The explosion of the BP oil rig Deepwater Horizon resulted in the single largest oil spill recorded in the Gulf of Mexico (Cleveland 2010). As a result, there are long-term concerns regarding the environmental health of the northern Gulf of Mexico (GOM) region (the Florida Panhandle to Texas). It is difficult to predict the effect of oil on marshes as there is little information on the spatial distribution of oil after the spill.
There is the perception that Alabama coasts did not receive the magnitude of oil exposure from the Deepwater Horizon spill that other states (i.e., Louisiana) did but it was evident that Alabama coasts were exposed. It is uncertain if oil exposure was limited to the immediate shoreline areas (e.g., beaches, barrier islands) or if it traveled further up into coastal rivers and creeks. Also, within any wetland, the amount of residual oil may spatially vary based on proximity to open water. Marsh plants along the waters edge may have been exposed to the most oil but because of greater tidal fluctuations and energy, more oil may have been exported after initial exposure. Interior sections of the marsh may be less prone to tidal oil export and therefore more susceptible to impacts.
We have proposed a study to evaluate the distribution of oil and its impact on marsh vegetation along coastal Alabama. Marshes in this area tend to be dominated by Juncus roemerianus which, compared to other species, are not as well represented in the oil impact literature. Using baseline data collected before oil reached the shoreline (May 10-11, 2010) along with data collected in 2011, we have proposed a study to evaluate the distribution of oil and its impact on coastal marsh plants along the Alabama coast. Specifically, the objective of this study is to 1) examine the distribution of residual oil within and among coastal Alabama marshes and 2) determine any effect of residual oil on marsh structure (plant height, cover, density, and biomass).
Our study is intended to meet the following objectives:
- O1: Within each wetland, determine where the highest concentrations of residual oil (and possibly the greatest impact to plants) occur: at the edge or interior of the marsh.
- O2: Determine if residual oil exposure has caused a change in marsh plant structure/biomass (above ground biomass, stem height, cover) and if there is a relationship between oil exposure and plant structure/biomass.