The content and distribution of acid-volatile sulfide （AVS） and simultaneously extracted metals （SEM） （Cr Cu, Zn, Cd and Pb） were studied in surface sediments collected from the tidal fiat of Donghai Island, Zha...The content and distribution of acid-volatile sulfide （AVS） and simultaneously extracted metals （SEM） （Cr Cu, Zn, Cd and Pb） were studied in surface sediments collected from the tidal fiat of Donghai Island, Zhanjiang. The results indicated that for most stations, the AVS concentration was higher in summer with the average of 0.449 μmol/g than that in winter with the average of 1.816 μmol/g. The AVS contents were higher in southern and northern areas and lower in western and eastern areas. The average content of ∑SEM was between 0.56 μmol/g and 4.60 μmol/g in summer and between 0.65μmol/g and 2.21 μmol/g in winter. The concentration change of single metal was Zn〉Cr〉Pb〉Cu〉Cd for most stations. The content percentage in ∑ SEM was below 1% for Cd and over 70% for Zn. SEMZn was the key pattern to control the distribution of T. SEM due to its high concentration percentage. Based on the assessment methods of （∑SEM/AVS） with （∑ SEM-AVS） and thresholds for metal toxicity to benthic organism, most values of （∑ SEM-AVS） in intertidal flats of Donghai Island were between 0 and 5. The most toxicity region was in Tongminghai area located in the west tidal zone of Donghai Island, and the most toxicity metal was zinc in Tongminghai area in summer. The land-based pollution and the environmental parameters such as sunlight, atmosphere temperature and hydrodynamic characteristics were the main affecting factors on the content level and distribution characteristics of AVS and SEM in intertidal sediments of Donghai Island.展开更多
Based on the interpretation of the remote sensing data presented by the resource satellite, this paper states the fact that the land-use area in Donghai Island, which is located in the south of Zhanjiang, Guangdong Pr...Based on the interpretation of the remote sensing data presented by the resource satellite, this paper states the fact that the land-use area in Donghai Island, which is located in the south of Zhanjiang, Guangdong Province, had expanded by 576.71 hm2 in the 25 years from 1986 to 2010 because of human activities such as land reclamation; in the meantime, great changes in types of land cover on the island have occurred. The definite change in land use leads to the remarkable transition in its ecosystem service value. Therefore, by applying the Costanza method in this paper to quantificationally analyze the changes in its ecosystem services on this island; the Costanza method is a calculation technique that shows the service value per unit area of island. It is found that from 1986 to 2010, especially in the recent years, due to the rapid development in the petrifaction, steel and port industries, the areas of cultivated land, woodland, grassland and desert have decreased in different degrees, while the lands for residence, industry and traffic construction and the areas of water and wetlands have increased. Consequently, compared with the number of RMB 547.57x10^6 yuan per year in 1986, the ecosystem service value of Donghai Island was greatly reduced to RMB 493.94x10^6 yuan per year in 2010. As for the spatial distribution, it presents a feature that it is higher in the west and low in the east. The results manifest that it is of great significance to analyze the changes in the ecosystem service function on the basis of the service value of the island presented by the remote sensing data in a quantificational way, which will contribute to the promotion of ecological compensation.展开更多
利用广东省闪电探测系统资料、卫星云图资料、探空资料及雷击点附近的风廓线雷达、多要素自动站等资料,对发生在湛江市东海岛气象综合探测基地内的一次强雷暴天气过程进行综合分析。结果表明:该次强雷暴天气发生在受高空槽和弱冷空气共...利用广东省闪电探测系统资料、卫星云图资料、探空资料及雷击点附近的风廓线雷达、多要素自动站等资料,对发生在湛江市东海岛气象综合探测基地内的一次强雷暴天气过程进行综合分析。结果表明:该次强雷暴天气发生在受高空槽和弱冷空气共同影响的天气过程中,雷击电流强度-54.463 66 k A,雷电流上升陡度28.665 08 k A/μs。雷击点在低涡云团内,雷击点雷达回波强度超过45 d BZ,风向从底层向上随时间顺转,雷击发生前后雷击点附近的降雨量、风向风速、本站气压和能见度等气象要素产生了明显的突变。发生雷击的当日是处在大气层结由不稳定转变为稳定的过渡时段,弱冷空气、强降水和雷暴的共同作用消耗了大气中的能量和水汽,使大气层结回复到相对稳定状态。展开更多
基金supported by Marine Public Industry Research of Oceanic Administration, China (2013418038-6)
