TY - JOUR
T1 - Transient exposure to oxygen or nitrate reveals ecophysiology of fermentative and sulfate-reducing benthic microbial populations
AU - Saad, Sainab
AU - Bhatnagar, Srijak
AU - Tegetmeyer, Halina E.
AU - Geelhoed, Jeanine S.
AU - Strous, Marc
AU - Ruff, S. Emil
N1 - Funding Information:
We gratefully acknowledge Brandon Kwee Boon Seah for support with data processing, Miriam Sadowski, Veronika Will and Gunter Wegener for assistance with AOM enrichment cultures, and Kirsten Imhoff for sulfide measurements. We thank Fridjof Boness for help with nomenclature as well as Katrin Knittel, Emmo Hamann and Manuel Kleiner for discussions. Z.B. was supported by a Yousef Jameel Scholarship. S.E.R. was supported by an AITF/Eyes High Postdoctoral Fellowship. The research was funded by an ERC starting grant (MASEM, 242635), a Campus Alberta Innovation Chair and a NSERC Discovery grant awarded to M.S., the German Federal State North Rhine Westphalia and the Max Planck Society. The authors declare no conflict of interest.
Publisher Copyright:
© 2017 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd
PY - 2017/12
Y1 - 2017/12
N2 - For the anaerobic remineralization of organic matter in marine sediments, sulfate reduction coupled to fermentation plays a key role. Here, we enriched sulfate-reducing/fermentative communities from intertidal sediments under defined conditions in continuous culture. We transiently exposed the cultures to oxygen or nitrate twice daily and investigated the community response. Chemical measurements, provisional genomes and transcriptomic profiles revealed trophic networks of microbial populations. Sulfate reducers coexisted with facultative nitrate reducers or aerobes enabling the community to adjust to nitrate or oxygen pulses. Exposure to oxygen and nitrate impacted the community structure, but did not suppress fermentation or sulfate reduction as community functions, highlighting their stability under dynamic conditions. The most abundant sulfate reducer in all cultures, related to Desulfotignum balticum, appeared to have coupled both acetate- and hydrogen oxidation to sulfate reduction. We describe a novel representative of the widespread uncultured candidate phylum Fermentibacteria (formerly candidate division Hyd24-12). For this strictly anaerobic, obligate fermentative bacterium, we propose the name ‘USabulitectum silens’ and identify it as a partner of sulfate reducers in marine sediments. Overall, we provide insights into the function of fermentative, as well as sulfate-reducing microbial communities and their adaptation to a dynamic environment.
AB - For the anaerobic remineralization of organic matter in marine sediments, sulfate reduction coupled to fermentation plays a key role. Here, we enriched sulfate-reducing/fermentative communities from intertidal sediments under defined conditions in continuous culture. We transiently exposed the cultures to oxygen or nitrate twice daily and investigated the community response. Chemical measurements, provisional genomes and transcriptomic profiles revealed trophic networks of microbial populations. Sulfate reducers coexisted with facultative nitrate reducers or aerobes enabling the community to adjust to nitrate or oxygen pulses. Exposure to oxygen and nitrate impacted the community structure, but did not suppress fermentation or sulfate reduction as community functions, highlighting their stability under dynamic conditions. The most abundant sulfate reducer in all cultures, related to Desulfotignum balticum, appeared to have coupled both acetate- and hydrogen oxidation to sulfate reduction. We describe a novel representative of the widespread uncultured candidate phylum Fermentibacteria (formerly candidate division Hyd24-12). For this strictly anaerobic, obligate fermentative bacterium, we propose the name ‘USabulitectum silens’ and identify it as a partner of sulfate reducers in marine sediments. Overall, we provide insights into the function of fermentative, as well as sulfate-reducing microbial communities and their adaptation to a dynamic environment.
UR - http://www.scopus.com/inward/record.url?scp=85029407820&partnerID=8YFLogxK
U2 - 10.1111/1462-2920.13895
DO - 10.1111/1462-2920.13895
M3 - Journal Article
C2 - 28836729
AN - SCOPUS:85029407820
SN - 1462-2912
VL - 19
SP - 4866
EP - 4881
JO - Environmental Microbiology
JF - Environmental Microbiology
IS - 12
ER -