Premium
Hydroxide decomposition of dimethylsulfoniopropionate to form dimethylsulfide
Author(s) -
Dacey John W. H.,
Blough Neil V.
Publication year - 1987
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl014i012p01246
Subject(s) - dimethylsulfoniopropionate , seawater , hydroxide , decomposition , reaction rate constant , chemistry , kinetics , reaction rate , dimethyl sulfide , artificial seawater , environmental chemistry , inorganic chemistry , organic chemistry , catalysis , geology , sulfur , oceanography , physics , nutrient , phytoplankton , quantum mechanics
The kinetics of DMS production resulting from reaction of OH − with DMSP were investigated as a function of hydroxide concentration and temperature. The reaction was first‐order with respect to DMSP and OH − . The second order rate constant at 20+/−1°C is 0.0044 M −1 sec −1 . The activation energy for this reaction is 14.4 kcal mole −1 . Our investigation indicates that the rate of reaction of DMSP with OH − is very slow at the pH of seawater (half‐life of about 8 years at 10°C), suggesting that DMSP, which may be a major precursor of DMS in seawater, decomposes in the ocean by other mechanisms. We have cultured a bacterium which produces DMS from DMSP quantitatively at rates many orders of magnitude higher than indicated by OH −1 decomposition, suggesting that enzymatic processes accelerate the production of DMS from DMSP in seawater.