The effects of landscape-level disturbance on the composition of Minnesota caddisfly (Insecta: Trichoptera) trophic functional groups: evidence for ecosystem homogenization

Over 300,000 caddisfly specimens representing 249 species were collected from nearly 250 sites throughout Minnesota during 2000 and 2001 to determine the effects of human disturbance on the composition of caddisfly trophic functional groups at the landscape level. Canonical correspondence analysis determined that stream width was the most important variable influencing functional group composition in regions of the state with relatively low disturbance, and that differences in the caddisfly fauna between sizes of streams generally followed trends predicted by the river continuum concept. In regions of the state with moderate disturbance, both stream width and the percentage of disturbed habitat upstream of a site were important variables influencing functional group composition. In highly disturbed regions, no variables corresponded to changes in the composition of caddisfly functional groups. Instead, ecosystems were homogeneous: fine-particle filtering collectors dominated in all sizes of streams. The observed aquatic ecosystem homogenization is attributed mostly to input of fine-particle organic and inorganic sediment from extensive agriculture.     

Adsorption of Cr(Ⅲ) from acidic solutions by crop straw derived biochars

Cr（Ⅲ） adsorption by biochars generated from peanut, soybean, canola and rice straws is investigated with batch methods. Adsorption of Cr（Ⅲ） increased as pH rose from 2.5 to 5.0. Adsorption of Cr（Ⅲ） led to peak position shifts in the FFIR-PAS spectra of the biochars and made zeta potential values less negative, suggesting the formation of surface complexes between Cr^3＋ and functional groups on the biochars. The adsorption capacity of Cr（Ⅲ） followed the order： peanut straw char 〉 soybean straw char 〉 canola straw char 〉 rice straw char, which was consistent with the content of acidic functional groups on the biochars. The increase in Cr^3＋ hydrolysis as the pH rose was one of the main reasons for the increased adsorption of Cr（Ⅲ） by the biochars at higher pH values. Cr（llI） can be adsorbed by the biochars through electrostatic attraction between negative surfaces and Cr^3＋, but the relative contribution of electrostatic adsorption was less than 5%. Therefore, Cr（Ⅲ） was mainly adsorbed by the biochars through specific adsorption. The Langumir and Freundlich equations fitted the adsorption isotherms well and can therefore be used to describe the adsorption behavior of Cr（Ⅲ） by the crop straw biochars. The crop straw biochars have great adsorption capacities for Cr（Ⅲ） under acidic conditions and can be used as adsorbents to remove Cr（Ⅲ） from acidic wastewaters.     

Systematic Temporal Patterns in the Relationship Between Housing Development and Forest Bird Biodiversity

As people encroach increasingly on natural areas, one question is how this affects avian biodiversity. The answer to this is partly scale‐dependent. At broad scales, human populations and biodiversity concentrate in the same areas and are positively associated, but at local scales people and biodiversity are negatively associated with biodiversity. We investigated whether there is also a systematic temporal trend in the relationship between bird biodiversity and housing development. We used linear regression to examine associations between forest bird species richness and housing growth in the conterminous United States over 30 years. Our data sources were the North American Breeding Bird Survey and the 2000 decennial U.S. Census. In the 9 largest forested ecoregions, housing density increased continually over time. Across the conterminous United States, the association between bird species richness and housing density was positive for virtually all guilds except ground nesting birds. We found a systematic trajectory of declining bird species richness as housing increased through time. In more recently developed ecoregions, where housing density was still low, the association with bird species richness was neutral or positive. In ecoregions that were developed earlier and where housing density was highest, the association of housing density with bird species richness for most guilds was negative and grew stronger with advancing decades. We propose that in general the relationship between human settlement and biodiversity over time unfolds as a 2‐phase process. The first phase is apparently innocuous; associations are positive due to coincidence of low‐density housing with high biodiversity. The second phase is highly detrimental to biodiversity, and increases in housing density are associated with biodiversity losses. The long‐term effect on biodiversity depends on the final housing density. This general pattern can help unify our understanding of the relationship of human encroachment and biodiversity response. Patrones Sistemáticos Temporales en la Relación entre Desarrollos Urbanos y la Biodiversidad de Aves de Bosque     

环境司法专门化下的特殊环境诉讼规则

我国的环境司法处于发展初期,有关环境纠纷的司法救济程序散落在不同的部门法中。为了维护国家环境安全和公共环境利益,构建环境司法专门化势在必行,但是在特殊的环境保护法院进行专门化的环境审判过程中,出现环境诉讼保护对象的争议性、生态环境损害责任承担的特殊性等问题亟待解决,环境民事公益诉讼和生态环境损害赔偿诉讼等特殊环境诉讼规则应运而生,虽然目前还面临着一些困境,但是整体上构建环境司法体系的进程依然在不断推进。     

新型树脂对氯酚类物质的吸附研究

合成了乙酰氯修饰树脂NDA-O,与Purolite公司的MN-200相比,合成的树脂比表面积较小,但酸性官能团较多.用两种树脂吸附2-氯酚、4-氯酚和2,4-二氯酚发现,吸附结果可以用Langmuir和Freundlich等温吸附方程很好地模拟,合成的NDA-O对3种氯酚类物质的吸附能力优于MN-200.两种树脂对氯酚类物质的吸附量随着温度的升高而减少,表明吸附是放热过程,同时对氯酚类物质的吸附焓变随着吸附量的增大而减小.对同一种树脂来说,吸附量随着氯代程度的增加而增加,取代氯数相同的时候,吸附量与吸附质的K..成正相关.进一步研究了pH对吸附的影响,在pH大于9时,3种氯酚类物质的吸附量均急剧减少.     

