Lowstand lake conditions in NW Anatolia during the Little Ice Age: Multi-proxy evidence from Lake Sünnet

Abstract

Despite global and local evidence of significant precipitation changes since the Little Ice Age (LIA), their impact upon lake hydrology and surrounding vegetation has yet to be investigated in NW Anatolia. Moreover, the LIA, as a trigger to the social/political recession of the Ottoman Empire in the 17th century is expected to have these impacts. To address this important gap, we studied three cores from Lake Sünnet, a landslide-dammed high altitude lake with extreme sedimentation rates, by using a wide range of proxies including lithology, stable isotopes of O and C, diatoms, pollen, and ostracods. The LIA timespan of AD 1510–1750 is represented by poorly preserved diatom flora and scarce ostracod fauna that collectively suggest very shallow aquatic conditions. The period AD 1640–1710 within the LIA is standing out with higher Abies and total herb pollen percentages that denotes considerably cooler conditions. During and soon after this cold and dry period precisely overlapping the Maunder Minimum, the currently deep Lake Sülüklü in close vicinity was a dry lowland where tall trees were growing. Progressive warming/lake level rise in Lake Sünnet after the AD 1750s is suggested based on a continuous diatom record with increasing planktonic share, increase in diverse and warm demanding arboreal cover, and a positive shift in δ18O of the lake muds. Following the relatively dry/cold period of AD 1800–1850 (Dalton Minimum) when the lake level was stationary and Artemisia cover became the most expanded of the whole record, a relatively warmer climate has dominated the area until the end of the 20th century.