Photos of bizarre creatures discovered in Antarctica
February 19, 2008
The stalked structures looking like glass tulips are actually animals known as tunicates. They are early colonizers of areas recently disturbed by ice-berg scouring. They filter food particles from the water by pumping it through an internal mesh structure and the stalk is supported by hydrostatic pressure created by their pump. Feather stars (crinoids), sea cucumbers (holothurians) and another species of tunicate have used the stalked tunicates to gain height to give them an advantage in intercepting food particles from the water before it reaches the sea-bed. The sediment surface is covered with a mass of tubes, probably of small polycheate worms. 220m on the continental shelf. Image courtesy of the Census of Antarctic Marine Life.
The glass sponges, with skeletons made of glass-like silicate fibres, and coralline bryozoans form a home for deep living grenadier fish, their large eyes adapted to pick-up the dim light created by bioluminescence. The only light to ever reach these depths is light created by animals with special organs that glow (bioluminescence). 900m down the slope off the front of the continental shelf.
400m on the edge of the continental shelf. At this depth every inch of the sea-bed is covered with a complex mixture of sponges, bryozoans, hydroids and octocorals which form a home to a many species of fish, brittle stars, sea-urchins and a great variety of crustaceans and mollusks.
600m down a canyon leading off the front of the continental shelf. This is one of the most diverse sites sampled during the CEAMARC voyage. The main structural components are the brightly colored coralline bryozoans and sponges, which create a habitat for many other species including brittle stars, octopus, mollusks and fish. Although in a different biological group from the tropical corals, the coralline bryozoans have similar calcium carbonate skeletons and are particularly susceptible to ocean acidification caused by rising CO2 levels because calcium carbonate becomes more soluble with increasing acidity.
Video capture of a giant spider-like Crinoid or feather star.
"Some of the video footage we have collected is really stunning — it's amazing to be able to navigate undersea mountains and valleys and actually see what the animals look like in their undisturbed state," said Aurora Australis voyage leader Dr Martin Riddle. "In some places every inch of the sea floor is covered in life. In other places we can see deep scars and gouges where icebergs scour the sea floor as they pass by. Gigantism is very common in Antarctic waters — we have collected huge worms, giant crustaceans and sea spiders the size of dinner plates."
The voyage comes as one of Australia's International Polar Year projects, a census of life in the cold Southern Ocean known as the Collaborative East Antarctic Marine Census (CEAMARC). The researchers say their work could shed light on some of the changes occurring in the Antarctic Ocean ecosystem.
"This survey establishes a point of reference to monitor the impact of environmental change in Antarctic waters. For example, ocean acidification, caused by rising atmospheric carbon dioxide levels, will make it harder for marine organisms to grow and sustain calcium carbonate skeletons," explained Riddle. "It is predicted that the first effects of this will be seen in the cold, deep waters of Antarctica. Our results provide a robust benchmark for testing these predictions."
"This research will help scientists understand how communities have adapted to the unique Antarctic environment. Our work also has wider applications, for example understanding fish community composition and structure is particularly important to explain the impacts of commercial trawling," added CEAMARC Project Leader Dr Graham Hosie. "Specimens collected will be sent to universities and museums around the world for identification, tissue sampling and bar-coding of their DNA. Not all of the creatures that we found could be identified and it is very likely that some new species will be recorded as a result of these voyages."