Effects of nitrate concentration in interstitial water on the bioremediation of simulated oil-polluted shorelines

Nutrient addition has been proved to be an effective strategy to enhance oil biodegradation in marine shorelines.To determine the optimal range of nutrient concentrations in the bioremediation of oil-polluted beaches,nitrate was added to the simulated shoreline models in the initial concentration of 1,5 and 10 mg/L.Whenever the NO3-N concentration declined to 70% of its original value, additional nutrients were supplemented to maintain a certain range.Results showed adding nutrients increased the oil biodegradation level,the counts of petroleum degrading bacteria(PDB)and heterotrophic bacteria (HB),and the promoted efficiency varied depending on the concentration of nitrate.Oil degradation level in 5 mg/L(NO_3-N)group reached as much as 84.3% accompanied with the consistently highest counts of PDB;while in 1 mg/L group oil removal efficiency was only 35.2%,and the numbers of PDB and HB were relatively low compared to the other groups supplemented with nutrients.Although counts of HB in the 10 mg/L group were remarkable,lower counts of PDB resulted in poorer oil removal efficiency (70.5%) compared to 5 mg/L group.Furthermore,it would need more NO_3-N(0.371 mg)to degrade 1 mg diesel oil in the 10 mg/L group than in the 5 mg/L group(0.197 mg).In conclusion, Nitrate concentration in 5 mg/L is superior to 1 and 10 mg/L in the enhancement of diesel oil biodegradation in simulated shorelines.     

全工班呼吸性粉尘测定及防尘措施研究

针对呼吸性粉尘对矿井工人身体健康的危害,对煤矿综采工作面、综掘工作面、炮掘工作面等进行分工种个体性的全尘和呼尘监测,测定了各工作面粉尘(全尘和呼尘)的浓度、粉尘分散度和SiO2浓度。其结果表明:全工班呼吸性粉尘测定的方法更加真实可靠,更真实地反映了呼吸性粉尘对井下各操作工种的致病危害,测得的各工作面各工种的呼尘浓度均高于国家标准。通过数据的分析以及工人的建议,提出了一些新式的、有效的防尘措施来降低呼吸性粉尘对人体健康的危害。     

Media Storms and Policy Expertise: How Environmental Beat Journalists Gained Influence During a Shale Gas Controversy

This article examines the conditions under which environmental beat journalists can gain credibility as expert informants. It shows that media storms foster a particular dynamic that can add to this credibility. Comparing a media storm over shale gas development in Quebec with regular coverage of the same issue in British Columbia, this article shows that the coverage space given to environmental beat journalists during a media storm can render their alliance with protest groups mutually beneficial. Beat journalists can benefit from the willingness of these groups to participate in their stories, while the groups benefit from increased visibility. Beat journalists also benefit by being perceived as expert informants in policy networks, a role that they use to encourage policy-makers to take the concerns of protest groups seriously. This dynamic also increases the negativity of the news coverage. The article makes a contribution to knowledge on the role of environmental journalists in policy-making processes.     

WATER RESOURCES MANAGEMENT IN THE PUBLIC INTEREST1

ABSTRACT. The water resources manager, concerned with providing for citizen needs for water in all its varied aspects, is obliged to consider the public interest in his decision making. But the public interest, although inferring the superiority of public over purely private interests, is more of a concept of political ethics than an operational objective. Recent attacks on water resources developments place in question just how responsive the water resources manager has been to the public at large during the planning process. The recent broadening of planning objectives beyond economic efficiency to include greater attention to social goals is an encouraging development. Efforts should be expanded toward greater citizen participation and more attention should be given to sampling surveys to determine citizen attitudes on water resources proposals. In the last analysis, the decision-making process must combine the expertise of the water resources manager and the participation of the people through the political process.     

Science and the Consequences of Mistruct: Lessons from Recent GM Controversies

In 2001, it was announced thattransgenic DNA had introgressed intotraditional strains of maize in Mexico. Acontroversy erupted and raged throughout 2001and 2002. This episode represents an acutebreakdown in scientific discourse. Given thestakes in the genetically modified organismdebate, a breakdown in scientific discourse isalarming. The following inquiry looks into thecauses of this breakdown. Ultimately, it willbe argued that the underlying problem is thecurrent institutional structure of science,particularly in the United States. If thediagnosis is correct, then the proper course oftreatment is to pursue a program ofinstitutional reconstruction.