Depth-dependent patterns of microbial carbon and nitrogen metabolism functions in deep East African Rift Valley Lakes

East African Great Lakes are globally important waters that regulating carbon and nitrogen sources and sinks. Yet, microbial carbon and nitrogen cycling functions as well as their underlying environmental drivers in tropical deep lakes remain largely unexplored. Here, were collected vertical samples from typical large deep lakes in East African Rift Valley to assess environmental gradients and microbial metabolism functions of primary biogenic elements. We examined vertical distributions of nutrients, dissolved organic matter (DOM) properties, and quantified microbial carbon, nitrogen, and phosphorus cycling genes using high-throughput Quantitative Microbial Ecology Chip (QMEC) technique. Preliminary analyses indicate clear depth-dependent patterns in nutrient availability and microbial functional genes. Dissolved organic matter properties are likely important drivers of the depth patterns of these functional genes. The observed relationships between microbial functional genes and environmental variables provide insights into the vertical organization of microbial biogeochemical functions in deep tropical lakes.