A prevailing,controversial hypothesis is that fishing pressure has played a greater role than climatic and environmental drivers,in changing fish species succession and biomass fluctuation in the South China Sea(SCS)....A prevailing,controversial hypothesis is that fishing pressure has played a greater role than climatic and environmental drivers,in changing fish species succession and biomass fluctuation in the South China Sea(SCS).Based on otter trawl survey data from 1959 to 2010 in the outer Beibu Gulf(OBG),northern SCS,large seasonal and interannual variation is reported for fish species composition,the proportional abundances of dominant taxa,and fish biomass.Generalized additive models are developed to quantify relationships between fish biomass and the external factors of fishing pressure and climate change.Fishing pressure proved to be the main driver of sharp declines in demersal fish stocks,with high-value species being replaced by low-value ones over time.Abrupt decreases in fish biomass during the years of 1993 and 1998 correspond to El Nino events,with climate change possibly the main driver of proportional representation of pelagic species in fisheries trawl catch.The need to differentiate impacts of fishing and environmental drivers on fish species with different life history strategies is stressed to better understand fish community dynamics.展开更多
人类活动对全球气候变化的影响是学科前沿也是热点和难点,其中城市不透水表面(IS)的热岛、雨岛等气候现象是研究重点,但有关其他气候要素的研究尚有待开展。本文以全球30 m IS数据集(GAIA)和中国区0.1°地面气象要素数据集为数据源...人类活动对全球气候变化的影响是学科前沿也是热点和难点,其中城市不透水表面(IS)的热岛、雨岛等气候现象是研究重点,但有关其他气候要素的研究尚有待开展。本文以全球30 m IS数据集(GAIA)和中国区0.1°地面气象要素数据集为数据源,通过Mann-Kendall(MK)突变检验法和贝叶斯模型等方法,对滇中高原湖滨城市群在1985—2018年间IS的时空变化特征、气象要素变化与IS的关系,以及反常气候现象进行了刻画。结果表明,相较1985年滇中城市群的IS面积增加了227.56%,2007—2018年增长速度达到最快(89.85 km/a),主要在S、NE、SE、W 4个方向扩张;34 a滇中城市群气候整体经历冷湿(1985—1995年)、暖湿(1996—2006年)、暖干(2007—2018年)3个快速转化阶段;IS具有显著的“热岛现象(气温+0.63℃,长波+4.49 W m)”“雨岛现象(降水+38.27 mm)”“湿岛现象(比湿+0.51 g/kg)”“风速低岛现象(风速-0.025 m/s)”和“气压高岛现象(气压+602.64 Pa)”;滇中城市群的长波辐射主要分布在313~329 W m、比湿8.9~9.9 g/kg、气压76235~79946 Pa、短波186~194 W m、降水840~876 mm和876~998 mm、风速2.08~2.38 m/s、气温13.85~15.85℃区间内,且显著受IS分布影响。IS对气压和湿度的影响具有“气压反温度现象”和“湿度反常现象”,这可能与副热带高压带控制、海拔和大型湖泊(湖陆风)影响有关。展开更多
In this paper we present the results of a survey of indoor radon concentration levels in Mexico. In order to investigate whether differences in climate translate into significant differences in indoor radon concentrat...In this paper we present the results of a survey of indoor radon concentration levels in Mexico. In order to investigate whether differences in climate translate into significant differences in indoor radon concentrations, the country was divided into three climate regions: the northern semi-desert region, the central semitropical region and the southern tropical region. The survey was carried out using nuclear track methodology. The dosimeters employed for the survey were based on the passive closed-end cup device, developed at the Physics Institute of the National Autonomous University of Mexico, and used PADC as detector material. A well-established protocol for chemically etching and reading the detectors was followed. Average annual temperatures differ between regions (from 15℃ to 28℃) but vary relatively little within each region. Atmospheric temperature is one of the most important factors which need to be considered when carrying out a survey of indoor radon concentrations because temperature largely determines building ventilation habits, and ventilation habits are known to have significant effects on indoor radon concentrations. Other factors, including building construction materials, architectural styles, geological and hydrological characteristics, and seismicity, vary from region to region and within each region. In each of the three regions low levels of indoor radon (from 37 to 179 Bq·m-3) were found.展开更多
基金The Science and Technology Basic Resources Investigation Program of China under contract No.2017FY201405the Open Research Fund Program of Guangxi Key Lab of Mangrove Conservation and Utilization under contract No.GKLMC-201403+2 种基金the National Natural Science Foundation of China under contract No.41666008the Fund of Key Laboratory of Open-Sea Fishery Development,Ministry of Agriculture of China under contract No.LOF 2018-01the Natural Science Foundation of Guangxi under contract No.2016GXNSFDA380035
文摘A prevailing,controversial hypothesis is that fishing pressure has played a greater role than climatic and environmental drivers,in changing fish species succession and biomass fluctuation in the South China Sea(SCS).Based on otter trawl survey data from 1959 to 2010 in the outer Beibu Gulf(OBG),northern SCS,large seasonal and interannual variation is reported for fish species composition,the proportional abundances of dominant taxa,and fish biomass.Generalized additive models are developed to quantify relationships between fish biomass and the external factors of fishing pressure and climate change.Fishing pressure proved to be the main driver of sharp declines in demersal fish stocks,with high-value species being replaced by low-value ones over time.Abrupt decreases in fish biomass during the years of 1993 and 1998 correspond to El Nino events,with climate change possibly the main driver of proportional representation of pelagic species in fisheries trawl catch.The need to differentiate impacts of fishing and environmental drivers on fish species with different life history strategies is stressed to better understand fish community dynamics.
文摘In this paper we present the results of a survey of indoor radon concentration levels in Mexico. In order to investigate whether differences in climate translate into significant differences in indoor radon concentrations, the country was divided into three climate regions: the northern semi-desert region, the central semitropical region and the southern tropical region. The survey was carried out using nuclear track methodology. The dosimeters employed for the survey were based on the passive closed-end cup device, developed at the Physics Institute of the National Autonomous University of Mexico, and used PADC as detector material. A well-established protocol for chemically etching and reading the detectors was followed. Average annual temperatures differ between regions (from 15℃ to 28℃) but vary relatively little within each region. Atmospheric temperature is one of the most important factors which need to be considered when carrying out a survey of indoor radon concentrations because temperature largely determines building ventilation habits, and ventilation habits are known to have significant effects on indoor radon concentrations. Other factors, including building construction materials, architectural styles, geological and hydrological characteristics, and seismicity, vary from region to region and within each region. In each of the three regions low levels of indoor radon (from 37 to 179 Bq·m-3) were found.
