Summary:
Most post-spill assessments of coastal salt marsh status will be limited to habitat delineation and documentation of change in area. However, to address the central question about the large scale perturbations of the northern Gulf of Mexico wetland ecosystem structure and function due to the Macondo 252 oil spill, assessment of marsh health before-during-after the spill is essential.
This study will allow the identification of 'hotspots' of marsh degradation and the extent of recovery (if any) because of the oil spill which can only be delineated by evaluating marsh biophysical characteristics including distribution of chlorophyll content, green leaf area index (a ration of green foliage area vs. ground area), green vegetation fraction (percent green canopy cover), and green biomass. We intent to combine field data with the Landsat 3 0-m datasets to retrieve the biophysical characteristics in salt marshes across three states (LA, MS, and AL) before and after the spill.
The overall goal of the proposed research is to quantify and map the ecological impact of the oil spill on the photosynthetic activity, physiological status, and primary productivity of the coastal salt marshes to facilitate the prioritization of future restoration actions. The field data collected during the Phase 1 will be used in satellite model calibration through a remote sensing mapping protocol to generate monthly time-series map used in satellite model calibration through a remote sensing mapping protocol to generate monthly time-series map products for the salt marsh biophysical properties along the LA-MS-AL coast.
The marsh biophysical products developed through this project will be used in combination with the biogeochemical and climatological data for assessing and evaluating the productivity of marshes that are impacted by the massive oil spill, thus providing state regulators important information for restoration and management.
The specific questions to be answered through study are:
1. Which wetland patches (location) are most degraded due to the spill?
2. Which salt marsh species is the most vulnerable to the spill?
3. What is the degree of damage and extent of recovery in the spill impacted marsh habitats?
4. Is the damage due to sedimentary biogeochemical processes resulting from the degradation of the oil and increased microbial production of reduced chemical species such as sulfide?
5. Was some of the damage due to local climatic perturbation and early senescence rather than the spill?
6. Is there a high probability of marsh fire due to spill related marsh degradation or browning?
The proposed research develops scientific products that can be used to assess marsh physiological characteristics at large spatial scales, which will directly inform restoration and conservation decision-making. The maps and tools produced by this study will be immensely helpful to the coastal managers across LA-MS-AL to evaluate and prioritize the massive marsh restoration effort that is going to take place because of the spill.