Author: Marie Collison, Class of ‘25

Sponges are a diverse group of multicellular organisms that inhabit aquatic ecosystems all over the globe. Scientists estimate that there are over 9000 unique species of sponges. The vast diversity of sponges enables them to provide a diverse range of habitats for a variety of aquatic taxa. They provide structure to environments that otherwise have minimal variation in elevation. The complicated system of canals found in sponges often produce a net-like architecture with open spaces that serve as refuge for a variety of cryptic taxa. “Cryptic”, in the world of biodiversity, refers to species that are  difficult, if not impossible, to distinguish from one another using morphological data alone. Biodiversity estimates are often impeded by a lack of distinction between cryptic species, thus fueling the need for increased research into distinctions between similar-looking species. 

Anita M. George, a Stony Brook Research Fellow and Postdoctoral Researcher at the Queensland Museum in Australia, spearheaded research efforts into quantifying sponge-associated biota (SAB) of three distinct sponge species: Coelocarteria singaporensis, Coscinoderma mathewsi, and Ircinia microconulosa (chosen because they are largely unexplored in comparison to other species). They also observed variability of SAB between the wet and dry seasons as well as throughout the day. A total of 8,489 individuals were observed, representing 12 separate phyla, in 77 collected sponge specimens. The phylum of Mollusca was observed the most in all three species. C. mathewsi was found to contain the highest average SAB. In contrast, I. microconulosa was observed to have the smallest average SAB. Statistical analysis indicated that host species had a significant effect on SAB abundances, but no effect on SAB was found based on season or time of day. 

The significance of the cryptic biodiversity found in this study highlights the important role that sponges play in aquatic ecosystems. The differences in SAB due to host sponge species could reflect the unique morphologies of the different sponge species. The greater abundance of SAB quantified in C. mathewsi and C. singaporensis may be due to their more open architecture, allowing for easier access and greater water pumping capacity (two traits found in habitats good for SAB survival). Overall, this study further highlights the importance of biodiversity in aquatic environments and implicates sponges as a key factor in maintaining species variability. It also showcases why sponges need to be included in conservation efforts with research focusing on the vast diversity of species that call sponges their home. 

Figure 1: Picture of the floor of the Great Barrier Reef found off the coast of Australia provided by the Australian Institute of Marine Sciences.

[1] George, A., Abdo, D., Wahab, M. a. A., Ekins, M., Hooper, J. N. A., & Whalan, S. W. (2023). Cryptic biodiversity inhabiting coral reef sponges. Marine Ecology, 44(2). https://doi.org/10.1111/maec.12747 

[2] Image retrieved from: Corals | AIMS