After yesterday's surprise appearance by what was most likely a polychaete of some sort, today we encountered a strange creature that we are having a lot of trouble identifying. We first spotted it at the water-sediment interface in a megacore tube, looking like this:

An unknown invertberate brought up in a megacore sample
Invertebrate captured in a megacore sample taken in Cranton Bay, Amundsen Sea, Antarctica

When I tried to extract it using a scientific instrument (a metal soup spoon from the galley), it retracted deeper into the sediment. I was able to gently dig it out, and we placed it in a jar with some sea water and then put the jar in Little Antarctica (the walk-in cooler). A few hours later, it looked like a lumpy pink volcano:

Unknown invertebrate captured in a sediment sample of Cranton Bay
After three hours in a seawater-filled jar in the walk-in cooler, the unknown invertebrate has taken on a different form. Cranton Bay, Amundsen Sea, Antarctica.

As of right now, we are calling it "Bruce" and my best guess is that it is some sort of sea anemone? But I'd love to hear from any invertebrate experts out there- what exactly are we looking at?

Sidebar- please get back to us quickly if we should be afraid.

Update: This morning, Bruce had again changed his appearance, looking more like the sea anenome I think he is, with hints of a pink Jabba the Hut.

Invertebrate organism captured in a megacore sample, Cranton Bay, Antarctica
An unknown invertebrate organism captured in a surface sediment sample from Cranton Bay, Antarctica

Author
Date
Location
Onboard the R/V Nathaniel B. Palmer icebreaker in the Amundsen Sea off the southwest coast of Antarctica
Weather Summary
Chilly with low winds and occasional breaks of sun
Temperature
-1.1 C
Wind Speed
6.4 knots from the northeast
Wind Chill
-8.7 C

Comments

Stan

You know you have at least one invertebrate biologist up the Tower of Ice, right?

Stan

Sorry, meant to say Marine Biologist.. didn't you say that at some point in another blog? Or have they had a look with no joy?

Sarah S.

Unfortunately, they are knowledgeable about marine vertebrates but not the invertebrates. Marine biologists with a charismatic macrovertebrate focus.

Carlos Brunet

Try Urticinopsis antarctica - has column height of up to 120 mm and is common in the area.

Sarah S.

I looked it up on 2017 Offline Wikipedia and it seems plausible- although they are so malleable in their appearance, it is hard to say for sure.

Ms Cheung

So cool! - I love how Bruce can change into so many different forms.

Emily Fano

This must be such an exciting and rewarding trip for you Sarah! Once in a lifetime experience.