Field Assessment and determination of concentration levels of Dimethylsulphide in Tropical Seawater

Abstract

Dimethylsulphide (DMS) is an important climatically reactive trace gas which is emitted from the seawater to the atmosphere. It undergoes various oxidative reactions to produce cloud condensation nuclei, which affect the earth radiation budget. DMS and its precursor dimethylsulphoniopropionate (DMSP) were measured using a modified vapour generation - chemiluminescence (VG-CL) detection system that was designed for this study. The chosen sampling locations used for the measurement were Nigeria Institute of oceanography and marine research (NIOMR) and ELEGUSHI. They are situated along the Gulf of Guinea. The modified VG-CL analyser was used for trace analysis of dimethylsulphide in the study area. The mean concentrations of DMS in the surface seawater at the two sampling locations ranged from 0 to 35.53±2.34 nM, 10.67±0.28 and 44.95±0.27 nM, respectively. The average minimum and maximum concentrations of DMS and DMSP across the two locations were between 0 and 44.95 nM, respectively. The concentrations of DMS and DMSP were compared across the sampling locations, and the observed pattern showed that DMS for ELEGUSHI has a higher concentration than NIOMR. The result further revealed that the concentration of the DMS is a function of the sea surface temperature (SST) of the aquatic ecosystem. The observed DMS concentration data of this study provides a baseline measurement for the tropical Atlantic Ocean (Lagos), thus a significant addition to the global DMS database.