Lai Dengxun, Hedlund Brian P, Xie Wei, Liu Jingjing, Phelps Tommy J, Zhang Chuanlun, Wang Peng
State Key Laboratory of Marine Geology, Tongji University, Shanghai, China.
School of Life Sciences, University of Nevada, Las Vegas, NV, United States.
Front Microbiol. 2020 Nov 5;11:572017. doi: 10.3389/fmicb.2020.572017. eCollection 2020.
Archaea are widespread in marine sediments and play important roles in the cycling of sedimentary organic carbon. However, factors controlling the distribution of archaea in marine sediments are not well understood. Here we investigated benthic archaeal communities over glacial-interglacial cycles in the northern South China Sea and evaluated their responses to sediment organic matter sources and inter-species interactions. Archaea in sediments deposited during the interglacial period Marine Isotope Stage (MIS) 1 (Holocene) were significantly different from those in sediments deposited in MIS 2 and MIS 3 of the Last Glacial Period when terrestrial input to the South China Sea was enhanced based on analysis of the long-chain n-alkane C. The absolute archaeal 16S rRNA gene abundance in subsurface sediments was highest in MIS 2, coincident with high sedimentation rates and high concentrations of total organic carbon. Soil Crenarchaeotic Group (SCG; ) species, the most abundant ammonia-oxidizing archaea in soils, increased dramatically during MIS 2, likely reflecting transport of terrestrial archaea during glacial periods with high sedimentation rates. Co-occurrence network analyses indicated significant association of SCG archaea with benthic deep-sea microbes such as and in MIS 2 and MIS 3, suggesting potential interactions among these archaeal groups. Meanwhile, abundance was positively correlated with total organic carbon (TOC), along with n-alkane C and sedimentation rate, indicating that may be particularly important in processing of organic carbon in deep-sea sediments. Collectively, these results demonstrate that the composition of heterotrophic benthic archaea in the South China Sea may be influenced by terrestrial organic input in tune with glacial-interglacial cycles, suggesting a plausible link between global climate change and microbial population dynamics in deep-sea marine sediments.
古菌广泛存在于海洋沉积物中，在沉积有机碳的循环中发挥着重要作用。然而，控制海洋沉积物中古菌分布的因素尚未得到充分了解。在此，我们研究了南海北部冰期 - 间冰期旋回中的底栖古菌群落，并评估了它们对沉积物有机质来源和种间相互作用的响应。基于对长链正构烷烃C的分析，间冰期海洋同位素阶段（MIS）1（全新世）期间沉积的沉积物中的古菌与末次冰期MIS 2和MIS 3期间沉积的沉积物中的古菌有显著差异，当时南海的陆源输入增强。地下沉积物中古菌16S rRNA基因的绝对丰度在MIS 2中最高，这与高沉积速率和高总有机碳浓度一致。土壤泉古菌组（SCG； ）物种是土壤中最丰富的氨氧化古菌，在MIS 2期间急剧增加，这可能反映了冰期期间高沉积速率下陆地古菌的传输。共现网络分析表明，SCG古菌在MIS 2和MIS 3中与底栖深海微生物如 和 有显著关联，表明这些古菌类群之间可能存在相互作用。同时， 丰度与总有机碳（TOC）、正构烷烃C和沉积速率呈正相关，表明 可能在深海沉积物中有机碳的处理过程中特别重要。总体而言，这些结果表明，南海异养底栖古菌的组成可能受陆源有机输入的影响，并与冰期 - 间冰期旋回相协调，这表明全球气候变化与深海海洋沉积物中的微生物种群动态之间存在合理的联系。
