During the summers of 2007 and 2008, we determined net, new and regenerated primary production and phytoplankton biomass in Arctic and Sub-Arctic marine waters around North America. Carbon and nitrogen uptake rates were measured using the 15N and 13C tracer technique in 24-hr on-deck incubations, and phytoplankton biomass was determined by in vitro fluorometry. Average net primary production was highest in the north Bering and south Chukchi Seas (998 mg C m-2 d-1) and defined as primarily new production (f-ratio of 0.57), potentially indicating high particulate export from surface waters. Phytoplankton biomass was also high (39 mg chl a m-2) in this region and comprised mostly (61%) of cells >5 μm, supporting the conclusion of a high export system. Average net primary production was lowest in the Canada Basin (50 mg C m-2 d-1) with an f-ratio of 0.17 and characterized by low phytoplankton biomass (8 mg chl a m-2), comprised of mostly (19%) cells <5 μm. In much of the study area, the presence of ice cover appeared influential in affecting Arctic primary production patterns. Water column stratification in the wake of retreating sea ice produced conditions favorable to initiating seasonal blooms, which most likely terminated due to nutrient exhaustion. Areas characterized by persistent sea ice cover were particularly unproductive, most likely due to light limitation, and nutrient exhaustion due to reduced wind-mixing. These results indicate that primary production in Arctic and Sub-Arctic waters is highly variable, and provide an important baseline for future studies of phytoplankton dynamics in this rapidly changing region. / Graduate

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In order to produce ethanol derived from lignocellulosic feeds at a cost that is competitive with current gasoline prices, the fermentation process, converting sugars to produce ethanol and the subsequent purification steps, must be enhanced. Due to their comparatively lower costs, the widespread availability across a range of climates, and their status as a dedicated energy crop, lignocellulosic biomass feeds are ideal raw materials that can be used to produce domestic fuels to partly displace our dependence on non-renewable sources. Currently, a major drawback of the technology is the relatively low ethanol tolerance of the micro-organisms used to ferment xylose and glucose. To alleviate the ethanol inhibition of Escherichia coli KO11 (ATCC 55124) during fermentation, online ethanol sequestration was achieved through the implementation of an externally located packed bed adsorber for the purpose of on-line ethanol removal (using F-600 activated carbon). By removing ethanol from the broth during the fermentation, inhibition due to the presence of ethanol could be alleviated, enhancing the substrate utilization and fermentation rate and the ethanol production of the fermentation. This study details a comprehensive adsorbent screening to identify ethanol selective materials, modelling of multi-component adsorption systems, and the design, implementation and modelling of a fermentation unit coupled with an externally located packed bed adsorber.

The purpose of this study was to assess feedstock logistics for a mobile pyrolysis system and to quantify the amount of soil loss caused by harvesting agricultural feedstocks for bioenergy production. The analysis of feedstock logistics was conducted using ArcGIS with the Network Analyst extension and model builder. A square grid methodology was used to determine biomass availability of corn stover and bioenergy sorghum in Texas. The SWAT model was used to quantify soil erosion losses in surface runoff caused by sorghum residue removal for bioenergy production in the Oso Creek Watershed in Nueces County. The model simulated the removal of 25, 50, 75, and 100 percent residue removal. The WEPS model was used to quantify wind erosion soil loss caused by corn stover removal in Dallam County. Nine simulations were run estimating soil loss for corn stover removal rates of 0 percent to 50 percent. The results of the SWAT and WEPS analyses were compared to the NRCS tolerable soil loss limit of 5 tons/acre/year for both study areas. The GIS analysis determined the optimum route distances between mobile unit sites were 2.07 to 58.02 km for corn and 1.95 to 60.36 km for sorghum. The optimum routes from the mobile pyrolysis sites and the closest refineries were 49.50 to 187.18 km for corn and 7.00 to 220.11 km for sorghum. These results were used as input to a separate bioenergy economic model. The SWAT analysis found that maximum soil loss (1.24 tons/acre) occurred during the final year of the simulation where 100 percent of the sorghum residue was removed. The WEPS analysis determined that at 30 percent removal the amount of soil loss starts to increase exponentially with increasing residue removal and exceeds the tolerable soil loss limit. Limited harvesting of biomass for bioenergy production will be required to protect crop and soil productivity ensuring a sustainable biomass source.

Thesis (M.S.)--University of Hawaii at Manoa, 2007. / Includes bibliographical references (leaves 66-68). / viii, 68 leaves, bound ill. 29 cm

Thesis (Ph. D.)--Oklahoma State University, 2007. / Vita. Includes bibliographical references (p. 124-132). Also available as an Adobe Acrobat pdf.file (xii, 201 p.); Adobe Acrobat Reader required to view the file.