Phase Speciation of Carbohydrates and Dioxins in Rivers and Coastal Waters in the Northern Gulf of Mexico

<p>Dissolved carbohydrates (d-CHO), including monosaccharide (MCHO) and polysaccharides (PCHO), and particulate carbohydrates (p-CHO) are major components of natural organic matter and play an important role in biogeochemical cycles of carbon and other trace elements in marine environments. This study aimed to examine the abundance and partitioning of CHO between dissolved and particulate phases and their seasonal variations in the Mississippi Sound/Bight and Lake Pontchartrain. Laboratory mixing experiments were also carried out to examine the behaviour of CHO species along a salinity gradient. The phase partitioning of dioxin among three different phases, i.e., colloidal organic matter, particulate organic matter and sediments, was also determined for Mississippi River and Pearl samples. MCHO was the dominant species in the dissolved CHO, with high concentrations during high riverine discharge in March and May 2011, showing the influence of the Pearl River and flooding event from the Mississippi River through Bonnet Carr spillway. There was a strong seasonality in the distribution and partitioning of CHO. Terrestrial inputs seemed to play a significant role in the seasonal variation of dissolved and particulate CHO in the Mississippi Sound/Bight. The concentration of p-CHO and acidic polysaccharides (APS) increased with increasing salinity with a mid-salinity maximum and then decreased towards offshore. There was a positive correlation between p-CHO and chlorophyll-a (Chi-a) indicating phytoplankton as a source of p-CHO. The dioxin concentration increased from COM to POM to sediments, with much higher dioxin concentrations in the Mississippi River than the Pearl River, suggesting less anthropogenic impacts in the Pearl River Basin.</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Masters Thesis

Discipline thesis:degree_discipline

Marine Science

Year dc:date.available

2012

Author dc:creator

• Mitra, Kusumica

Contributors dc:contributor

• Laodong Guo
• Alan Shiller
• Karen Orcutt

• Life Sciences
• Marine Biology

Repository record dc:identifier

https://aquila.usm.edu/masters_theses/448

OAI identifier oai:identifier

oai:aquila.usm.edu:masters_theses-1530