Geothermal Fumarole Subsurface Mt. Erebus, Antarctica

Study Extent

The study encompassed two locations in the permitted area of the Tramway Ridge ASPA 130. http://www.nature.com/ncomms/2014/140520/ncomms4875/fig_tab/ncomms4875_F1.html

Sampling

Sediment samples were collected within the Tramway Ridge Antarctic Specially Protected Area (ASPA 130) in February 2009 from two sites (site A: 77° 31.103' S, 167° 6.682' S and site B: 77° 31.106' S, 167° 6.668' E). All suggested sterilization protocols for entering into this protected site were adhered to, following the ASPA 130 Management Plan (http://www.scar.org/publications/bulletins/151/aspa130.html). Sites were chosen based on measuring a surface temperature of 65°C with a stainless steel Checktemp1 temperature probe (Hanna Instruments, Rhode Island, USA), sterilized with 70% ethanol immediately prior to each use. Surface "crust" was set aside prior to collecting samples. Samples were collected by aseptically removing the top 2 cm of sediment in an approximately 25cm2 area. Sediment was placed into a fresh 50 mL Falcon tube. Sampling continued with the collection of a second (2-4 cm depth) and third (4-8 cm depth) layer following the same procedures. Temperature measurements were repeated for each layer sampled. All samples were immediately frozen and maintained at -80°C in the laboratory until analysed.

Quality Control

Sampling conditions resulted in a high probability of cross-contamination between sampling depths. We used standard quality filtering for our 454 datasets, including denoising and chimera removal with AmpliconNoise. Sequence abundances, as inferred from library abundance, were used to cluster individual OTUs into correlated clusters which defined whether a given sequence was likely of surface or subsurface origin. Shotgun metagenomics was utilized to extract full-length 16S rRNA sequences for high-resolution phylogenetic analysis.

Method steps

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ASPA 130 - Tramway Ridge Specially Protected Area on the northwest summit of Mt. Erebus, Antarctica