RAPID: Collaborative Research: Deepwater Horizon Oil Spill, Marine Snow and Sedimentation

University Of Southern Mississippi, Hattiesburg MS

Investigators

Abstract

The accident at the BP oil well in the Gulf of Mexico in April 2010 resulted in an oil spill of unprecedented magnitude and consequences. Preliminary data collected in the beginning of May at the site of the accident show very high concentrations of marine snow in the water, especially in close proximity to the oil/ dispersants. The goal of this project is to evaluate the role these large marine snow-like particles play in the ecosystem during the following weeks to months. Neither the formation mechanisms nor the aggregate composition are known. These investigators will monitor the distribution of marine snow, characterize these particles and measure sedimentation rates to try to understand the role of snow formation and sedimentation in the ecosystem response. Intellectual Merit The characteristics and the potential fate of these marine snow like aggregates, which may potentially sink or float, be grazed, degraded or remain suspended in the water for a long period of time, is unknown. This accident is an opportunity to evaluate and expand our knowledge on reactions of marine ecosystems to such large disturbances in general and more specifically to study the role of aggregation and sedimentation in the process. Marine snow formation and its sedimentation are an essential component of elemental cycling. It has been postulated that sedimentation of material "cleans" the water column from particles. Marine snow is also thought to be hotspots of microbial activity. Potentially this oily marine snow could not only represent hotspots of activity for oil degrading organisms, but may also function to isolate oil into small volumes. However, rapid sedimentation of such oil aggregates may lead to anoxia at depths. Scientifically we do not understand the possible interactions between marine snow, marine particles, oil and dispersant. Broader Impacts The need to understand the impact of this largest oil spill to date on ecosystems and biochemical cycling is self evident. The consequences of the disaster and accompanying clean up measures (e.g. the distribution of dispersants) need to be evaluated to guide further mediating measures and to develop and improve responses to similar disasters in the future. Would it be advantageous if such oil aggregates sink, or should it rather remain suspended? Possibly measures can be developed to enhance sinking or suspension (e.g. addition of ballast minerals) once we understand their current formation and fate. Understanding the particle dynamics following the input of large amounts of oil and dispersants into the water is a prerequisite to develop response strategies for now and in the future.