Documents - Publications - Conference Papers

Abstract - This paper describes the development and initial implementation of a Coastal Water Quality Monitoring Metadata Database for the Southeast region (from NC to FL), which was developed with funding from the National Park Service. The database was designed to store detailed information on water quality monitoring programs operated by federal, state and municipal agencies, as well as by research institutions, including monitoring station locations, measured parameters, program contacts, and links to program web pages and data downloads. Water quality parameter records are classified into parameter groups and categories to support searches at varying levels of specificity, and are matched to US EPA STORET codes when possible for interoperability with federal databases. Fields for defining sample media, units and methodology are also provided for additional context. A prototype web portal, web services and mapping services were developed to support search and display of database contents, and to support leveraging by other database and portal efforts. Information from 41 monitoring programs in the South Atlantic was initially loaded into the database in 2009, including metadata on 16,182 stations at which 1093 distinct parameters are measured; the number of programs is currently being expanded. This database provides an ongoing inventory of monitoring activities for the southeast region and will help to facilitate identification of data gaps or under- or over-sampled areas. On a broader scale, the project’s water quality metadata database and web portal have timely relevance to the broad community of coastal managers, researchers, planners and constituents as they make significant progress in leveraging and focusing regional associations and partnerships.

Abstract - The volume of monitoring data that can be acquired and managed by Long Term Ecological Research sites and environmental observatories has increased exponentially over time, thanks to advances in sensor technology and computing power combined with steady decreases in data storage costs. New directions in environmental monitoring, such as sensor networks and instrumented platforms with real-time data telemetry, are raising the bar even higher. Quality control is often a major challenge with real-time data, though, due to poor scalability of traditional software tools, approaches and analysis methods. Software developed at the Georgia Coastal Ecosystems Long Term Ecological Research Site (GCE Data Toolbox for MATLAB) has proven very effective for quality control of both real-time and legacy data, as well as interactive analysis during post processing and synthesis. This paper describes the design and operation of the dynamic, rule-based quality control framework provided by this software, and presents quantitative performance data that demonstrate these tools can efficiently perform quality analysis on million-record data sets using commodity computer hardware.

Abstract - We recently completed an assessment of Fort Pulaski National Monument for the Water Resources Division of the National Park Service. The report provides information on park resources, water quality and impairments, and other issues of concern. Although there are no real sources of pollutants at Fort Pulaski itself, both point and nonpoint sources of pollutants can be found nearby that have the potential to affect its water resources. We identified nutrients and contaminants as currently existing problems. A majority of nutrient samples were classified as either fair or poor, and there is evidence for elevated contaminants (primarily arsenic and PAHs) in sediment and animal tissue taken from both tidal creeks and the main channel of the Savannah River. Dissolved oxygen was identified as a potential problem due to the amount of organic material and nutrients associated with industrial activity. Fecal bacteria concentrations are low and not considered a problem. Continued water quality monitoring at the Park is particularly important in order to note any change occurring with the Savannah Harbor Expansion Project. The report provides a list of recommendations for additional observations that would allow us to better evaluate coastal water resources.

Abstract - Emerging environmental grand challenges demand new scientific approaches that require collaboration and integration of long-term, multi-site data across broad spatial and temporal scales. The LTER Network and USFS Experimental Forest Network sites collect extensive long-term ecological, climatological, and hydrological data. While many of the LTER and USFS databases are available on-line with adequate metadata, researchers find it problematic to locate, access, and assemble data from multiple sites. LTER and USFS Information Managers developed ClimDB/HydroDB (http://www.fsl.orst.edu/climhy/) as one approach to improving access to crosssite data. As information systems at LTER and USFS are geographically decentralized and autonomous, this approach relied upon scientific interest, organizational and personal commitment, and participation incentives to build this integrated, cross-site information product. ClimDB/HydroDB is a web harvester and data warehouse that provides uniform access to common daily streamflow and meteorological data through a single portal. Participating sites manage and control original source data within their local information systems, but routinely contribute data to the warehouse. This approach establishes service development at the central node, permitting rapid adaptation to changing needs, while maintaining low-overhead and technological neutrality for data providers. The ClimDB/HydroDB approach is an effective bridge technology between older, more rigid data distribution models and modern service-oriented architectures.

