Award: OCE-1155320

Methane is a greenhouse gas that has a global warming potential that is 45 times more powereful than carbon dioxide over a 100 year times scale. In the ocean, methane is produced deep in the sea floor, and various transport processes move it towards the surface, towards the water column. As it is transported upwards, methane encounters sulfate, which is the second most abundant element in seawater. Bacteria live at this interface, where methane intersects sulfate, and they essentially eat the methane and breath the sulfate. In this sense, "food" is anything that donates electrons, and what is respired or "breathed" accepts the electrons. This process is called anaerobic methane oxidation, and it "shields" the water column or acts as a biofilter for methane coming up from below. The results of our study indcate that in this interfacial zone, there are other processes that use up the sulfate, interfering with this biofilter, so that the biofilter is only 55-65% effecient. Part of this interferant is aged dissolved organic carbon which is also coming up from below and it encoutners the sulfate and is oxidized similarly to the methane. Some 30% of this dissolve organic carbon is oxidized. In addition to making these measureents we developed mathematical models of these processes which allow us to verify that we understand the chemistry. These models are basically complex accounting that add the processes together to see if we can reproduce the outcome. Last Modified: 06/15/2016 Submitted by: Jeffrey P Chanton