Air temperature-driven CO₂ consumption by rock weathering at short timescales: Evidence from a Holocene lake sediment record

The role that air temperature plays in the interaction between atmospheric CO₂ levels and continental rock weathering at relatively short time scales is still a matter of debate. Laboratory studies reveal a strong dependence of mineral dissolution on temperature, but field comparisons among watersheds under different climate conditions often indicate correlations with other environmental factors. Using a paleolimnological approach, here we show that there has been an extremely good coupling between rock weathering, water alkalinity (CO₂ consumption), and air temperature during the last 10,000years at sub-millennial time scales in a small watershed of silicate bedrock and scarce vegetation. The calculation of apparent activation energy for the weathering reaction (as a means to describe the temperature dependence of the process) provides a value (E_a=67±7kJmol^-1) that is comparable to those found for silicate rocks similar to those in the watershed in laboratory experiments and some field studies. Our results provide evidence that regulatory constraints between air temperature, atmospheric CO₂ and silicate rock weathering can be fine-tuned at geological timescales and may not be negligible in the current context of global change.