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Final technical report for DOE DE-FG02-02ER63472

Description: This document is the final report for DOE grant number DE-FG02-02ER63472: "The impact of enhanced nitrogen fixation on carbon sequestration: a reassessment of the inorganic carbon system in LNLC regions" to Patricia L. Yager at the University of Georgia School of Marine Programs. This project examined the inorganic carbon system associated with nitrogen fixation in the “low nutrient low chlorophyll” (LNLC) regions of the western tropical North Atlantic (WTNA) and subtropical Pacific Oceans. Total dissolved inorganic carbon (DIC) and alkalinity (ALK) data were measured on seven expeditions. Data have been finalized, checked for quality assurance, and uploaded to the Carbon Dioxide Information Analysis Center website (http://cdiac.ornl.gov/). Two manuscripts using this data are published or in press so far and we are current working on two others. The first (Cooley and Yager, 2006, JGR) uses a mixing model to remove the dilution effects of the Amazon River from the WTNA inorganic carbon data set. Once the physical effect is removed, the paper then estimates net community production (NCP) for each station. Enhanced rates of production (over respiration) are seen in the river plume, establishing a large biogenic atmospheric carbon sink in this region that is otherwise a source of carbon to the atmosphere. We note that this sink occurs in the absence of a measurable nitrate flux, and correlates well with the abundance of diatoms containing endosymbiotic diazotrophs, so it must be supported by nitrogen fixation. The second manuscript (Cooley et al., in press, GBC) compares our WTNA data (from Winter 2001, Spring 2001, and Summer 2003) to previously collected datasets (Ternon et al. 2000, Kortzinger et al. 2003) for the purposes of identifying seasonal and interannual variability in Amazon River-associated carbon sequestration. For the mid-salinity regions of the plume only, we estimate a carbon sink of 15±6 TgC per year. ...
Date: June 27, 2007
Creator: Yager, Patricia L.
Partner: UNT Libraries Government Documents Department

Biorefinery and Carbon Cycling Research Project

Description: In this project we focused on several aspects of technology development that advances the formation of an integrated biorefinery. These focus areas include: [ 1] pretreatment of biomass to enhance quality of products from thermochemical conversion; [2] characterization of and development of coproduct uses; [3] advancement in fermentation of lignocellulosics and particularly C5 and C6 sugars simultaneously, and [ 4] development of algal biomass as a potential substrate for the biorefinery. These advancements are intended to provide a diverse set of product choices within the biorefinery, thus improving the cost effectiveness of the system. Technical effectiveness was demonstrated in the thermochemical product quality in the form of lower tar production, simultaneous of use of multiple sugars in fermentation, use ofbiochar in environmental (ammonia adsorption) and agricultural applications, and production of algal biomass in wastewaters. Economic feasibility of algal biomass production systems seems attractive, relative to the other options. However, further optimization in all paths, and testing/demonstration at larger scales are required to fully understand the economic viabilities. The coproducts provide a clear picture that multiple streams of value can be generated within an integrated biorefinery, and these include fuels and products.
Date: June 8, 2012
Creator: Das, K. C., Adams; Thomas, T; Eiteman, Mark A; Kastner, James R; Mani, Sudhagar & Adolphson, Ryan
Partner: UNT Libraries Government Documents Department

Characterization of Laccase-like Multicopper Oxidases (LMCOs) in Arabidopsis thaliana

Description: Laccase-like multicopper oxidases (LMCOs) have repeatedly been associated with the process of lignification in plants, and previous work suggested that these enzymes might be acting as specific marker for highly localized, small-scale lignification events in tissues not typically thought of as lignified. However, plant LMCOs typically occur as members of gene families and different family members can display disparate enzyme activities and overlapping patterns of expression in bulk tissues. This study used reporter genes and knockout mutants to document the involvement of a specific Arabidopsis thaliana LMCO family member (At2g30210 ) in early root development, specifically with development of endodermal tissues. Expression of the gene product was found to be under the control of sucrose levels, but the gene also responded to fluctuations in salt concentrations. The expression patterns of this gene were consistent with its involvement in the formation of suberin in the Casparian strip of root endodermis. An additional LMCO (At5g58910) displayed a more generalized expression in the radicles emergent seedlings. Additional members of the Arabidopsis LMCO family (At2g29130, At5g01190, and At5g05390) were also investigated with reporter gene constructs and knockout mutants. Expression of these LMCOs was associated with lignifying xylem, and the genes had over-lapping expression. Single knockout mutants did not display obvious phenotypes, suggesting that the gene products might have degenerate functionality that could compensate for loss of a single LMCO function.
Date: June 9, 2008
Creator: Dean, Jeffrey F.D.
Partner: UNT Libraries Government Documents Department