Recent biological inventory data shows a consistent decline in molluscan abundance and biodiversity in the Conasauga River Basin in Northwest GA. This study was initiated to monitor sediment and water quality by stable nitrogen isotope ratio analyses (IRMS) of snails and sediments, permeable membrane devices (PMD), polar organic chemical integrative samplers (POCISTM), and conventional water quality analyses for the Conasauga River Basin. Atrazine, metalochlor, prometon, and simazine were the most frequently detected herbicides throughout the basin. Most of the ambient concentrations of detected organic contaminants are at or near the method detection limit and all are well below any aquatic life criteria. Recent evaluation of water quality criteria for ammonia and nitrate suggest that these criteria levels are not protective for mussels. Data suggests that a shift to livestock and row crop land-use results in greater water nutrient levels and increased ä15N signatures for aquatic snails. Mean ä15N values for snails collected at national forest sites are significantly different from ä15N in snails collected in agricultural areas of the Conasauga River Basin (Student t-test, p<0.05). ä15N signatures of cow manure (6.71? wet, 8.40? dry) and poultry manure treated soil (9.47?) were similar to those of the snails collected in the agricultural areas of the Conasauga. Dissolved nitrate had elevated ä15N signatures that reflected the upper range of ä15N signatures for the aquatic snails. Elevated nitrogen isotope signatures indicate the fact that a shift in land use within in the basin is impacting the dominant nitrogen source to the aquatic environment. Continued evaluation of water quality criteria levels are needed to determine if aquatic habitats are viable for mussel reproduction, growth, and survival.
| Identifer | oai:union.ndltd.org:NCSU/oai:NCSU:etd-06212005-121444 |
| Date | 28 June 2005 |
| Creators | Sharpe, Adam James |
| Contributors | Elizabeth G. Nichols, James Gregory, Chris Hofelt |
| Publisher | NCSU |
| Source Sets | North Carolina State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://www.lib.ncsu.edu/theses/available/etd-06212005-121444/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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