AQUIFER PARAMETERS FROM CONSTANT DRAWDOWN NONSTEADY-LEAKY TYPE CURVES1

ABSTRACT: A drain function and set of type curves were defined for the mathematical solution that represents one-dimensional flow under nonsteady conditions in a leaky aquifer for the constant drawdown boundary condition. A match point procedure was developed for determining the aquifer parameters transmissivity, storage coefficient, and leakance based on the drain function and type curves. Use of the procedure is illustrated by an example that utilizes simulated aquifer drawdowns and flowrate data. The drain function and type curves developed in this investigation include the effects of leakage for the constant drawdown boundary condition, which is not included in the existing drain function and type curve found in the literature. Thus, a new set of type curves was developed that can be used to analyze drawdowns for one-dimensional flow in a leaky aquifer with constant drawdown at a line sink. Applications would include flow to a canal or river, drainage of agricultural lands, and dewatering associated with strip mining operations.     

鄂东南铁矿区地面塌陷、滑坡灾害与安全生产

本文以广山铁矿区所引起的地表塌陷、滑坡等地质灾害为例，阐述了鄂东南铁矿区在采矿过程普温存在地面塌陷、滑坡等地质灾害，严重威胁矿山井下安全生产，并指出了引发灾害的原因及有关安全的防治措施。     

Comparative study of carbonic anhydrase activity in waters among different geological eco-environments of Yangtze River basin and its ecological significance

This study provides the presence of carbonic anhydrase(CA) activity in waters of the Yangtze River basin, China, as well as the correlation of CA activity with HCO-3 concentration and CO_2 sink flux. Different degrees of CA activity could be detected in almost all of the water samples from different geological eco-environments in all four seasons. The CA activity of water samples from karst areas was significantly higher than from non-karst areas(PP3-concentration(r = 0.672, P2 sink flux(r = 0.602, P = 0.076) in karst areas. This suggests that CA in waters might have a promoting effect on carbon sinks for atmospheric CO_2 in karst river basins. In conditions of similar geological type, higher CA activity was generally detected in water samples taken from areas that exhibited better eco-environments, implying that the CA activity index of waters could be used as an indicator for monitoring ecological environments and protection of river basins. These findings suggest that the role of CA in waters in the karst carbon sink potential of river basins is worthy of further in-depth studies.     

我国典型陆地生态系统固碳重要区范围界定

全球变暖已成为当今最主要的全球性环境问题之一,建立固碳重要区也是应对全球气候变化的重要途径之一.根据我国陆地生态系统现状以及固碳相关的最新研究结果和政府文件,以森林、草地生态系统为主要研究对象,采用GIS空间叠置分析方法,界定我国典型陆地生态系统固碳重要区(注:涉及“全国”的各要素范围均未包含港澳台地区)的空间范围.研究结果:固碳重要区评价指标体系包括生态系统碳储量、碳汇和固碳潜力3个核心因子,界定过程包括界定范围选择、固碳高值区识别、固碳重要区范围确定和分区命名等步骤.在全国尺度界定了森林、草地两大类共计20个固碳重要区,总面积285.6×104 km2.其中,森林生态系统固碳重要区主要分布在我国东北部、西南部的深山区和东南部的山地丘陵,草地生态系统固碳重要区主要分布在内蒙古高原中东部、新疆西北部山地和青藏高原东南部.固碳重要区面积占全国国土总面积的29.8%,所提供的NPP(净初级生产力)量占全国NPP总量的40.7%,固碳能力是全国平均水平的1.37倍.固碳重要区范围界定结果符合“以较小面积获取较大服务”原则,适于作为我国实现碳减排目标的优先保护区域.      

Local Extinction of Dragonfly and Damselfly Populations in Low‐ and High‐Quality Habitat Patches

Abstract: Understanding the risk of extinction of a single population is an important problem in both theoretical and applied ecology. Local extinction risk depends on several factors, including population size, demographic or environmental stochasticity, natural catastrophe, or the loss of genetic diversity. The probability of local extinction may also be higher in low‐quality sink habitats than in high‐quality source habitats. We tested this hypothesis by comparing local extinction rates of 15 species of Odonata (dragonflies and damselflies) between 1930–1975 and 1995–2003 in central Finland. Local extinction rates were higher in low‐quality than in high‐quality habitats. Nevertheless, for the three most common species there were no differences in extinction rates between low‐ and high‐quality habitats. Our results suggest that a good understanding of habitat quality is crucial for the conservation of species in heterogeneous landscapes.     

