Oxygen "sags" and oil "snow storm" near spill site, Nature.com (The Great Beyond), September 07, 2010:
The oil [buried 3cm below the seafloor 30km from wellhead] is in the form of tiny aggregates in the sediment, which [Biogeochemist Samantha Joye, from the University of Georgia in Athens] and her colleagues term "marine snow".
The snow was likely produced by biological breakdown, dispersant application, or a combination of both, Joye says. The team is doing experiments to determine how this material is generated.
Read the report here.
We propose to investigate the dynamics of marine snow formed in the oil spill area in the Gulf of Mexico. We will monitor the distribution of this marine snow in the water column using a marine snow camera and characterize these aggregates in terms of composition, density, sinking velocity, fragility etc. Additionally we will experimentally investigate their formation and potential fates. Using drifting sediment traps we will measure sedimentation rates of organic carbon and organic and inorganic particles and compare the composition of sinking material with that of marine snow. The overall goal of this research is to understand the role of oil and dispersant in the occurrence of the large amounts of marine snow like particles in the water and to assess their role and fate in the ecosystem and in biochemical cycling. We suggest that the marine snow at the oil spill side has formed due to the presence of oil and dispersant and its characteristics differ significantly from those of natural marine snow. We suggest that oil or oil derivatives aide in the formation of these marine snow-like particles and that oil contributes a significant fraction to this marine snow. As a consequence we expect this snow to be more physically sturdy, less microbial labile and less dense than most natural marine aggregates, leading to an accumulation of this material in the water column on timescales of weeks to months. Observations made 2 weeks ago by V. Asper and A. Diercks suggest that indeed these particles are sturdier than natural marine snow. Also the comet shaped oil-snow appears to be oriented differently than natural marine snow with the 'larger end pointing upward rather than downward, indicating very different sinking dynamics.