Terasmaa J., Puusepp L., Vandel E., Marzecová A., Koff T., Vaasma T., Kangur M.,
Main drivers affecting the Holocene sedimentary record –
implications from small lake in Latvia
Abstract A multi-indicator paleolimnological study of
sediments from Lake Ķūži (central Latvia) was used to obtain a comprehensive
record of environmental changes in the Holocene. Periodicity in the changes and
the main drivers (lake basin development, catchment properties, climate, human
activities) of the sedimentary record was studied. In order to comprehend the
whole-lake sedimentation during the Holocene, a detailed multi-indicator record
from the central part of the lake was integrated with records of sediment mass
accumulation rates from four cores from different parts of the lake and a GPR
(ground-penetrating radar) survey of the lake basin. The observed changes in
the sedimentation regime that took place during the early Holocene are strongly
linked with variations in climatic conditions, but the catchment and lake basin
also played an important role. In the middle Holocene the water level was
stable and the lake was influenced by climate mediated through changes in the
catchment vegetation. Around 5 000 cal. BP sedimentation pattern changed, and
three of the four main drivers made a comparably strong impact on the
sedimentary signal. Since 2 000 cal. BP multiple indicators point to a major
disturbance clearly related to human activity, which conceals the impact of the
natural drivers.