Current Projects

Storm surge is often considered the greatest threat to life and property associated with a hurricane. Studies of the ecosystem effects of storm surge often focus on exposed coastal areas such as beaches. However, the upstream delivery of salt water can have long-lasting effects and can result in the decline of valuable freshwater tidal areas, which provide habitat to fish and wildlife, protect and improve water quality, and store floodwaters. This is especially important given the fact that these areas are already facing potential loss due to upstream salt water intrusion as a result of sea level rise. Hurricane Irma, which passed over the US on Sept. 11, 2017, caused the highest storm surge ever recorded on the central Georgia coast and resulted in salt water moving much further upstream than usual. The NSF-sponsored Georgia Coastal Ecosystems Long Term Ecological Research Project (GCE-LTER) has long-term experiments and monitoring programs that provide “before” data and a context for understanding the effects of this event. The investigators anticipate that the salt water delivered by the storm surge will affect multiple components of intertidal wetland ecosystems, including plants, animals, water chemistry, and soil surface elevation. The results of this research will be shared with coastal managers through the Georgia Coastal Research Council and the Georgia Coastal Hazards Community of Practice. The LTER researchers will also host K-12 teachers as part of the GCE Schoolyard Program and work with them to use this experience in the classroom.

Understanding the effects of disturbances like Hurricane Irma is difficult because they are hard to manipulate experimentally and can act differently on different parts of the landscape. The investigators hypothesize that: 1) the effects of the storm surge will be greater in upstream as opposed to downstream areas, with the greatest effects and longest recovery times in tidal fresh sites; 2) areas that have had previous exposure to salt water will show greater effects based on their history; and 3) changes will be more likely in areas that are at the borders between different wetland habitats (i.e. the edge between salt marsh and brackish marsh plants). They will test these hypotheses by 1) augmenting sampling of the GCE-LTER wetland monitoring sites, which are distributed along and extend inland from the central Georgia Coast; 2) taking advantage of an ongoing GCE-LTER field experiment to determine how prior saline disturbance treatments affect responses to the hurricane storm surge; and 3) collecting aerial imagery that will allow them to look at landscape level shifts in vegetation type compared to pre-storm maps, and doing additional sampling in pre-established transitional plots. The LTER researchers speculate that rare but severe events like this storm are the major occasions that re-set the distribution of habitats in these valuable intertidal wetlands.

This project will expose the spatial relationships and mechanisms of interaction between the two dominant ecosystem engineers of Georgia’s estuaries — Spartina cordgrass and oyster reefs — as well as how their distributions and relationships are likely to change over time. The research is intended to directly inform resource management (Oyster Restoration and Living Shorelines design) and predictive modeling – Sea Level Affecting Marshes Model.

We recognize that there is often insufficient communication between research and stakeholders. For this reason, a cross-cutting objective for our entire project is partnership and communication via audience-appropriate means. From this project’s inception we have gained advice and support from stakeholders such as DNR, MAREX and TNC and will continue to do so through the project’s progression. These partners will be critical in helping to disseminate results by useful and intuitive means, e.g. hosting a stakeholder workshop.

Elevated temperatures as a result of Climate Change, coupled with Sea Level Rise, are likely to have dramatic effects on oyster and Spartina distribution patterns. Here we examine the effect of predicted elevated air temperatures on oysters and Spartina, both separately and combined in a field and mesocosm experiment. Variable air temperatures will be created through the use of small greenhouses. Temperature will be regulated by thermostat controlled cooling vents. We will analyze survival probabilities of the two species as a function of species combinations (i.e., solo or combined), temperature, and tidal height. We will also investigate oyster reef accretion potential under present and predicted temperatures. Oyster reef accretion potential has been shown to be greater than extreme SLR predictions in North Carolina, however Georgia oyster reef ecology has been shown to function differently than regions even 100 miles north or south. We will measure accretion potential using oyster growth rates across intertidal reef gradients.

Katharine Napora and Dr. Victor Thompson of the University of Georgia will undertake research on the effects of climate shifts on the Native American groups who lived along the Georgia Coast from 4500 to 3100 years ago. This research will clarify the temporal relationships between abandonments of coastal shell ring village sites and environmental change. This research into the dynamics of human-environmental interactions on the Georgia Coast contributes to broader knowledge of responses to major climatic change, long-term environmental trends, and differential resilience during pivotal transitions in the southeastern U.S. This project will contribute information about how such groups were able to adapt to dramatic ecological shifts. This work will also provide opportunities both for undergraduate researchers to gain experience in dendrochronological methodologies and for the broader public to learn about the deep cultural and environmental history of the Southeast coast through outreach and educational events held during the course of the project.

To conduct this research, the project will examine terminal radiocarbon dates from shell middens and create a 6000-year bald cypress ringwidth chronology from excavated samples from the region. Dendrochronology is a methodology uniquely suited for an integrated study of events experienced at the human timescale and understood within the context of a deep time framework. Using tree-ring data combined with modeling the final occupational dates of large terminal Late Archaic sites, this research aims to reconstruct climatic conditions and provide a more precise timeline of shell ring abandonments for the northern Georgia Coast. This study will generate annual-scale data on environmental conditions during this period and will model extant and new radiocarbon dates from shell ring and shell midden sites to compare to the dendrochronological sequence, allowing for greater precision in understanding the timing of shifts in subsistence and settlement traditions.

