Sustainability: a Dissent

Abstract:  Broadly conceived and considered in its many usages, sustainability has grave defects as a planning goal, particularly when used by conservationists: it confuses means and ends; it is vague about what is being sustained and who or what is doing the sustaining; it is uninspiring; it is little more than Pinchot-era conservation (and thus ignores the many lessons learned since then); it need not be linked to land, to the land's functioning, or to any ecological science; it need not include a moral component; it is consistent with the view of humans as all-powerful manipulators of the planet; and, in general, it is such a malleable term that its popularity provides only a facade of consensus. When sustainability is defined broadly to include the full range of economic and social aspirations, it poses the particular risk that ecological and biodiversity concerns will be cast aside in favor of more pressing human wants. Given these many defects, the conservation movement should discard the term in favor of a more alluring goal, attentive to nature and its ecological functioning. A sound goal would incorporate and distill the considerable ecological and moral wisdom accumulated since Pinchot's day while giving conservationists the rhetorical tools needed to defend the land against competing pressures. In our view, conservation would be well served by an updated variant of "land health," Aldo Leopold's ecologically grounded goal from the 1940s. Land health as an independent understanding should set the essential terms of how we live and enjoy the earth, providing the framework within which we pursue our many social and economic aims.     

Characterization of microbial communities from coastal waters using microarrays

Molecular methods, including DNA probes, were used to identify and enumerate pathogenic Vibrio species in the Chesapeake Bay; our data indicated that Vibrio vulnificus exhibits seasonal fluctuations in number. Our work included a characterization of total microbial communities from the Bay; development of microarrays that identify and quantify the diversity of those communities; and observation of temporal changes in those communities. To identify members of the microbial community, we amplified the 16S rDNA gene from community DNA isolated from a biofilm sample collected from the Chesapeake Bay in February, 2000. The resultant 75 sequences were 95% or more similar to 7 species including two recently described Shewanella species, baltica and frigidimarina, that have not been previously isolated from the Chesapeake. When the genera of bacteria from biofilm after culturing are compared to those detected by subcloning amplified 16S fragments from community DNA, the cultured sample exhibited a strong bias. In oysters collected in February, the most common bacteria were previously unknown. Based on our 16S findings, we are developing microarrays to detect these and other microbial species in these estuarine communities. The microarrays will detect each species using four distinct loci, with the multiple loci serving as an internal control. The accuracy of the microarray will be measured using sentinel species such as Aeromonas species, Escherichia coli, and Vibrio vulnificus. Using microarrays, it should be possible to determine the annual fluctuations of bacterial species (culturable and non-culturable, pathogenic and non-pathogenic). The data may be applied to understanding patterns of environmental change; assessing the health of the Bay; and evaluating the risk of human illness associated with exposure to and ingestion of water and shellfish.     

云南省土壤污染状况调查中样品的保存与管理

主要介绍了土壤污染状况调查中,应通过规范要求土壤样品的保存与管理步骤,确保土壤污染状况调查数据的准确性与可比性。     

西藏自治区土地资源的适宜性评价与利用

本文综合评价了西藏自治区土地资源的适宜性及其质量．阐明了影响土地资源潜力发挥的主要限制因素，分析了土地资源利用现状、存在问题和开发潜力。并在此基础上、提出了西藏自治区土地资源合理开发利用的方向、对策和措施。     

岷江上游半干旱河谷土壤成土特征研究：以大沟流域为例

岷江上游半干旱河谷位于新构造运动活动带，其土壤形成和发育过程有着鲜明的区域特征。本文结合该区域的自然地理特点，综合分析各成土因素和土壤性状，对该区域土壤的成土特征进行了深入的分析和研究。     

水入渗条件下边坡破坏离心模型试验研究

水的人渗能对土体强度产生较大的影响,它是造成边坡破坏的一个主要因素.不同含水量土质边坡的离心模型试验表明:边坡的破坏类型与其含水量大小有关,且主要存在两种破坏类型:一种是含水量较小时形成的拉裂缝破坏,另一种是含水量较大时形成的整体滑塌破坏;同时,含水量与边坡的最大稳定高度呈非线性关系.进一步的损伤力学分析表明,随着土体含水量的增加,损伤变量增大,并存在一个突变点;通过同离心模型试验结果比较,发现该突变点对应的含水量可作为两种破坏类型的判据.     

水-苦草-沉积物系统对聚乙烯微塑料的响应

水生态系统中的微塑料对生态安全和环境健康造成严重威胁,受到广泛关注.为了揭示水-苦草-沉积物系统对于微塑料暴露的响应,将苦草暴露于不同质量分数（1%～5%,沉积物湿重质量分数）的聚乙烯微塑料（PE-MPs）中,分别研究了PE-MPs对系统中水质理化指标、沉水植物形态特征、生理性状、抗氧化系统和沉积物中微生物群落结构的影响.结果表明,PE-MPs处理组对于水体理化性质的改变不显著,PE-MPs处理组显著抑制了植株株高、氧化应激指标和抗氧化系统. 1% PE-MPs处理组株高的增长仅为对照组的47.44%,叶绿素a含量为对照组的81.04%,过氧化氢酶（CAT）活性、丙二醛（MDA）含量和过氧化物酶（POD）活性较对照组分别提高了233.70%、 117.82%和61.62%.不同质量分数的PE-MPs对沉积物中的微生物群落结构存在一定的影响.上述结果有助于完善水-沉水植物-沉积物系统中PE-MPs生态风险的评价体系.     

黄棕壤不同粒级组分对镉的吸附动力学与热力学研究

采用一次平衡法研究了黄棕壤不同粒级组分(粘粒≤2 μm、粉粒2～20 μm、细砂粒20～200 μm、粗砂粒200～2000 μm)对镉的吸附动力学与热力学,并采用拉格朗日假一级动力学方程、假二级动力学方程、颗粒内扩散模型对试验数据进行拟合.结果表明,2种温度下各粒级组分对镉的吸附均可分为快反应和慢反应2个阶段,0～15 min内为快反应阶段,吸附量达到饱和吸附量的95%以上,此后为慢反应阶段;随着温度由25℃升高到45℃,各组分对镉的饱和吸附量增加了4.86%～25.3%;各组分对镉的吸附动力学符合拉格朗日假二级动力学方程,吸附过程以化学吸附为主;二级动力学吸附速率常数表明,随着各组分粒级增大,吸附速率降低;在试验温度范围内随着温度升高,吸附速率加快;吸附过程的限速步骤为颗粒间扩散;各粒级组分对镉的吸附为吸热反应,反应能自发进行.     

长江下游典型滨海地区农业土壤重金属污染特征

为揭示长江下游滨海地区农业土壤重金属污染状况,以滨江临海的南通市为例,网格化布点,采集表层农业土壤样品共计334个,对其重金属Cu、Pb、Cr、As、Hg含量进行了测定分析.结果表明,研究区域表层农业土壤中各重金属含量均已超过其背景值,且以Pb污染最为严重;区域性差异较大,以滨海的如东、海门、启东污染最为严重,且以海门、启东As含量最高;各重金属间相关性不显著,来源途径不止一种.从而提出南通市农业土壤重金属污染的防治应立足于防重于治的方针,着重滨海地区,以Pb、As污染源为主,并对污染土壤进行修复.