BIOGENIC AND ABIOGENIC COMPONENTS OF DUST STORMS

Abstract

The article is devoted to the study of biogenic (pollen and diatoms) and abiogenic components in the composition of aeolian particles carried by dust storms. Studies of atmospheric dust were performed using a Carl Zeiss EVO 40 XVP scanning electron microscope equipped with an EDS (Energy-dispersive spectroscopy) “Inca Energy” microanalysis system. The studied samples were collected in the cities of Rostov-on-Don and Taganrog, as well as on the northern coast of the Taganrog Bay of the Sea of Azov (village Varenovka, Neklinovsky district) during a large-scale dust storm in September 2020, and a local storm in October 2019. Viewing of dust samples using a scanning electron microscope showed the predominance of mineral particles of pelitic and fine aleurite fractions in all samples. In the samples of Aeolian materials, it was possible to identify diatoms (Amphora ovalis, Staurosirella martyi, Hantzschia cf. amphioxys, Cocconeis pediculus, Actinocyclus octonarius var. tenellus, Navicula sp., Nitzschia sp., Anomoeoneis sp., Epithemia sp., Tryblionella sp., Pinnularia sp.), as well as pollen of ragweed, wormwood, cornflower, cereals and other representatives of the inter-seasonal grass of the steppe zone. To study the abiogenic component of the Aeolian material, the method of mapping elements was used. The microanalysis was carried out at a qualitative level, for clarity and information when constructing maps, the elements with the highest concentration (Si, Ca, Al) were selected. Oxygen distribution maps were analyzed separately. This method can be useful in cases where the samples contain fragmented valves of diatoms, whose identification by morphological features is very difficult. This method can be no less useful when identifying microplastic in soil, water, and Aeolian sediments.