A single expedition to a cluster of remote seamounts in the Indian Ocean turned up 149 species new to science, ranging across corals, mollusks and deep-water fish gathered from underwater peaks that had never been formally surveyed. The haul is part of a broader push by marine researchers to document seamount ecosystems before they are altered by fishing or mineral exploration.
What Turned Up on the Seamounts
The expedition worked a series of seamounts, underwater mountains that rise from the ocean floor without breaking the surface, and came back with 149 species that had not previously been described. Seamounts tend to concentrate marine life because their slopes disrupt deep ocean currents, pushing nutrients up into the water column and supporting denser communities of filter feeders and the predators that follow them.
A haul spanning corals, mollusks and fish in a single trip reflects how seamount surveys typically sample across several depth zones and habitat types rather than focusing on one narrow group of organisms, according to reporting from Mongabay. Corals and sponges tend to dominate the harder rocky slopes near a seamount’s summit, while soft-sediment mollusks and free-swimming fish are more often found in the surrounding basins, so a single expedition covering the full structure can realistically expect to log new species across very different branches of the tree of life. That range of habitat types within one formation is part of why a single seamount survey can outproduce broader but shallower surveys spread across a much larger area.
Why Remote Seamounts Harbor Unknown Life
Because seamounts are scattered across open ocean far from coastlines and often sit well below diving depth, most have never been directly sampled by researchers, even though satellite data has mapped their locations. Each seamount can function almost like an isolated island for slow-moving or immobile species such as corals and sponges, which means neighboring seamounts separated by open water sometimes host distinct sets of species rather than a shared population. That isolation is a major reason expeditions to previously unsampled seamounts so reliably turn up species new to science.
Estimates of how many seamounts exist worldwide run into the tens of thousands, yet only a small fraction have ever been visited by a research vessel equipped to sample life at depth. That gap between how many seamounts satellites can detect and how many have actually been surveyed up close is a large part of why remote formations, particularly in less-studied ocean basins such as parts of the Indian Ocean, keep producing discoveries at a rate that would be unusual in more accessible coastal waters.
The Expedition’s Place in the Ocean Census Program
The Indian Ocean seamount survey sits within the wider Ocean Census program, a global initiative organizing expeditions specifically aimed at accelerating the discovery and formal description of ocean species. Coordinating expeditions under one program lets participating taxonomists share reference collections and identification work across finds from different oceans, rather than each expedition processing its specimens in isolation, which helps explain how a single trip can process and confirm well over a hundred new species relatively quickly.
That shared infrastructure also means a discovery made on one expedition can be cross-checked more quickly against specimens collected elsewhere in the program, cutting down on the risk of the same organism being independently described twice under different names. For a remote, rarely visited stretch of seamounts like these, that kind of cross-referencing is especially valuable, since there is little prior baseline data from the immediate area to compare new finds against.
How Deep-Sea Species Get Identified and Named
Specimens collected during the expedition still have to pass through the same identification pipeline as any other new species claim: comparison against existing collections, detailed physical or genetic analysis, and eventual publication that formally assigns a scientific name. For deep-sea organisms in particular, that process can be complicated by how fragile some specimens are after being brought up from extreme pressure and cold, which is part of why researchers rely heavily on high-resolution imagery and preserved tissue samples taken at the time of collection rather than live specimens alone.
Genetic barcoding has become a standard part of that process in recent years, letting taxonomists compare a small tissue sample against global genetic databases even when a specimen’s physical condition has degraded during recovery from extreme depth. That technique has meaningfully shortened the time between an expedition ending and researchers confirming which specimens represent species new to science, though full formal description and naming still generally follows well behind the initial genetic match.
What Undiscovered Seamount Life Means for Ocean Science
Seamounts are also increasingly targeted for deep-sea mining exploration and are affected by bottom trawling in some regions, which gives expeditions like this one an added purpose beyond basic cataloguing: establishing what lives on a given seamount before any large-scale disturbance reaches it. Documentation gathered on trips like this one becomes the baseline that regulators and conservation groups can later use to judge how much a seamount’s ecosystem has changed, making the timing of these surveys as significant as the species counts themselves.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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