"The Deepwater Horizon oil spill resulted in heavy oiling conditions in the salt marshes of Northern Barataria Bay, including portions of Bay Jimmy, Bay Batiste, Wilkinson Bay, St. Mary's Point, and vicinity. Following source control and the completion of nearshore on - water recovery and bulk oil removal from many shoreline areas, persistent oiling conditions in the marshes of Northern Barataria Bay included heavily oiled vegetation mats and wrack lines that in some cases overlaid a thick layer of emulsified oil (mousse) on the marsh substrate. Much of the mousse layer averaged 2 - 3 centimeters (cm) in thickness and did not appear to be weathering or naturally degrading over time. Under maximum oiling conditions , 49 kilometers (km) (31 miles) of heavily oiled marsh shorelines were documented in Northern Barataria Bay"--Executive summary.

Deepwater Horizon Materials
National Ocean Service (NOS)