AME 78:177-185 (2017)  -  DOI: https://doi.org/10.3354/ame01812

ABSTRACT: The marine diatom Thalassiosira pseudonana NCMA 1335 produces dimethylsulfoniopropionate (DMSP), a compound thought to be the start of an antioxidant system in some marine algae that ends with methanesulfonate (CH₃SO₃^-, MS). We demonstrate that T. pseudonana is able to use MS as a sole sulfur source, which implies a capacity to recycle sulfur derived from MS for growth. Growth on MS-only cultures was similar to controls (0.25 ± 0.05 d^-1 versus 0.33 ± 0.04 d^-1, respectively) but resulted in lower total biomass (2.4 ± 0.3 × 10⁶ cells ml^-1 versus 5.7 ± 0.5 × 10⁶ cells ml^-1). Growth on trifluoromethanesulfonate was extremely limited. DMSP content was not significantly affected when grown on MS, but cellular formaldehyde and sulfite contents were significantly higher, suggesting that MS metabolism is similar to that of bacteria and yeast. These results are the first demonstration of T. pseudonana being able to grow on a sulfonate as the exclusive sulfur source and hint at a rich sulfur metabolism that has hitherto been unexplored and which may play a role in the biogeochemical cycling of sulfur. These results also underscore the potential for DMSP and its derived compounds to act as an antioxidant system.

KEY WORDS: Nutrient dynamics · Biogeochemistry · Dimethylsulfoniopropionate · Dimethylsulfide