Wetland Research and Training Centre, Chilika Development Authority, Balugaon 752030, Odisha, India.
Center for Climate Change Adaptation, National Institute for Environmental Studies, Tsukuba 305-8506, Japan.
Sci Total Environ. 2020 Mar 1;706:135709. doi: 10.1016/j.scitotenv.2019.135709. Epub 2019 Nov 23.
Benthic Archaea play a crucial role in the biogeochemical cycles and food webs, however, their spatiotemporal distribution and environmental drivers are not well investigated in brackish sediments. The composition and abundances of benthic archaeal communities were examined from a coastal lagoon; Chilika (India) which is experiencing an intense pressure from anthropogenic and natural factors. High-throughput sequencing of 16S rRNA genes revealed that sediment (n = 96) archaeal communities were largely composed of Crenarchaeota (18.76%), Euryarchaeota (18.34%), Thaumarchaeota (13.45%), Woesearchaeota (10.05%), and Pacearchaeota (4.21%). Archaeal taxa affiliated to methanogens, sulfate-reducers, and ammonia-oxidizers were detected suggesting that carbon, sulfur, and nitrogen cycles might be prominent in benthic sediments. Salinity, total organic carbon, available nitrogen, available phosphorus, macrophyte (Phragmites karka) and inter-taxa relationships between community members and with bacterial communities played steering roles in structuring the archaeal communities. Marine sites with mesohaline-polyhaline regime were dominated by Nitrosopumilus and Thaumarchaeota. In contrast, riverine sites with oligohaline regime demonstrated a higher abundance of Thermoprotei. Macrophyte dominated zones were enriched in Methanomicrobia and Methanobacteria in their rhizosphere sediments, whereas, bulk (un-vegetated) sediments were dominated by Nitrosopumilus. Spatial patterns in archaeal communities demonstrated 'distance-decay' patterns which were correlated with changes in physicochemical factors over geographical distances. Heterotrophic microbial communities showed much higher metabolic diversity and activity in their carbon utilization profiles in rhizosphere sediments than the bulk sediments. This baseline information on benthic archaea and their environmental drivers would be useful to assess the impact of anthropogenic and natural pressures on these communities and associated biogeochemical cycles.
底栖古菌在生物地球化学循环和食物网中起着至关重要的作用，然而，它们在咸淡水沉积物中的时空分布和环境驱动因素还没有得到很好的研究。本研究从一个受到人为和自然因素强烈压力的沿海泻湖——印度奇利卡湖（Chilika），调查了底栖古菌群落的组成和丰度。通过高通量测序 16S rRNA 基因，发现沉积物（n=96）古菌群落主要由广古菌门（Crenarchaeota）（18.76%）、古菌门（Euryarchaeota）（18.34%）、泉古菌门（ Thaumarchaeota）（13.45%）、沃氏古菌门（ Woesearchaeota）（10.05%）和古菌门（ Pacearchaeota）（4.21%）组成。检测到与产甲烷菌、硫酸盐还原菌和氨氧化菌相关的古菌类群，表明碳、硫和氮循环可能在底栖沉积物中很突出。盐度、总有机碳、有效氮、有效磷、大型植物（Phragmites karka）以及群落成员之间和与细菌群落之间的种间关系，在古菌群落的结构形成中发挥了主导作用。具有中盐-高盐生境的海洋地点主要由硝化螺旋菌属和泉古菌门主导。相比之下，低盐生境的河流地点则表现出较高的耐热古菌属丰度。大型植物占主导地位的区域在根际沉积物中富含甲烷微菌科和甲烷杆菌科，而在未植被的沉积物中则主要由硝化螺旋菌属主导。古菌群落的空间格局表现出“距离衰减”模式，与地理距离上理化因子的变化相关。在根际沉积物中，异养微生物群落的碳利用谱显示出更高的代谢多样性和活性，而在未植被的沉积物中则较低。这些关于底栖古菌及其环境驱动因素的基础信息将有助于评估人为和自然压力对这些群落和相关生物地球化学循环的影响。
