Week 4: Ob Tube

A short post about climbing down a tube to glimpse under the sea ice. Also featuring THREE SEAL FACTS!!!

Every year in McMurdo, the rec department installs the Observation Tube (aka Ob Tube). The Ob Tube is a ~15ft long vertical pipe, about 3ft in diameter, that gets poked down through the sea ice. At the bottom of the tube is a tiny room with a stool in the center, with 6 windows that look out into the ocean beneath the ice.

The Ob Tube unassumingly sticking out of the sea ice (Ob Hill in the background... why is everything around here named "Ob"??).

The Ob Tube is only installed for a few weeks every year, and only when the sea ice is thick enough to support it. Last season, I arrived too late; the Ob Tube had already been removed.

A signup sheet with time slots is posted in the hallway next to the galley, and groups of 2-4 people can sign up for a 45 minute trip. You have to check out and grab a radio from Central Communications before you head out.

The PASSCAL team had our 7am morning meeting at the Ob Tube instead of in the office. What a great way to start off a Monday!

The Ob Tube opened late this year; they installed it 2 weeks ago, but went out to do a final safety check and found that the tube was flooded. The seal on one of the windows was busted. I think it probably wouldn't be a fun experience to be trapped in the tube as it started filling with sea water. So they fixed the seal and reinstalled it, then opened it last week.

Here I am, climbing down the Ob Tube (with the Transantarctic mountains in the background!).

Unfortunately... two separate groups got stuck in the tube in the wee hours of the morning, and someone couldn't get out, so SAR (Search-and-Rescue) had to be called to rescue them. SAR was not pleased about having their sleep interrupted, so the tube was briefly shut down. It just recently re-opened again, but with no time slots to see it between 10pm and 6am...

Another view of the Transantarctics. What a view!!!

The rec department provides the "Ring of Fire", a wooden ring the same diameter as the tube, so you can check if you fit (or if you fit with less layers) before descending into the tube, so you don't risk getting stuck. The tube is so narrow that I could let go of the ladder with my hands and not fall down (my back rested against the wall).

Down I go!

At the bottom, you step down onto a small wooden box that doubles as a stool. The view was completely other-worldly. And the sounds..... I heard seals talking and singing! This is one of the most amazing things I've ever experienced. I could have sat down there for hours listening to the seals. If you haven't heard underwater Weddell seal sounds before, go listen right now!!

Under the ice, looking back towards the shore.

I am not good at prose or pictures, so enjoy 2 terrible pictures and 3 Fun Seal Facts instead of watching me struggle to describe just how beautiful and amazing this experience was.

SEAL FACT: Weddell seals can dive underwater for over an hour, and the only seal that can dive for longer is the Elephant seal!

Under the ice, looking out into the open ocean.

SEAL FACT: Weddell seal pups learn how to swim when they are 1-2 weeks old!

In the Ob Tube looking back up towards the surface.

SEAL FACT: Weddell seals have special front teeth that they use to rake the sea ice to keep breathing holes open into the ocean, and to make ramps for their babies to climb in/out of the water (so it's not too slick).

Seal Facts provided by Weddell Seal Science. Go check out that blog for more Seal Facts and extremely adorable seal pictures.