Sekundarni povzetek: |
The thesis presents parameters affecting the presence of methyl-mercury (MeHg) in the water column of the Mediterranean Sea. The area is polluted with mercury due to a wide variety of sources stemming from the cinnabar belt underlying the Mediterranean from Spain to Turkey, where the most of the world mercury stock can be found. Mercury is transported through the air and rivers into marine environment.
Numerous parameters that affect the concentrations of methyl-mercury and the methylation in the water column (microbial activity, temperature, pH, organic matter, redox conditions, sulfide, and salinity) are still not clarified. These parameters are described in detail on the basis of available literature.
Several analyses were performed on data obtained in the framework of the MERCYMS and MED-OCEANOR projects in order to investigate possible connections between environmental parameters, concentrations, and transformation coefficients of mercury in marine environment. Such a parameterisation and possible new reaction coefficients would represent a valuable tool in modelling of mercury methylation and demethylation in the water column.
Correlation coefficients were extremely low in all performed analyses (< 0.5); therefore, it was not possible to establish any connections between the measured environmental parameters and the concentrations of methyl-mercury from the obtained trendlines. Seasonally averaged concentrations within different layers and parts of the Mediterranean Sea showed elevated concentrations of MeHg in the Adriatic Sea, and higher MeHg concentrations at the sea-bottom in the autumn, which is consistent with previously published research studies. |