Reconstructing the Late Holocene paleoclimate and paleoenvironmental changes in Southeastern Anatolia (Gölbaşı, Adıyaman, SE Türkiye) through fossil pollen and non-pollen palynomorphs (NPP)

Fossil pollen and non-pollen palynomorphs are useful indicators to reconstruct paleoclimate and paleoenvironmental changes. In palynological investigations, evaluating the difference between anthropogenic effects and paleoclimatic conditions is important for understanding the causes of paleoecological changes during the Holocene. Non-pollen palynomorphs can be observed in pollen slides owing to their acid-resistant organic structure, providing complementary insights into erosion, pastoralism, cultivation, and trophic state in wetlands.

This study investigates paleoclimate and paleoenvironmental variations in the Gölbaşı Basin, located in the East Anatolian Fault Zone (EAFZ), through palynological analyses that have been done on two sediment cores taken from Lakes Gölbaşı and Azaplı for the first time. The GLB-01 core, obtained from Lake Gölbaşı and dating back to 1995 +/- 35 cal BP, measures 129 cm in length and is predominantly composed of uniform, laminated reddish-brown mud. In comparison, the AZP-03 sediment core from Lake Azaplı spans 138 cm, with laminated green mud observed from the core's surface down to 96 cm depth. At the lowermost level of the AZP-03 core, peat deposits are present, containing gastropod shells (Gyraulus sp.) and wood remains attributed to Quercus bratii/libani, along with sandy detrital inputs. The top of the peat deposit dates back to 2889 +/- 27 cal BP. According to this study, cultivated trees are identified by Juglans, Pistacia, and Olea europea, while anthropogenic plants are represented by Caryophyllaceae, Amaranthaceae, Sanguisorba minor type, Centaura, Polygonum, and Plantago. Alongside the analysis of pollen grains, 39 sediment samples have been examined for Non-Pollen Palynomorphs (NPPs) at various percentages along the sediment cores. Notably, green algae Pediastrum, free-floating green algae Spirogyra, and the filter feeder Bosmina sp. exhibit high proportions within the initial 30 cm of the cores. Furthermore, Glomus, a mycorrhizal fungus linked to soil erosion, increases in abundance where herbaceous pollens are prevalent. Herbaceous plants, characterized by non-woody stems, may not provide the same level of soil protection as trees. In the absence of a dense tree canopy, herbaceous plants may be less effective in preventing soil erosion. The increase in Glomus in the cores could be indicative of a response to the changing soil conditions resulting from erosion. This study is supported by the ITU- Scientific Research Projects Coordination Unit (Project Number: MYL-2022- 43676) and TÜBİTAK Project (Grant Number: 121Y287).