Production and consumption of dimethylsulfide (DMS) in North Atlantic waters

Abstract

Production and consumption of dimethylsulfide (DMS) were studied in surface waters of the northwest Atlantic between latitude 32°and 45°N during May 1998. The kinetics of DMS production by the whole planktonic community were studied in short-term (3 h) experiments using additions of dissolved dimethylsulfoniopropionate (DMSP d ) (0 to 3000 nM). Measurements of DMS production and DMSP d consumption showed that the DMS production rate increased in direct proportion to the concentration of added DMSP d . This rate relationship did not saturate, suggesting acclimation of the microbial community to DMSP d concentrations much higher than the average for bulk seawater. Longer-term experiments were performed in which DMSP d consumption and DMS production were measured over 48 to 60 h. The DMSP d consumption rate decreased as the concentration of DMSP d decreased during the incubations. However, the DMS production rate was initially constant for the first 36 h. When DMSP d concentrations fell below 50 nM, DMS production stopped, even though DMSP d consumption continued. A possible explanation is that DMSP cleavage might dominate the total DMSP consumption at high DMSP d concentrations while DMSP demethylation and other processes dominate at low DMSP d concentrations. DMS consumption was measured both directly and by using the DMS consumption inhibitors dimethyl disulfide (DMDS) and methyl butyl ether (MBE). DMS consumption was generally undetectable except at 1 station dominated by a dense population of the DMSP-producing phytoplankton Chrysochromulina sp. and where ambient DMS concentrations were high. This suggests that the potential for DMS consumption is highest where ambient DMS levels are elevated. Pooling results from these experiments with earlier results from more northerly waters revealed an inverse exponential relationship (r 2 = 0.75, p < 0.0001) between the potential rate constant and chlorophyll a standing stock across a wide area of the Northwest Atlantic. This finding is potentially useful for the development of DMS production models.

Impact of ocean acidification on Arctic phytoplankton blooms and dimethyl sulfide concentration under simulated ice-free and under-ice conditions

“…Samples of both DMSP d and DMSP T were preserved by adding 50 µL of a 50 % sulfuric acid (H 2 SO 4 ) solution to the 5 mL tubes, which were then stored at 4 • C in the dark until analysis in the laboratory. DMSP concentrations were determined as DMS through hydrolysis with a 5 N solution of NaOH, purging and cryo-trapping in liquid nitrogen, followed by analysis on a Varian 3800 Gas Chromatograph equipped with a pulsed flame photometric detector (PFPD, Varian 3800) with a detection limit of 0.1 nmol L −1 (Scarratt et al, 2000;Lizotte et al, 2012;Galindo et al, 2016). All DMSP samples were calibrated against multiple micro-injections of a 100 nmol L −1 solution of standardised dimethyl-B-propiothetin (DMPT from Research Plus) hydrolysed with a 5 N solution of NaOH.…”

Spatial distribution of dimethylsulfide and dimethylsulfoniopropionate in the Yellow Sea and Bohai Sea during summer

“…Kiene and Service (1991) found that rates of DMS biological production and consumption increased when temperatures were between 16 and 30°C, and that, because of low biological activity, biological production rates were low at 4 and 49°C. Scarratt et al (2000) showed that production rates of DMS were higher when water temperatures were between 16 and 20°C. However, in this study, water temperature and DMS production or consumption rates were not correlated.…”

Influence of phytoplankton taxonomic profile on the distribution of dimethylsulfide and dimethylsulfoniopropionate in the northwest Atlantic

“…and G. flagellare, may dominate the production and distribution of DMS and DMSP in this region of the NW Atlantic at this time of year. The data presented here comprise part of a larger data set covering several years of observations in this region, including in situ and shipboard incubations, which is described in part elsewhere (Scarratt et al 2000b). …”