What recreating Scott’s Antarctic expedition reveals about our seas today | Marine life

TPots of glass samples full of satsuma size echinoderms, or sea urchins, sitting on the desk of Dr. Hugh Carter at the Natural History Museum. Each, collected in the depths of the southern ocean by polar teams led by Sir Ernest Shackleton, Captain Robert Falcon Scott and the Norwegian Carsten Borchgrevink, tells a story of heroic exploration and scientific effort.

Now, more than a century later, Carter, curator of marine invertebrates of the natural museum (NHM), hopes that preserved antarctic sea urchins, 50 in all, will help tell a different and more and more urgent story of modern times: how the changes in the southern waters of the world can affect marine life.

In January, the biologist undertook a six -week research trip to visit the exact sites sampled by the southern cross of Borchgrevink, the discovery of Shackleton and the unhappy terra nova expedition of Scott between 1898 and 1913.

His trip, which is part of a multidisciplinary expedition led by the National Institute of Water and Atmosphere (NIWA), supported by the Antarctic Scientific Platform in New Zealand, was partly traced by the route traveled by Scott. Scott and four other explorers, including chief scientist, Edward Wilson, died in the ice around one month after samples sitting on Carter’s desk were taken.

In Antarctica, which warms the global average to twice, a lack of basic scientific data makes it difficult to assess the physical and biological changes that have occurred over time.

Carter’s theory is that the comparison of the “tests” or the sea urchin shell in the NHM collection with modern samples will help to find out more about the impact of ocean acidification, often called “evil twin” of the climate crisis. Acidification is caused when carbon dioxide is quickly absorbed into the ocean, where it then reacts with the water molecules leading to a fall in the pH of sea water.

The preliminary results on Carter’s ship, the deep water research vessel, RV Tangaroa, seemed to confirm its worst fears.

“We know that the ocean has become more acidic, but in most cases, we do not know what the impacts are,” he said. “We had suspected that [due to ocean acidification] You will get less calcium carbonate in water. This would make it more difficult to build a body if this body is made from calcium carbonate. »»

Corals, sea snails, oysters and small unicellular organisms called foraminifera, a component of plankton, all rest on calcium carbonate to build shells. Calcium carbonate dissolves very easily in acid, so the more acid is difficult, the more difficult it is for animals like these to survive.

In June, new research has shown that 60% of global waters have exceeded the safety limit for acidification, in what scientists described as a “ICT time bomb” for planetary health.

Although the tests of historical sea urchins on the Carter desk are “robust and healthy”, those who made the surface in January were thinner and more fragile in comparison, so much so that they were crushed by the force of the pipe used to clean them.

“All those we have collected were fragile and some of them collapsed,” explains Carter. “According to initial appearances, the modern specimens that we have collected have weaker tests than historical tests, but we have to do more work to establish to what extent and exactly what causes this.

“There are of course confounding variables, but the new ones are thinner.”

The biological implications of an acidifying ocean could be huge, adds Carter. “It could make the seas prompts for things with a calcium skeleton.”

During the expedition, the impact of the climate crisis was tangible; Some study sites were only accessible because of the merger of ice. And that coincided with sudden results that the world’s sea ice level fell to its lowest recorded level, a symptom of our warming planet.

But there were also positive discoveries on the expedition. Carter saw up to 150 whales during his trip, as well as what he described as “crazy levels” of fauna at the west border of the island of Coulman, which had 17 species of starfish in just 100 meters, the same number found in all the shallow waters of the United Kingdom.

“It is a pleasure to know that the environment is not as bad in certain parts of the world as possible,” he says. “This is the only piece in the world that you do not see any plastic or human impact of fishing.”

Professor Craig Stevens, an oceanographer from Niwa who co-directed the Tangaroa expedition, described their work as “sweet and sour”.

“This lack of ice has training effects not only for the regional ocean, but throughout the planet. This work is very soft and sour. It is incredible to get the opportunity to advance science, but at the same time, we see a future for the planet that we really want to avoid.