Three New Deep Cave Species: Freshwater Species of the Week

This amphipod discovered in a deep cave in New Zealand is confirmed as a new species.


In 2010 and again in 2011, a team of Australian divers descended down one of the deepest, coldest freshwater caves in the world, in a remote part of New Zealand’s South Island. The expedition was led by Richard Harris, who has received support from National Geographic as well as the Waitt Foundation.

The divers probed the icy depths of an underground section of the Pearse River, called the Pearse Resurgence, in a search for the (still elusive) source of the flow. They reached a depth of 636 feet (194 meters), working in extremely challenging, dangerous conditions.

To obtain such depths, divers breathe a mix of compressed gases. But if they exert themselves too much, it can lead to carbon dioxide poisoning, which can be lethal.freshwater species of the week

In 1995, an exploring diver died at the site.

The water is a chilly 43 degrees F. And there’s a strong current.

The team didn’t reach the end of the cave, which is thought to extend for at least 3,281 feet (1,000 meters) based on dye experiments. But they did discover three species of invertebrate “stygofauna”–named after the River Styx from mythology–that they suspected were new to science. Now, their findings have been confirmed, reports the Nelson Mail.

One of the new species is a small amphipod crustacean. The colorless animal is six to eight millimeters long.

“The divers could see it crawling over rocks; it really is a beautiful animal,” Graham Fenwick told the Nelson Mail. Fenwick is a researcher with New Zealand’s National Institute of Water and Atmospheric Research, which studied the new species.

The other new creatures are a tiny gastropod snail (1.5mm in diameter) and an oligochaete worm (about 8mm long). These were collected from rare deposits of fine sandy sediments at depths of 49 to 112 feet (15 to 34 meters).

The mysterious Pearse Resurgence calls out for more exploration, as do many other of the world’s deep, dark places.

Check out this NG video of the expeditions:



Brian Clark Howard is an Environment Writer and Editor at National Geographic News. He previously served as an editor for and E/The Environmental Magazine, and has written for,,, Yahoo!, MSN, Miller-McCune and elsewhere. He is the co-author of six books, including Geothermal HVACGreen Lighting and Build Your Own Small Wind Power System.