Pteropods & B-134 / by Shaun O'Boyle

B-134 is a biology group here at Crary lab made up of Dr. Gretchen Hofmann, primary investigator; Kevin Johnson, grad student; Umi Hoshijima, grad student; Juliet Wong, grad student and Cailan Sugano, technician. I visited them in their lab and out on the sea ice where they are studying pteropods, free swimming pelagic sea snails that live in the open water of McMurdo Sound. These small snails, currently the size of a grain of sand but which will grow to about 1/4", have evolved their snail foot to act as wings to swim in the water column. They are found in large schools and are a key component in the food chain here in Antarctica. A simple look at the food chain here is: phytoplankton > pteropods > fish > seals & penguins > larger predators like sea leopards and orcas. Fish rely on the pteropods as a primary source of food. B-134 is studying ocean acidification as a result of the ocean absorbing historic high amounts of carbon dioxide. They are measuring the effect of this acidification on pteropods. What they are finding is that the rise is acidic levels is causing problems with shelled animals like the pteropod. They are seeing evidence of the higher acid levels dissolving their shells. Microscopic images show shell erosion and shell layers being dissolved. The study is trying to determine what the pteropod's response will be to higher levels of carbon dioxide, and how this will effect their shells. This study will indicate if the higher PH levels of the ocean has the potential to collapse this vital link in the food chain. For more information on what the B-134 group is up to check out their facebook page at www.facebook.com/hofmannB134 Kevin Johnson driving us out on the sea ice in a piston bully.

Arriving at Hut 3, with McMurdo station in the background.

When we entered the hut we found a visitor waiting for us in the ice hole.

Umi Hoshijima and a very chilled out Weddell seal.

Kevin and Umi taking Pteropods from the drift net.

Kevin sorting Pteropods into groups.

Placing them into vials that are kept at sea water temperature.

About every 15 minutes the seal return for air, and she really blows some air when she comes up.

Pteropods in the aquarium at Crary Lab.

Technician Cailan Sugano working in Crary Lab.

Kevin Johnson, Juliet Wong and Umi Hoshijima in the Crary aquarium at the tank where they are experimenting with different Carbon Dioxide levels.

Pteropod showing the "foot" that acts as wings for swimming. Photo by Kevin Johnson.