Antarctic Shells from 100 years ago reveal alarming effect of acid seas

Three glass specimen jars full of satsuma-sized sea urchins, sit on Dr Hugh Carter's desk in the Natural History Museum.

- Karen McVeigh

Each one, collected from the depths of the Southern Ocean by polar teams led by Sir Ernest Shackleton, Capt Robert Falcon Scott and the Norwegian Carsten Borchgrevink, tells a tale of heroic exploration and scientific endeavour.

Now, more than a century later, Carter, the Natural History Museum's (NHM) curator of marine invertebrates, hopes the preserved Antarctic urchins, 50 in all, will help tell a different, increasingly urgent story of modern times: how changes in the world's southernmost waters may be affecting marine life.

In January, the biologist undertook a six-week trip to visit the sites sampled by Borchgrevink's Southern Cross, Shackleton's Discovery and Scott's Terra Nova expedition between 1898 and 1913.

His voyage, part of a multidisciplinary expedition run by the National Institute of Water and Atmosphere (Niwa), supported by the Antarctic Science Platform in New Zealand, partly retraced the route made by Scott. Scott and four other explorers, including the chief scientist, Edward Wilson, perished in the ice about a month after the samples sitting on Carter's desk were collected.

In the Antarctic, which is warming at twice the global average, a lack of baseline scientific data makes it difficult to assess the physical and biological changes that have occurred over time.