28 research outputs found
Community-Based Watershed Planning in the Kingston Lake Watershed of Northeastern South Carolina
2008 S.C. Water Resources Conference - Addressing Water Challenges Facing the State and Regio
Community-Based Watershed Planning in the Kingston Lake Watershed of Northeastern South Carolina: Activities During 2008-2010
2010 S.C. Water Resources Conference - Science and Policy Challenges for a Sustainable Futur
Stable isotope geochemistry of nitrogen in marine particulates
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution January 1983Isotope studies of nitrogen and carbon were undertaken to
investigate the fate of particulate organic matter (POM) during its
residence in the water column and after deposition on the seafloor. The
processes focused on were water-column transformations and sedimentary
diagenesis. Sampling sites were chosen to provide POM subject to
different specific mineralization processes (nitrification,
denitrification, and sulfate reduction), different lengths of water
column (duration of the mineralization process), and differences in the
size of the organic-matter flux. The δl5N and δ13C of plankton, POM,
and sediments from several oceanic sites were related to biological and
hydrographic processes identified from nutrient, temperature, and
salinity profiles. This was done to determine what effect these
processes have on the δ15N of POM. Four stations were studied in the
upwelling area off the coast of Peru and one station was studied in the
Gulf of Maine.
Important factors controlling the δ15N of plankton appear to be
the concentration and δl5N of nitrate in the surface waters, and the
relative zooplankton and phytoplankton abundances. Plankton from the
Peru Upwelling Area are enriched in 15N as compared to plankton from
other parts of the world's oceans where denitrification is absent. This
enrichment may be due to the assimilation of 15N-enriched nitrate,
produced by the selective reduction of 14N during denitrification.
Zooplankton are 3 to 4% enriched in 15N as compared with
phytoplankton. Production of 14N -enriched fecal pellets is suggested
as a mechanism for this trophic enrichment.
In the surface waters, the δl5N of POM is similar to that of
plankton. In the Peru Upwelling Area, the δ15N of POM from the
oxygen-deficient waters decreases with increasing depth. In the Gulf of
Maine, below the euphotic zone in the oxic deep waters, the δ15N of POM
increases with increasing depth. The difference in isotopic alteration
may be due to the effect of different redox conditions on the mechanism
and sequence by which specific organic nitrogen compounds, variably
enriched in 15M, undergo degradation. Furthermore, bacterial growth on
nitrogen-poor particles in the deep waters of the Peru Upwelling Area may
contribute to the low δ15N of POM.
In contrast to the large range in δ15N (-2 to +17%) of the
POM, the range of δ15N in the sediments is small (+5 to +9%).
Within a core, the average variation in δ15N was only 1.8%.
Temporal variability in the δ15N of sedimenting POM and benthic
activity appear to be important in determining the δ15N of the
sediments. The large changes in POM concentration and isotope content at
the sediment/water interface as compared with the more constant values
found down-core, suggest that processes occuring at the sediment/water
interface are critical, although bioturbation may also be important in
determining the δ15N of oxic sediments. If diagenesis causes a
significant loss of organic matter, profiles of organic carbon and
nitrogen contents should show decreases with increasing depth and C/N
ratios should increase with increasing depth (Reimers, 1981). Since none
of the sedimentary profiles exhibited such trends, it is concluded that
diagenesis was insufficient to erase the percent carbon, nitrogen and C/N
ratio signatures generated by the POM flux and alterations at the
sediment/water interface. Temporal variability in the δ15N of
bottom-water POM may be caused by changes in deep-water currents which
transport POM horizontally and to changes in bacterial and possibly other
biological activity in the water column.
This thesis work suggests that δ15N may be a useful tool in
studying the geochemistry of POM in the marine environment. In addition,
this research has shown that interpretation of the sedimentary 15N
record must include consideration of isotopic alteration associated with
bacterial remineralization of POM and benthic activity.Funds for this
research were provided by the Massachusetts Institute of Technology /
Woods Hole Oceanographic Institution Joint Program in Oceanography, the
National Science Foundation under Grant No. OCE-8024442, and the Andrew
W. Mellon Foundation through the Center for Coastal Research of the Woods
Hole Oceanographic Institution
Application of qPCR Technologies in Stormwater Source Tracking and Determination of Host Contributions of Fecal Indicator Bacteria
2012 S.C. Water Resources Conference - Exploring Opportunities for Collaborative Water Research, Policy and Managemen
Assessment of Water Quality Benefits from Stormwater Treatment Train and Ocean Outfall for the Main Street Drainage Basin in N. Myrtle Beach
2014 S.C. Water Resources Conference - Informing Strategic Water Planning to Address Natural Resource, Community and Economic Challenge
Long Bay Hypoxia Monitoring Consortium
In October 2011, the coastal municipalities of North Myrtle Beach, Myrtle Beach, Surfside, and Horry County signed a resolution, under the aegis of their Coastal Alliance of mayors, to develop and implement the Long Bay Hypoxia Monitoring Consortium. The goal of this consortium is to support monitoring and studies that further characterize hypoxia and its causes in Long Bay. The baseline data will enable assessments of water quality management efforts. Monitoring stations are to be maintained at three piers, Cherry Grove (NMB), Apache (Horry County), and Second Ave N. Pier (Myrtle Beach). Turbidity and chlorophyll sensors will be deployed at two piers and radon detectors at three piers. All piers will have weather stations. Data will be accessible via a real-time public website. Biological responses to low dissolved oxygen (DO) will be assessed via monitoring of larval recruitment and net plankton. The S.C. Department of Natural Resources (SCDNR) is also conducting creel surveys at the piers. These efforts are being coordinated with a marine education outreach campaign that includes signage at the piers, presentations at pier events, and web-based content
Watershed-Based Planning for Murrells Inlet: Source Assessment of Fecal Bacteria using Volunteer and Shellfish Sanitation Program Data
2014 S.C. Water Resources Conference - Informing Strategic Water Planning to Address Natural Resource, Community and Economic Challenge
Crabtree Swamp Stream Restoration in Horry County, South Carolina
2010 S.C. Water Resources Conference - Science and Policy Challenges for a Sustainable Futur
Watershed Management Planning for the Murrells Inlet Estuary using GIS: Delineation, Assessment, Identification, and Solutions for Fecal Coliform Loading,
2014 S.C. Water Resources Conference - Informing Strategic Water Planning to Address Natural Resource, Community and Economic Challenge