Microbial Diversity of Deep-sea Sponges - an Ecological Perspective across Scales

Sponge-dominated communities are found in diverse deep-sea environmental settings such as seamounts, mid-ocean ridges, canyons, slopes, shelves and fjords. This project investigates the biodiversity of microbial consortia associated with deep-sea sponges in the North Atlantic. 19 deep-sea expeditions were conducted to collect data for a next-generation biodiversity assessment of deep-sea sponge-microbiomes that were integrated with extensive oceanographic and ecological metadata. Our study aims to determine the main drivers of microbiome variability within deep-sea sponges. Our amplicon data reveal that sponges represent diverse reservoirs of microbes in the dark ocean. We find that different host species harbor their own, characteristic microbiomes which are different from seawater and sediment microbiomes originating from the same sampling location. We propose that the microbial diversity within deep-sea sponges is driven additionally by environmental factors such as nitrate, temperature and oxygen. With approximately 1000 sponge individuals analyzed in the present study, we are spanning various spatial scales reaching from individual sponge holobionts to an integrated North Atlantic-wide assessment.