Abstract - This study explored differences in the transit times of dissolved substances through salinity zones in the Altamaha and Ogeechee River estuaries under a range of flow conditions. Salinity distributions and transit times were estimated from box models generated using the SqueezeBox modeling framework. The estuaries were compared in spite of the large difference in their river flow ranges by using flow rates ranging from the 10th-90th percentile within each range. In each case, zone lengths and transit times were calculated for the tidal freshwater, oligo-mesohaline, and polyhaline zones. Although the two estuaries have similar lengths, the slower-flowing Ogeechee grades from a zone of tidal freshwater (except at very low flows) through oligo-mesohaline zones to a polyhaline zone inside the mouth whereas the Altamaha always has a fairly long (>25 km) extent of tidal freshwater but only a short (or non-existent) polyhaline zone. Transit times through the whole Ogeechee estuary are 3.3-4.7 times longer than those in the Altamaha, but the lengths of time water spends in the tidal freshwater reaches of the estuaries are comparable whereas there are large differences in the times spent in oligo-mesohaline and polyhaline reaches. These types of predictions may be useful in interpreting nutrient and pollutant dynamics in estuaries as well as in studies that compare the relative susceptibility of estuaries to perturbations.

Abstract - We compiled USDA Census of Agriculture data on livestock production and agricultural land use along with USGS estimates of fertilizer use to evaluate trends in agricultural sources of nitrogen (N) to the watershed of the Altamaha River. Between 1954 and 2002, the estimated contribution of N from the three major livestock crops (cattle, chickens, and pigs) remained fairly stable, averaging approximately 1,000 kg N/km2. However, the source of the waste shifted from primarily cattle in 1954 to a mix of cattle and chickens in 2002, due in large part to a ten-fold increase in the number of chickens in the watershed. We did not have fertilizer data through 2002, but between 1954 and 1991 estimated fertilizer N use doubled, from 503 to 1,055 kg N/km2 (calculated based on the area of the watershed). These changes in N sources were accompanied by decreases in the amount of cultivated land in the watershed. The amount of land classified as harvested cropland decreased from 6,528 in 1954 to 2,448 km2 in 1992, which suggests there has been an increase in the amount of fertilizer applied per unit area. The amount of pastureland showed an even larger decrease, from 11,421 in 1954 to 3,294 km2 in 2002, which we take as evidence of increased confinement of livestock. When these numbers are considered in the context of all of the sources of N to the watershed, we estimate that the proportion of agriculturalderived N accounted for approximately 66% of the N input to the watershed in 2000, with the remainder coming from human waste and atmospheric deposition.

Abstract - A directed studies research project to understand turbulent mixing processes in Altamaha Sound has been carried out as part of the Georgia Coastal Ecosystems Long Term Ecological Research (GCE-LTER) project. In this study we analyze the flow and salinity characteristics, which has a periodic component of stratification that interacts with turbulent mixing to control water column stability. There is a contrast between the ebb and flood phases of the tides showing that during ebb, the water column is well mixed indicating that shear instabilities give rise to turbulent mixing and that during flood, density gradients stabilize the variations caused by the current shear. These results are contrary to tidal straining theory and are hypothesized to be related to shoaling surrounding the Altamaha channel towards the ocean. Because of shoaling, surface gravity waves may play a key role in enhancing bottom stress variability during flood flow. The physical factors that control turbulence in the coastal ocean are very important for understanding the mixing of water masses and thus the distribution of chemical, biological and physical properties that directly affect water quality.

