Evaluation of sediment dynamics using geochemical tracers in the Pamlico Sound estuarine system, North Carolina / by Lancen S. Tully.
| Author/creator | Tully, Lancen S. author. |
| Other author | Corbett, D. Reide (David Reide), 1971- degree supervisor. |
| Other author | East Carolina University. Department of Geology. |
| Format | Theses and dissertations |
| Production | 2004. |
| Description | xv, 180 leaves : illustrations, maps ; 28 cm |
| Supplemental Content | Access via ScholarShip |
| Subjects |
| Summary | The purpose of this study was to characterize geochemically the sediment dynamics operating within Pamlico Sound and to quantify the significance of marsh erosion as a sediment source to Pamlico Sound. A total of fifteen sediment cores, seventeen marsh grabs, and one marsh core were collected from Pamlico Sound and the surrounding marshes in 2002 and 2003. The estuarine cores are characterized by organic-rich mud (ORM) of varying thickness. The marsh grabs were collected from mainland and barrier island sites and represent two broad peat categories including: 1) surface peat and 2) subsurface peat. The geochemical tracers employed in this study include radionuclides (²¹⁰Pb, ¹³⁷Cs, and ⁷Be), carbon ([delta]¹³C) and nitrogen ([delta]¹⁵N) stable isotopes and C:N ratios, and metal abundances (Al, Fe, Zn, and Cu). Additionally, the estuarine sediments were analyzed for grain-size distribution. These parameters provided a geochemical and sedimentological basis for comparing the estuarine muds and marsh peats, assessing changes in sediment dynamics and sediment quality over time, and illustrating the modem pathways of organic matter transport and organic matter sources. Sediment accumulation rates of ORM vary throughout Pamlico Sound (0.1 to 0.5 cm y⁻¹), and are generally the greatest in deeper portions of the central and southern subbasins or in shallower water located in protected coves and embayments. Stable carbon and nitrogen isotopic data acquired from Abbene (2004) indicate that sediments are transported toward the center of the sound, in accordance with sediment accumulation rates. The data show that a major shift in either sediment dynamics or sediment source occurred in the 1960's. Probable causes of this could be related to natural (storms) and anthropogenic (trawling) resuspension events and/or changes in sediment source (i.e., increases in marsh erosion) over time. Comparing estuarine shoreline erosion rates calculated by Riggs and Ames (2003) with excess ²¹⁰Pb modeled accumulation rates for Pamlico Sound sediments, estuarine shoreline erosion accounts for ~9 to 14% of sediment to the sound. This represents the first time that the marsh erosion portion of the sediment budget has been calculated for Pamlico Sound. Trace metal (Zn, Cu) data correspond well with previous studies in the region and show that Pamlico Sound is relatively unpolluted (with respect to Zn and Cu) compared to the neighboring Neuse and Pamlico Rivers, Albemarle Sound, and many other estuaries globally. |
| General note | Presented to the faculty of the Department of Geology. |
| General note | Advisor: D. Reide Corbett |
| Dissertation note | M.S. East Carolina University 2004 |
| Bibliography note | Included bibliographical references (leaves 140-153). |
| Genre/form | dissertations. |
| Genre/form | Academic theses. |
| Genre/form | Academic theses. |
| Genre/form | Thèses et écrits académiques. |
Availability
| Library | Location | Call Number | Status | Item Actions |
|---|---|---|---|---|
| Joyner | University Archives | ASK AT SPECIAL COLLECTIONS DESK | ✔ Available | Request Material |
| Electronic Resources | Access Content Online | ✔ Available |