Linn, L. J. University of South Alabama, llinn@mobile.gulf.net
Kiene, R. J. University of South Alabama, rkiene@jaguar1.usouthal.edu

 
THE FATE OF DMSP SULFUR IN SEAWATER FROM THE GULF OF MEXICO: TRACER STUDIES WITH 35S-LABELED DMSP AND DMS.
 
Previous studies of DMSP cycling focused mainly on production of gases while neglecting other possible fates of the sulfur. In this study we used tracer additions of 35S-DMSP and 35S-DMS to study the fate of DMSP-sulfur at natural concentrations. Dissolved 35S-DMSP added to coastal seawater was consumed, on the order of minutes to hours, with the sulfur partitioning into three major operational pools: particulates (50%), dissolved non-volatiles (40%) and volatiles (10%). Transient accumulation of 35S-DMSP in bacteria accounted for some of the particulate 35S, but most of the DMSP was rapidly transformed into compounds that were stable in cells over many hours. 35S-labeled volatiles were produced rapidly from 35S-DMSP, but were also quickly consumed, the kinetics suggesting methanethiol as the major product. Dissolved non-volatile 35S accumulated steadily and approximately half of this pool was confirmed to be sulfate. Experiments with 35S-DMS revealed that turnover of this compound was much slower than for DMSP, and retention of the DMS-sulfur in particulates was only a minor fraction of the total amount metabolized. The majority of 35S-DMS was transformed into dissolved non-volatile products. Natural turnover of dissolved DMSP results in minor production of sulfur gases, and substantial production of previously unrecognized products.
 
Day: Thursday, Feb. 4
Time: Poster
Location: Sweeney Center
 
Code: SS37TH0314S