Award: OCE-1924540

Coral reefs harbor an incredible diversity of animal species; however, despite this high biodiversity, they are found in nutrient-poor habitats that are equivalent to “marine deserts.” The limited nutrients means that animals rely on recycling and retention of nutrients within the reef ecosystem. On coral reefs, sponges are prominent filter-feeding animals that also contain microbial symbionts residing within the sponge. As a result of the filter-feeding activity of the sponge and activity of the microbes, sponges can change the amount and types of organic nutrients (e.g., amino acids, vitamins) in seawater as it passes through the sponge, thereby influencing which nutrients are available to other coral reef organisms. Here, we showed for the first time that sponges consume a subset of dissolved nutrients and that this subset differs for some sponge species, meaning that the presence of certain species on the reef could impact the types and amounts of nutrients on a reef. We also showed for the first time that the ‘excurrent’ seawater that is released from sponges as they filter-feed, supports the growth of commonly found microbes in the water column and this subset did not include those typically associated with coral disease. We also uncovered for the first time a nutrient connection between sponges and corals, where corals and their algal symbionts consumed sponge-derived nutrients with implications for future work in coral restoration and ecosystem management.

This project supported training and mentoring of high school, undergraduate, graduate, and postdoctoral mentees and included outreach with elementary and middle school students. The mentees involved in the project were exposed to cutting-edge techniques in field methods and analytical tools, professional network development, scientific project logistics, and mentored in scientific analysis and communication. The research conducted as part of this project has produced entirely new data on, and improved our understanding of how sponges, keystone members of the reef ecosystem, contribute to the base of the coral reef food web.  As reefs continue to change their composition of reef organisms due to human and climate impacts, this understanding is necessary to examine and predict changes to reef microbial food webs.  This knowledge framework is also essential for scientists, reef managers and policy decision makers.

Last Modified: 11/29/2025
Modified by: Cara Fiore