Microbiome diversity and function in the Sør Rondane Mountains, East Antarctica Follow the updates on the expeditions of the MICROBIAN project to continental Antarctica!
27-01-2018
The Dry Valley between Vikinghøgda and the highest mountain of the Sør Rondane mountains, Widerøefjellet
After trying out the assembly of the two snow fences, we still needed to find the appropriate locations to install them. After visiting Perlebandet, it immediately became clear we would never be able to install one of the fences over there: none of the relatively flat spots was big enough and exposed to the right wind direction. Exposure to wind is important, because the mechanism behind the snow fences is that they will create a small windscoop, by acting as a miniature version of a mountain or nunatak. The wind becomes turbulent after the snow fence, resulting in the deposition of extra snow. We will install permanent sampling plots in the zone with increased snow cover (behind the snow fences) as well as in an area that is not affected by the installation. The latter plots will serve as control sites. Temperature, humidity and light loggers will allow us to compare the environmental conditions between the areas with increased snow cover and the control plots. Sampling of the permanent plots within a few years should enable us to make comparisons in microbial community structure.
After discussing with Gigi and Alain, Gigi suggested three potentially suited locations for installing one of the snow fences. One of them was the so-called Dry Valley between the Vikinghøgda mountain range and the highest mountain of the Sør Rondane mountains, Widerøefjellet. On Thursday we crossed the Ketelersbreen glacier, passing Mt Vengen on our left, and soon we found the right spot. The valley is actually the catchment of the Ketelersbreen glacier, and is a very wide, ice-free, relatively flat area. It is highly exposed to the dominant easterly winds: perfect for our experiment. After sampling the area for our study aimed at assessing the effect of microclimatic conditions and bedrock type on the microbial communities, we returned to the base and enjoyed a delicious meal, which was prepared by Thomas. He is the only remaining cook on the station, now that David left with Alain, Christian, Pierre and Jacques for a traverse to the coast. Their mission is to pick up the last remaining containers with the construction equipment for finalizing the building below the station. During dinner we were informed that the next 2 days will probably be white-out days, and hence with little to no visibility. Weather conditions force us to stay inside: two days at the office (with a view)!
The past few days have been very busy for the MICROBIAN team. After the field training, Valentina, Sam and Elie immediately started with the sampling program. First, the snow fences were pre-assembled and all sampling protocols were tested. On Thursday we went to Teltet nunatak (Fig.1) to sample the Open-Top-Chambers (OTCs) which were installed there in 2010 by Dr. Zorigto Namsaraev within the framework of the BelSPO project BELDIVA. These OTCs will allow us to study the effect of increased temperatures on the diversity and composition of the soil communities.
Fig.1: Map of the Sør Rondane Mountains showing the sampling sites visited during the past few days by the MICROBIAN team
Unfortunately, both OTCs were for more than 1/3 covered by snow so we had to remove the upper snow layer (Fig.2), thereby ensuring not to touch and disturb the soil communities below.
Fig.2: Valentina and Sam near the OTCs in Teltet.
On Friday, Saturday and Monday we went to the Perlebandet nunatak which is situated West of Utsteinen (Fig.1). We found quite a diverse set of communities consisting of microbial biofilms and various species of lichens. In the Northern and Southern nunatak we sampled 15 of these communities and installed i-button loggers. These devices will measure temperature and relative humidity every three hours during the next year. These data will help us to understand the relation between microclimatic conditions and the presence of particular communities and microbial organisms. We also installed new OTCs in the area and sampled them in triplicate (Fig.3).
Fig.3: Valentina and Sam sampling the newly installed OTCs in Perlebandet nunatak.
Because we need to work sterile, we are wearing latex gloves. However, because of the wind chill our hands were really getting cold. Latex gloves are certainly not Antarctic weather proof! Even undergloves were not sufficient to keep our hands warm enough. After our work in Perlebandet we sampled the OTCs in Teltet on Monday. We cant wait to see the results of the DNA sequencing analysis!
On Tuesday we sampled soil communities in the Pingvinane nunatak. The existing OTCs there were also snow covered so we removed the upper snow layer and hope to sample them later this week. Today it was snowy and the visibility was poor. Hence, we needed to stay at the station, but Valentina and Sam used their time to try out the assembly of the snow fences together with Pierre-Yves, our field guide, and Paul, who is a member of the technical staff (Fig.4). Paul is probably one of the most experienced technicians in Antarctica!
Fig.4: Pierre-Yves and Sam measuring the snow fence so it can be safely attached to the sledge (left of picture).
The snow fences will allow us to assess the effect of increased snow cover on the microbial communities. This is interesting because several climate models predict increased snow cover in some Antarctic regions the coming century as a result of global change. The pre-assembly was really important, because Alain advised us to strengthen the installation to make it really wind proof. Paul installed an iron bar near the base of the snow fence which resulted in a very rigid structure (see picture). We believe we are ready to start the experiments with the snow fences!
