Antarctic marine life

December 20, 2013

McMurdo Station, Antarctica

Since I had some time this afternoon I did not anticipate having due to our delay, I decided to take a trip to the Crary Aquarium.  Now, I have the opportunity to give you all a tour of Antarctic marine fauna.

Exhibit A

Exhibit B.  The funny thing about this "touch tank" is that because it is -2 deg C, by the time your finger touches any of the organisms you can't feel anything.  The average annual temperature in McMurdo Sound is -1.86 deg C.

This seastar, Odontaster validus, is the most common seastar in Antarctica.  It may live beyond 100 years.  It has "eyes" on the end of each of its arms which allow it to see light and dark.  

It looks like this seastar just finished eating.

The white thing in front is a nudibranch, which means "naked gills" for the fringe on its exterior.  I think this species is Tritonia challengariana.  The colloquial name is sea slug

The Collossendeis sea spider in the mid-right are a deep sea species.  Their legs can span 50 centimeters, making them the largest sea spider.  They suck the juices from soft-bodied invertebrates like jellies or anemones.  The anemone on the left is also predatory and eats sea urchin and seastars.  I saw the spiky remains of a sea urchin in its mouth last week.

This sea urchin, Strechinus neumayeri, is abundant at <15m water depth.  It is slow growing, reaching ~7 cm at 40 years old.  In shallow waters, it eats seal poop.  For protection, it attaches bits of shell and debris to itself.

Tunicates, more commonly called sea squirts, are more closely related to vertebrates than invertebrates.  They have a nerve cord down their backs and a semi-rigid tail.

The yellow blob on the lower right is an Iamellarian gastropod, Marseniopsis  mollis.  Ir ranges between 1.4 cm and 7 cm (this one was on the large side).  You would think that this yellow color would not be a good strategy against predators, and it has no protective shell (mollis means soft).  It releases a chemical, homarine, which may deter predators.

These Lumitula hodgsoni are very common between 6 and 600 m water depth.  You can make out tubules between its two shells.  There is a variety of seastar which is its primary predator.

Isopod, or Glyptonotus antarcticus.  It can grow to 20 cm in length.  It eats anything it finds, including young isopods.  The isopod is also nocturnal.

This fish is a rockcod, or Trematomus bernacchii.  It lives on the seafloor and is a benthic feeder by ambush or hunt-and-peck feeding.  It is well-adapted to cold temperatures.