Theses and Dissertations at Montana State University (MSU)
Permanent URI for this communityhttps://scholarworks.montana.edu/handle/1/732
Browse
4 results
Search Results
Item Radiocesium in Montana soils and applications for soil erosion measurement(Montana State University - Bozeman, College of Agriculture, 1984) Arnalds, Olafur Gestur; Chairperson, Graduate Committee: Gerald A. NielsenRadiocesium levels in soils were measured at eleven sites throughout Montana. Cesium was mostly confined to the top of the soil profile. Both lateral and vertical displacement of cesium was attributed to mechanical movement of soil particles. The areal activity of cesium was strongly correlated to annual precipitation (R^2 = 0.92). An equation is given to predict cesium activity from annual rainfall. Methods of calculating soil erosion and deposition are discussed and performed for a wind erosion study site in Pondera County and a small watershed in Teton County. The results indicate that deposition at the wind erosion study site can be quantified. Soil deposition of 70 to 1290 m^3 ha^-1 was measured on the leeward sides of a fence and tree windbreaks while an average of 450 m^3 was lost from the windward sides. An average of 740 m^3 ha^-1 was lost since 1962 from an adjacent wind eroded field. This amounts to 34.8 Mg ha^-1 yr^-1. Soil loss since about 1962 ranged from 300 to 820 m^3 ha^-1 within the upper areas of the watershed studied. A pond at the outlet of the watershed and deposition areas at the toeslope accounted for a relatively small fraction of the soil loss within the watershed. Most of the losses are likely to be from wind erosion. Length of slopes or position within the field were more related to erosion than was steepness of slopes, Estimates of erosion rates based on 137Cs ranged from 16.5 Mg ha^-1 yr^-1 at the summit of the watershed to 45.1 Mg ha^-1 yr^-1 at the midslope. Predictions by conventional methods (wind erosion equation and the Universal Soil Loss Equation) agreed rather closely with the estimates from 137Cs.Item Amorphous character in twenty western Montana forest soils with apparent eolian influence(Montana State University - Bozeman, College of Agriculture, 1977) Ottersberg, Robert JosephItem Sand dunes of the Darhat Valley Mongolia : understanding their origins, dynamics, and impacts on soils and vegetation(Montana State University - Bozeman, College of Agriculture, 2001) O'Connell, Patrick HaroldItem Wind as an ecological factor in the McMurdo Dry Valleys, Antarctica(Montana State University - Bozeman, College of Agriculture, 2012) Sabacka, Marie; 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.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.