SKLEC/ECNU(No.2011KYYW02)the National Natural Science Foundation of China(No.41676175)
文摘King George Island, situated in the South Shetland Islands archipelago, is one of the most visited sites in Antarctica. Antarctica attracts much attention because it is one of the most sensitive areas under the influence of global warming. To understand its hydrochemistry characteristics, we collected various types of water samples, including samples from streams, meltwaters, ground waters, snow and ice from around the Great Wall Station, Fildes Peninsula, King George Island, from January to February, 2015. Major ions, alkalinities, silicate, pH, dissolved oxygen, temperature, and electric conductivities were measured. Several approaches were applied to identify processes that af fect the hydrochemistry on Fildes Peninsula, including ternary diagrams, principal components analysis and cluster analysis. Our data suggest that atmospheric seasalt deposition is the main factor controlling the hydrochemistry on Fildes Peninsula. After atmospheric influences were corrected for seasalt, we defined the weathering of local rocks to be another important factor on the Peninsula's hydrochemistry. Processes such as Ca dissolution from the Ca-bearing basalt, Si loss through secondary mineralization and biological uptake influence the chemical composition of runof fs on the peninsula. Cluster analysis identified 4 groups of streams based on their hydrochemical features, which reflect their original weathering characters under icecap and the combined effects with melt snow, biological activity and the anthropogenic input.
基金This work was supported by the National High Technology Research ＆ Development Program of China （No. 2012AA06A301） and the National Natural Science Foundation of China （Grant Nos. 21337001 and 21177076）.
文摘Sea salt particles containing NaCl are among the most abundant particulate masses in coastal atmosphere. Reactions involving sea salt particles potentially generate Cl radicals, which are released into coastal atmosphere. Cl radicals play an important role in the nitrogen and O3 cycles, sulfitr chemistry and particle formation in the troposphere of the polluted coastal regions. This paper aimed at .the heterogeneous reaction between gaseous HNO3 .and solid NaCl. The mech.anis.m was in.vestigatedby density functional theory （DFT）. The results imply that water molecules induce the surface reconstruction, which is essential for the heterogeneous reaction. The surface reconstruction on the defective （710） surface has a barrier of 10.24 kcal.mol-1 and is endothermic by 9.69 kcal.mol-1, whereas the reconstruction on the clean （100） surface has a barrier of 18.46 kcal.mol-1 and isendothermic by 12.96 kcal.mol-1. The surface reconstruction involved in water-adsorbed （710） surface is more energetically favorable. In comparison, water molecules adsorbed on NaCl （100） surface likely undergo water diffusion or desorption. Further, it reveals that the coordination number of the Cl-out is reduced after the surface reconstruction, which assists Clout to accept the proton from HNO3. HCl is released from heterogeneous reactions between gaseous HNO3 and solid NaCl and can react with OH free radicals to produce atomic Cl radicals. The results will offer further insights into the impact of gaseous HNO3 on the air quality of the coastal areas.