Abstract - Ammonium (NH4+), nitrate+nitrite (NOx), dissolved inorganic phosphorus (DIP) and dissolved organic carbon, nitrogen and phosphorus (DOC, DON and DOP) were measured in the Altamaha River and several tributaries during a two year period from September 2000 through September 2002. Temporal variations in concentration as well as nutrient and dissolved organic matter loading from the Altamaha to the coastal zone were determined. Loading rates were heavily dependent on river discharge, as was the form of nitrogen. All measured dissolved compounds in the Altamaha River were significantly correlated with river discharge (p<0.05) with the exception of NH4+. Concentrations of DOC, DON, DOP and DIP increased during periods of high flow, while levels of NOx dropped. This resulted in NOx dominating dissolved N loading during low river discharge, and DON increasing in importance during periods of high flow. Overall rates of C, N and P loading were much greater during high discharge times. Although loading rates of N were greater during high discharge, the shorter residence time in the coastal zone and the higher fraction of DON may alleviate some of the impacts of loading during high flow. Longer residence times and the availability of NOx for rapid uptake may contribute to coastal eutrophication during periods of low flow.

Abstract - The Georgia Coastal Research Council is a newly-formed organization established to provide mechanisms for improved scientific exchange between coastal scientists and decision makers in the State of Georgia and to promote the incorporation of best-available scientific information into State and local resource management. The Council is not a policy organization, but rather seeks to provide unbiased, objective information about scientific issues through informal consultation and the development of white papers and management tools. In September 2002, the Council hosted the first Coastal Georgia Colloquium, which was attended by coastal scientists representing many of the Universities in the State as well as scientists and managers from both federal and state agencies. As of November 2002, coastal scientists from throughout the State have started meeting on a regular basis with representatives from the Coastal Resources Division of the Georgia Department of Natural Resources. This ongoing partnership among coastal scientists and managers may be a useful model for other water resource efforts in Georgia.

Abstract - 1-D optimum-boundary box models were used to simulate the movement of dissolved pollutants or other conservatively mixing constituents through the Altamaha River estuary. Tracers were introduced into the models as point sources at various locations within the estuary and as a non-point input to the entire system. In each case, models were run at four different river flow rates and were used to simulate both the movement of tracer within the estuary and its rate of removal. When tracer was introduced at head of tide, it moved rapidly (from 1-2 d, depending on flow) to the head of the mixing zone 30 km downstream. Tracer released anywhere in the estuary, including farther downstream at 2 km, moved toward an area 4-6 km upstream of the mouth, where it remained centered as overall removal continued. Movement toward this zone was observed regardless of flow rate. Introduction of tracer as a non-point source also resulted in distributions centered at 4-6 km, suggesting that this area is a potential convergence zone in the Altamaha River estuary. Maximum exposure to tracer, measured as the amount of time that concentration exceeds a given threshold, depends on where in the estuary tracer is released. When released at head of tide, maximum exposure is experienced at 6-10 km. Simulations of the type presented here are useful for evaluating the conservative movements of both point- and non-point-source constituents in the estuary.

Abstract - Changes in freshwater inflow can cause changes in the distribution and diversity of marsh vegetation in estuarine habitats. In the fall of 2002 bankside vegetation was surveyed along the 24 km length of the Altamaha River estuary (n= 14 sites). Sites were quantified for multiple plant and edaphic parameters, including plant density, height, and tiller diameter. In this paper we present the characteristics of the bankside marsh vegetation as they change along the estuarine salinity gradient, and evaluate the use of a proportional relationship between two marsh grasses, Spartina cynosuroides and S. alterniflora, as a way to identify a transition line between salt and brackish marsh communities. S. alterniflora densities were greatest at the mouth of the estuary and decreased upstream and S. cynosuroides densities showed the opposite pattern, but there was not a well defined transition between these two plant communities. The percent S. cynosuroides cover along the estuary is a potentially useful way to document the response of the estuary to changing amounts of freshwater inflow.

