Arredondo cave microbiome. Characterization of taxonomic composition and functional potenntional in Arredondo cave (Cantabria, Spain)

Microorganisms are a major component of karstic ecosystems and play an important role in cave development. Cave microbiomes are among the least studied biomes but they have recently attracted great scientific interest due to their potential as source for drug discovery. Microbes have developed a broad range of adaptive capabilities to thrive in the cave oligotrophic environment. However, very little is known about the diversity and the functional potential of these communities. In this study, we aim to explore the taxonomic composition of the microbial communities present in different habitats in a cave. Samples were collected across the light gradient of the cave wall from the entrance to the aphotic zone and from two lakes in the dark zone. We have implemented a metabarcoding approach using different primer sets for archaea, bacteria and eukaryotes to explore the taxonomic composition of the microbial community. We have combined this with a shotgun sequencing metagenomic approach to get insights into the functional potential and the energy metabolism of the cave ecosystem. The data analysis pipeline is designed to answer the followinng questions: 1) How homogeneous is the microbial community across the different habitats? Is there connectivity? 2) How light penetration affects the microbial community compositon? 3) What metabolic genes can be found in the different habitats of the cave (photosynthetic, sulfur metabolism, iron metabolism, biomineralization, etc)? 4) Is there a gradient from autotrophs to chemotrophs in the cave wall due to differential light exposure?