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Full-Text Articles in Physical Sciences and Mathematics

The Use Of Biological Soil Health Indicators To Quantify The Benefits Of Cover Crops, Alexander Wu Apr 2023

The Use Of Biological Soil Health Indicators To Quantify The Benefits Of Cover Crops, Alexander Wu

Masters Theses

Soils provide many essential functions that support the world. With a decline in soil health, these functions also decrease in efficiency, and can threaten the health of billions of people around the world. Typically, soil health tests do not use biological indicators, however microbes drive and perform vital functions to increase soil health. One way to increase soil health is through the use of cover crops to reduce soil erosion during fallow periods, increasing soil organic matter, as well as collecting nutrients from soil into their biomass. These cover crops are then terminated through various methods such as herbicides, disk …


Modeling Spatial Distributions Of Tidal Marsh Blue Carbon Using Morphometric Parameters From Lidar, Bonnie Turek Apr 2023

Modeling Spatial Distributions Of Tidal Marsh Blue Carbon Using Morphometric Parameters From Lidar, Bonnie Turek

Masters Theses

Tidal marshes serve as important “blue carbon” ecosystems that accrete large amounts of carbon with limited area. While much attention has been paid to the spatial variability of sedimentation within salt marshes, less work has been done to characterize spatial variability in marsh carbon density. Driven by tidal inundation, surface topography, and sediment supply, soil properties in marshes vary spatially with several parameters, including marsh platform elevation and proximity to the marsh edge and tidal creek network. We used lidar to extract these morphometric parameters from tidal marshes to map soil organic carbon (SOC) at the meter scale. Fixed volume …


Hydrologic Controls On Phosphorus Speciation And Mobilization In A Subalpine Watershed (East River, Colorado), Lucia Isobel Arthen-Long Oct 2021

Hydrologic Controls On Phosphorus Speciation And Mobilization In A Subalpine Watershed (East River, Colorado), Lucia Isobel Arthen-Long

Masters Theses

The cycling of phosphorus (P) through floodplain environments is critical to ecosystem productivity and has significant implications on both water quality and soil fertility. P export from soils in response to saturation has been well documented, but the relative vulnerability of specific P pools to mobilization remains poorly constrained, as do the mechanisms mediating its release. The prediction of P availability in and export from mountainous floodplain soils is of great importance as global climate change is projected to significantly alter precipitation regimes in alpine systems. This study combined a thorough characterization of P distribution across a hillslope to floodplain …


Root-Driven Weathering Impacts On Mineral-Organic Associations Over Pedogenic Time Scales, Mariela Garcia Arredondo Mar 2019

Root-Driven Weathering Impacts On Mineral-Organic Associations Over Pedogenic Time Scales, Mariela Garcia Arredondo

Masters Theses

Plant roots are critical weathering agents in deep soils, yet the impact of resulting mineral transformations on the vast deep soil carbon (C) reservoir are largely unknown. Root-driven weathering of primary minerals may cause the formation of reactive secondary minerals, which protect mineral-organic associations (MOAs) for centuries or millennia. Conversely, root-driven weathering may also transform secondary minerals, potentially enhancing the bioavailability of C previously protected in MOAs. Here we examined the impact of root-driven weathering on MOAs and their capacity to store C over pedogenic time scales. I compared soil that experienced root-driven weathering, resulting in the formation of discrete …


Mineral And Redox Controls On Soil Carbon Cycling In Seasonally Flooded Soils, Rachelle Lacroix Oct 2018

Mineral And Redox Controls On Soil Carbon Cycling In Seasonally Flooded Soils, Rachelle Lacroix

Masters Theses

Soils contain nearly three times the amount of carbon (C) than the atmosphere, with C turnover times ranging from centuries to millennia. Although wetland soils represent a relatively small portion of the terrestrial landscape, they account for an estimated 20-30% of the global C reservoir. Seasonally flooded soils are likely the most vulnerable wetlands to climate change, as changing temperature and precipitation patterns are expected to alter the timing and duration of flooding. Seasonal variations in soil moisture are recognized as a critical control on soil C stocks and CO2emissions. However, the relative influence of associated changes in …