Ostracods from the Layla Lakes in Saudi-Arabia – first results

The former Layla Lake Area in Saudi Arabia were covered by a couple of lakes which dried up until the 1980th, caused by man-made irrigation processes. The running DFG founded project „Zwischen der Westwindzone und der Innertropischen Konvergenzzone: ein hochaufgelöstes Paläoklima- und Paläoumweltarchiv holozäner Sedimente der Layla-Seen in Saudi Arabien“ investigates the lake sediments by applying a multi proxy approach to reconstruct the lake history and link it to climate changes during the Holocene. The applied methods include sedimentology, geochemistry, hydrology, diatoms, palynology and micropalaentology. Here we present the results of the ostracod analysis of the master section L-2-1. We identified at least four species (Pseudocandona spp., Cyprideis torosa, Darwinula stevensoni and Heterocypris salina), which indicate different water qualities, probably based on changing water levels and development of a phytal zone. Additionally, we used the ostracod valves of two selected species for stable isotopes analyses. Although the pollen association indicates the increasing aridisation of the Arabian peninsula during the late Holocene, the ostracod assemblages do not follow this trend and point to a water column which seems to be independent from the general climate trends. More intense investigations of the population structure the detailed ostracod shell features and a comparison with the four other sections of the Layla Lakes are needed for further details and will be carried out in near future.