Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
Environ Microbiol. 2011 Dec;13(12):3219-34. doi: 10.1111/j.1462-2920.2011.02544.x. Epub 2011 Sep 6.
Abyssal marine sediments cover a large proportion of the ocean floor, but linkages between their microbial community structure and redox stratification have remained poorly constrained. This study compares the downcore gradients in microbial community composition to porewater oxygen and nitrate concentration profiles in an abyssal marine sediment column in the South Pacific Ocean. Archaeal 16S rRNA clone libraries showed a stratified archaeal community that changed from Marine Group I Archaea in the aerobic and nitrate-reducing upper sediment column towards deeply branching, uncultured crenarchaeotal and euryarchaeotal lineages in nitrate-depleted, anaerobic sediment horizons. Bacterial 16S rRNA clone libraries revealed a similar shift on the phylum and subphylum level within the bacteria, from a complex community of Alpha-, Gamma- and Deltaproteobacteria, Actinobacteria and Gemmatimonadetes in oxic surface sediments towards uncultured Chloroflexi and Planctomycetes in the anaerobic sediment column. The distinct stratification of largely uncultured bacterial and archaeal groups within the oxic and nitrate-reducing marine sediment column provides initial constraints for their microbial habitat preferences.
深海沉积物覆盖了海洋底部的很大一部分，但它们的微生物群落结构与氧化还原分层之间的联系仍然知之甚少。本研究比较了南太平洋深海沉积物柱中微生物群落组成与孔隙水氧和硝酸盐浓度剖面的垂向梯度。古菌 16S rRNA 克隆文库显示，古菌群落呈分层分布，从好氧和硝酸盐还原的上层沉积物柱中的海洋 I 组古菌逐渐变为硝酸盐耗尽、厌氧沉积物层中分枝很深的未培养古菌和广古菌谱系。细菌 16S rRNA 克隆文库在细菌门和亚门下也揭示了类似的变化，从好氧表层沉积物中复杂的α-、γ-和δ-变形菌、放线菌和芽单胞菌门群落逐渐变为厌氧沉积物柱中未培养的绿弯菌门和浮霉菌门。在好氧和硝酸盐还原的海洋沉积物柱中，大部分未培养的细菌和古菌群体的明显分层为它们的微生物栖息地偏好提供了初步的限制。
