The labile organic sulfur pool: characterization, quantification, and distribution in the surface ocean

Marine organic matter has historically been thought of in terms of its carbon, nitrogen, and phosphorus content, yet we now recognize sulfur as a fundamental component of phytoplankton stoichiometry with one sulfur atom assimilated into biomass for every 95 atoms of carbon (C₁₂₄N₁₆P₁S_1.3). This stoichiometry indicates a large global inventory of labile organic sulfur in marine phytoplankton (~28 Tg S). As organic sulfur metabolites travel through the ocean's organic matter reservoir attached to carbon backbones, their transformation represents a link between marine carbon and sulfur cycles. Yet, many labile organic sulfur compounds present in the ocean remain uncharacterized. Here, we leverage methods that identify sulfur-containing compounds through isotopic patterns to explore environmental metabolomic data through the lens of organic sulfur cycling. For a subset of chemically identified sulfur metabolites, we track their abundance and distributions and their potential metabolic links between phytoplankton producers and associated bacterial consumers. Exploring data from the North Pacific, North Atlantic, and Gulf of Mexico provides a means to assess organic sulfur inventories and distributions across a range of ocean biomes. Enhanced resolution of microbial sulfur metabolites improves our ability to decipher sulfur-based microbial metabolic networks that influence ocean biogeochemical cycles. 

Presentation Preference: Oral

Primary Presenter: Bryndan Durham, University of Florida (b.durham@ufl.edu)

Authors:

Bryndan Durham, University of Florida  (b.durham@ufl.edu)

Rebecca Key, University of Florida  (rebeccakey@ufl.edu)

Laurel Meke, University of Florida  (lmeke@ufl.edu)

Angela Boysen, Pacific Lutheran University  (aboysen@plu.edu)

Katherine Heal, Pacific Northwest National Laboratory  (katherine.heal@pnnl.gov)

Laura Carlson, University of Washington  (truxal@uw.edu)

Laura Burchill, University of Melbourne  (laura.burchill@unimelb.edu.au)

Spencer Williams, University of Melbourne  (sjwill@unimelb.edu.au)

Anitra Ingalls, University of Washington  (aingalls@uw.edu)