NEW METHODS OF MODELING WATER AVAILABILITY FOR AGRICULTURE UNDER CLIMATE CHANGE: THE U.S. CORNBELT1

ABSTRACT: This paper reports on new methods of linking climate change scenarios with hydrologic, agricultural an water planning models to study future water availability for agriculture, an essential element of sustainability. The study is based on the integration of models of water supply and demand, and of crop growth and irrigation management. Consistent modeling assumptions, available databases, and scenario simulations are used to capture a range of possible future conditions. The linked models include WATBAL for water supply; CERES, SOYGRO, and CROPWAT for crop and irrigation modeling; and WEAP for water demand forecasting, planning and evaluation. These models are applied to the U.S. Cornbelt using forecasts of climate change, agricultural production, population and GDP growth. Results suggest that, at least in the near term, the relative abundance of water for agriculture can be maintained under climate change conditions. However, increased water demands from urban growth, increases in reservoir evaporation and increases in crop consumptive use must be accommodated by timely improvements in crop, irrigation and drainage technology, water management, and institutions. These improvements are likely to require substantial resources and expertise. In the highly irrigated basins of the region, irrigation demand greatly exceeds industrial and municipal demands. When improvements in irrigation efficiency are tested, these basins respond by reducing demand and lessening environmental stress with an improvement in system reliability, effects particularly evident under a high technology scenario. Rain-fed lands in the Cornbelt are not forced to invest in irrigation, but there is some concern about increased water-logging during the spring and consequent required increased investment in agricultural drainage. One major water region in the Cornbelt also provides a useful caveat: change will not necessarily be continuous and monotonic. Under one GCM scenario for the 2010s, the region shows a significant decrease in system reliability, while the scenario for the 2020s shows an increase.     

美国环境执法特点及其启示

从美国环保局的权力、地位、守法援助、守法激励、守法监督、民事与刑事执法、经济处罚额计算以及公众参与和执法协调等方面总结了美国的环境执法经验,得出兼顾环境和市场经济目标,执法与守法相结合,恩威并重、科学执法,民主、公平执法4条执法启示,供我国环境执法借鉴.      

Implementing Ecosystem Management in Public Agencies: Lessons from the U.S. Bureau of Land Management and the Forest Service

Abstract:  Ecosystem management was formally adopted over a decade ago by many U.S. natural resource agencies, including the Forest Service and the Bureau of Land Management. This approach calls for management based on stakeholder collaboration; interagency cooperation; integration of scientific, social, and economic information; preservation of ecological processes; and adaptive management. Results of previous studies indicate differences in the extent to which particular components of ecosystem management would be implemented within the U.S. Forest Service and the Bureau of Land Management and suggest a number of barriers thought to impede implementation. Drawing on survey and interview data from agency personnel and stakeholders, we compared levels of ecosystem-management implementation in the Forest Service and Bureau of Land Management and identified the most important barriers to implementation. Agency personnel perceived similarly high levels of implementation on many ecosystem-management components, whereas stakeholders perceived lower levels. Agencies were most challenged by implementation of preservation of ecological processes, adaptive management, and integration of social and economic information, whereas the most significant barriers to implementation were political, cultural, and legal.     

从拒绝《京都议定书》看美国政府环境外交意图

作为国际社会最具影响力的环境协约,《京都议定书》却被美国政府拒之门外,通过对美国近年来针对该协约的态度及对全球变暖问题的外交举措分析,可以看出,美国政府环境外交行为的意图主要体现在三个方面,即规避不利条款的束缚;设计和实施替代性方案;积极争取国际环境领域的领导地位。     

Aspergillus tubingensis介导植酸盐水解促进U(VI)-PO43-生物矿化

从广东某铀尾矿库水下沉积物中分离筛选出了一株能水解植酸盐的真菌M5-1,对其菌落形态、ITS序列、最适生长pH值、对铀的耐受性及其水解植酸盐的效果进行了分析,随后对M5-1生物矿化铀过程中pH值、正磷酸盐浓度、铀浓度、铀去除率的变化进行了监测,对矿化产物的主要元素和矿物组成进行了分析.证实了真菌M5-1为Aspergillus tubingensis（MH978623）,其最适生长pH值范围为6~7,对铀（~0.84mmol/L）具有较强的耐受性;Aspergillus tubingensis介导植酸盐水解促进U（VI）-PO₄^3-矿化62d后,铀的去除率达95.2%;Aspergillus tubingensis介导U（VI）-PO₄^3-矿化过程中可能形成了难溶的氢铀云母和变钠铀云母矿物.结果表明,Aspergillus tubingensis能有效水解植酸盐释放可溶性正磷酸盐,从而促进U（VI）-PO₄^3-矿化.研究结果为采用Aspergillus tubingensis介导植酸盐水解原位修复铀污染地表水提供了试验依据.     

