Introduction
When Robert Falcon Scott and Ernest Shackleton set out for the far south more than a century ago, their ambitions were as much about scientific discovery as they were about national glory. At the turn of the 20th century, Antarctica was a vast blank space on the map—an uncharted wilderness where men risked their lives for the promise of knowledge and the hope of planting a flag at the Earth’s most remote frontier. What they could not have imagined was that their meticulous collections of marine life, preserved in museum drawers for over 100 years, would one day help answer pressing questions about the health of the planet’s oceans.
Today, in an era of sophisticated satellites and submersible robotics, scientists are retracing those same routes, revisiting the very waters explored by these pioneers. Their work has revealed a subtle but significant change in the Southern Ocean: the shells of sea urchins collected today are thinner and more fragile than those gathered in the age of sledges and canvas tents. This quiet but telling difference offers fresh evidence of ocean acidification—a modern environmental challenge whose roots are tied to industrial carbon emissions.
The Heroic Age of Antarctic Exploration
The late 19th and early 20th centuries marked what historians call the “Heroic Age” of Antarctic exploration, a period defined by feats of endurance and a drive to map and study the most inaccessible place on Earth. Carsten Borchgrevink’s Southern Cross Expedition (1898–1900) laid the groundwork for sustained Antarctic science. Scott’s Discovery Expedition (1901–1904) brought back the first major collections of Antarctic marine life, including echinoderms, mollusks, and sponges, meticulously preserved for study. Shackleton’s Nimrod Expedition (1907–1909) pushed further into the interior but also devoted resources to coastal biological surveys.
These expeditions faced unimaginable hardship: frostbite, starvation, blizzards, and months of isolation in lightless winters. Yet the scientific method they carried with them was as disciplined as any in London’s Royal Society. Naturalists cataloged species, recorded water temperatures, and preserved specimens in alcohol or dried storage—never suspecting that their careful labeling and precise coordinates would one day allow direct century-scale comparisons.
A Legacy Rediscovered
In 2025, a modern research team led by Dr. Hugh Carter of the Natural History Museum set sail aboard New Zealand’s RV Tangaroa, armed with historical expedition charts, museum catalogs, and GPS mapping tools. Their mission: locate the exact sampling sites where Scott, Shackleton, and Borchgrevink’s teams had collected sea urchins between 1898 and 1913. By matching archival notes with contemporary oceanographic data, they were able to replicate the original collection process with remarkable accuracy.
The researchers returned with both fresh specimens and an unprecedented opportunity. Lined up in the lab beside their century-old counterparts, the differences were undeniable. The old shells were thicker, heavier, and more structurally sound. The modern ones, by contrast, often crumbled under gentle handling. These changes were not the result of different preservation methods—the degradation was intrinsic to the modern shells themselves.
Acidification: The Invisible Sculptor
The most likely culprit is ocean acidification, a phenomenon virtually unknown in Scott’s day but now well documented. As the oceans absorb increasing amounts of atmospheric CO₂, the resulting chemical changes lower seawater pH and reduce the carbonate ions needed by organisms like sea urchins to build their calcium carbonate shells. The Southern Ocean is particularly sensitive, not only because its cold waters absorb CO₂ more readily, but also because its deep mixing cycles bring naturally carbon-rich waters to the surface.
In practical terms, the chemical balance that once allowed Antarctic sea urchins to build robust, interlocking plates is shifting. Weaker shells make them more vulnerable to predation and environmental stress, and because sea urchins play key roles in Antarctic benthic ecosystems, the ripple effects could alter entire food webs.
Echoes of the Explorers’ Methods
What makes this research so compelling is that it could not have been done without the precision and discipline of the early expeditions. The explorers’ habit of recording latitude and longitude by sextant, their practice of preserving multiple specimens from each site, and their insistence on cataloguing environmental notes—all of these practices allowed modern scientists to return not just to the same general region, but to the very points in the Southern Ocean where those first collections were made.
In many ways, the 2025 expedition is a scientific relay race across time. The baton passed from the Heroic Age to the present, not in the form of a flag or a diary, but as a tangible biological record—a set of shells that could endure for more than a century, waiting for the right question to be asked.
Resilience Amid Change
The news is not entirely grim. During their voyage, the modern team reported surprisingly high biodiversity in certain remote sectors, including sightings of hundreds of whales and a thriving community of echinoderms. These pockets of abundance suggest that, while the chemical and physical environment of the Southern Ocean is changing, there remain areas of resilience—places where protection and preservation efforts could still be effective.
Conclusion
The story of these sea urchin shells is more than a tale of environmental chemistry—it is a testament to the enduring value of exploration. Scott, Shackleton, and their contemporaries sought to expand the boundaries of human knowledge, often at great personal cost. In doing so, they left behind the data and specimens that today allow us to measure, with remarkable clarity, the changes unfolding in one of Earth’s most remote and fragile environments. A century on, their legacy is not just in the maps they drew or the peaks they named, but in the living record they unknowingly created—one that continues to guide science toward understanding, and perhaps preserving, the world they first revealed.
Citations:
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“Crumbling shells, melting ice and a wildlife boom: what recreating Scott’s Antarctic trip reveals about our seas today,” The Guardian, 7 Aug 2025.
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“Scientists retrace Antarctic explorers’ paths to reveal ocean acidification effects on sea urchin shells,” Associated Press, 7 Aug 2025.
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Historical expedition records from the Discovery (1901–1904) and Nimrod (1907–1909) voyages, Natural History Museum archives.
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Ocean acidification impacts on Antarctic calcifiers, Royal Society Special Report on the Southern Ocean, 2023.
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Southern Ocean CO₂ absorption patterns and carbonate ion depletion, NOAA Global Ocean Chemistry Data, 2024.