Studies on the Impact of Sewage-Associated Microorganisms on Indigenous Seal and Bacterial Populations and Drinking Water Quality at McMurdo Station

南极洲的麦克默多站多年来一直在向海岸附近的原始海水中排放经过浸渍处理的未经处理的人类污水。受污水羽流影响的海水有时会延伸到进水口码头的饮用水入口。此外，位于污水影响区域内的沉积物摄食无脊椎动物已被证明不仅吸收与污水有关的营养物质，而且还表现出增加的平均身体和器官大小。先前的一项研究发现了初步但不确定的证据，表明与污水有关的细菌，产气荚膜梭菌，正在受影响地区觅食的威德尔海豹身上定植。假设（!）威德尔海豹被与污水有关的细菌和病毒占领，与污水有关的细菌正在与本地物种交换DNA，(3)与污水有关的细菌和病毒正在进入麦克默多站的饮用水系统；(4)目前用于监测麦克默多站海洋和饮用水微生物质量的方法低估了与它们各自接触和/或摄入相关的风险。这些假设将通过使用分子技术（例如脉冲场凝胶电泳、聚合酶链式反应）、基因转移实验的原位微环境、更敏感的基于培养的技术来确定海水、沉积物和海豹粪便和粪便中的污水污染程度，以及迄今为止对饮用水分配系统进行最广泛的微生物调查来解决。这项工作的一个主要重点将是确定污水中存在的相同的产气荚膜梭菌基因型是否与从海豹粪便和粪便、海水和沉积物以及饮用水样本中分离出来的基因型有关。这种方法已在其他系统中用于建立细菌源与定植（受感染）宿主之间的直接流行病学联系。总的来说，这项研究的结果将提供资料，可用于监测和设计麦克默多站附近沿海水域和南极洲周围其他沿海水域的补救工作，这些水域受到未经处理的人类污水排放的影响。这些数据还将作为麦克默多站计划安装污水处理厂后生态系统恢复研究的基线。

McMurdo Station, Antarctica, has been releasing macerated, untreated human sewage into the pristine marine waters off the coast for years. The marine waters impacted by the sewage plume sometimes extend to the drinking water intake at Intake Jetty. Additionally, deposit feeding invertebrates located within the area impacted by the sewage effluents have been show to not only assimilate the nutrients associated with the sewage but also exhibit increased mean body and organ sizes. A previous study found preliminary, but inconclusive, evidence that the sewage-associated bacterium, clostridium perfringens, was colonizing Weddell seals feeding in the impacted area. It is hypothesized that (!) Weddell seals are being colonized by sewage -associated bacteria and viruses, (2) sewage-associated bacteria are exchanging their DNA with indigenous species, potentially altering the procaryotic gene pool of this ecosystem (3) sewage-associated bacteria and viruses are entering the drinking water system at McMurdo Station and (4) the current methods used to monitor the microbiological quality of marine and drinking waters at McMurdo Station are underestimating the risks associated with their respective contact and/or ingestion. These hypotheses will be addressed by using molecular techniques (e.g., pulse field gel electrophoresis, PCR), in situ microcosms for gene transfer experiments, more sensitive culture based techniques for determining the extent of sewage contamination in marine waters, sediments and seal feces and scat and performing the most extensive microbiological survey of the drinking water distribution system to date. A major focus of this work will be determining if the same C. perfringens genotypes that are present in the sewage are related to those isolated from seal feces and scat, marine waters and sediments and drinking water samples. This approach has been used in other systems to establish a direct epidemiological link between a bacterium's source and the colonized (infected) host. In general, the results from this study will provide information which can be used in the monitoring and design of remediation efforts of coastal waters off of McMurdo Station and other coastal waters around Antarctica that are being impacted by the discharge of untreated human sewage. The data will also be as a baseline for studies of ecosystem recovery following the planned installation of a sewage treatment plant at McMurdo Station.