Abstract

Globally, carbon burial to the deep ocean by marine snow fluxes is of comparable magnitude as anthropogenic carbon emission. Recent proposals call for large-scale commercial fertilization of the ocean as a way to enhance marine snow fluxes and thereby sequester atmospheric carbon and lessen the greenhouse effect. The hidden danger of such proposals, however, lies in the fact that very little is known about the ecological impacts marine snow may have on the surrounding environment. Far from being inert sinking particles, marine snow constantly interacts with the ambient microbial communities. Intensive bacterial and protist activities on and around marine snow transform and degrade marine snow materials, with significant ramifications for carbon fluxes. Field observations show specific scaling relationships between the size (age) of marine snow and the associating microbial abundances, although the underlying causes are not known. We have constructed and tested simple models that adequately describe the initial colonization, growth and mortality of bacteria on marine snow particles. Our subsequent laboratory and mesocosm studies, however, show that the succession and inter-specific interactions of the microbial community on marine snow is more complex than it is previously thought.

Light refreshments are served in the Interaction Area (4th floor of the Oceanography/Physics Building) at 4:00 p.m.

All seminars begin at 3:00 p.m. and are held in room 200 of the Oceanography/Physics building.