Measurement of lignin and organic carbon in Lake Mead sediment

Lignin distribution in sediment is a useful tool for tracing the transport of land derived organic matter in an aquatic environment. Tetramethylammonium hydroxide (TMAH) thermochemolysis at sub-pyrolysis temperatures of 300°C followed by GC-MS analysis showed a great promise in being able to semi quantitatively assess the nature of organic carbon in sediments. TMAH chemopyrolysis produces methylated syringyl (S), vanillyl (V), and cinnamyl (C) phenols from lignin, these methylated phenols are an indirect measure of lignin in sediment. The concentration of lignin phenols is indicative of the contribution of terrestrial runoff to lake sediments because lignin is exclusively a product of land plants. The S/V ratio is a powerful tool to trace the terrestrial origin of organic matter in sediment; Two chemolysis methods (on-line and off-line) were examined and compared. Organic carbon and lignin in several cores from Lake Mead were investigated. The results from sediment cores indicate significant variations in the sources of sedimentary materials. The concentration of organic carbon and the composition and amount of lignin provides an interpretable record of historical changes.

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Chemistry

Grantor dc:publisher

University of Nevada, Las Vegas

Year

2004

Author dc:creator

• Nemr, Ekhlas Lisa

Contributors dc:contributor

• Spencer M. Steinberg

Statement dc:rights

• IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

Language dc:language

English

Identifier

https://oasis.library.unlv.edu/rtds/1651

OAI identifier oai:identifier

oai:oasis.library.unlv.edu:rtds-2650