Scientists aboard the Schmidt Ocean Institute’s research vessel Falkor (too) have cataloged 28 possible new species of snails, urchins, and worms living inside the largest known colony of the cold-water coral Bathelia candida, discovered off the coast of Argentina. The expedition, part of a $1.5 million research project funded by CORDAP and led by Temple University researchers, ran from December into January and focused on locating, characterizing, and restoring deep-sea coral reefs in the Southwest Atlantic. The sheer size of the colony and the volume of potentially undescribed organisms found within it raise immediate questions about how much deep-sea biodiversity remains hidden in waters that have barely been surveyed.
Why the largest Bathelia candida colony changes the biodiversity calculus
Cold-water corals build physical frameworks on the ocean floor, and those frameworks function as shelter, nursery habitat, and feeding grounds for hundreds of other organisms. When a single colony grows large enough and persists long enough, it generates a wider range of microhabitats, from crevices and overhangs to sediment pockets trapped between branches. The hypothesis that larger, unbroken Bathelia candida structures support higher rates of new species discovery follows directly from this logic: more stable architecture over longer timescales means more ecological niches, and more niches mean more chances for species to specialize and diverge.
Peer-reviewed research on deep-sea assemblages in the Falkland Islands has already documented Bathelia candida’s distribution and reef-forming behavior across the Southwest Atlantic. Those records describe mound provinces where the coral builds substantial three-dimensional habitat. But the Argentine site identified during the Falkor (too) cruise stands apart because of its reported scale, which apparently dwarfs previously known colonies. If 28 candidate species can be pulled from a single large framework, smaller or fragmented mounds in the same region may harbor far fewer undescribed organisms simply because they lack the structural complexity and long-term stability needed to support them.
That distinction matters for conservation planning. Protecting a handful of large, intact colonies could preserve far more biodiversity per square meter of seafloor than scattering protections across many small patches. The finding also suggests that survey effort in the Southwest Atlantic has been too thin to capture the true species richness of these ecosystems. If one enormous colony yields dozens of potential new species, then other unsurveyed reefs along the continental margin may host similarly rich but undocumented communities.
CORDAP funding, Temple’s cruise, and the species inventory
The discovery traces back to a CORDAP-backed project designed to locate, characterize, and restore cold-water coral reefs off Argentina. Temple University researchers led the effort, and the at-sea work took place aboard the Falkor (too) during a cruise that spanned from December into January. CORDAP provided the funding mechanism, while the Schmidt Ocean Institute supplied the vessel, remotely operated vehicles, and seafloor mapping technology needed to reach and document the colony in several hundred meters of water.
During the cruise, the team collected and cataloged organisms living within the Bathelia candida framework. The 28 candidate species span multiple invertebrate groups, including gastropod snails, sea urchins, and polychaete worms. Each of these groups occupies a different ecological role inside the reef: snails graze on organic films, urchins process detritus, and worms build tubes that add secondary structure to the coral framework. Finding potentially new species across such varied functional groups suggests the colony supports a self-sustaining community that has been evolving in relative isolation on the deep seafloor.
Those ecological roles matter because they influence how energy and nutrients move through the reef. Grazers help control microbial films on coral surfaces, detritivores recycle organic matter that settles from surface waters, and tube-building worms stabilize sediments that would otherwise smother living coral branches. Newly discovered species in each of these roles could alter scientists’ understanding of how cold-water reefs function and how resilient they might be to disturbance.
Temple’s institutional reporting ties the cruise directly to restoration goals. The project is not limited to discovery; it aims to develop methods for rehabilitating damaged cold-water reefs, a task that requires knowing which species depend on the coral and how they interact. Without that baseline, restoration efforts risk rebuilding physical structure while failing to recover the biological community that makes the reef ecologically functional. For a university that also invites prospective students to visit campus and learn about its research strengths, the expedition serves as a high-profile example of how academic science can link fundamental biodiversity work with applied conservation.
Gaps in the species data and what to watch next
The 28 candidate species have not yet been formally described in peer-reviewed literature. No morphological descriptions, genetic sequences, or taxonomic assignments from the cruise are publicly available as of early March 2026. Until those data are published, the count of 28 remains provisional. Some candidates may turn out to be known species with unusual morphology, while others could split into multiple distinct lineages once DNA analysis is complete. The gap between field cataloging and formal taxonomy can stretch for years in deep-sea biology, where reference collections are sparse and specialist taxonomists are few.
A second open question involves the colony’s age and growth history. Bathelia candida frameworks accumulate slowly in cold, deep water, and the size of this colony implies it has been growing for a long time. But no radiometric dating or growth-rate estimates have been released. Knowing the colony’s age would help scientists assess whether the associated species assemblage developed in place over centuries or colonized the structure more recently from nearby source populations. Age estimates could also clarify how often such massive colonies arise and how vulnerable they are to bottom trawling, seabed mining, or climate-driven changes in ocean chemistry.
The restoration component of the CORDAP project also faces practical unknowns. Rehabilitating a cold-water coral reef at depth is far more difficult than restoring a shallow tropical reef. Access requires expensive ship time and remotely operated vehicles. Growth rates are slow, meaning any recovery would take decades to measure. And the physical stresses on transplanted or artificially settled corals-from strong currents to sediment resuspension-are not yet well quantified for Bathelia candida in this region.
Researchers must also determine whether the newly cataloged invertebrates can recolonize restored structures on their own or whether some will need to be actively reintroduced. If certain snails, urchins, or worms are highly specialized to particular microhabitats within the coral framework, then restoration plans may have to recreate those conditions very precisely. That in turn requires detailed knowledge of how water flow, food availability, and sediment dynamics vary within the reef.
Implications for deep-sea protection in the Southwest Atlantic
The Argentine Bathelia candida colony underscores how little is known about deep-sea ecosystems along the Southwest Atlantic margin. Large portions of the seafloor there have never been surveyed with high-resolution sonar, let alone visited with cameras or sampling gear. The discovery of dozens of candidate species in a single reef suggests that standard biodiversity estimates based on sparse trawl records and limited imagery likely underestimate true species richness.
For policymakers, the find strengthens the case for precautionary protection of deep-sea habitats. Establishing marine protected areas that encompass known coral mounds-and potential undiscovered ones-could safeguard biodiversity that scientists have not yet had time to document. Because cold-water corals grow slowly and are easily damaged by bottom-contact fishing gear, avoiding disturbance in areas where large colonies are suspected may be the only realistic way to preserve them at scale.
For scientists, the colony functions as both a natural laboratory and a baseline. Future expeditions can revisit the site to track how its community responds to environmental change, test restoration techniques, and refine models of deep-sea connectivity between reefs. If genetic analyses reveal that some of the candidate species are unique to this colony, the site will take on added importance as a reservoir of evolutionary history that exists nowhere else on Earth.
Ultimately, the Falkor (too) cruise off Argentina illustrates how a single, well-equipped expedition can reshape understanding of an entire region’s biodiversity. By tying species discovery to restoration research and conservation planning, the project suggests a template for future deep-sea work: find the largest, most structurally complex habitats, document their inhabitants in detail, and use that knowledge to guide protection before human impacts reach them. In the cold, dark waters of the Southwest Atlantic, the newly revealed Bathelia candida reef is a reminder that some of the planet’s richest ecosystems are still waiting to be mapped, named, and, crucially, preserved.
More from Morning Overview
*This article was researched with the help of AI, with human editors creating the final content.