桂林水南洞1号石笋的年龄与稳定同位素测定及其古气候意义

本文通过对桂林水南洞 1号石笋进行α能谱铀系测年及碳氧同位素分析 ,获得了距今 2 0～ 8万年的古气候信息。石笋大于 2 0万年前开始生长 ,8.0 7万年后停止生长 ,属中更新世的产物。其年龄与δ1 8O的变化可与深海岩芯V2 8-2 3 8同位素记录所揭示的第五和第六阶段进行对比。它反映此阶段区内经历了寒冷 (间夹短暂的小温期 )和温暖 (间夹短暂的小冷期 )等气候变化 ,与全球古气候变化波动基本一致 ,同时也存在地区性的气候变化     

锆石的成因和U-Pb同位素定年的某些进展

锆石是岩浆岩、变质岩、沉积岩和月岩中最重要的副矿物。本文分别从锆石的形态、以及影响锆石形态的因素、锆石的主量、微量、稀土元素地球化学和氧同位素特征等方面进行系统综述。同时 ,论述了目前国内外有关锆石U Pb法定年的研究进展 ,并对各种方法的局限性加以总结     

Genetic Data and the Listing of Species Under the U.S. Endangered Species Act

Abstract:  Genetic information is becoming an influential factor in determining whether species, subspecies, and distinct population segments qualify for protection under the U.S. Endangered Species Act. Nevertheless, there are currently no standards or guidelines that define how genetic information should be used by the federal agencies that administer the act. I examined listing decisions made over a 10-year period (February 1996–February 2006) that relied on genetic information. There was wide variation in the genetic data used to inform listing decisions in terms of which genomes (mitochondrial vs. nuclear) were sampled and the number of markers (or genetic techniques) and loci evaluated. In general, whether the federal agencies identified genetic distinctions between putative taxonomic units or populations depended on the type and amount of genetic data. Studies that relied on multiple genetic markers were more likely to detect distinctions, and those organisms were more likely to receive protection than studies that relied on a single genetic marker. Although the results may, in part, reflect the corresponding availability of genetic techniques over the given time frame, the variable use of genetic information for listing decisions has the potential to misguide conservation actions. Future management policy would benefit from guidelines for the critical evaluation of genetic information to list or delist organisms under the Endangered Species Act.     

Rural and Suburban Sprawl in the U.S. Midwest from 1940 to 2000 and Its Relation to Forest Fragmentation

Abstract:  Housing growth and its environmental effects pose major conservation challenges. We sought to (1) quantify spatial and temporal patterns of housing growth across the U.S. Midwest from 1940–2000, (2) identify ecoregions strongly affected by housing growth, (3) assess the extent to which forests occur near housing, and (4) relate housing to forest fragmentation. We used data from the 2000 U.S. Census to derive fine-scale backcasts of decadal housing density. Housing data were integrated with a 30-m resolution U.S. Geological Survey land cover classification. The number of housing units in the Midwest grew by 146% between 1940 and 2000. Spatially, housing growth was particularly strong at the fringe of metropolitan areas (suburban sprawl) and in nonmetropolitan areas (rural sprawl) that are rich in natural amenities such as lakes and forests. The medium-density housing (4–32 housing units/km²) category increased most in area. Temporally, suburban housing growth was especially high in the post-World War II decades. Rural sprawl was highest in the 1970s and 1990s. The majority of midwestern forests either contained or were near housing. Only 14.8% of the region's forests were in partial block groups with no housing. Housing density was negatively correlated with the amount of interior forest. The widespread and pervasive nature of sprawl shown by our data is cause for conservation concern. Suburban sprawl has major environmental impacts on comparatively small areas because of the high number of housing units involved. In contrast, rural sprawl affects larger areas but with less intensity because associated housing densities are lower. The environmental effects per house, however, are likely higher in the case of rural sprawl because it occurs in less-altered areas. Conservation efforts will need to address both types of sprawl to be successful.     

铀尾矿库地下水污染风险评价方法研究

针对尾矿库中铀对地下水的污染风险,通过选取污染物废液产生量、污染毒性、污染物迁移性和场地运行时间4个污染源特征指标建立污染源荷载风险评价体系,并采用层次分析法确定权重,再结合地下水的固有脆弱性评价,用两者风险等级相叠加的方法划分出5种地下水污染风险等级。同时,以某铀尾矿区为例进行地下水污染风险评价,结果表明该地区地下水污染风险级别为中低风险等级。