Wind as an ecological factor in the McMurdo Dry Valleys, Antarctica

• Main Author: Sabacka, Marie
• Other Authors: Chairperson, Graduate Committee: John C. Priscu., John C. Priscu, Hassan J. Basagic, Andrew G. Fountain, Diana H. Wall, Ross A. Virginia and Mark C. Greenwood were co-authors of the article, 'Aeolian flux of biotic and abiotic material in Taylor Valley, Antarctica' in the journal 'Geomorphology' which is contained within this thesis., John C. Priscu, J. E. Barrett, Diana H. Wall, Ross A. Virginia and Diane McKnight were co-authors of the article, 'Aeolian fluxes of carbon, nitrogen and phosphorus among landscape units in the Taylor Valley, Antarctica' in the journal 'Arctic, antarctic and alpine research' which is contained within this thesis., John C. Priscu was a co-author of the article, 'Spatial distribution of microorganisms in the McMurdo Dry Valleys, Antarctica' in the journal 'Polar biology' which is contained within this thesis., Alexander B. Michaud and John C. Priscu were co-authors of the article, 'Spatial scaling of cyanobacterial diversity in the Taylor Valley, Antarctica' in the journal 'Polar biology' which is contained within this thesis.
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Montana State University - Bozeman, College of Agriculture 2012
• Subjects: Winds; Cyanobacteria; Ecology; McMurdo Dry Valleys; Antarc*; Antarctica
• Online Access: https://scholarworks.montana.edu/xmlui/handle/1/2171

The aim of this work was to investigate the role of wind on the ecology of the McMurdo Dry Valleys in Antarctica (MDV), one of the coldest and driest deserts on Earth. The MDV landscape consists of a mosaic of permanently ice-covered lakes, ephemeral streams, exposed soils, and glaciers, all of which contain habitats dominated by microorganisms. Data on wind-driven flux of sediments and associated organic matter were collected using passive aeolian traps and dynamic mass erosion particle counters to investigate the timing, direction and magnitude of aeolian sediment transport. Combination of genomic techniques and phenotypical fingerprinting (pigment analysis) was used to examine microbial diversity over a wide variety of wind-eroded habitats across the MDV landscape to elucidate the role of wind dispersal on the contemporary distribution of microorganisms across the MDVs. Sediment entrainment occurs predominantly within 20 cm of the ground surface and has character of saltation bursts that occupy <3% of the total time within a year. The high-energy winter föhn winds uplift sediments in the upper parts of the MDVs and transport them down-valley where they are deposited onto the surface of perennially ice-covered lakes and surrounding soils. The sediment that enters the water column of the lakes does not provide a significant source of organic carbon for bacterioplankton communities compared to the in situ production by phytoplankton but can be a source of new microbial propagules. The aeolian material is low in organic matter (<1% dw) but is composed of a relatively large numbers of cyanobacterial taxa (~20 OTUs) that can be found in all other MDV habitats. In conclusion, wind distributes microorganisms across the MDV landscape but local environment selects for specific taxa. Predicted climate warming will increase the importance of wind transport, which will affect nutrient cycling and connectivity among MDV ecosystem components.