This study provides the first comprehensive evidence of active oxalate–carbonate pathways (OCPs) in India’s tropical dry evergreen forests, identifying four novel tree–microbe systems that mediate calcium carbonate formation. The findings reveal a previously unrecognized mechanism contributing to coupled organic and inorganic carbon cycling in tropical forest ecosystems of southern India.

The study analyzed lake sediments from the southwest Maya lowlands to track past land use and population size. The authors found that over 3,300 years, land use was highly variable, with more fire and maize agriculture earlier (3500-2000 BP) with a denser population but less burning in a later period (1600-1000 BP). Surprisingly, their hydrogen isotope data showed no strong signature of drought locally, suggesting that climate in that area remained relatively stable. Therefore, the authors argue that collapse or population decline in the southwest Maya lowlands was likely driven more by social, political, or regional factors than by local drought.

Mesozooplankton are a size group of zooplankton (0.2 mm to 2 cm) that is often lumped together with smaller, microzooplankton taxa, and treated as a functionally homogeneous group in oceanic surveys and biogeochemical models. Di Matteo used a trait-based modeling approach that accounts for the strong functional differences among mesozooplankton taxa, here grouped as cruisers, ambushers, and flux-feeders. Integration of model results with observational data revealed clear biogeographical distribution patterns that suggest distinct roles of major mesozooplankton groups with respect to their contributions to oceanic food webs and the export of carbon to the deep ocean.