Researchers from the Hawai’i Institute of Marine Biology (HIMB) Toonen-Bowen (ToBo) Lab have made significant strides in marine biology by identifying 10 new species of marine sponge. This exciting discovery was detailed in a series of groundbreaking studies published recently in the journals PeerJ and Zootaxa. Utilising a method that examines both genetic and structural traits, the team highlights the importance of these ancient organisms, which play a crucial role in maintaining coral reef ecosystems, yet remain largely overlooked in scientific research.
The research took place in Kāne’ohe Bay, home to numerous small, isolated “patch reefs” that are rich in both undiscovered sponge species and non-native varieties from the Caribbean and Western Indo-Pacific. These findings enhance our understanding of sponge diversity not only in the Hawaiian archipelago but also across Oceania.
“We used autonomous reef monitoring structures (ARMS) to collect sponges from within the reef,” explains Rachel Nunley, a Scientists in Parks (SIP) Intern at Kaloko-Honokōhau National Historical Park and lead author of the PeerJ study in which 6 new sponge species were identified. “These structures mimic the reefʻs cryptic environment, allowing us to observe and document the species without causing harm to the surrounding reef. After sponge collection, we used DNA to narrow down what species we were looking at. Then we dug into the literature to see if these sponges existed anywhere else in the world. I created a database and compared characteristics to find the closest relatives. Through this integrative taxonomic approach, we found that these species found in Kāneʻohe Bay were new to science and have not been documented anywhere else in the world.”
Sponges are notoriously difficult to study, for a variety of reasons.
“Sponges are found within the ‘nooks and crannies’ of the reef, making them difficult to collect without destroying the reef,” shares Jan Vicente, a ToBo Lab post-doctoral researcher and lead author on the Zootaxia article, in which four new sponge species were detected. “Sponges are also very small and fragile, with very limited morphological characters which make identification difficult with the unaided eye. The sponge community within these cryptic spaces is also highly dynamic, because sponges have a lifespan of only two months! One month they are present, and they can be gone the next. These are all reasons why we have yet to fully understand the complex diversity of sponges and other metazoans deep within the reef matrix.”
“Taxonomy is tedious!” adds Nunley. “It involves every tiny detail. Missing a detail can change your species entirely. But the challenges make it that much more rewarding, and taxonomy is so much more than just describing species. It involves creating detailed visual representations of species, engaging with and collaborating with local communities, and contributing valuable information to the scientific community.”
The hard work truly paid off, and the research team was amazed to discover so many previously unknown species in the patch reefs surrounding their island laboratory.
“Previous assessments of sponge diversity in Kāneʻohe Bay have totaled only around 30 sponge species in the bay,” notes Vicente. “But these earlier studies did not target the nooks and crannies of the reef. The coral reef of Moku o Loʻe surprises us daily with how little we know about its biodiversity. After decades of research on this patch reef, we have yet to reach a full understanding of its sponge biodiversity.”
As the ocean evolves and coral reefs encounter significant challenges, it’s essential to grasp the dynamics of coral reef ecosystems. Sponges are vital in maintaining and supporting these environments.
“Sponges are widely underappreciated, even though they play an essential role in cycling nutrients that help maintain coral reef biodiversity in remote island archipelagos where nutrients in coral reefs are scarce,” emphasizes Vicente. “Discovering such a remarkable diversity of these ecologically important species sheds light on their role in nutrient cycling.”
The research team chose names for the new sponge species that pay tribute to the mo’olelo of Moku o Loʻe and the ʻŌlelo Hawaiʻi, reflecting the unique characteristics of each species.
“Many of the species we found are new to science,” explains Principal Investigator of the ToBo lab and co-author on both studies, Robert Toonen. “They were found in Kāneʻohe Bay off the island of Moku o Loʻe, and their names come from Native Hawaiian stories. “Lo‘e,” for example, “was the sister of three brothers who kept honesty within the family.”
Toonen mentions that these discoveries are probably just the beginning. The research team has collected over 1,000 samples from the coral reef’s hidden fauna using ARMS in Kāneʻohe Bay, and they have also retrieved ARMS from five distinct ecoregions throughout the Pacific. Eventually, they aim to gain a comprehensive understanding of Oceania’s biodiversity. Their goals include identifying which species are endemic, native, or have been introduced to the Hawaiian Archipelago, as well as exploring the biogeographical connections among these species.
This research was made possible through funding from the National Science Foundation (NSF) and the National Oceanic and Atmospheric Administration (NOAA Ocean Acidification Program).
[Image: Stelletta hokuwanawana is among the 10 species of newly discovered marine sponge. Photo courtesy of Rachel Nunley, Kaloko-Honokōhau National Historical Park]
