Post-graduate theses
Current Record: 4842 of 6576
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| Identifier |
000280457 |
| Title |
Επίδραση των φυτοπλαγκτονικών ομάδων στην κατανομή και παραγωγή των ολικών και διαλυμένων μορφών διμεθυλοσουλφονιοπροπιονικού ιόντος (DMSP) και διμεθυλοσουλφοξειδίου (DMSO), στην περιοχή του Β,Αιγαίου |
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Author
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Μάρα, Παρασκευή
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Thesis advisor
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Μιχαλόπουλος, Νίκος
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| Abstract |
During last years, the biogeochemical cycling of seawater and atmospheric role. Dimeth in the euphotic layer of the oceans. The main to the a aining part is cycled within the water column through bacterial transformation/consumption and oxidation dimethylsulfoxide (DMSO). In order to investigate the possible climatic impact of DMS, numerous efforts have been carried out both through modelling and experimental studies. In this study, seawater measurements of the total and dissolved form of DMSP and DMSO which are though to be the main precursors of DMS, were taken during 2 oceanographic cruises, (September 2003/July 2004) in order to perform a research concerning the spatial distribution, the vertical profiles in the water column and the possible relation of the above substances with phytoplankton species in North Aegean Sea. The spatial occurrence of DMSP in the North Aegean Sea is determined by a number of biogeochemical factors controlling the area such as the abundance specific phytoplankton species. The abundance of Gymnodinium sp. and generally small sized dinoflagellates as well as ccolithophores, seemed to be high correlated with both forms of DMSP during both cruises. On the contrary, diatoms and especially Rhizosolenia, Nitzchia and Chaetoceros sp., which were the dominant species during the 2ond cruise, didnt correlate with the above biogenic forms. At the same time physicochemical factors, such as temperature and chlorophyll a, (Chla) correlated with the total and dissolved form of DMSP only in specific occasions. form of dimethylsulfide (DMS) has received an increased attention. It is proposed that atmospheric DMS through its oxidation products, could play an important climatic MS, which is the most abundant volatile sulfur compound in surface seawater, is a byproduct of the plankton activity, yielded by a cleavage of ylsulfoniumpropionate (DMSP) precursor of this compound is the DMSP which is thought to play a very important role in the regulation of the osmotic pressure in phytoplankton cells. DMS is mainly produced during senescence phases of phytoplankton and grazing by zooplankton. Surface seawater is always supersaturated in DMS. Thus a fraction of DMS is emitted tmosphere at the interface ocean-atmosphere, and the rem w to DMSO was found in higher concentrations on the surface layers between 2- 10m, yielding the relation with DMS, which is transformed due to photooxidation procedures that take place mainly in the upper layers of the water column, in the above aquatic form. At the same time the concentrations of DMSO, were highly correlated with chlorophyll a, (Chla) implying a possible relation with phytoplanktonic species.
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| Language |
Greek |
| Issue date |
2005-07-01 |
| Collection
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School/Department--School of Sciences and Engineering--Department of Chemistry--Post-graduate theses
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Type of Work--Post-graduate theses
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| Permanent Link |
https://elocus.lib.uoc.gr//dlib/e/7/8/metadata-dlib-2005mara.tkl
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| Views |
193 |
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