文摘The content and distribution of acid-volatile sulfide （AVS） and simultaneously extracted metals （SEM） （Cr Cu, Zn, Cd and Pb） were studied in surface sediments collected from the tidal fiat of Donghai Island, Zhanjiang. The results indicated that for most stations, the AVS concentration was higher in summer with the average of 0.449 μmol/g than that in winter with the average of 1.816 μmol/g. The AVS contents were higher in southern and northern areas and lower in western and eastern areas. The average content of ∑SEM was between 0.56 μmol/g and 4.60 μmol/g in summer and between 0.65μmol/g and 2.21 μmol/g in winter. The concentration change of single metal was Zn〉Cr〉Pb〉Cu〉Cd for most stations. The content percentage in ∑ SEM was below 1% for Cd and over 70% for Zn. SEMZn was the key pattern to control the distribution of T. SEM due to its high concentration percentage. Based on the assessment methods of （∑SEM/AVS） with （∑ SEM-AVS） and thresholds for metal toxicity to benthic organism, most values of （∑ SEM-AVS） in intertidal flats of Donghai Island were between 0 and 5. The most toxicity region was in Tongminghai area located in the west tidal zone of Donghai Island, and the most toxicity metal was zinc in Tongminghai area in summer. The land-based pollution and the environmental parameters such as sunlight, atmosphere temperature and hydrodynamic characteristics were the main affecting factors on the content level and distribution characteristics of AVS and SEM in intertidal sediments of Donghai Island.
基金The scientific research fund of the Second Institute of Oceanography,State Oceanic Administration under contract No.JG1214the Natural Science Foundation of Guangdong Province,China under contract No.2014A030313603+3 种基金Foundation for Excellent Young Teachers in Higher Education of Guangdong Province,China under contract No.Yq2014001the Doctoral Start-up Fund Research of Guangdong Ocean University under contract No.E11097Guangdong Planning of Philosophy and Social Science Funding Projects under contract No.GD12YGL04Foundation for Distinguished Yong Talents in Higher Education of Guangdong,China under contract No.2012WYM_0077
文摘Based on the interpretation of the remote sensing data presented by the resource satellite, this paper states the fact that the land-use area in Donghai Island, which is located in the south of Zhanjiang, Guangdong Province, had expanded by 576.71 hm2 in the 25 years from 1986 to 2010 because of human activities such as land reclamation; in the meantime, great changes in types of land cover on the island have occurred. The definite change in land use leads to the remarkable transition in its ecosystem service value. Therefore, by applying the Costanza method in this paper to quantificationally analyze the changes in its ecosystem services on this island; the Costanza method is a calculation technique that shows the service value per unit area of island. It is found that from 1986 to 2010, especially in the recent years, due to the rapid development in the petrifaction, steel and port industries, the areas of cultivated land, woodland, grassland and desert have decreased in different degrees, while the lands for residence, industry and traffic construction and the areas of water and wetlands have increased. Consequently, compared with the number of RMB 547.57x10^6 yuan per year in 1986, the ecosystem service value of Donghai Island was greatly reduced to RMB 493.94x10^6 yuan per year in 2010. As for the spatial distribution, it presents a feature that it is higher in the west and low in the east. The results manifest that it is of great significance to analyze the changes in the ecosystem service function on the basis of the service value of the island presented by the remote sensing data in a quantificational way, which will contribute to the promotion of ecological compensation.
文摘利用广东省闪电探测系统资料、卫星云图资料、探空资料及雷击点附近的风廓线雷达、多要素自动站等资料,对发生在湛江市东海岛气象综合探测基地内的一次强雷暴天气过程进行综合分析。结果表明:该次强雷暴天气发生在受高空槽和弱冷空气共同影响的天气过程中,雷击电流强度-54.463 66 k A,雷电流上升陡度28.665 08 k A/μs。雷击点在低涡云团内,雷击点雷达回波强度超过45 d BZ,风向从底层向上随时间顺转,雷击发生前后雷击点附近的降雨量、风向风速、本站气压和能见度等气象要素产生了明显的突变。发生雷击的当日是处在大气层结由不稳定转变为稳定的过渡时段,弱冷空气、强降水和雷暴的共同作用消耗了大气中的能量和水汽,使大气层结回复到相对稳定状态。
