Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA 23062, USA.
Environ Microbiol. 2011 Feb;13(2):378-90. doi: 10.1111/j.1462-2920.2010.02335.x. Epub 2010 Sep 16.
Aggregates and zooplankton may provide refuge for aquatic bacteria against external hazards. The ability of attached bacteria to survive and recover from stressors commonly used for water treatment was tested in the laboratory. Without zooplankton or aggregates, both UV and ozone significantly reduced abundance of free-living bacteria in both freshwater and marine medium. The presence of zooplankton carcasses and aggregates, however, allowed some of the attached bacteria to survive and recover quickly within 3 days. Heat exposure was the least effective as both free-living and attached bacteria were able to recover quickly. Selective survival of bacterial phylotypes led to large changes in bacterial community composition after stress exposures, and some of the bacteria that recovered belonged to groups with known pathogens. This study demonstrates that zooplankton and aggregates protected various aquatic bacteria from external stressors, and organic remains generated from zooplankton and aggregates after stress exposure even enabled the surviving bacteria to quickly regrow and subsequently be released into the surrounding water. Hence, water disinfection treatments that overlooked the potential persistence of bacteria associated with organisms and aggregates may not be effective in preventing the spread of undesirable bacteria.
聚集物和浮游动物可为水生细菌提供抵御外部危害的避难所。本研究在实验室条件下测试了附着细菌在承受水处理常用压力源时的生存和恢复能力。在没有浮游动物或聚集物的情况下，淡水和海水中的游离细菌数量在紫外线和臭氧的作用下均显著减少。然而，浮游动物尸体和聚集物的存在使部分附着细菌能够在 3 天内快速生存和恢复。热暴露的效果最差，因为游离和附着细菌都能迅速恢复。在压力暴露后，细菌的选择性存活导致了细菌群落组成的巨大变化，并且一些恢复的细菌属于已知病原体的群组。本研究表明，浮游动物和聚集物保护了各种水生细菌免受外部应激源的影响，而浮游动物和聚集物在应激暴露后产生的有机残留物甚至使存活的细菌能够快速生长，并随后释放到周围的水中。因此，忽视与生物体和聚集物相关的细菌潜在持久性的水消毒处理可能无法有效防止不良细菌的传播。
