Stranger Things below the Ice

What really lies below the Antarctic sea ice? Not everything is pretty sea stars and cute anemones. A spookier truth lies beneath to those that dare to go...

Around our main study site, Cinder Cones, an ominous presence dominates the sea. Up to six feet in length and with an acidic slime, these creatures are one of the main inhabitants of the seafloor. What do you think they are? Vote below!

What do we think of this?

• Obviously a ball of intestines
• Maybe a worm

Parborlasia corrugatus (species), a nemerdian worm, lives in our hearts as one of Cinder Cones's enigmatic creatures. (Pictured above)

Going deeper to 50ft, you might be greeted by the eight legged sea spiders. These curious arthropods, Colossendeidae (family), can get up to the size of a dinner plate!

Spookier things are beyond what you can see, and more into what you can hear. From thumping to clicking sounds coming at you in all directions, you never know when a seal might come your way! Once they do though, the eerie sounds turn into the most wholesome moments of the dive.

As we go below the seafloor and into the mud, a whole new world of weird organisms come to light (Image to the right). From scaleworm to clams, they live and breathe for the spooky season all year long.

A Song of Ice and Inspire

Fully geared up, I twist and drop into the dive hole at the McMurdo Jetty. I see nothing but bubbles and white, but I open my drysuit valve, and begin my descent. The column of ice passes in an instant and a world of darkness opens up around me with a ceiling of icy blue covered in thin spiky sheets of platelet ice.

After two years of intensive SCUBA training, and a journey across the world, I begin my first dive into the waters of Antarctica. It's cold, there's no doubt about it, but the clarity is unrivaled. Each direction I turn I can see for hundreds of feet, watching trails of ice cracks above and anemone fields below.

Everywhere I turn are animals that are familiar, yet larger and more abundant. Sponges and tubeworms reach from the rocks, sea stars and Trematomus fish fill the crevices.

I follow my dive buddy for this checkout dive, Alex Brett, as he guides me through this unfamiliar plane, showing me the wonders within. A rock encrusted with eggs, he points underneath, the mother dragonfish lies below, guarding her clutch. We swim further, a large pycnogonid sea spider stares at me, menacingly. It moves slowly, but I know it's waiting to pounce and exsanguinate me.

As we swim through this ice-capped landscape, surprisingly not feeling claustrophobic, echoes of seals can be heard. A low thumping, an eerie trilling, the sounds are directionless, yet all around. This area does not belong to me. I am merely a visitor. As such I try not to disturb any creature, stir up any sediment, or turn over any rock. Taking only memories and adjusting to the waters I'll spend the season diving in.

There were so many incredible parts of this dive. My favorite part - seeing Clione sea angels and comb jellies lit up with our dive lights, dancing in the beams and reflecting rainbow lights.

The dive support team of Alex Brett, Steve Rupp, and Rob Robbins, in tandem with my dive team - Paola, Andrew, and Lily, and divers of additional projects, I know it's going to be a great season. I can't wait to keep diving here, at the end of the world.

I feel so privileged to be here. I know that I worked hard to get here. I'm excited to conduct science and share these experiences with you all.

Cracking the code: Sea Ice Edition

Sea Ice forms seasonally across the Ross Sea during the Winter months in Antarctica. Every year brings a unique landscape, and with it new formations and cracks. As the sea surface starts to freeze, we can observe frazil ice begin to form. Depending on the wind stress over them, they can take the texture of an icy drink, called Nilas ice, or a form of pancakes called, wait for it, pancake ice!

Left: McMurdo Sound (red pin) during Summer season 2025; Right: McMurdo Sound during Winter Sound 2025. Both images from NASA WorldView.

As the ice accumulates, it can thicken over 5 feet easily! Now called columnar ice, it is usually paired with stalactites-looking ice underneath called platelet ice (although this fragile ice below is not considered part of the ice true thickness).

Below the sea ice, platelet ice formation in the McMurdo Sound.

As ice sheets collide into each other, they form pressure ridges between them - which leads to cracks. Due to the cool geometry of ice molecules, working cracks usually expand in a stair like pattern. The start of the stair like feature marks the actual crack width, while the crack width that it is unreliable to cross due to little sea ice thickness is considered the effective crack width. To safely cross them, either by foot or by our vehicles like the Pisten Bully, we dig them up and profile them!

A cool trick to spot sea ice cracks: look for the seals! Seals love the cracks as a way to get in and out of the water - where there is a seal, there must be a crack.

To profile a sea ice crack, we dig into the snow until we hit ice. Starting from the crack itself, we dig outward until we find the first “stair” step. Once we found ice, our goal is to get:

1. Actual and Effective crack width

2. Ice Thickness

On the crack itself, we drill (see the picture below!) until we hit water. The drill itself is 100cm, so if no water is touched, we are good to pass it! If it does, we proceed to measure the sea ice thickness with a measuring tape through the hole.

How do we know what is the minimum thickness? We have a handy little table! Depending of the vehicle you are driving, different minimum values for thickness and width will exist to ensure a safe passage of the vehicles.

For our Pisten Bully vehicle we require at least 12in of ice thickness with an effective crack width of no more than 36in. Because we found less than 12in of thickness, we moved outward the crack in 1ft increments and drilled again. With each drill, we were expanding our effective crack width. If the drilling went past 36in without getting a thickness of more than the 12in, it would not have been safe to cross. Lucky for us, we were able to find a thickness of more than 12in within a length of 36in, safe to cross!

No year or day is the same. Cracking the code on the cracks is a daily effort from anyone that passes its way!