Meet the supergiant that's quietly lurking across 60 per cent of Earth's oceans
It turns out this 'rare' supergiant isn't so rare, after all.
Alicella gigantea was once believed to be a rare 'supergiant' sea crustacean, but new research suggests it may be abundant, inhabiting up to 59 per cent of the world's oceans.
The study, led by Dr. Paige Maroni from the University of Western Australia's School of Biological Sciences, appears in the journal Royal Society Open Science.
A. gigantea is the largest-known amphipod species. Most amphipods top out at less than the size of a fingertip, but A. gigantea is a bonafide giant, with the largest specimen found to date measuring a whopping 13.4 inches long.
Researchers examined 195 records of the giant amphipod from 75 areas in the Pacific, Atlantic, and Indian Oceans at a depth range of 3,890 to 8,931 metres.
The specimens came from a diverse range of conditions, including trenches and fracture zones.
DNA analysis found the crustacean's presence in nearly 60 per cent of the world's oceans, making it far from rare.
“Historically, [A. gigantea] has been sampled or observed infrequently relative to other deep-sea amphipods, which suggested low population densities,” Dr Maroni says in a statement.
“And, because it was not often found, little was known about the demography, genetic variation, and population dynamics with only seven studies published on DNA sequence data.”
A. gigantea congregating around a bait station at 6500–6700 m from the Murray Fracture Zone, North Pacific. Scale: 20 cm. (Maroni et al., R. Soc. Open Sci., 2025)
What's going on down there?
The findings are yet another example of how little is known about the deep sea.
Despite their apparently large numbers in the world's oceans. A. gigantea samples are rarely collected because i lives in what is known as the lower abyssal (3,000 to 6,000 metres) and upper hadal zones (6,000 to 11,000 metres), which is a whole other world.
Sunlight loses its ability to penetrate water at about 1000 metres, meaning the abyssal and hadal zones are very dark and very cold, with temperatures hovering around the freezing mark. The weight of the water pushing downward creates crushing pressure, meaning only specialized equipment can enter these zones to collect data.
Human impact on A. gigantea
Despite living at such great depths, previous studies have detected evidence of human-caused chemical contamination in the crustaceans, including the presence of the now-banned pesticide DDT.
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Header image: Wikipedia/Hadal Zone cc by sa 4.0) /Hadal Zone CC BY SA 4.0
