作者：Boussagol, P., Vennin, E., Motreuil, S., Bonnotte, A., Jouve, G., Millet, L., Munier, T. & Visscher, P.

From spring 2022 to late summer 2024, a study of Lake Ilay's water column and sediment cores analyzed key environmental parameters. Conductivity, temperature, and chlorophyll-a were measured at 2 m, while pH, conductivity, temperature, calcium (Ca2+), and alkalinity were monitored within the top 20 m. The lake exhibited significant seasonal variations, remaining thermally and chemically stratified for at least 8 months yearly. Six sediment cores (1-23 m depth) were analyzed for mineralogy, dry bulk density, and organic/inorganic carbon, complemented by cryo-scanning electron microscopy observations. This multi-analytical approach provided insights into micrite precipitation, the primary component of lacustrine carbonate muds. Building on these findings, an integrated model for carbonate production in stratified lakes was developed. It incorporates ionic circulation between the water column and sediment, offering a novel framework for micrite formation. This approach carries broad implications for lacustrine and marine systems over geological timescales, shedding light on carbonate precipitation processes, ion dynamics, and their availability across the fluid envelope and the sedimentary reservoir. A key finding is that carbonate production in the water column is brief in time, with preservation and accumulation restricted to shoreline platforms, submerged under shallow water, that form a belt around the lake. However, lacustrine micrite formation continues in sediments at all depths, linked to exopolymer degradation. The carbonate platforms result from vertical accretion, and their lateral extent is defined by the lower boundary of carbonate dissolution along the topographic slope.

（来源：Limnology and Oceanography 2026 Issue 2  DOI: 10.1002/lno.70334）