RUI: Stability and structure of temperate and tropical marine sponge symbiont communities in response to climate change.

University Of Richmond, Richmond VA

Investigators

Abstract

This project will examine symbiotic associations between sponges and their microflora and the consequences of increased sea surface temperatures (SSTs) on these symbiont communities. Projected increases in SSTs over the next 100 years indicate that stressful conditions will intensify in many marine habitats and that the destructive effects on communities will become more severe. While sponges are recognized for the vital ecological roles they perform, they remain an understudied group in terms of their response to climate change. The experiments will advance our understanding of important aspects of host-symbiont associations, and the ecological consequences of warmer oceans, for marine sponges with temperate and tropical distributions. Two major types of sponge symbioses will be examined. First, sponge zooxanthellar associations will be used to test important hypotheses regarding the dynamics of symbioses involving these dinoflagellates. Second, sponge-bacterial associations will be used to study ecological consequences of increased SSTs. The project will develop Sponge-symbiont associations as model systems for understanding ecological and evolutionary aspects of multiple partner associations using field and laboratory experiments. Additionally, these sponges will be used to explore the molecular integration of host and symbiont partners via studies of differential gene expression. The experiments will link dynamic interactions at three levels of organization (i.e., the gene, the individual symbiont and/or host, and the community). Zooxanthellae perform vital physiological functions for these sponges but major gaps exist in our understanding of the flexibility in these associations and their response to increased SSTs. Microbial symbionts have also been found to enhance sponge growth rates, translocate carbon, fix nitrogen, and produce important secondary metabolites. SSTs increases may lead to a reduction in the ability of sponges to produce secondary metabolites of ecological and pharmaceutical interest. This research will involve undergraduates in hands-on field and laboratory research and they will benefit from the collaborative nature of the project. The investigators will integrate these studies into their training of undergraduates and graduate while all resources generated during this project will be freely and widely disseminated.