Gorrasi Susanna, Franzetti Andrea, Brandt Angelika, Minzlaff Ulrike, Pasqualetti Marcella, Fenice Massimiliano
Laboratory of Microbiology, Department of Ecological and Biological Sciences, University of Tuscia, Viterbo, 01100, Italy.
Laboratory of Microbiology, Department of Earth and Environmental Sciences, University of Milano-Bicocca, Milano, 20126, Italy.
Environ Microbiome. 2023 Aug 2;18(1):67. doi: 10.1186/s40793-023-00522-9.
The Kuril-Kamchatka Trench (maximum depth 9604 m), located in the NW Pacific Ocean, is among the top seven deepest hadal trenches. The work aimed to investigate the unexplored abyssal-hadal prokaryotic communities of this fascinating, but underrated environment.
As for the bacterial communities, we found that Proteobacteria (56.1-74.5%), Bacteroidetes (6.5-19.1%), and Actinobacteria (0.9-16.1%) were the most represented bacterial phyla over all samples. Thaumarchaeota (52.9-91.1%) was the most abundant phylum in the archaeal communities. The archaeal diversity was highly represented by the ammonia-oxidizing Nitrosopumilus, and the potential hydrocarbon-degrading bacteria Acinetobacter, Zhongshania, and Colwellia were the main bacterial genera. The α-diversity analysis evidenced that both prokaryotic communities were characterized by low evenness, as indicated by the high Gini index values (> 0.9). The β-diversity analysis (Redundancy Analysis) indicated that, as expected, the depth significantly affected the structure of the prokaryotic communities. The co-occurrence network revealed seven prokaryotic groups that covaried across the abyssal-hadal zone of the Kuril-Kamchatka Trench. Among them, the main group included the most abundant archaeal and bacterial OTUs (Nitrosopumilus OTU A2 and OTU A1; Acinetobacter OTU B1), which were ubiquitous across the trench.
This manuscript represents the first attempt to characterize the prokaryotic communities of the KKT abyssal-hadal zone. Our results reveal that the most abundant prokaryotes harbored by the abyssal-hadal zone of Kuril-Kamchatka Trench were chemolithotrophic archaea and heterotrophic bacteria, which did not show a distinctive pattern distribution according to depth. In particular, Acinetobacter, Zhongshania, and Colwellia (potential hydrocarbon degraders) were the main bacterial genera, and Nitrosopumilus (ammonia oxidizer) was the dominant representative of the archaeal diversity.
位于西北太平洋的千岛-堪察加海沟（最大深度9604米）是世界七大最深的超深渊海沟之一。这项研究旨在调查这个迷人但未得到充分重视的环境中未被探索的深渊-超深渊原核生物群落。
对于细菌群落，我们发现所有样本中变形菌门（56.1 - 74.5%）、拟杆菌门（6.5 - 19.1%）和放线菌门（0.9 - 16.1%）是最主要的细菌门类。奇古菌门（52.9 - 91.1%）是古菌群落中最丰富的门类。古菌多样性主要由氨氧化的亚硝化侏儒菌代表，潜在的烃降解细菌不动杆菌属、中山菌属和科尔韦利亚菌属是主要的细菌属。α多样性分析表明，如高基尼指数值（> 0.9）所示，两个原核生物群落的特征都是均匀度低。β多样性分析（冗余分析）表明，正如预期的那样，深度显著影响原核生物群落的结构。共现网络揭示了在千岛-堪察加海沟深渊-超深渊区域共同变化的七个原核生物组。其中，主要组包括最丰富的古菌和细菌OTU（亚硝化侏儒菌OTU A2和OTU A1；不动杆菌OTU B1），它们在整个海沟中普遍存在。
本手稿首次尝试描述千岛-堪察加海沟深渊-超深渊区域的原核生物群落特征。我们的结果表明，千岛-堪察加海沟深渊-超深渊区域中最丰富的原核生物是化能自养古菌和异养细菌，它们没有呈现出随深度变化的独特分布模式。特别是，不动杆菌属、中山菌属和科尔韦利亚菌属（潜在的烃降解菌）是主要的细菌属，亚硝化侏儒菌属（氨氧化菌）是古菌多样性的主要代表。
