After nearly 20 years of limited natural recovery of intertidal habitats along the Gulf Coast of the Kingdom of Saudi Arabia, large-scale remediation projects were conducted on approximately 1800 ha of tidal flat and salt marsh habitat. In Fall, 2011, multiple passes of mechanical tilling were used to break up oiled cohesive sediment layer across a heavily degraded sand tidal flat, to reduce subsurface liquid oil, and accelerate natural recovery.

Rates and degrees of test deformities in three foram genera were measured from samples collected at degraded and healthy sand tidal flat sites. Dominant genera and rates of test deformity at a heavily oiled sand tidal flat (average surface and subsurface total petroleum hydrocarbon (TPH) = 10,000 ppm ) were: Peneroplis (41.0%), Ammonia (38.7%), Elphidium (54.7%). Rates of deformity in the same three genera collected at a healthy sand tidal flat habitat were: Peneroplis (11.8%), Ammonia (7.5%), Elphidium (13.9%).

Nearly two years after the remediation event, results indicate a decreasing trend in percent foram deformities at the remediation site, which suggests oil toxicity as an ecological stressor has decreased as a result of remediation activities.

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