Award: OCE-2048457

Given the critical importance of sponges to coral reef food webs, it is surprising that they remain so understudied. This project investigates whether the biodiversity gradient observed in tropical marine environments applies to sponges, with a focus on the Hawaiian Archipelago. Using an integrative taxonomic approach that combined morphological, histological and molecular evaluation of sponges to identify the species present on Autonomous Reef Monitoring Structures (ARMS) throughout the Hawaiian Archipelago, American Sāmoa, Guam and Oman. Comparisons of these coral reef sponge communities enabled assessment of patterns of diversity, ecological succession, and species range of coral reef sponge communities with a particular focus on four questions. 1) which species of coral reef sponges are present across the gradient of the Hawaiian Archipelago? 2) are the same species of sponges found on reefs across other island chains throughout the Indo-Pacific? 3) Where did these sponges originate and are they previously unknown native species or new introductions of alien species? And 4) How do sponge communities differ between the densely populated Main Hawaiian Islands and uninhabited remote Northwestern Hawaiian Islands, and are differences in these coral reef sponge communities linked to environmental stress?

The project successfully met our intellectual merit and broader impact goals. We showed that the species richness of sponges in the Central Pacific is more than four-fold greater than previously realized, and that most of the species were restricted to a single location rather than being broadly distributed among archipelagos. While there were some new detections of alien species, most of these sponges were new species that are likely regional endemics that were not detected elsewhere. This work contributes to our understanding of coral reef biodiversity, the history of dispersal among isolated archipelagos across the Pacific, and the role of sponges in maintaining coral reef species richness.

This work trained more than 20 undergraduate and graduate students, formed the primary basis of four Masters and two undergraduate theses to date, with three more MS theses currently underway.  An additional three MS and one PhD student are using data or resources from this project. Most of these students have already been included as co-authors on publications, and all are expected to be included among the papers currently underway. A total of 14 peer-reviewed publications and 6 public data repositories have been generated thus far from this work, with several more currently in preparation. Two post-docs were trained, one of which went on to a museum curator position directly from this project, and the other went on to a second post-doc. Our educational modules were well received and the reference database for the identification of Indo-Pacific sponges has already been used by researchers from across the globe.

 

Last Modified: 04/04/2026
Modified by: Robert J Toonen