Nearly half of the world’s population lives within 100 km of the coast, the area ranked as the most vulnerable to climate-driven sea-level rise (SLR). Projected rates of accelerated SLR are expected to cause massive changes that would transform both the ecological and social dynamics of low-lying coastal areas. It is thus essential to improve understanding of the sustainability of coupled coastal human-environment systems in the face of SLR. Salt marshes are intertidal habitats that provide a buffer for coastal communities to SLR and are also valued for many other ecosystem services, including wildlife habitat, nutrient cycling, carbon sequestration, aesthetics, and tourism. They are highly dynamic systems that have kept pace with changes in sea level over millennia. However, projected rates of SLR and increased human modification of coastal watersheds and shorelines may push marshes past a tipping point beyond which they are lost. Developing realistic scenarios of marsh vulnerability demands an integrated approach to understanding the feedbacks between the biophysical and social factors that influence the persistence of marshes and their supporting functions. This project will examine the comparative vulnerability of salt marshes to SLR in three U.S. Atlantic coastal sites that vary with respect to sediment supply, tidal range and human impacts. The research team will also address how feedbacks from potential adaptations influence marsh vulnerability, associated economic benefits and costs, and practical management decisions. Additional broader impacts include incorporating research results into curriculum used at local schools, an on-line cross-disciplinary graduate course, and on-going teacher-training programs, as well as training one postdoctoral researcher, four graduate students, and eight undergraduate researchers. This project is supported as part of the National Science Foundation’s Coastal Science, Engineering, and Education for Sustainability program – Coastal SEES.

This project leverages the long-term data, experiments and modeling tools at three Atlantic Coast Long-Term Ecological Research sites (in MA, VA, GA), and addresses the broad interdisciplinary question “How will feedbacks between marsh response to SLR and human adaptation responses to potential marsh loss affect the overall sustainability of the combined socio-ecological systems?” The goals of the project are to understand: 1) how marsh vulnerability to current and projected SLR, with and without adaptation actions, compares across biogeographic provinces and a range of biophysical and social drivers; and 2) which marsh protection actions local stakeholder groups favor, and the broader sustainability and economic value implications of feasible adaptation options. The biophysical research uses historical trends, “point” and spatial models to determine threshold and long-term responses of marshes to SLR. Social responses to marsh vulnerability are integrated with biophysical models through future scenario planning with stakeholders, economic valuation of marsh adaptation options, and focus groups that place the combined project results within a concrete policy planning context to assess how marshes fit into the larger view of coastal socio-ecological sustainability. This integrated approach at multiple sites along gradients of both environmental and human drivers will allow for general conclusions to be made about human-natural system interactions and sustainability that can be broadly applicable to other coastal systems.

More than fifty shell rings – large circular deposits of shellfish, artifacts, and other food remains surrounding broad, open plazas – can be found along the southeastern U.S. coast. Dating to the Late Archaic (circa 5,000 – 3,500 cal B.P.), these sites appear across roughly 2,500 km of shoreline between South Carolina and Mississippi and contain exceptionally well-preserved evidence of the first large-scale settlements in the region, though they are now gravely threatened by rising sea levels. With support from the National Science Foundation, Drs. Matt Sanger of Binghamton University, Victor Thompson of the University of Georgia, and Thad Bissett of Northern Kentucky University will investigate these sites by focusing on how previously mobile Late Archaic peoples adapted to a changing landscape (e.g., fluctuating sea levels) and built larger, more complex, and increasingly diverse societies. In seeking to settle long-standing disagreements over the function of shell rings, this project will generate new data and new models that will be of interest a broad range of archaeologists, anthropologists, and other researchers studying the earliest stages of large-scale human settlement, both in the U.S. and in other parts of the world. Comparative analysis across the thirteen sites selected for this study will help resolve a decades-long debate over whether shell rings were ritual gathering points, year-round villages, or a mix of the two. Likewise, this work will also look at factors behind the development of such large Late Archaic communities – namely, whether they were driven by incipient sedentism, religious communality, expansive exchange systems, localized adaptations, or shared encounters on a daily or intermittent basis.

Few shell rings have been studied systematically using comparable standards and methods, which has made it impossible to create dependable models for how or why the Late Archaic ring builders developed larger and more expansive societies in these places. This project seeks to create a robust, dependable corpus of data on shell rings by establishing shared standards of fieldwork and laboratory analysis that will be applied across all shell ring sites. The collaborative team will conduct geophysical surveys, excavations, and radiometric and isotopic analyses at thirteen key sites along the Georgia Bight. In addition to testing, refining, and disseminating best practices for current and future archaeologists interested in studying shell rings, this work will create a comparative dataset capable of answering critical questions about how the function of these sites may have varied over time and across space.

