Transient exposure to oxygen or nitrate reveals ecophysiology of fermentative and sulfate-reducing benthic microbial populations
Saad, S.; Bhatnagar, S.; Tegetmeyer, H.E.; Geelhoed, J.S.; Strous, M.; Ruff, S.E. (2017). Transient exposure to oxygen or nitrate reveals ecophysiology of fermentative and sulfate-reducing benthic microbial populations. Environ. Microbiol. 19(12): 4866-4881. https://dx.doi.org/10.1111/1462-2920.13895 In: Environmental Microbiology. Blackwell Scientific Publishers: Oxford. ISSN 1462-2912; e-ISSN 1462-2920, more |   |
| Authors | | Top | - Saad, S.
- Bhatnagar, S.
- Tegetmeyer, H.E.
| - Geelhoed, J.S., more
- Strous, M.
- Ruff, S.E.
| |
| Abstract | SummaryFor the anaerobic remineralization of organic matter inmarine sediments, sulfate reduction coupled to fer-mentation plays a key role. Here, we enriched sulfate-reducing/fermentative communities from intertidalsediments under defined conditions in continuousculture. We transiently exposed the cultures to oxygenor nitrate twice daily and investigated the communityresponse. Chemical measurements, provisionalgenomes and transcriptomic profiles revealed trophicnetworks of microbial populations. Sulfate reducerscoexisted with facultative nitrate reducers or aerobesenabling the community to adjust to nitrate or oxygenpulses. Exposure to oxygen and nitrate impacted thecommunity structure, but did not suppress fermenta-tion or sulfate reduction as community functions,highlighting their stability under dynamic conditions.The most abundant sulfate reducer in all cultures,related toDesulfotignum balticum, appeared to havecoupled both acetate- and hydrogen oxidation to sul-fate reduction. We describe a novel representative ofthe widespread uncultured candidate phylum Fermen-tibacteria (formerly candidate division Hyd24-12). Forthis strictly anaerobic, obligate fermentative bacte-rium,weproposethename‘USabulitectum silens’andidentify it as a partner of sulfate reducers in marinesediments. Overall, we provide insights into the func-tion of fermentative, as well as sulfate-reducingmicrobial communities and their adaptation to adynamic environment. |
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