Surfactant associated bacteria in the sea surface microlayer: Case studies in the Straits of Florida and the Gulf of Mexico

Abstract

Certain genera of bacteria found in the near-surface layer of the ocean can be involved in the production and decay of surface active materials (surfactants), resulting in slicks on the sea surface. Slicks can be observed with airborne or satellite-based synthetic aperture radar (SAR). Here, we report results, which point to a connection between the presence of surfactant-producing bacteria in the upper layer of the ocean and slicks, observed visually and in SAR imagery of the sea surface. From DNA analysis of in situ samples taken during RADARSAT-2 satellite overpass in the Straits of Florida during the 2010 Deepwater Horizon oil spill, we found a higher abundance of known surfactant-producing bacteria in the slick as compared to the non-slick area; furthermore, a higher abundance of these bacteria were observed in the water column as compared to those taken from the sea surface. Surfactants produced by marine bacteria in the organic matter-rich water column can then be transported to the sea surface through diffusion or advection. Within a certain range of wind-wave conditions, the organic materials (such as dissolved oil) in the water column processed by surfactant associated bacteria can thus be monitored with high resolution remote sensing techniques.