TY  - GEN
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/7671/
A1  - Batsaikhan, Ariunaa
N2  -    Annually 1000-3000 Tg mineral dust aerosol are emitted into the atmosphere, and transported over the oceans from one continent to the other. During the transport dust particles interact with components in the marine atmosphere and also with seawater as they fall into the ocean. Increased methyl iodide concentrations were observed during a field campaign on the Atlantic Ocean when dust storms occurred.    Volatile halogenated organic compounds (VHOC) are photolyzed to produce reactive halogen species which are responsible for ozone depletion. An abiotic production mechanism for VHOC, involving humic-like substance (HULIS), iron and halide, was supposed to produce methyl iodide through the interaction of dust particles with seawater as all necessary ingredients were present. The main goal of this study was to test this hypothesis and to further elucidate the process. For this, simple dust-seawater addition experiments in headspace glasses were conducted in the laboratory, following a purge-and-trap GC-MS analysis of the headspace gas.    Dust samples were collected in the source regions in southern Algeria and the Gobi Desert and, as representatives for aeolian dust, samples from Cape Verde Island and Lanzarote Island were used. To exclude the biological contribution, sterilized samples were also employed in this study. As assumed, methyl iodide was produced abiotically and the concentration increased tenfold after addition of Fe (III) within half an hour. Methylene chloride was also produced abiotically along with methyl iodide. In contrast to methyl iodide and methylene chloride, methyl chloride and isoprene were produced biologically, provided the production occurred after at least 24 hours of interaction of only non-sterilized samples with seawater. If the microorganisms responsible for the production of isoprene are common soil organisms found everywhere in the world, this process can be the reason for a hitherto not fully explained increase in atmospheric isoprene concentration during wet seasons, especially when the rain falls practically everyday. The results of this study show the importance of natural dust aerosols for the production and emission of volatile organic compounds to the atmosphere and open interesting questions for further studies. 
Y1  - 2007///
TI  - Reactive organic species on natural dust
AV  - public
KW  - Staub 
KW  -  Isopren 
KW  -  Methyliodid 
KW  -  Methylchlorid 
KW  -  SaharaDust 
KW  -  Isoprene 
KW  -  Methyl iodide 
KW  -  Methyl chloride 
KW  -  Sahara
ID  - heidok7671
ER  -