Holocene hydrological variability of Lake Ladoga, northwest Russia, as inferred from diatom oxygen isotopes

• Published in: Boreas
• Main Authors: Kostrova, Svetlana S., Meyer, Hanno, Bailey, Hannah L., Ludikova, Anna V., Gromig, Raphael, Kuhn, Gerhard, Shibaev, Yuri A., Kozachek, Anna V., Ekaykin, Alexey A., Chapligin, Bernhard
• Other Authors: Bundesministerium für Bildung und Forschung
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2019
• Subjects: Age Lake; Lower Lake; Neva; Northwest Russia
• Online Access: http://dx.doi.org/10.1111/bor.12385; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fbor.12385; https://onlinelibrary.wiley.com/doi/pdf/10.1111/bor.12385; https://onlinelibrary.wiley.com/doi/full-xml/10.1111/bor.12385

This article presents a new comprehensive assessment of the Holocene hydrological variability of Lake Ladoga, northwest Russia. The reconstruction is based on oxygen isotopes of lacustrine diatom silica (δ 18 O diatom ) preserved in sediment core Co 1309, and is complemented by a diatom assemblage analysis and a survey of modern isotope hydrology. The data indicate that Lake Ladoga has existed as a freshwater reservoir since at least 10.8 cal. ka BP . The δ 18 O diatom values range from +29.8 to +35.0‰, and relatively higher δ 18 O diatom values around +34.7‰ between c . 7.1 and 5.7 cal. ka BP are considered to reflect the Holocene Thermal Maximum. A continuous depletion in δ 18 O diatom since c . 6.1 cal. ka BP accelerates after c . 4 cal. ka BP , indicating Middle to Late Holocene cooling that culminates during the interval 0.8–0.2 cal. ka BP , corresponding to the Little Ice Age. Lake‐level rises result in lower δ 18 O diatom values, whereas lower lake levels cause higher δ 18 O diatom values. The diatom isotope record gives an indication for a rather early opening of the Neva River outflow at c . 4.4–4.0 cal. ka BP . Generally, overall high δ 18 O diatom values around +33.5‰ characterize a persistent evaporative lake system throughout the Holocene. As the Lake Ladoga δ 18 O diatom record is roughly in line with the 60°N summer insolation, a linkage to broader‐scale climate change is likely.