中国种植业碳汇盈余动态变化及地区差异分析——基于31个省(市、区)2000—2012年的面板数据

在科学测算31个省(市、区)2000—2012年种植业碳汇盈余量的基础上,利用基尼系数系统考察了其地区差距及动态演变特征。研究结论揭示:1)中国种植业碳汇盈余量呈现较为明显的空间差异性。基于总量变化趋势的不同可将31个地区划分为"持续增长型"、"波动增长型"、"波动下降型"与"持续下降型"等4类地区。16个地区种植业碳汇水平得到提升但增幅差异较大;余下15个地区则处于下降态势。2)基尼系数测算结果表明,中国种植业碳汇盈余的地区差距在样本考察期内虽存在一定的年际起伏,但总体处于逐步扩大趋势。从三大区域来看,东部地区差距变化幅度居中,经历了差距缩小期、波动扩大期和波动平稳期等变化阶段;中部地区差距变化幅度最大,其绝对差距也高于东、西部地区,经历了差距持续扩大期、波动平稳期、波动缩小期与小幅扩大期等变化阶段;西部地区差距变化幅度最小,经历了"扩大"与"缩小"的循环演变。     

潮间带湿地碳循环及其环境控制机制研究进展

有高等植被覆盖的潮间带湿地（红树林沼泽、盐沼）植被生产力高,有机碳分解速率低,CH4排放较弱,碳沉积速度快,是单位面积碳封存速率最高的生态系统之一。作为全球“蓝色碳汇”的主要贡献者,潮间带湿地在减缓含碳温室气体排放,降低全球温室效应方面具有重要潜力。潮间带湿地大多地处经济发达和人口密集的河口海岸地区,近年来其碳汇功能受到了越来越多人为干扰的威胁,正在发生着的气候变化则更增加了这种碳汇功能的不确定性。在全球变化背景下,对潮间带湿地碳循环及其环境控制机制的深入了解可以帮助更好地管理这种具有重要碳减排潜力的生态系统。文章综述国内外的相关研究,分析了潮间带湿地碳循环的基本过程和环境影响因素,探讨了多种人为干扰和气候变化要素对潮间带湿地碳循环的影响。潮间带湿地碳循环的基本过程主要包括垂直方向土壤（水）-大气界面和植被-大气界面CO2、CH4交换和沉积过程驱动的碳封存,以及水平方向与近海的碳交换。潮间带湿地的碳循环主要受潮汐/流、光合有效辐射、温度、盐度、水位、植物群落特征等非生物和生物因素的影响。围垦、富营养化、放牧很可能削弱潮间带湿地的碳汇功能,而外来植物入侵却可能在一定程度上增加其碳汇潜能。海平面上升、气温升高会增加潮间带湿地碳汇功能的脆弱性,CO2浓度升高的作用依赖于优势植物群落的光合作用途径,而多种并存气候变化要素的作用则更为复杂。全球范围内大量潮间带湿地已经遭受破坏甚至丧失,水文调控是对受损潮间带湿地碳汇功能进行修复和重建的有效措施。未来的研究需要更好的理解多种并存气候变化要素,及人为干扰和气候变化同时存在对潮间带湿地碳循环的交互效应,利用过程模型预测不同人为干扰和气候变化情境下潮间带湿地碳收支变化规律,并完善受损潮间带湿地碳汇功能修复的基础理论和实施方法。     

中国近海石油污染现状及防治

概述了本世纪初我国近海海域石油烃类污染状况，并对海洋环境中石油烃类的存在形式、源、汇以及转化过程作了详细介绍，讨论了石油污染对海洋的危害，论述了石油烃类污染分析防治的各种措施及其优缺点，提出了对当前和今后研究的一些建议。     

碳汇生态产品的科学内涵、价值评估与实现路径

在碳达峰碳中和与共同富裕双重目标驱动下,拓展和完善生态产品价值实现机制具有重大的理论与现实意义。本文界定了碳汇生态产品的概念内涵,根据功能属性将其划分为生态调节类碳汇生态产品和物质供给类碳汇生态产品,总结了两类产品对应的实物量核算与价值量评估方法。在此基础上,提出了政府主导、市场主导和耦合互馈的碳汇生态产品价值实现路径,并提出了相应的政策保障建议。研究认为,碳汇生态产品不仅是生态产品价值实现的创新举措,也是推动碳达峰碳中和目标与共同富裕协同实现的重要路径。