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Full-Text Articles in Physical Sciences and Mathematics

Leaf Litter Processing In Aquatic Systems Two Variable Model, Boyd Jay Hanson Dec 1977

Leaf Litter Processing In Aquatic Systems Two Variable Model, Boyd Jay Hanson

Theses and Dissertations

The adequacy of the negative exponential model with one independent variable, days or accumulated time, as a descriptive equation for aquatic leaf litter processing was examined. The effect of adding a second independent variable, degree days or accumulated temperature, to the model was also examined. The two variable negative exponential model was shown to have at least two advantages over the single variable model. The two variable model adequately fits litter processing data for more cases than the single variable model. The expanded model also allows determination of rate coefficients for various temperature levels of the experiment rather than assuming …


Certain Edaphic And Biotic Factors Affecting Vegetation In The Shadscale Community Of The Kaiparowits Area, Vane Orlan Campbell Mar 1977

Certain Edaphic And Biotic Factors Affecting Vegetation In The Shadscale Community Of The Kaiparowits Area, Vane Orlan Campbell

Theses and Dissertations

A study area on the southern extensions of the Great Basin cold desert (Kaiparowits Basin, Utah) was selected which has had varying amounts of disturbance. Areas with similar slope and exposure in the Shadscale community were sampled. At each site, soil samples were collected and percent sand, percent clay, percent silt, soluble salts, and hydrogen ion concentrations were measured. Cluster analysis based on percent frequency of the perennial species showed that eight groups or sub-communities were definable within the area sampled. Patterns within the vegetation were shown to be independent with the use of cluster analysis. Discriminant analysis on soil …


The Effect Of Recreational Uses On Vegetation And Soil In The Buffalo Campground, Targhee National Forest, Island Park, Idaho, Susan Daines Foster Aug 1975

The Effect Of Recreational Uses On Vegetation And Soil In The Buffalo Campground, Targhee National Forest, Island Park, Idaho, Susan Daines Foster

Theses and Dissertations

The effect of trampling on vegetation and soil, as a result of recreational pressure, was studied in the Buffalo campground of the Targhee National Forest, Idaho. Site deterioration was most evident in the forty-two year old site. The tree stand had matured, but there were few young trees and tree reproduction had been reduced to ten seedlings per acre for Pinus contorta. Only two shrub species were sampled with a combined population of eight individuals per acre. Most of the grass species had been seeded; forbs provided 20% of the ground cover, 13% was bare ground and 71% litter. The …


Metabolism Of 3-Isopropyl-4h-2,1,3-Benzothiadiazin-4-(3h)-One-2,2-Dioxide (Bentazon) In Agitated And Non-Agitated Sediment, David Cortez Gutierrez Aug 1974

Metabolism Of 3-Isopropyl-4h-2,1,3-Benzothiadiazin-4-(3h)-One-2,2-Dioxide (Bentazon) In Agitated And Non-Agitated Sediment, David Cortez Gutierrez

Theses and Dissertations

Bentazon, (3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-l-2,2-dioxide) a new experimental herbicide, was studied under the effects of sterile and non-sterile conditions, 12 hours light: 12 hours dark and totally dark conditions, and agitated and non-agitated conditions in aquatic sediment. The effects of the different levels of BOD/COD values on the decomposition of Bentazon were studied. Photoperiod, sterility, and BOD/COD levels appeared to have no influence in the breakdown of Bentazon. Agitation-time interaction appeared to be the only factor that influenced the more rapid degradation of Bentazon. Bentazon was the major 14C-residue found in the water; it was followed by an unknown. The third major metabolite …