A sediment core from Lake Butrint in southwestern Albania contains an annually-layered sequence covering
the last ∼300 years. It provides thus an exceptionally well-dated time series to study past climate-driven
environmental changes, as well as anthropogenic perturbations along the coast of the Ionian Sea. The varves
are composed of organic-rich carbonate couplets and detritus-dominated clay layers. The first are deposited
during spring-to-fall, and reflect the chemistry of the lake, which, in turn, is sensitive to 1) the relative
importance of marine versus freshwater inputs, 2) relative evaporation rates, and 3) the productivity cycle
within the lake. The detrital laminae are deposited during winter, reflecting precipitation and runoff
conditions during the wet season. A 2–3‰ stable carbon isotope ratio shift in both bulk organics and
authigenic carbonates was attributed to increasing eutrophication towards the end of the 20th century, and
validated by historical and instrumental data. An increase in the δ18O of authigenic carbonates by more than
8‰ indicates the progressive salinization of the lake, which can primarily be attributed to man-made
perturbations that reduced the freshwater input to the lake and/or enhanced the exchange with seawater
from the nearby Ionian Sea. A recent increase in the relative evaporation versus precipitation rates may have
additionally contributed to the observed 18O enrichment in the Lake Butrint carbonates. The interdecadal
cyclicity in the thickness of the detrital laminae seems to be at least partially controlled by NAO and/or
ENSO-like phenomena that modulate precipitation patterns in the eastern Mediterranean. Thus, this study
demonstrates the potential of combining microstratigraphic and stable isotopic tools to disentangle
anthropogenic and natural environmental changes in Lake Butrint, validated by historical records.