Abstract - This study was designed to examine the forest composition, structure and species richness of vegetation among undeveloped back-barrier islands near Sapelo Island, Georgia. Known colloquially as “marsh hammocks,” back-barrier islands are completely or partially encircled by estuarine salt marsh. There are upwards of 1200 hammocks along the Georgia coast, comprising approximately 6900 ha. In the face of increased development pressure, the cumulative impacts caused by small-scale construction of homes, roads, bridges, and septic fields may alter natural hydrologic and ecological processes. We surveyed vegetation on 11 undeveloped hammocks in four size classes and found that overall species diversity is low, but the abundance and diversity of vascular plants may increase with island size. Local and regional planners and conservation organizations may use this information to help develop land-based projects that are consistent with the sustainable use of coastal resources.

Abstract - The existence of public databases for archiving genetic sequence data, such as GenBank and the Ribosomal Database Project, coupled with the availability of standardized sequence alignment and comparison tools has led to rapid advances in the field of bacterial genetics and systematics. Many microbial ecologists now routinely submit gene sequences obtained from environmental isolates, clones, and bands excised from electrophoretic gels to public sequence databases. As the amount of environmental sequence data in these systems has increased, ecologists have begun using sequence databases for broader classes of studies, such as biogeography and community ecology. Unfortunately, the general lack of documentation and data quality control standards has resulted in many sequences being entered without appropriate metadata, effectively orphaning records from their ecological context information and making comparisons impossible.In order to address the shortcomings of public sequence databases, an independent 16S rRNA sequence database was recently developed at the Sapelo Island Microbial Observatory (SIMO) in Georgia, USA. The database was created to store complete information from all SIMO research activities using a hierarchical structure designed to reflect the actual flow of information from sample collection through final publication. By incorporating key fields from external databases, such as GenBank, the SIMO database is able to serve both as an independent research tool for SIMO scientists and as a reference source for SIMO data stored in other databases.

Abstract - We examined water use patterns in the hydrologic units that comprise the watersheds of the 5 major coastal rivers in Georgia (Savannah, Ogeechee, Altamaha, Satilla, St. Marys). The data for this analysis were obtained from the Georgia Water Use Program, which regularly surveys both water sources (groundwater and surface water) and water uses (domestic, commercial, industrial, mining, irrigation, livestock, thermoelectric, and hydroelectric) as part of the USGS National Water Use Synthesis. Total water withdrawal in the study area totaled 5749 million gallons per day (mgd) in 1995, with no large changes in either water withdrawal or water use patterns for the last 3 reporting years (1985, 1990, and 1995). Surface water accounted for 91% of the water withdrawal in the region, and much of this was for thermoelectric use in the watersheds of the Savannah and Altamaha Rivers. However, most of the groundwater that was withdrawn was withdrawn in the Coastal Plain. Only 10% of the water withdrawn was actually consumed, with the remainder returned to the surface water. Irrigation represented the largest consumptive use, and much of this occurred in the Coastal Plain.

Abstract - Georgia's vast brackish water landscape is maintained, to a large extent, by the hydrostatic pressure of freshwater discharges which keep the sea out of these areas. The salinity regime throughout this landscape responds to fluctuations in discharge. We describe the salinity regime in the Satilla River Estuary based on two intensive field campaigns in 1999 (20 Jan - 20 Mar and 9 Sept - 19 Oct). River discharge varied from almost 150 m^3s^-1 in February (twice the average) due to a single rain event in late January, to below 10 m^3s^-1 in May and June, after which it remained relatively low. The single discharge event resulted in large decreases in salinity throughout the estuary that lasted for about one week. (Salinity in Crows Harbor Reach was between 12-14 practical salinity units (PSU) on 20 Jan but fell to less than 2 PSU by 5 Feb) After early February, salinity slowly increased and had returned to near January levels by mid-April. Thus, during the ramp-up of river discharge in late January, the estuary flushed out much of its salt within about 20 days, and it took more than 2 months (70 days) to return to the salinity levels observed in January. The events analyzed here are described within the context of a series of salinity surveys over the course of 1999 and 2000, which should enable managers to gain insight into the interactions between river discharge, salinity structure, and flushing times in this system.