However, scientific studies and monitoring that could link land-use changes and water quality changes in these systems have been conducted only in the last 30 to 40 years. These studies provide only a limited view of short term changes in the system—changes that may reflect seasonal or annual shifts and not long-term human influences.

Nevertheless, a record does exist that can be used to provide managers and regulators with a much broader picture of how the systems have changed with human and climatic influences as well as the data to separate climatic from human impacts. That record lies in the accumulated sediments that underlie the estuaries and is accessible through the use of paleoecological methods.

Paleoecology is the study of relationships between past organisms and the environment in which they lived. Paleoecological methods are used to reconstruct past ecosystems and to measure human influences against the naturally occurring state of those ecosystems.

In this project, Dr. Sherri R. Cooper of the Duke Wetland Center will collect and use paleoecological data to re-create the history of water quality and diatom community structure in the Tar-Pamlico and Neuse estuaries through time and to relate changes in water quality to changes in watershed land use history and other anthropogenic influences.

She will take sediment cores from each estuary and examine them to discover and assess indicators of past water quality. Using radiocarbon dating, Pb-210 dating and Cs-137 dating along with pollen dating techniques, she will calculate sedimentation rates for each interval of the core and produce a time axis dating from about 1,000 years ago to the present, along which she can plot corresponding water quality and geochemical parameters.

Plant and animal fossils, particularly pollens and preserved silica exoskeletons of diatoms (a form of algae), can be used to assess past eutrophication, nutrient availability, light availability, and sedimentation rates.

Organic carbon in sediment layers can reveal information about past benthic oxygen demand, and sulfur compounds can tell whether oxic or anoxic conditions prevailed at the time sulfur was deposited.

The paleoecological record resulting from this work will help illuminate the debate concerning the primary factors contributing to declining water quality in estuaries and will support hindcasting models in which predictions about the effects of future environmental change on the ecology can be made.

The History of Water Quality in North Carolina Estuarine Waters as Documented in the Stratigraphic Record (70161)
Dr. Sherri Rumer Cooper (slcooper@acpub.duke.edu)
Duke University
May 1, 1997, to June 30, 1998
Funded by WRRI