This project investigates how the interconnected socio-ecological processes of uneven exurban development, growing urban-rural connections, and potential increased flooding due to sea-level rise interact to transform land-use and vulnerability in coastal environments. The investigators will analyze how historical landscape modifications increase the vulnerability to flooding of marginalized coastal communities, and how that vulnerability impacts current economic development strategies intended to increase rural community resilience amidst increasing exurban development pressures. A coupled socio-ecological approach will be used in to understand the dynamics of regional population growth and the possible impacts of sea-level rise on coastal landscapes and communities. Despite widespread recognition, the uneven ways that the history of racial inequality has raised vulnerability for some while decreasing it for others continues to be absent from much of the research that is explicitly socio-ecological, and this project seeks to add this aspect. Findings from this research project will improve planning along vulnerable coastlines by providing relevant information to state and local government managers. Additionally, the research will create educational, training, and engagement opportunities for diverse scholars, undergraduate, and graduate students.

To understand the broader importance of uneven exurban development on differential communities and the impact of sea-level rise through interconnected interactions, the theoretical framing of this research will integrate insights from, and contribute to theory on, political ecology, Long-Term Socio-Ecological Research, and geographic studies of race relations. The investigators will use a mixed methods approach for data collection and analysis including archival research and ethnographic methods as well as land-use and land-cover change analysis along with hydrologic mapping. Through a case study of Sapelo Island, Georgia, this project asks three specific questions: (1) How did racialized agricultural development and population dynamics drive changes to Sapelo Island’s drainage ditch network across antebellum, postbellum, and State-owned periods? (2) To what extent does the contemporary drainage ditch network increase the likelihood of vulnerability to flooding driven by future sea-level rise? (3) How will African-American economic development strategies be impacted by the coupled dynamics of socio-demographic change and sea-level rise inundation? The investigators hypothesize that the same ditches that current African-American residents’ancestors built as slaves could now worsen sea level inundation and prevent those same communities from realizing their economic development objectives.

The Georgia Coastal Ecosystems (GCE) Long Term Ecological Research (LTER) program, which is based at the University of Georgia Marine Institute on Sapelo Island, Georgia, was established in 2000 to study long-term change in coastal ecosystems. Estuaries (places where salt water from the ocean mixes with fresh water from the land) and their adjacent marshes provide food and refuge for fish, shellfish and birds; protect the shoreline from storms; help to keep the water clean; and store carbon. The GCE LTER researchers study marshes and estuaries to understand how these ecosystems function, to track how they change over time, and to predict how they might be affected by future changes in climate and human activities. They accomplish this by tracking the major factors that can cause long-term change in coastal areas (e.g. sea level, rainfall, upstream development), and measuring the effects of these factors on the study site. They also conduct focused studies to assess how key marsh habitats will respond to major changes expected in the future, including large-scale experiments to evaluate the effects of a) increases in the salinity of the water that floods freshwater marshes (mimicking drought and/or sea level rise), b) changes in water runoff from land into the upland marsh border (mimicking drought or upland development), and c) exclusion of larger organisms in the salt marsh (mimicking long-term declines in predators). During this award they will initiate additional studies to systematically evaluate how coastal wetlands respond to disturbances. Disturbances, or disruptions in the environment, are particularly important to understand in the context of long-term background changes such as increasing sea level, and GCE researchers are working to assess the cumulative effects of multiple disturbances on the landscape. The GCE education and outreach program works to share an understanding of coastal ecosystems with teachers and students, coastal managers, citizen scientist and the general public.

The GCE-LTER project has four goals. 1) Track environmental and human drivers that can cause perturbations in our focal ecosystems. This will be accomplished this through continuing long-term measurements of climate, water chemistry, oceanic exchange, and human activities on the landscape. 2) Describe temporal and spatial variability in physical, chemical, geological and biological characteristics of the study system (coastal wetland complexes) and how they respond to external drivers. This will be accomplished through field monitoring in combination with remote sensing and modeling. 3) Characterize the ecological responses of intertidal marshes to disturbance. This will be accomplished by ongoing monitoring and experimental work to evaluate system responses to major perturbations in three key marsh habitats (changes in inundation and predator exclusion in Spartina-dominated salt marshes; increases in salinity in fresh marshes; changes in runoff in high marshes), by implementing standardized experimental disturbances along salinity and elevation gradients, and by tracking responses to natural disturbances. 4) Evaluate ecosystem properties at the landscape level (habitat distribution, net and gross primary production, C budgets) and assess the cumulative effects of disturbance on these properties. The project will also develop relationships between drivers and response variables, which can be used to predict the effects of future changes. This will be accomplished through a combination of data synthesis, remote sensing and modeling. The GCE “Schoolyard” program provides K-12 teachers with research experience that they use to develop classroom activities. The GCE will distribute a popular children’s book (now in its second edition) with accompanying lesson plans, and will produce a comic book with associated educational content. They will promote two citizen science web applications focused on the salt marsh. The GCE will provide research opportunities through internships for a diverse group of undergraduates, and will run web-based courses that provide interdisciplinary training for graduate students. The GCE will partner with the Georgia Coastal Research Council to exchange information with managers and promote science-based management of coastal resources. GCE data, reports and other information is broadly available on the GCE website.