Date

2016-10-04

Author

Yılmaz, Gültekin

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Bulk aerosol samples were collected using a high volume sampler at a rural site (Erdemli) on the coast of Eastern Mediterranean. The sampling was carried out on a daily basis between April 1 – 30 2015 and July 20 – August 20, 2015, and intermittently before April (n=68). The sampling periods were chosen to reflect the aerosol population such as, Saharan dust dominated, mixed and anthropogenic dominated. In addition to high-volume sampling, wet deposition samples were also collected covering the same period and the samples were segregated by size via filtration. An acid digestion scheme was applied to samples for total concentrations. For speciation of elements, a preconcentration setting of serially connected cationic and anionic exchange columns was applied to selected samples. Samples were selected according to their air mass back trajectory history to reflect their sources and origins. All samples were analysed with ICPMS for the elements of interest (Al, Fe, Mn, Co, Cr, Ni, V, Ca, Cu, Zn, As, Cd, Pb and P) Clear reciprocal relationship was established between dust episodes and elements of crustal origin. Soluble fractions of elements were separated from total concentration, and anionic and cationic forms of soluble part was determined to assess their bioavailability, as anionic forms of trace elements are generally associated with organic complexation. It has been observed that major fraction of soluble Al is found in anionic form, while the concentration of anionic soluble Fe is 1.2 times greater than of cationic Fe. It has been established that contribution of polyphosphates to water soluble phospates can reach up to 20%. The two main sources of phosphorus was determined to be mineral dust and agriculture, accounting for 34 and 33 % of total concentration, respectively. Surface waters which were obtained from both coastal and open waters were treated with atmospheric dust of two different compositions. In the course of experiments, chlorophyll-a was recorded to increase in all treatments while phosphorus was assimilated from the medium down to 0,3 nM. Results of the atmospheric dust addition experiments confirmed the effect of aerosols, as Chl-a concentration increased up to 4-fold with regard to controls, in both coastal and open water samples alike.

Subject Keywords

Eastern Mediterranean, atmospheric aerosols, marine productivity, micronutrients

URI

https://hdl.handle.net/11511/95093

Collections

Graduate School of Marine Sciences, Thesis