Grantee Research Project Results
2005 Progress Report: Effect of Sea Level Rise and Climate Variability on Ecosystem Services of Tidal Marshes
EPA Grant Number: R832220Title: Effect of Sea Level Rise and Climate Variability on Ecosystem Services of Tidal Marshes
Investigators: Craft, C. B. , Ehman, Jeffrey , Park, Richard , Joye, Samantha , Pennings, Steven
Institution: Indiana University - Bloomington , University of Houston , Pangaea Information Technologies, Ltd. , University of Georgia
Current Institution: Indiana University - Bloomington , Eco Modeling , Pangaea Information Technologies, Ltd. , University of Georgia , University of Houston
EPA Project Officer: Packard, Benjamin H
Project Period: April 1, 2005 through June 30, 2009
Project Period Covered by this Report: April 1, 2005 through June 30, 2006
Project Amount: $749,974
RFA: Effects of Climate Change on Ecosystem Services Provided by Coral Reefs and Tidal Marshes (2004) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Water , Ecological Indicators/Assessment/Restoration , Climate Change , Watersheds
Objective:
The objective of this research project is to develop a conceptual model that describes how ecosystem services vary along the salinity gradient and how sea level rise and climate variability will affect the delivery of ecosystem services.
Progress Summary:
Field sites were selected along three river-dominated estuaries (Altamaha, Ogeechee, Satilla Rivers) along the Georgia coast in July 2005. On each estuary, six tidal marshes (two tidal fresh-, two brackish-, and two salt-water marshes) were selected for sampling. Two soil cores (levee, plain), 0-60 cm in length, were collected at each wetland for a total of 36 cores. Cores were processed and are being analyzed for bulk density, 137Cs, 210Pb, organic carbon (C), nitrogen (N), and phosphorus (P) to determine rates of C sequestration, N and P retention, and sediment accumulation. Results from the Altamaha River estuary (six cores) are complete and indicate that tidal fresh- and brackish-water marshes sequester C at rates that are three to four times greater than salt marshes (Figure 1a). Tidal fresh- and brackish-water marshes also exhibit higher N retention than salt marshes (Figure 1b). Laboratory analysis of soils from the Ogeechee and Satilla Rivers is underway to determine sediment and nutrient accumulation in marshes within these estuaries.
Feldspar marker layers, used to measure short-term accretion and sediment deposition, were established in all 18 marshes in July 2005. Marker layers were sampled in February 2006 to gauge short-term sediment accretion and accumulation. We are in the process of compiling and statistically analyzing the data.
The National Elevation Dataset (NED) and the National Wetlands Inventory geospatial layers were compiled for the Altamaha, Ogeechee, and Satilla River estuaries during Year 1 of the project. These data are being preprocessed in preparation for the Sea Level Affects Marshes Model (SLAMM) simulation model. Additionally, all of the counties along the Georgia-South Carolina coast were contacted to obtain higher resolution and more accurate elevation data in an effort to improve model performance.
Modeling efforts began in the fall with an orientation meeting of the modeling group October 6-8 on Sapelo Island, Georgia. Using the Altamaha River estuary as a test case, SLAMM was used to simulate changes in wetland area and cover type in response to sea level rise under the A1B SRES (mean) climate scenario. The model predicts that 75 percent of tidal freshwater marsh and 38 percent of salt marsh will be converted by 2100, mostly through a corresponding increase in tidal flat and inland open water. Based on the data in Figures 1a and 1b, we estimate that, in the Altamaha River estuary, C sequestration will be reduced by more than 3400 MT annually (Table 1). N retention by tidal wetlands in the estuary will be reduced by approximately 225 MT each year.
We are making modifications to SLAMM by: (1) adding a salinity sub-routine to better drive marsh migration up the estuary as sea level rises, and (2) accounting for increased vertical accretion as sea level rises. We will incorporate and test these modifications in April 2006.
(a) | (b) |
Figure 1. (a) Organic Carbon and (b) Nitrogen Accumulation in Two Tidal Fresh-, Brackish-, and Salt-Water Marshes of the Altamaha River Estuary. Rates are calculated using 137Cs-based accretion, bulk density, and organic C and total N concentrations in cores from levee and marsh plain locations (n = 4 cores).
Table 1. Predicted Change in Wetland Area and C Sequestration of Tidal Fresh-, Brackish- and Salt-Water Marshes of the Altamaha River Estuary Between 1986 and 2100 Based on SLAMM. Numbers in parentheses represent N accumulation and retention in soil.
Marsh Type |
Carbon Accumulation (kg/ha/yr) |
Change in Wetland Area (ha) |
Change in C Sequestration (MT) |
Tidal fresh |
1020 (71) |
-2500 |
-2550 (-178) |
Brackish |
1500 (95) |
+400 |
+600 (+38) |
Salt |
270 (16) |
-5400 |
-1460 (-86) |
Future Activities:
We anticipate an active period of field sampling during Year 2 of the project. In May and August, samples will be collected from diked and undiked marshes for trace gas (CO2, CH4, denitrification) analysis. We also will collect soil cores from diked marshes to determine C sequestration, N and P retention, and sediment accumulation. In October, we will sample vegetation in diked and undiked marshes to measure productivity and (plant) biodiversity.
We intend to locate light detection and ranging (LIDAR_ data, where available, for our sites to improve the precision of our elevation data inputs relative to the NED. SLAMM presently uses differences in elevation among wetland types to produce the model output; coarser resolutions of NED relative to LIDAR sometimes do not allow us to distinguish between wetland types in our river-dominated estuaries. If we are not able to acquire LIDAR data, we will move forward with incorporating the salinity variable to drive wetland migration up the estuary rather than relying on differences in elevation. Our preliminary search indicates that LIDAR data are available for some portions of the Ogeechee River and several other areas along the Georgia and South Carolina coasts.
With respect to the modeling effort, we plan to move forward with modifications to SLAMM using the Altamaha River estuary, and then apply it to the Ogeechee River and Satilla River estuaries.
Journal Articles:
No journal articles submitted with this report: View all 51 publications for this projectSupplemental Keywords:
estuary, ecological effects, ecosystem, scaling, regionalization, modeling, climate models, Atlantic coast, Georgia, GA, South Carolina, SC, EPA Region 4,, RFA, Scientific Discipline, Air, Ecosystem Protection/Environmental Exposure & Risk, Aquatic Ecosystems & Estuarine Research, climate change, Air Pollution Effects, Chemistry, Monitoring/Modeling, Aquatic Ecosystem, Ecological Risk Assessment, Atmosphere, environmental monitoring, environmental measurement, meteorology, climatic influence, global ciruclation model, global change, climate, tidal marsh, climate models, ecosystem indicators, aquatic ecosystems, environmental stress, coastal ecosystems, global climate models, coral reef communities, sea level rise, ecological models, climate model, ecosystem stress, South Atlantic Coast, Global Climate Change, atmospheric chemistry, climate variabilityProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.