Impact of solar radiation on the biological removal of dimethylsulfoniopropionate and dimethylsulfide in marine surface waters

D Slezak*, A Brugger, G J Herndl

*Corresponding author for this work

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Abstract

The effect of natural surface solar radiation on the biological removal of dimethylsulfo-niopropionate (DMSP) and dimethylsulfide (DMS) was determined and compared to the photochemical removal of DMSP and DMS. Natural bacterial assemblages (0.8 mum filtered seawater) from the northern Adriatic Sea and the coastal North Sea were exposed to surface solar radiation and incubated in the dark; the DMSP and DMS concentrations were measured concurrently. Photochemical removal rates were determined in 0.2 mum filtered seawater. Biological removal of DMSP in the light was 62 +/- 14% lower than the biological removal rate obtained in the dark. High spatial and temporal variability in the biological removal rates was observed for the dark treatments, as well as for its sensivity to solar radiation, with rates for light treatments varying from 29 to 81% of those in the dark. The DMSP concentration above which no further increase of the biological DMSP removal rate was observed was substantially lower in the light treatments (similar to 30 nM) than in the dark treatments (> 80 nM). UV-B radiation only accounted for a minor inhibitory effect (similar to 15% of total inhibition), whereas UV-A and PAR (photosynthetically active radiation) both contributed similar to 42% of total inhibition. Biological DMS removal under solar radiation was only similar to 40 +/- 14% of the biological DMSremoval in the dark, Under surface solar radiation, photochemical removal was always higher than the dark biological removal. Our results indicate therefore, that the DMSP and DMS dynamics in the oceanic surface waters are severely influenced by solar radiation due to the partial inhibition of the microbial consortia responsible for DMSP and DMS turnover.

Original languageEnglish
Pages (from-to)87-97
Number of pages11
JournalAquatic Microbial Ecology
Volume25
Issue number1
DOIs
Publication statusPublished - 10-Aug-2001
Externally publishedYes

Keywords

  • DMSP
  • DMS
  • ultraviolet (UV) radiation
  • bacteria
  • biological removal
  • photochemical alteration
  • DISSOLVED ORGANIC-MATTER
  • ULTRAVIOLET-B RADIATION
  • GULF-OF-MEXICO
  • ATMOSPHERIC SULFUR
  • OZONE DEPLETION
  • UV-RADIATION
  • SUBSTRATE CONCENTRATION
  • LEUCINE INCORPORATION
  • DNA PHOTODAMAGE
  • BACTERIOPLANKTON

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