Carbon isotopes and alkalinity gradient for biogeochemical processes in modern stratified lakes

Redox-stratified water columns are a prevalent feature of Earth history, and ongoing environmental changes tend to promote a resurgence of such settings. Better understanding of these multifaceted carbon isotope signals requires further evaluation of how the processes occurring in redox-stratified water columns are transferred to the sediments. We therefore characterized and compared the isotopic signatures of dissolved inorganic carbon (DIC), carbonate, and organic matter reservoirs, at different depths in the water column and upper sediments of four stratified Mexican lakes that follow a gradient of alkalinity/salinity.

氧化还原分层水体（redox-stratified water columns）是地球地质历史中广泛存在的特征，当前持续发生的环境变化往往会推动这类环境的再度发育。要更深入地理解这些复杂多样的碳同位素信号，需进一步评估氧化还原分层水体中发生的过程如何向沉积物传递。为此，我们对四座沿碱度/盐度梯度分布的分层墨西哥湖泊的水体及上层沉积物不同深度处的溶解无机碳（dissolved inorganic carbon, DIC）、碳酸盐以及有机质储库的同位素特征进行了表征与对比分析。