LTER: Georgia Coastal Ecosystems III

Intellectual Merit - The Georgia Coastal Ecosystems (GCE) LTER is located along three adjacent sounds (Altamaha, Doboy, Sapelo) on the Georgia coast and includes both intertidal marshes and estuaries. Although there are multiple, complex ways in which long-term drivers of climate change, sea level rise and human alterations of the landscape will affect the GCE domain, one of the primary consequences will be alterations in the amount and pattern of the delivery of water. These changes in water delivery can be conceptualized as presses and pulses in river inflow, local runoff, groundwater input, and tidal inundation, which will in turn manifest themselves as changes in salinity and inundation patterns in the domain. The research proposed for GCE-III is geared towards understanding how variations in salinity and inundation, driven by climate change and anthropogenic factors, affect biotic and ecosystem responses at different spatial and temporal scales, and to predict the consequences of these changes for habitat provision and C sequestration across the coastal landscape. The goals of the current funding cycle are: 1) To track long-term changes in climate (both average conditions and extreme events like storms) and human actions (in the watershed and adjacent uplands), and to evaluate the effects of these drivers on domain boundary conditions (riverine input, runoff and infiltration from adjacent uplands, sea surface height). We will accomplish this through long-term measurements of climate, water chemistry, oceanic exchange, and human activities on the landscape. 2) To describe temporal and spatial variability in physical (stratification strength, estuarine intrusion length, residence time), chemical (salinity, nutrient concentration and speciation, organic matter lability), geological (accretion) and biological (organism abundance and productivity, microbial processes) properties in the domain and to evaluate how they are affected by variations in river inflow and other boundary conditions. We will accomplish this by tracking both water and marsh conditions at our core monitoring sites, remote sensing, and hydrodynamic modeling. 3) To characterize the responses of the marsh habitats in the domain (Spartina marsh, fresh/brackish marsh, high marsh) to pulses and presses in salinity and inundation. We will accomplish this through monitoring, field manipulations, and modeling designed to evaluate changes in inundation in the Spartina marsh, increased salinity in the fresh/brackish marsh, and changes in hydrologic connectivity in the high marsh. 4) To describe patterns of habitat provisioning and C sequestration and export in the GCE domain, and to evaluate how these might be affected by changes in salinity and inundation. We will accomplish this by using modeling and field observations to evaluate habitat provision and C flow under different scenarios. These efforts will be synthesized into a synoptic understanding of both biotic and ecosystem responses to variations in salinity and inundation of different timing and intensity, which will be used to assess thresholds between habitats and the potential for state changes in the domain.   Broader Impacts – The goal of GCE outreach is to enhance scientific understanding of coastal ecosystems by teachers and students, coastal managers, and the general public. The GCE Schoolyard program is built around long-term contact and mentoring of educators. The Schoolyard program, which works in partnership with the UGA Marine Extension Service, is also developing activities and distribution plans for the GCE Children’s book. The GCE Peach LSAMP partnership will provide research opportunities for minority undergraduates, and a cross-site interdisciplinary course will provide training for graduate students. Our partnership with the Georgia Coastal Research Council helps us to promote science-based management of coastal resources by facilitating information transfer between scientists and managers. GCE scientists also routinely participate in meetings and other public outreach forums. GCE information is also broadly accessed via our website, which uses a state-of-the art information system to manage and display information on study sites, research, taxonomy, data sets, publications, and project administration.