Past climate variations recorded in needle-like aragonites correlate
with organic carbon burial efficiency as revealed from lake sediments in
Croatia
Abstract
The drivers of the efficiency in organic carbon (OC) burial are still
poorly understood despite their key role in reliable projections of
future climate trends. Here we shed new light on this question by
presenting paleoclimate time series including OC content in sediments
from Lake Veliko jezero, Croatia. The Sr/Ca ratios of the bulk sediment
mainly derives from Sr and Ca concentrations of needle like aragonite in
Core M1-A and was used as a palaeotemperature and palaeohydrology
indicator. Four major and six minor cold and dry events were detected in
the 8.3 to 2.6 cal ka BP interval. The combined assessment of Sr/Ca
ratios, OC content, C/N ratios, δ13C data, and modelled proxies for
palaeoredox conditions and aeolian input reveals that cold and dry
climate state promoted anoxic conditions in the lake enhancing
preservation of organic matter and leading to increased OC burial
efficiency. Our study contributes to that projected future increase of
temperature might play an important role in OC burial efficiency of
meromictic lakes.