USAP-DC

The McMurdo Dry Valleys in Antarctica are recognized as being the driest, coldest and probably one of the harshest environments on Earth. In addition to the lack of water, the biota in the valleys face a very limited supply of nutrients such as nitrogen compounds - necessary for protein synthesis. The glacial streams of the Dry Valleys have extensive cyanobacterial (blue green algae) mats that are a major source of carbon and nitrogen compounds to biota in this region. While cyanobacteria in streams are important as a source of these compounds, other non-photosynthetic bacteria also contribute a significant fraction (~50%) of fixed nitrogen compounds to valley biota. This research effort will involve an examination of exactly which non-phototrophic bacteria are involved in nitrogen fixation and what environmental factors are responsible for controlling nitrogen fixation by these microbes. This work will resolve the environmental factors that control the activity, abundance and diversity of nitrogen-fixing microbes across four of the McMurdo Dry Valleys. This will allow for comparisons among sites of differing latitude, temperature, elevation and exposure to water. These results will be integrated into a landscape wetness model that will help determine the impact of both cyanobacterial and non-photosynthetic nitrogen fixing microorganisms in this very harsh environment.

The Dry Valleys in many ways resemble the Martian environment, and understanding the primitive life and very simple nutrient cycling in the Dry Valleys has relevance for understanding how life might have once existed on other planets. Furthermore, the study of microbes from extreme environments has resulted in numerous biotechnological applications such as the polymerase chain reaction for amplifying DNA and mechanisms for freeze resistance in agricultural crops. Thus, this research should yield insights into how biota survive in extreme environments, and these insights could lead to other commercial applications.

Person	Role
Cary, Stephen	Investigator and contact

Antarctic Organisms and Ecosystems

Award # 1246292

USAP-1246292_1

Deployment	Type
Taylor Valley Camp	field camp

None in the Database

Repository	Title (link)	Format(s)	Status
NCBI GenBank	Importance of Heterotrophic and Phototrophic N2 Fixation in the McMurdo Dry Valleys	None	exists
EMBL	Microbial population dynamics along a terrestrial wetted gradient	None	exists
NCBI GenBank	Microbial community composition of transiently wetted Antarctic Dry Valley soils.	None	exist
EMBL	Microbial population dynamics along a terrestrial Antarctic moisture gradient	None	exist
KNB	Carbon-fixation rates and associated microbial communities residing in arid and ephemerally wet Antarctic Dry Valley soils	None	exist
NCBI GenBank	Carbon-fixation rates and associated microbial communities	None	exist

1. Chown, S.L., Clarke, A., Fraser, C.I., Cary, S.C. Moon, K.L., McGeoch, M.A.. "The changing form of Antarctic biodiversity," Nature, v.522, 2015, p. 431. (doi:10.1038/nature14505 )
2. Fierer N and Cary, SC. "The importance of sample archiving in microbial ecology," Nature Reviews Microbiology, v.12, 2014, p. 789. (doi:10.1038/nrmicro3382)
3. Fierer, N., Cary, S.C.. "Don't let microbial samples perish," Nature, v.512, 2014, p. 253 (doi:10.1038/512253b)
4. Niederberger TD, Sohm JA, Gunderson TE, Parker AE, Tirindelli J, Capone DG, Carpenter EJ and Cary SC. "Microbial community composition of transiently wetted Antarctic Dry Valley soils," Frontiers Microbiology, v.6, 2015. (doi:10.3389/fmicb.2015.00009)
5. Niederberger TD, Sohm JA, Gunderson TE, Parker AE, Tirindelli J, Capone DG, Carpenter EJ and Cary SC. "Carbon-fixation rates and associated microbial communities residing in arid and ephemerally wet Antarctic Dry Valley soils," Frontiers Microbiology, 2015. (doi:10.3389/fmicb.2015.01347)
6. Niederberger, T. D., Sohm, J. A., Gunderson, T. E., Parker, A. E., Tirindelli, J., Capone, D. G., Carpenter, E. J. & Cary, S. C.. "Microbial community composition of transiently wetted Antarctic Dry Valley soils.," Frontiers in microbiology, v.6, 2015. (doi:10.3389/fmicb.2015.00009 )
7. Archer SDJ, McDonald IR, Herbold CW, Lee CK, Niederberger TS, Cary S.C. "Temporal, regional and geochemical drivers of microbial community variation in the melt ponds of the Ross Sea region, Antarctica.," Polar Biology, v.39, 2015. (doi:10.1007/s00300-015-1780-2)
8. Coyne, K. J., Parker, A. E., Lee, C. K., Sohm, J. A., Kalmbach, A., Gunderson, T., … Cary, S. C. (2020). The distribution and relative ecological roles of autotrophic and heterotrophic diazotrophs in the McMurdo Dry Valleys, Antarctica. FEMS Microbiology Ecology, 96(3). (doi:10.1093/femsec/fiaa010)