Sea of glass: the underwater world of Leopold Blaschka

The 19th century glassblower's intricate sculptures of marine life are a window on the ocean 150 years ago, says ecology professor Drew Harvell

In the 1860s, when the Bohemian glassblower Leopold Blaschka began sculpting models of underwater creatures, the Industrial Revolution, population growth and climate change had yet to take their toll on marine biodiversity. Over three decades, using techniques that still baffle experts, Leopold and his son, Rudolf, handmade about 10,000 marine sculptures, each one rendered in minute detail: impossibly delicate anemones, livid orange cuttlefish - creatures at once alien and unnervingly lifelike.

In a world before scuba diving, underwater photography or ocean life surveys, the Blaschkas' models proved an invaluable educational resource, with universities worldwide purchasing collections of glass specimens. One of the largest, with 570 models, belongs to Cornell University in the US, where until recently it was all but forgotten, stowed in a warehouse in a state of disrepair. As a young professor in the 1990s, Dr Drew Harvell began cataloguing the collection, discovering a "time capsule" of 19th-century marine biology. "There's value in the entire collection," she says. "It's what you could see 150 years ago, frozen in time."