Stratification stability of tropical lakes and their responses to climatic changes: Lake Towuti (Indonesia)

Abstract

Tropical lakes have different physical dynamics. They can be permanently stratified by temperature gradients alone (thermogenic meromixis). This project aims to investigate the strength and dynamics of thermogenic meromixis in tropical lakes. To address this problem, physical and chemical dynamics of tropical Lake Towuti are simulated. The simulations reveal that Lake Towuti may be oligomictic and there is a possibility that whole water column mixing happened as recently as 2008. A weak mixing event lasting a few weeks during the dry season would be consistent with the observed chemical profiles of oxygen, hydrogen sulfide, and reduced dissolved iron. Findings suggest that, under the future climate characterized by warmer air temperatures, Lake Towuti is likely to be more stable. Stronger stability and isolation of monimolimnion water would lead to further accumulation of dissolved iron.