United States Gulf of Mexico Coastal Marsh Vegetation Responses and Sensitivities to Oil Spill: A Review

The present review summarizes the literature on the effects of oil spill on the U.S. Gulf of Mexico coastal vegetation including freshwater-, brackish-, and salt-marshes. When in contact with plant tissues, oil may have adverse impacts via physical and chemical effects. Oil may also become detrimental to plants by covering soil surfaces, leading to root oxygen stress and/or penetrate into the soil where it becomes in contact with the roots. The affected vegetation may survive the impact by producing new leaves, however, an episode of oil spill may impose severe stress. Oil spills may lead to partial or complete plant death but in many situations plants recover by regenerating new shoots. Plant sensitivity to oil varies among species; plants from salt marshes appear to be more sensitive than freshwater species. In addition, sensitivity appears to be dependent on the oil characteristics and the quantity of oil being spilled, repeated oiling events, season of spill, greenhouse vs. field conditions, and plant age are among the many factors that interact simultaneously. Many aspects of coastal plant responses to oiling remain in need of additional research, including the possibility that differences in oil sensitivity may interact with changes in the environment, and contribution to additional wetland losses through coastal erosion. Environmental stressors such as drought and salinity may also interact with oil, leading to the observed changes in plant species community composition following an oil spill.