Potential microbial contamination from drilling lubricants into subseafloor rock cores
<p>International Ocean Discovery Program (IODP) Expedition 357: “Serpentinization and Life” drilled shallow cores into the Atlantis Massif near the Mid-Atlantic Ridge in October 2015 using seabed drills. Serpentinization and other geochemical processes occurring within the Atlantis Massif rele...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2021-04-01
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| Series: | Scientific Drilling |
| Online Access: | https://sd.copernicus.org/articles/29/49/2021/sd-29-49-2021.pdf |
| Summary: | <p>International Ocean Discovery Program (IODP) Expedition 357: “Serpentinization and Life” drilled shallow cores into the Atlantis
Massif near the Mid-Atlantic Ridge in October 2015 using seabed drills. Serpentinization and other geochemical processes occurring within the
Atlantis Massif release hydrogen, methane, and other chemicals that can
potentially fuel microorganisms through chemosynthesis. The subseafloor rock
cores collected during IODP Exp. 357 are the first of their kind, meaning
the analysis and interpretation of these samples required new methodologies,
including a specialized approach for distinguishing endemic subsurface
inhabitants from potential contaminants from various sources. Background
samples of various potential contamination sources were collected during
sampling: 109 samples of seawater collected before, during, and after
drilling; 20 samples of greases and oils associated with the drilling
equipment; and samples of the laboratory's ambient air. Despite the
widespread usage of drilling lubricants and the importance of controlling
contamination in drill-core samples for microbiological analyses, no studies
to date have looked at DNA in drilling greases and oils. In this study,
drilling lubricants were analyzed as possible sources of microbial
contamination of subseafloor rock core samples by environmental sequencing
of 16S rRNA genes. We find that microbial signatures from drilling
lubricants are only found in low abundance in seafloor samples (at most a
few percent of total sequence counts), with laboratory contaminants being a
greater source of contamination.</p> |
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| ISSN: | 1816-8957 1816-3459 |