Collaborative Research: Chronic Stress in Ecosystems Project

随着生物群落适应持久性毒性，生态系统对重金属污染的反应发生在几十年到几个世纪的时间里。例如，在蒙大拿州的克拉克福克河谷，一个近100年前被含有铅和锌等重金属的矿山废物污染的地区，关键的生态系统过程(如生物质生产)受到抑制，而微生物群落的多样性却没有受到抑制。据推测，即使适应的生物体没有遭受污染物的致命影响，耐受毒素的能量成本也会导致生态系统功能受到抑制。新的和经典的微生物学方法将被用来比较从受污染和未受污染的河流中培养的密切相关的生物对金属耐受性的能量成本。对导致两对之间金属耐受性差异的遗传元件--与染色体DNA分离的DNA抗金属分子--的分析，将有助于深入了解物种之间的基因转移在维持受污染生态系统中群落多样性方面的作用，这一过程可能代表着微生物和高等生物群落生态的根本差异。这项研究将增加对污染物对生态系统的长期影响的了解，并可能导致改进根据综合环境应对、补偿和责任法案(CERCLA)对自然资源损害进行量化的方法。此外，来自蒙大拿州拉姆鹿市首席迟钝刀社区学院的美国原住民学生将参加旨在将知识转移到他们的学院的实地和实验室项目。

The response of ecosystems to heavy-metal contamination occurs over decades to centuries as the biological communities adapt to persistent toxicity. For example, in the Clark Fork River Valley, Montana, an area contaminated nearly 100 years ago by mine wastes containing heavy metals such as lead and zinc, critical ecosystem processes (e.g. biomass production) are suppressed while the diversity of microbial communities is not. It is hypothesized that the energetic cost of tolerating toxins leads to suppressed ecosystem functioning even where adapted organisms do not suffer lethal effects of contaminants. New and classical microbiological methods will be employed to compare the energetic cost of metal tolerance in closely related pairs of organisms cultured from contaminated and uncontaminated rivers. Analysis of the genetic elements - metal-resistant molecules of DNA separate from chromosome DNA - responsible for differences in metal tolerance between the pairs will lend insight into the role of gene transfer among species in maintaining community diversity in contaminated ecosystems, a process that may represent a fundamental difference in the community ecology of microorganisms and higher organisms. This research will increase understanding of the long term effects of contaminants on ecosystems and potentially lead to improved methods for quantifying natural resource damage under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). Also, Native American students from Chief Dull Knife Community College in Lame Deer, Montana, will participate in field and laboratory projects geared toward transferring knowledge to their college.