Smithsonian Tropical Research Institute, Panama City, Panama.
Department of Civil and Environmental Engineering, University of Massachusetts at Amherst, Amherst, MA, United States of America.
PeerJ. 2024 Sep 6;12:e18007. doi: 10.7717/peerj.18007. eCollection 2024.
Monitoring of stream water quality is a key element of water resource management worldwide, but methods that are commonly used in temperate habitats may not be appropriate in humid tropical systems. We assessed the influence of four land uses on microbial water quality in 21 streams in the Panama Canal Watershed over a one-year period, using a common culture-based fecal indicator test and 16S rDNA metabarcoding. Each stream was located within one of four land uses: mature forest, secondary forest, silvopasture, and traditional cattle pasture. Culturing detected total coliforms and across all sites but found no significant differences in concentrations between land uses. However, 16S rDNA metabarcoding revealed variability in the abundance of coliforms across land uses and several genera that can cause false positives in culture-based tests. Our results indicate that culture-based fecal indicator bacteria tests targeting coliforms may be poor indicators of fecal contamination in Neotropical oligotrophic streams and suggest that tests targeting members of the Bacteroidales would provide a more reliable indication of fecal contamination.
对河流水质进行监测是全球水资源管理的重要内容,但在温带生境中常用的方法可能并不适用于潮湿的热带系统。我们在巴拿马运河流域的 21 条溪流中,利用常见的基于培养的粪便指示测试和 16S rDNA 代谢组学,在一年的时间里评估了四种土地利用方式对微生物水质的影响。每条溪流都位于四种土地利用方式之一:成熟森林、次生林、林牧和传统的牛牧场。培养法检测到了所有地点的总大肠菌群和 ,但在土地利用方式之间未发现浓度存在显著差异。然而,16S rDNA 代谢组学揭示了土地利用方式之间大肠菌群丰度的可变性,以及一些在基于培养的测试中可能会产生假阳性的属。我们的结果表明,针对大肠菌群的基于培养的粪便指示细菌测试可能是新热带贫营养溪流中粪便污染的不良指示物,并表明针对拟杆菌门成员的测试将提供更可靠的粪便污染指示。