GCE Research Program

Program Overview

The Georgia Coastal Ecosystems (GCE) LTER program focuses on estuarine and intertidal wetland ecosystems and how they respond to long-term change (see key findings). The program began in 2000 and is now in its fourth grant cycle (GCE-IV). During GCE-I we focused on describing the patterns of variability in estuarine processes with an emphasis on water inflow as a primary environmental forcing function. We built on this during GCE-II, conducting research to elucidate the mechanisms that underlie this variation and in particular the extent to which gradients in water inflow drive landscape patterns. In GCE-III, we asked how variation in salinity and inundation affect biotic and ecosystem responses at different spatial and temporal scales, and sought to evaluate the consequences of these changes for habitat distribution and C flow across the coastal landscape. Now, during GCE-IV (2018-2024), we are building on the major programmatic elements developed during the first three funding cycles but with an explicit focus on how perturbations affect the domain. We are using a combination of monitoring, focused studies, long-term field manipulations, and modeling to characterize perturbation patterns and their relationships to external drivers and to evaluate the consequences of disturbance responses at the landscape scale (see conceptual model and research portfolio below).

GCE-IV Focus Areas

The research being carried out in GCE-IV is designed to characterize perturbation patterns and their relationships to external drivers, to develop an understanding of disturbance responses, and to evaluate the consequences of these responses at the landscape scale.

We divide our research into 4 inter-related programmatic areas (color-coded to match the figures below).

External Drivers of Change (Area 1): We track long-term changes in external drivers such as climate change, sea level rise, and human alterations of the landscape and to statistically characterize these external drivers in terms of long-term trends, spatio-temporal variability, and occurrence of extreme events (e.g., storms, droughts) so that we can investigate the links between external drivers, domain perturbations, and ecosystem responses. (more information)

Long-term Patterns within the Domain (Area 2): We follow spatial and temporal variability in physical (estuarine salt intrusion length, residence time, and inundation), chemical (salinity, nutrient concentration and speciation, dissolved inorganic C, and pH), geological (accretion) and biological (organism distribution, abundance, and productivity) characteristics so that we can understand the biophysical template of the GCE domain in relation to external drivers and evaluate responses to domain perturbations. (more information)

Marsh Response to Disturbance (Area 3): We characterize the ecological responses of our three key marsh habitats—S. alterniflora-dominated salt marsh, fresh/brackish marsh, and high marsh—to disturbance so that we can track trajectories of response and recovery from disturbance and characterize transitions to new states. (more information)

Integration and Forecasting (Area 4): We evaluate ecosystem properties at the landscape level (habitat distribution, net and gross primary production, C budgets) and to assess the cumulative effects of disturbance on these properties so that we can produce synoptic estimates of ecosystem properties in the GCE domain and develop driver-response relationships for marsh ecosystems. (more information)

Conceptual Model Guiding GCE Research

Conceptual Diagram
Conceptual Model of Disturbance. Domain perturbations can be caused by external drivers and internal processes. Abiotic and disturbance (biotic) responses to these events are a function (ƒ) of the interaction between domain perturbations and the system state (biophysical template), which can feed back to the biophysical template. Information on both perturbations and disturbance responses are used to produce a cumulative disturbance-scape.

GCE-IV Research Portfolio

Research Portfolio

Signature Publications



This material is based upon work supported by the National Science Foundation under grants OCE-9982133, OCE-0620959 and OCE-1237140. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.