The life CYCLe assessment of the sponge microbiOME

Sexual reproduction is one of the key processes conferring marine animals with resilience to environmental shifts.

Since sponges are among the most important sessile organisms ensuring ocean’s health and their survival is threatened due to the increased water temperatures, a clear understanding of their life cycles and reproductive processes is needed to determine the faith of marine ecosystems under the current global warming scenario.

Sponges present intimate associations with bacteria, which can represent up to 90% of the organismal volume, provide fundamental nutrition to their hosts and have profound effects on the sponge physiology. However, the microbiome influence on sponge sexual reproduction has never been explored.

In this context, CYCLOME aims to advance our understanding of the role of microbiomes on the sponge reproductive processes by using a multidisciplinary approach that will allow us to elucidate changes in microbiome composition, functionality, and metabolism through the whole annual cycle of gonochoristic (male and female) sponges.

By using modern next generation sequencing technology and cutting-edge ‘omics techniques combined with traditional microscopical observations, we expect to detect changes in the sponge bacterial communities and whether specific symbiont functions are upregulated or downregulated during the sponge life cycle influencing the production of sponge secondary metabolites.

We hypothesize that the possession of large microbial consortia provides the sponges with nutritional benefits allowing to support sexual reproductive strategies during high energetic demand periods as well as helping them to survive during periods of post-reproduction recovery and overwinter, when waters are more oligotrophic.

Overall, our study will provide a comprehensive view of basic biological processes that allow sponges to recruit and adapt to shifting conditions, which will facilitate policy decisions regarding conservation of marine biodiversity.