GIS analysis, biological samples (soil microorganism, invertebrate and plant), automatic weather station data and vegetation and invertebrate surveys to determine the terrestrial biocomplexity of the McMurdo Dry Valleys
Abstract:
The McMurdo Dry Valleys are the largest area of snow-free land in Antarctica. Managers ability to promote and protect these areas would benefit if we knew the biodiversity present and what controls it distribution. The research therefore focused on describing and predicting biodiversity of terrestrial habitats in the Ross Dependency, Antarctica. The aim is to produce a GIS/biodiversity database ... that links biodiversity with environmental factors such as geology, and soil moisture content, to produce a model that is easily understood and useable by non-specialists and endusers. Samples of soil, invertebrates and mosses were collected from the Miers, Marshall, and Garwood Valleys for geochemistry and biological analysis. Over 450 sampling sites were visited although roughly 15 were inaccessible due to terrain or snow cover. A total 435 vegetation and invertebrate surveys were made and over 450 soil samples collected. At each location up-to-date molecular techniques were used to describe the biota from visible lichens, mosses and invertebrates to the hidden microbes. The soil samples were subsampled and analyses of soil geochemistry, soil respiration, microinvertebrate content (e.g. nematodes, rotifers, tardigrades), and microbiological assays. Samples were collected and split in the field using aseptic techniques for DNA analysis. New genomic approaches that examine microbial communities as a whole (i.e., metagenomics) or even their entire functional aspects (i.e., metatranscriptomics) were used to provide a comprehensive picture of systematic and functional biodiversity, which will help resolve the drivers of biodiversity in the environment. The samples are part of a major landscape scale study to determine the primary drivers of biodiversity and distribution of flora and fauna in the Dry Valleys. In addition, the SOM and other nutrient status including the form of subsidy was determined, and this information will be placed, together with site-specific variables such as aspect, slope, water, snow, stability. The use of GIS is central to the success of this project and considerable success in collating, analysing and preparing information for the GIS analysis. Two automatic weather stations were installed together with various trap systems to measure transfer of material within the Miers and Garwood Valleys in the 2007-2008 field season and in the 2008-2009 field season another was installed in the Marshall Valley.
In 2010-2011 the Hidden Valley research area was divided into individual tiles based on geographical and geological attributes using both remote sensing data and on-the-ground surveys. Teams of specialists then visit sampling sites identified within representative tiles to collect soil samples and conduct surveys of local flora and fauna. Soil collection (for molecular genetic analyses) and surveys of micro- and macro-invertebrates were carried out . A total of 160 soil samples were collected for speciation and molecular analyses. The collected soils are analysed in our laboratories for their geochemical properties and resident microbiota using molecular genetic techniques. A survey of lichens, mosses, hypolithic, and endolithic communities was carried out in the Miers and Hidden Valleys. A total of 63 lichen samples and 10 hypolith samples were collected for speciation and molecular analyses. We also deployed instruments in the Wright Valley to facilitate our fieldwork in the 11/12 field season.
In 2012 we deployed for the first time a SODAR system (Peyman Zawar-Reza) in Meirs valley in an effort to begin to understand the influence of wind and wind patterns on the distribution of organisms in the Valley. SODAR (Sonic Detection And Ranging) is a meteorological instrument used as a wind profiler to measure the scattering of sound waves by atmospheric turbulence. SODAR systems are used to measure wind speed at various heights above the ground, and the thermodynamic structure of the lower layer of the atmosphere. This unit has already provided compelling information for our model. We plan to deploy the same unit in the Wright Valley next year for more complete coverage and modelling. Further sampling was carried out in the Wright Valley in January 2012. A total of 59 soil samples were collected for speciation and molecular analyses. A survey of hypolithic and endolithic communities was carried out in the Miers, McKelvey, and Victoria Valleys in January 2012. A total of 64 hypolith and 13 endolith samples were collected for speciation and molecular analyses. In addition, 36 moss samples and 1 lichen samples were collected in Miers Valley. Instruments were deployed in the Victoria and McKelvey Valleys to facilitate our fieldwork in the 12/13 field season.
