The oil slick summary frequency maps derived from satellite data depict for each area how often it was affected by the oil spill between 20 April and 29 August 2010. The continuous monitoring of the oil spill extent from space allowed the area covered by the oil spill to be estimated and the sites of landfall to be identified from the first week of the accident until the oil could no longer be monitored from space 19 weeks later. Analysis of the satellite data and the shoreline land cover revealed that mainly unconsolidated shores, bare areas (i.e. beaches) and estuarine wetlands were affected by oil landfall in Louisiana, Mississippi, Alabama and western Florida. For example, in Louisiana, the percentage of affected wetland shorelines exceeded 15%. These habitats are home for many species and include important breeding sites and nursery grounds of marine animals, such as fishes, shrimps, sea turtles and birds. Common straight-line distance assessments of the affected coastline, revealed that approximately 167 km of Gulf Coast shoreline experienced moderate to heavy oil impacts. Satellite technology allows assessing the exact length of the affected shoreline, defined as the length of the edge of a body of water, thereby including all water boundaries of inlets, estuaries etc. This methodology reveals the fine scale impact and was used to gather the oil spill interaction information. To allow comparability of results with other impact assessments, the summaries of the presented key results were therefore provided in proportions of the affected shoreline versus the total length of the shoreline. To understand how far sea turtles were affected by the oil landfall, a detailed map of sea turtle nesting sites was intersected with the cumulative weekly maps. The number of weeks the oil spill was present at the nesting site is an important indicator for the state of the sea turtle population. Besides the impact on the coasts, marine species, such as the Atlantic Bluefin Tuna, were also affected by the oil spill. Using various satellite data and models it was possible to get a preliminary estimate of the Deepwater Horizon oil spill impact on the ABFT spawning habitat and larvae survival. The study demonstrated well how large scale disasters can be efficiently monitored from space to identify most impacted areas. Multi-source satellite data provided valuable input for models and for the direct mapping of oil slick extents, allowing a timely, synoptic, continuous and precise mapping of the oil spill extent in the Gulf of Mexico (GOM). The intersection of satellite derived oil spill extents with various GIS datasets on valuable coastal and maritime habitats allows providing detailed information on the impacts of the oil spill on natural habitats, on the shoreline and in the GOM. The results derived in this study also highlight hot spot areas where increased restoration efforts are needed. Necessary tools and processing chains to derive products for almost near real time and historical oils spill status and impact assessments were developed and are ready for operational applications or refinement for other oil related monitoring tasks. |