They’re big, they’re ugly, and luckily they’re a long way away. An Australian research cruise in the icy waters off Antarctica has discovered a whole host of giant sea beasts, including worms, crustaceans and sea spiders (press release, news coverage in Reuters, Xinhua, AFP).
“Gigantism is very common in Antarctic waters – we have collected huge worms, giant crustaceans and sea spiders the size of dinner plates,” says voyage leader Martin Riddle (press release).
Many of the species are likely to be new to science.
Sadly the cruise’s purpose is to conduct a census of marine life so we can see just how badly the ecosystem will be ruined by climate change (census website).
“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,” says Riddle.
This would be a tragedy given how cool some of the things he found are. While some are branding them “monsters”, others putting in the less judgmental “mysterious”, we prefer Voice of America’s line: “wondrous”. While we’re just discovering all these things it’s worth noting that a warming Antarctic will make many of the food for invading crabs and sharks (see Nature).
More pictures and video links below the fold.
All pictures © Martin Riddle, Australian Antarctic.
Descriptions as supplied.
220m on the continental shelf
The stalked structures looking like glass tulips are actually animals known as tunicates. They are early colonisers 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.
210m on the continental shelf
In the fore-ground is a rich community dominated by sponges, octocorals and mushroom-like colonial ascidians; living among these are many smaller echinoderms, crustacean and polychaete worms. Behind is a swathe cleared of most living things by a passing ice-berg.
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.
900m down the slope off the front of the continental shelf
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)