Influence of Igneous Basement on Deep Sediment Microbial Diversity on the Eastern Juan de Fuca Ridge Flank

Frontiers in Microbiology

Beth N. Orcutt¹  Mark A. Lever²  Jessica M. Labonté⁴  Katrina J. Edwards⁵ 

[1] Bigelow Laboratory for Ocean Sciences, East BoothbayME, United States;Center for Geomicrobiology, Aarhus UniversityAarhus, Denmark;Department of Biological Sciences, University of Southern California, Los AngelesCA, United States;;Department of Marine Biology, Texas A&Environmental Systems Science, ETH ZürichZurich, Switzerland;M University at Galveston, GalvestonTX, United States;

关键词: deep biosphere;    IODP;    basalt;    sediment;    Census of Deep Life;   

DOI  :  10.3389/fmicb.2017.01434

来源: DOAJ

【 摘 要 】

Microbial communities living in deeply buried sediment may be adapted to long-term energy limitation as they are removed from new detrital energy inputs for thousands to millions of years. However, sediment layers near the underlying oceanic crust may receive inputs from below that influence microbial community structure and/or activity. As part of the Census of Deep Life, we used 16S rRNA gene tag pyrosequencing on DNA extracted from a spectrum of deep sediment-basement interface samples from the subsurface of the Juan de Fuca Ridge flank (collected on IODP Expedition 327) to examine this possible basement influence on deep sediment communities. This area experiences rapid sedimentation, with an underlying basaltic crust that hosts a dynamic flux of hydrothermal fluids that diffuse into the sediment. Chloroflexi sequences dominated tag libraries in all sediment samples, with variation in the abundance of other bacterial groups (e.g., Actinobacteria, Aerophobetes, Atribacteria, Planctomycetes, and Nitrospirae). These variations occur in relation to the type of sediment (clays versus carbonate-rich) and the depth of sample origin, and show no clear connection to the distance from the discharge outcrop or to basement fluid microbial communities. Actinobacteria-related sequences dominated the basalt libraries, but these should be viewed cautiously due to possibilities for imprinting from contamination. Our results indicate that proximity to basement or areas of seawater recharge is not a primary driver of microbial community composition in basal sediment, even though fluids diffusing from basement into sediment may stimulate microbial activity.

【 授权许可】

Unknown