Antarctic Waters Yield a Surprising Visitor: The Greenland Shark
The frigid depths of the Antarctic Ocean have long been considered an unlikely habitat for sharks. Yet, recent discoveries are challenging that assumption. Researchers have captured the first-ever footage of a Greenland shark – a species known for its remarkable longevity and adaptation to extreme cold – swimming nearly 500 meters below the surface in Antarctic waters. This unprecedented sighting, published in National Geographic, is forcing scientists to reconsider the boundaries of where these apex predators can thrive and highlighting how much remains unknown about the biodiversity of the Southern Ocean.
The discovery, made by the Minderoo-UWA Deep-Sea Research Centre during a biodiversity survey in January 2025, showcases a sleeper shark, too known as a Greenland shark (Somniosus microcephalus), navigating the icy waters off the Shetland Islands, near the Antarctic Peninsula. The shark, estimated to be between 2 and 3 meters long, was filmed by underwater cameras deployed as part of the research mission. This finding is particularly significant given the shark’s known preference for the Arctic and North Pacific regions, and its previously assumed inability to tolerate the extreme conditions of the Antarctic.
A Master of Cold-Water Survival
Greenland sharks are renowned for their incredible lifespan, potentially exceeding 400 years, making them the longest-lived vertebrate known to science. National Geographic reports that this longevity is linked to unique genetic adaptations, including duplicated genes involved in DNA repair, immune function, and protection against oxidative stress. These adaptations minimize the physical wear and tear associated with aging, allowing these sharks to endure for centuries.
But their longevity is only one piece of the puzzle. Greenland sharks thrive in incredibly cold and deep waters, a habitat that presents significant physiological challenges. To survive in these conditions, they have developed several remarkable adaptations. Their metabolism is exceptionally slow, leading to a sluggish pace of life – they swim at speeds of less than 4 kilometers per hour and grow less than a centimeter per year. This slow metabolism conserves energy, crucial for survival in a food-scarce environment. Their tissues are saturated with urea and trimethylamine N-oxide (TMAO). Urea helps maintain osmotic balance with the surrounding seawater, while TMAO stabilizes proteins, allowing them to function effectively at near-freezing temperatures. All sharks possess TMAO, but Greenland sharks have significantly higher concentrations than most species.
Challenging Scientific Assumptions
Dave Ebert, a shark scientist at San Jose State University, described the discovery as “exciting, but not unexpected,” noting that Greenland sharks are “authentic polar sharks.” La Prensa Austral reported Ebert’s comments, emphasizing the species’ inherent ability to adapt to polar environments. Still, the sighting in Antarctica still represents a significant expansion of the known range for these sharks.
Dr. Jamieson, the researcher who reviewed the footage, expressed his surprise, stating he had only observed four Greenland sharks in his 25-year career. The individual filmed in the Antarctic was one of the largest he had encountered. The extreme rarity of these encounters underscores the challenges of studying deep-sea creatures and the potential for undiscovered biodiversity in remote regions like Antarctica. The shark’s presence in the Southern Ocean raises questions about whether it represents an isolated incident or a previously unrecognized population.
Possible Explanations for Antarctic Presence
Researchers hypothesize that the shark may have been drawn to a localized “warm corridor” of water within the Antarctic region. These warmer currents could provide a more hospitable environment, allowing the shark to venture further south than it typically would. Jamieson suggests this could explain the sighting, but acknowledges that further investigation is needed to determine whether it was a chance encounter or evidence of a more established presence. The Minderoo-UWA Deep-Sea Research Centre originally deployed the cameras to assess the biodiversity of the area, and the unexpected sighting highlights the value of such exploratory research.
The discovery also reinforces the idea that there may be few places in the ocean where sharks cannot survive, given the right conditions. However, it also underscores the vastness of our knowledge gap regarding marine ecosystems, particularly in the Antarctic. “There’s so much we still don’t know,” Jamieson emphasized, questioning whether other shark species may also inhabit Antarctic waters and whether the observed shark is part of a larger, undiscovered population.
The Resilience of Greenland Sharks and the Future of Antarctic Research
The Greenland shark’s ability to thrive in such extreme conditions is a testament to its evolutionary resilience. Its slow metabolism and unique physiological adaptations allow it to conserve energy and withstand the challenges of a cold, deep-sea environment. The discovery in Antarctica adds another layer to our understanding of this remarkable species and its capacity to adapt to changing ocean conditions.
Further research is crucial to determine the extent of Greenland shark presence in Antarctic waters and to assess the potential impact of climate change on their habitat. As the Southern Ocean warms and ice melts, these sharks may expand their range further south, potentially altering the delicate balance of the Antarctic ecosystem. Continued monitoring and research efforts are essential to track these changes and to inform conservation strategies.
The ongoing function of the Minderoo-UWA Deep-Sea Research Centre and other organizations is vital for unraveling the mysteries of the Antarctic Ocean and for protecting its unique biodiversity. The recent sighting of the Greenland shark serves as a powerful reminder of the hidden wonders that lie beneath the surface and the importance of continued exploration and conservation efforts.
Researchers plan to continue analyzing data collected from the underwater cameras and to conduct further surveys in the region to search for additional evidence of Greenland sharks and other deep-sea species. The next phase of the research, scheduled to begin in late 2026, will focus on mapping the distribution of key species and assessing the impact of environmental changes on the Antarctic ecosystem.
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