■大肠杆菌是一种常用的粪便指示细菌,用于评估水生环境中的粪便污染水平。然而,广泛的研究报告说,沉积物是肠道外环境中大肠杆菌的天然储库。大肠杆菌可以从沉积物中释放出来,这可能导致在水质监测过程中高估粪便污染水平。因此,我们旨在研究大肠杆菌栖息地从沉积物到水的过渡对其在水柱中丰度的影响。
■这项研究列举了吉隆坡-八打灵再也地区五个城市湖泊的水和沉积物中大肠杆菌的丰度,Selangor州,马来西亚。我们开发了一种新的方法来测量沉积物大肠杆菌向水柱的栖息地转换率,并在考虑了其在水柱中的衰减后,评估了生境转变对水柱中大肠杆菌丰度的影响。
■沉积物中大肠杆菌的丰度范围从检测以下到12,000cfug-1,比水柱(1至2,300cfumL-1)高约一个数量级。生境转换率范围为0.03至0.41h-1。相比之下,大肠杆菌的衰变率范围为0.02至0.16h-1。在大多数情况下(>80%),在我们的研究中,栖息地的转换率高于衰减率。
■我们的研究为大肠杆菌在热带湖泊中的持续存在提供了可能的解释。据我们所知,这是对大肠杆菌从沉积物到水柱的生境转变的首次定量研究。
UNASSIGNED: Escherichia coli is a commonly used faecal indicator bacterium to assess the level of faecal contamination in aquatic habitats. However, extensive studies have reported that sediment acts as a natural reservoir of E. coli in the extraintestinal environment. E. coli can be released from the sediment, and this may lead to overestimating the level of faecal contamination during water quality surveillance. Thus, we aimed to investigate the effects of E. coli habitat transition from sediment to water on its abundance in the water column.
UNASSIGNED: This study enumerated the abundance of E. coli in the water and sediment at five urban lakes in the Kuala Lumpur-Petaling Jaya area, state of Selangor, Malaysia. We developed a novel method for measuring habitat transition rate of sediment E. coli to the water column, and evaluated the effects of habitat transition on E. coli abundance in the water column after accounting for its decay in the water column.
UNASSIGNED: The abundance of E. coli in the sediment ranged from below detection to 12,000 cfu g-1, and was about one order higher than in the water column (1 to 2,300 cfu mL-1). The habitat transition rates ranged from 0.03 to 0.41 h-1. In contrast, the E. coli decay rates ranged from 0.02 to 0.16 h-1. In most cases (>80%), the habitat transition rates were higher than the decay rates in our study.
UNASSIGNED: Our study provided a possible explanation for the persistence of E. coli in tropical lakes. To the best of our knowledge, this is the first quantitative study on habitat transition of E. coli from sediments to water column.