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Bridging microbial diversity and chemodiversity of dissolved organic matter to better constrain processes in biogeochemical cycles
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Insight into microbial metabolisms in the deepest seawater on earth Tuesday 8th @ 1110-1130, Concert Hall Jiwen Liu, Ocean University of China Yanfen Zheng, Ocean University of China Jiwei Tian, Ocean University of China Xiao-Hua Zhang* , Ocean University of China Presenter Email: xhzhang@ouc.edu.cn |
The Mariana Trench is the deepest place on Earth, reaching a depth of ~11,000 m at the Challenger Deep. Its hadal waters (>6,000 m) constitute 45% of the vertical depth gradient1. Recent studies demonstrate that hadal waters harbor distinct microbial planktonic communities2,3. However, the ecological capacity of microbial communities within the hadal zone are poorly understood. Here we show an abrupt increase in the relative abundance of hydrocarbon-degrading bacteria from waters at 9,600 to >10,000 m in the Challenger deep of the Mariana Trench. These bacteria were represented mainly by Oleibacter, Thalassolituus and Alcanivorax (~25% of the metagenome), all of which include species that can consume aliphatic hydrocarbons4-7. This community shift towards hydrocarbon degraders was accompanied by an enrichment for genes involved in alkane degradation. Correspondingly, two Alcanivorax species that were isolated from 10,400 m, in addition to a reference Oleibacter strain, were able to efficiently degrade a wide range (C11-C36) of n-alkanes. n-alkanes (dominated by medium-chain lengths of C15-C23), derived from complex sources, were detected in both the sinking particles and surface sediment (~10,910 m), suggesting that these compounds support this hydrocarbon-degrading bacterial population. Overall, these results reveal an unexpected and unique biosphere dominated by hydrocarbon catabolism in the deepest seawater on earth, shedding new light on biological processes in extreme environments. |
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