Caption: Glass sponges, which provide habitat for feather and brittle stars in frigid Antarctic waters, flourished following the collapse of the Larsen A ice shelf.
This sudden expansion of a glass sponge is unprecedented," says Paul Dayton of the Scripps Institution of Oceanography in La Jolla, Calif.
In addition, five glass sponges
, Rhabdocalyptus sp.
Such reef-building glass sponges disappeared from the fossil record about 120 million years ago, about the same time that diatoms, a type of single-celled marine algae with cell walls built of silica, first appeared in large numbers, says Johnson.
Reef-building glass sponges had previously been found only in the protected waters of a near-shore strait, so researchers had presumed that the creatures could thrive only in certain restricted ecological niches.
In situ feeding and metabolism of glass sponges
(Hexactinellida, Porifera) studied in a deep temperate fjord with a remotely operated submersible.
Basket sponges, Geodia, and glass sponges comprised 66.
Only the basket sponges appeared to be affected; Geodia and glass sponges showed no evidence of necrosis.
More rigid species, such as Geodia, often found attached to cobbles, would probably be either crushed or rolled over; and glass sponges, flexible but usually associated with finer substrates and attached by tufts of spicules extending into the substrate (Brusca and Brusca, 1990), would be pulled from the substrate in their entirety.
By shining extremely short pulses of laser light into the transparent, liquid-filled glass sponges
, the researchers generate ultrasonic waves within the material, allowing them to monitor the liquid's behavior.