Microbial mat communities along an oxygen gradient in a pere

Details of Research

TitleMicrobial mat communities along an oxygen gradient in a perennially ice-covered Antarctic lakeAbstractLake Fryxell is a perennially ice-covered lake in the McMurdo Dry Valleys, Antarctica, with a sharp oxycline in a water column that is density stabilized by a gradient in salt concentration. Dissolved oxygen falls from 20 mg liter-1 to undetectable over one vertical meter from 8.9-to 9.9-m depth. We provide the first description of the benthic mat community that falls within this oxygen gradient on the sloping floor of the lake, using a combination of micro- and macroscopic morphological descriptions, pigment analysis, and 16S rRNA gene bacterial community analysis. Our work focused on three macroscopic mat morphologies that were associated with different parts of the oxygen gradient: (i) "cuspate pinnacles" in the upper hyperoxic zone, which displayed complex topography and were dominated by phycoerythrin-rich cyanobacteria attributable to the genus Leptolyngbya and a diverse but sparse assemblage of pennate diatoms; (ii) a less topographically complex "ridge-pit" mat located immediately above the oxic-anoxic transition containing Leptolyngbya and an increasing abundance of diatoms; and (iii) flat prostrate mats in the upper anoxic zone, dominated by a green cyanobacterium phylogenetically identified as Phormidium pseudopriestleyi and a single diatom, Diadesmis contenta. Zonation of bacteria was by lake depth and by depth into individual mats. Deeper mats had higher abundances of bacteriochlorophylls and anoxygenic phototrophs, including Chlorobi and Chloroflexi. This suggests that microbial communities form assemblages specific to niche-like locations. Mat morphologies, underpinned by cyanobacterial and diatom composition, are the result of local habitat conditions likely defined by irradiance and oxygen and sulfide concentrations. Copyright 2016, American Society for Microbiology.AcknowledgementsThe 16S rRNA sequence analysis was performed under the MiSeq Competition MkIIm by New Zealand Genome Limited and with the assistance of Patrick Biggs (NZGL) for MiSeq sequence processing. We thank Alexander Forrest for the loan of the Brancker CTD. We are grateful to three anonymous reviewers for their comments and suggestions. We thank the Antarctica New Zealand and U.S. Antarctic Program for logistics support and facilities, and we also thank Anthea Fisher (Antarctica New Zealand) for her assistance with the field work. The work was supported in part by NSF grant 1115245 to P.T.D., NASA Astrobiology grant NN13AI60G to D.Y.S., and a MiSeq Competition MkIIm by New Zealand Genome limited award to I.H. and A.D.J. FUNDING INFORMATION NSF provided funding to Peter T. Doran under grant number 1115245. NASA provided funding to Dawn Sumner under grant number NN13AI60G.Funding Details1115245, NSF, Norsk Sykepleierforbund; NN13AI60G, NASA, Norsk Sykepleierforbund

Details

1st AuthorJungblut, A.AuthorJungblut, A.Hawes, I.Mackey, T.Krusor, M.Doran, P.Sumner, D.Eisen, J.Hillman, C.Goroncy, A.Year2016JournalApplied and Environmental MicrobiologyVolume82Number2Pages620-630DOI10.1128/AEM.02699-15URLhttps://www.scopus.com/inward/recor.....e55228ee03fa7a1499d509f66KeywordsAlgaeBacteriaLakesMicroorganismsOxygenPhytoplanktonRNA, Bacterial community analysisBacteriochlorophyllsComplex topographiesMcmurdo dry valleysMicrobial communitiesMorphological descriptionSalt concentrationSulfide concentration, Dissolved oxygen, BacillariophytaBacteria (microorganisms)ChlorobiChloroflexiChloroflexi (class)CyanobacteriaDiadesmis contentaLeptolyngbyaPhormidium, rank5

Other

TypeArticleCitationJungblut, A., Hawes, I., Mackey, T., Krusor, M., Doran, P., Sumner, D., Eisen, J., Hillman, C. and Goroncy, A. (2016). Microbial mat communities along an oxygen gradient in a perennially ice-covered Antarctic lake. Applied and Environmental Microbiology, 82(2): 620-630IdentifierJungblut2016Relevancerank5

Linked To

Author