Antarctic Sea Urchin, Sterechinus Neumayeri

The Antarctic Sea Urchin (Sterechinus neumayeri), is a species of sea urchin in the family Echinidae. It is found in the Antarctic Ocean living on the seafloor. It is common around the circumpolar waters, including the Balleny Islands, South Georgia and the South Sandwich Islands, Terra Nova Bay, and Victoria Land. It is found at depths of about 820 feet.

The colors of this species range from bright red to dull purple and can grow to 2 inches in diameter. The test (shell) is globular with several vertical rows of long, strong, white-tipped spines between which there is a dense covering of smaller spines and vertical rows of tube feet. The spines and tube feet enable the animal to move across the ground. Fragments of red algae are often adhered to the spines.

The Antarctic Sea Urchin feeds mainly on diatoms and other algae, but may also consume foraminifera’s, amphipods, bryozoans, hydrozoans, polychaete worms, and sponges. It will also consume seal fecal matter when available. This species is often found living in association with the Antarctic Scallop and the Seastar.

Metabolic processes tend to slow down as the temperature decreases and the Antarctic Sea Urchin lives in an extremely cold environment. Researchers studying this species have found that the larvae use energy 25 times more efficiently than other organisms do. Mature urchins were collected and brought to a research lab at McMurdo Sound where they were induced to spawn.

Researchers used more than 10 million embryos to test the protein turnover rates and the associated changes in metabolic rates in the larvae as they developed. Through this process they were able to find the super-efficiency of their metabolic energy use. Despite this, it took larvae a year to develop into juveniles. It remained unclear how this energy efficiency worked in the species, but researchers believed if they could transfer that energy through genetic manipulation to other organisms, such as clams and fish, it could transform aquaculture as we know it.

Research was also done on the reproductive capacity of the Antarctic Sea Urchin would be able to cope with an increased ocean acidification that would be likely to accompany global warming. Researchers found that lowering the pH from a normal 8.0 to 7.3 lowered fertilization rates of the urchin. At lower pH concentrations there was also a considerable increase in abnormal embryos at later stages of development. The results were not any more significant, however, than those of other similar organisms from more temperate regions of the world.

Image Caption: Sea urchins, Sterechinus neumayeri. Credit: Zureks (CC BY-SA 3.0)