Sunday 1 July 2012
Divers discover new-to-science species
Divers discover new-to-science species in one of the deepest flooded caves in the world
In a recent diving expedition, Australian cave divers found three new-to-science species – a transparent amphipod, a worm, and a small snail – down in one of the world’s deepest underwater caves, near Nelson.
“It’s not easy to get inside the caves, and we want to know about the very specific life in them,” says NIWA expert Dr Graham Fenwick.
The discoveries were made in the Pearse Resurgence, a cave in the Mt Arthur Range, close to Nelson, where the divers were exploring underwater cave systems. They were collecting samples of stygofauna, which literally means animals from the River Styx, the mythical river that leads to the underworld.
There are 16 diveable caves in the world deeper than the Pearse Resurgence.
Only ten of these have been dived to depths greater than the current depth explored in the Pearse (194 metres freshwater). The divers were on site for 13 days, performing a total of 74 dives in the 6.5ºC water. The dives took place between 27 December 2010 and12 January 2011.
Worldwide, these aquifer studies are yielding rich troves of biodiversity. The importance of such stygofauna is twofold: they contribute to the health of the aquifer by biofiltration and, in turn, they may represent an important marker of the health of the water.
“It’s important to do an inventory of life in New Zealand, and in this case, it’s a pretty special type of environment, and we don’t have many limestone karst systems that are readily explored,” says Dr Fenwick.
A stygofauna biosurvey was performed in the cave using two techniques. Firstly, any invertebrates observed free swimming in the cave were captured by hand using a tube with a bulb on the end something like a turkey baster, “the stygoslurper as we call it,” says Dr Fenwick.
The second technique involved the deployment of baited fauna traps in the cave at depths from 5 -115 metres below the surface. Small plastic jars baited with a small shrimp were filled with nylon gauze and secured in various places in the cave, in crevices and amongst sediments.
One undescribed (new to science) species of amphipod crustacean dominated the stygofauna collected from the Pearse Resurgence. This species is completely colourless.
“It is six to eight millimetres long, the divers could see it crawling over rocks; it really is a beautiful animal. It belongs to the poorly known genus Paraleptamphopus, one of two genera within the New Zealand endemic Family Paraleptamphopidae,” says Dr Fenwick.
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