New Antimicrobial and Refractory Dissolved Organic Matter Tracers in the Deep Ocean

Dissolved organic matter (DOM) in the deep ocean is considered to be refractory. However, the term refractory DOM (RDOM) is somewhat arbitrary, especially when we divorce radiocarbon measurements from residence time. Evidence is growing that the 2-endmember mixing as the bases of radiocarbon age determination is failing due to additional 14C-free sources of organic carbon entering the interior of the oceans. Hence, we need alternative tracers for DOC residence time and turnover to better predict residence time. Determination of specific structures of deep ocean DOM and within the RDOM pool has been very slow and we are still lacking any true tracers that originate from in situ processes which accumulate in the deep ocean. Developments in mass spectrometry interfaced with liquid chromatography have advanced the field, but the presumed extremely low concentrations of individual compounds in complex DOM mixtures have restricted progress. Here I show that the utilization of the most sensitive and not high-resolution MS approaches is able to assist in structural elucidation. New structures will be presented that contain nitrogen and have antimicrobial properties. A newly developed quantification method of these intriguing new tracers for deep ocean DOM will also be presented.

Presentation Preference: Oral

Primary Presenter: Michael Gonsior, University of Maryland Center for Environmental Science (gonsior@umces.edu)

Authors:

Michael Gonsior, University of Maryland Center for Environmental Science  (gonsior@umces.edu)