LaMontagne Michael G, Zhang Yan, Guillen George J, Gentry Terry J, Allen Michael S
Department of Biology and Biotechnology, University of Houston - Clear Lake, Houston, TX, United States.
Department of Microbiology, Immunology and Genetics, University of North Texas Health Science Center, Fort Worth, TX, United States.
Front Microbiol. 2022 Jun 14;13:875234. doi: 10.3389/fmicb.2022.875234. eCollection 2022.
Extreme weather events can temporarily alter the structure of coastal systems and generate floodwaters that are contaminated with fecal indicator bacteria (FIB); however, every coastal system is unique, so identification of trends and commonalities in these episodic events is challenging. To improve our understanding of the resilience of coastal systems to the disturbance of extreme weather events, we monitored water quality, FIB at three stations within Clear Lake, an estuary between Houston and Galveston, and three stations in bayous that feed into the estuary. Water samples were collected immediately before and after Hurricane Harvey (HH) and then throughout the fall of 2017. FIB levels were monitored by culturing and Microbial community structure was profiled by high throughput sequencing of PCR-amplified 16S rRNA gene fragments. Water quality and FIB data were also compared to historical data for these water body segments. Before HH, salinity within Clear Lake ranged from 9 to 11 practical salinity units (PSU). Immediately after the storm, salinity dropped to < 1 PSU and then gradually increased to historical levels over 2 months. Dissolved inorganic nutrient levels were also relatively low immediately after HH and returned, within a couple of months, to historical levels. FIB levels were elevated immediately after the storm; however, after 1 week, levels had decreased to what would be acceptable levels for freshwater. levels collected several weeks after the storm were within the range of historical levels. Microbial community structure shifted from a system dominated by sp. before HH to a system dominated by and immediately after. Several sequences observed only in floodwater showed similarity to sequences previously reported for samples collected following Hurricane Irene. These changes in beta diversity corresponded to salinity and nitrate/nitrite concentrations. Differential abundance analysis of metabolic pathways, predicted from 16S sequences, suggested that pathways associated with virulence and antibiotic resistance were elevated in floodwater. Overall, these results suggest that floodwater generated from these extreme events may have high levels of fecal contamination, antibiotic resistant bacteria and bacteria rarely observed in other systems.
极端天气事件可暂时改变沿海系统的结构，并产生被粪便指示菌（FIB）污染的洪水；然而，每个沿海系统都是独特的，因此识别这些偶发事件中的趋势和共性具有挑战性。为了更好地理解沿海系统对极端天气事件干扰的恢复力，我们在克利尔湖（位于休斯顿和加尔维斯顿之间的一个河口）内的三个站点以及流入该河口的河湾中的三个站点监测了水质和FIB。在哈维飓风（HH）来临之前和之后立即采集水样，然后在2017年秋季期间持续采集。通过培养监测FIB水平，并通过对PCR扩增的16S rRNA基因片段进行高通量测序来分析微生物群落结构。还将水质和FIB数据与这些水体区域的历史数据进行了比较。在HH来临之前，克利尔湖内的盐度范围为9至11实用盐度单位（PSU）。风暴过后，盐度立即降至<1 PSU，然后在2个月内逐渐回升至历史水平。HH过后，溶解无机养分水平也相对较低，并在几个月内恢复到历史水平。风暴过后，FIB水平立即升高；然而，1周后，其水平已降至淡水可接受的水平。风暴过后几周采集的水平处于历史水平范围内。微生物群落结构从HH来临之前以 属为主导的系统转变为之后立即以 属和 属为主导的系统。仅在洪水中观察到的几个序列与之前报道的艾琳飓风过后采集的样本序列相似。β多样性的这些变化与盐度和硝酸盐/亚硝酸盐浓度相对应。根据16S序列预测的代谢途径差异丰度分析表明，与毒力和抗生素抗性相关的途径在洪水中有所升高。总体而言，这些结果表明，这些极端事件产生的洪水可能含有高水平的粪便污染、抗生素抗性细菌以及在其他系统中很少观察到的细菌。
