Community, Distribution, and Ecological Roles of Estuarine Archaea

Abstract

Archaea are diverse and ubiquitous prokaryotes present in both extreme and moderate environments. Estuaries, serving as links between the land and ocean, harbor numerous microbes that are relatively highly active because of massive terrigenous input of nutrients. Archaea account for a considerable portion of the estuarine microbial community. They are diverse and play key roles in the estuarine biogeochemical cycles. Ammonia-oxidizing archaea (AOA) are an abundant aquatic archaeal group in estuaries, greatly contributing estuarine ammonia oxidation. Bathyarchaeota are abundant in sediments, and they may involve in sedimentary organic matter degradation, acetogenesis, and, potentially, methane metabolism, based on genomics. Other archaeal groups are also commonly detected in estuaries worldwide. They include Euryarchaeota , and members of the DPANN and Asgard archaea. Based on biodiversity surveys of the 16S rRNA gene and some functional genes, the distribution and abundance of estuarine archaea are driven by physicochemical factors, such as salinity and oxygen concentration. Currently, increasing amount of genomic information for estuarine archaea is becoming available because of the advances in sequencing technologies, especially for AOA and Bathyarchaeota , leading to a better understanding of their functions and environmental adaptations. Here, we summarized the current knowledge on the community composition and major archaeal groups in estuaries, focusing on AOA and Bathyarchaeota . We also highlighted the unique genomic features and potential adaptation strategies of estuarine archaea, pointing out major unknowns in the field and scope for future research.

High Abundance of Thaumarchaeota Found in Deep Metamorphic Subsurface in Eastern China

“…To our knowledge, prior to our study, a high relative abundance of Thaumarchaeota has only been reported in rock samples from the Deccan Traps in India [ 26 ] and water samples from gold mines in South Africa [ 27 ]. Some members of Thaumarchaeota are not AOA, consisting of anaerobes or facultative aerobes [ 49 , 50 ]. A phylogenetic tree based on the 16S rRNA gene was constructed to inspect the relationship of these thaumarchaeotal sequences from the deep subsurface with non-AOA sequences ( Figure 3 ).…”

Distinct Features of Sedimentary Archaeal Communities in Hypoxia and Non-Hypoxia Regions off the Changjiang River Estuary

“…Ca. Nitrosopumilus are the most prevalent AOA found in a wide variety of environments ( 8 , 11 , 47 , 48 ). They contribute significantly to aerobic ammonia oxidation and are involved in a wide variety of biochemical cycles ( 16 , 49 , 50 ).…”

“…Although only few archaeal species are cultured to date, the cultivation-independent techniques, including metagenomics and single-cell genomics have offered a more comprehensive picture of archaea diversity, metabolic potential, and ecological significance ( 6 , 7 ). For example, two archaeal phyla, Thaumarchaeota and Bathyarchaeota , are repeatedly detected in estuarine and coastal surface sediments, where they play a significant role in the sedimentary nitrogen and carbon cycles, respectively ( 8 – 11 ). Marine sediments are one of the greatest reservoirs of prokaryotic cells ( 5 , 12 ).…”

Prevalence of microplastics, antibiotic resistant genes and microplastic associated biofilms in estuary - A review

“…Estuaries, serving as links between land and ocean, harbour numerous microbes that are relatively highly active because of the massive terrigenous input of nutrients [115]. Furthermore, ARGs such as tetracycline, sulfonamides, AmpC β -lactamase, and the class-1 integron gene were found in the leachate treatment plant effluent [116].…”