The HUMID project aims to advance understanding of microbial diversity in tropical peatlands across the South Pacific, focusing on high-elevation Lake Tagimaucia (Fiji) and low-elevation Lac Lanutuli (Uvea). Tropical peatlands are some of the most carbon-dense ecosystems in the world, yet their microbial diversity remains poorly understood. Our research investigates the environmental drivers of microbial community structure, tracks historical microbial turnover, and develops a novel inference model using contemporary microbial and abiotic data to reconstruct past environmental change and its links to carbon storage. NMDS will be used to explore links between microbial diversity and key abiotic factors such as vegetation, water table depth, and pH. Prokaryotic diversity and functional traits will be assessed through molecular tools, high-throughput sequencing, and community profiling. By connecting contemporary testate amoebae with both present-day prokaryotic diversity and down-core amoebae assemblages, we aim to infer past microbial dynamics and their role in long-term carbon cycling. Contemporary testate amoebae analysis shows distinct differences in community assemblage between the two sites, with vegetation and depth to the water table emerging as key environmental drivers of diversity. Prokaryotic diversity also appears to differ significantly, based on preliminary RAPD-PCR results, suggesting site-specific genetic variation. Metabolic diversity, assessed using BIOLOG EcoPlate assays, indicates active carbon utilisation across a range of substrates at both sites, reflecting functional microbial diversity despite differences in community composition. While further research is needed to fully characterise the microbial diversity of tropical peatlands, our preliminary findings underscore the ecological complexity and distinctiveness of these understudied ecosystems.