T66 From the Caspian to Mediterranean: Environmental Change and Human Response during the Quaternary (IGCP 610)

Sunday, 1 November 2015
1:30 PM - 5:30 PM
Room 325/326

NEW APPROACH TO PALYNOLOGICAL STUDY OF THE DANUBE DELTA AND SHELF

Paper number: T66-6
Program: Technical Sessions
Time: 2:40 PM – 2:55 PM

Authors

Abstract

New palynological studies have been carried out on surface sea-bed samples from the north-western part of the Black Sea, in order to obtain initial data on the distribution patterns of palynomorphs along two transects from the Danube River delta front to the outer shelf off the delta. These data will provide the baseline for developing future models of palaeo-delta evolution for the Danube delta, to replace present models which are limited by the absence of a comprehensive database for modern Black Sea surface samples. The other objective of the study was to compare the results of palynological processing using the method of Taras Shevchenko National University of Kyiv and the Standard Marine method, and to determine the magnitude of possible differences in the two methods. For the Standard Marine method each sample of 2-8 g is sieved at 10 microns, treated (without heating) with a 10% solution of HCl and 52% solution of HF. The Kyiv University method involves boiling of 2 g samples with HCl (10%), Na4P2O7 (15%), and cold treatment of HF (40%). Both methods use exotic Lycopodium spores to estimate pollen concentrations.

These parallel studies show that all samples contain an abundance of well-preserved pollen, dinoflagellate cysts and other NPP. Overall, the assemblages in the processed residues show a high similarity of taxa, regardless of method of preparation and chemical treatment. The salient difference is in changes of pollen concentrations dependant upon the distance from the shore: concentrations in the Standard Marine method samples tend to increase offshore, whereas the Kyiv method samples show an inverse trend. The other difference in the initial data set is in occurrences of the major dinoflagellate cyst taxa: Lingulodinium machaerophorum and Spiniferites. The samples processed using the Standard Marine method show the expected trend of increased offshore occurrence of these taxa, whereas the Kyiv results show lower recovery numbers and a random pattern of distribution. Overall, however, the new Kyiv University method in Black Sea palynology studies is efficacious, and may be good for pollen analysis and distribution models, but with restrictions for dinoflagellate studies.