Paleoenvironmental reconstruction of the changing water quality of the tidal Christina River, Wilmington, DE, USA
| Author(s) | Christie, Margaret A. | |
| Date Accessioned | 2017-12-12T13:10:00Z | |
| Date Available | 2017-12-12T13:10:00Z | |
| Publication Date | 2017 | |
| SWORD Update | 2017-09-05T16:31:10Z | |
| Abstract | The Mid-Atlantic Region of the United States has been altered by a variety of land-use changes imposed since European settlers arrived in the mid-17th Century. The commencement of agriculture increased the sediment and nutrient loads within watersheds. Later, urbanization and industrialization increased metals and other pollutants that had previously been absent or present only in low concentrations. This study aims to better understand the impacts of European Settlement and successive changes in land-use strategies on the water quality of the tidal Christina River, located near Wilmington, DE, USA. Cores were taken in the marshes adjacent to the river and dated using 137Cs, 210Pb, 14C, and changes in pollen ratios which indicate deforestation. Sediment cores included samples which were at least 1000 years old so that conditions prior to European settlement could be reconstructed. Changes in the percent of eutraphentic and mesotrophentic diatoms were determined in order to estimate the timing and impact of nutrients. A transfer function constructed using modern diatom abundances and chemistry data estimated total phosphorus (TP) concentrations related to agriculture, wastewater, and detergents. Sediment metal concentrations were used to identify industrialization. Trophic levels began increasing about 200 years before present and were highest in the most recent samples. TP, based on the transfer function, had good agreement with the trophic indices. Metals, increased in concentration around 1900 and decreased due to the closure of factories and environmental legislation in the 1950s through the 1990s. | en_US |
| Advisor | Martin, Ronald E. | |
| Advisor | Pizzuto, James E. | |
| Degree | Ph.D. | |
| Department | University of Delaware, Department of Geological Sciences | |
| DOI | https://doi.org/10.58088/x9aw-vk61 | |
| Unique Identifier | 1015239146 | |
| URL | http://udspace.udel.edu/handle/19716/21787 | |
| Language | en | |
| Publisher | University of Delaware | en_US |
| URI | https://search.proquest.com/docview/1958939804?accountid=10457 | |
| Keywords | Earth sciences | en_US |
| Keywords | Anthropogenic | en_US |
| Keywords | Diatoms | en_US |
| Keywords | Tidal river | en_US |
| Keywords | Transfer function | en_US |
| Keywords | Water quality | en_US |
| Title | Paleoenvironmental reconstruction of the changing water quality of the tidal Christina River, Wilmington, DE, USA | en_US |
| Type | Thesis | en_US |