I have been so glad to share my experiences with you in Antarctica and show imagery of the bizarre and incredible life under the ice. To show you this strange world, the first — and perhaps most crucial step — is finding a way under the Antarctic ice sheet. This requires a dive hole.
While a dive hole generally carries the same definition in Antarctica, the methods of making one vary widely. I have experienced two during my time here.
The first dive hole that I participated in making was an impressive feat of a large team of people with a range of specialties. This included heavy machine operators, carpenters, a sea ice profiler, divers, and scientists all working together to place a hole in the right spot and in the most efficient way possible. During this task, the biggest problem we had to overcome was moving large equipment over a crack in the sea ice, taking a number of ice thickness profiles to ensure the safety of everyone involved.
Once we found thick ice that could be driven over, the rest was relatively quick. The location of the hole was determined by GPS coordinates along with local expertise by Andrew and the Divers, and the machine operators drilled a hole in the sea ice that was 4 feet across and about 8 feet deep in less than 10 minutes.
The carpenters then towed a dive hut on top of the hole, and voila! We had a dive site and a great deal of gratitude.
The second dive hole I participated in making took place in New Harbor, a remote field camp on the edge of Antarctica’s Dry Valleys. Both ourselves and our equipment were dropped off by helicopters.
In this scenario, we were more resource-limited and therefore required more physical labor, time, and patience. This hole began with a jiffy drill — a large drill used to drill through ice to make fishing holes. Using the Jiffy drill, we drilled around 20 times through the first 3 feet of ice, making a large start. We then connected flights to the drill, or ~3-foot extensions to the drill bit, until we hit the water.
After hitting the water, we placed a continuously heated element down the jiffy drill hole for about 20 hours, and waited for the ice to melt into a divable hole!
For every dive hole, so much expertise and support is required from McMurdo station. I couldn’t be more thankful to all the people who made our work possible. Their work made our entry to the other world beneath the Antarctic ice possible.
So far this season, we have shown you some of the incredible fauna present under the ice in Antarctica. A lot of animals in Antarctica are significantly larger than their global counterparts because of the extremely high oxygen content in the cold waters here. Although the large fauna is incredibly unique and endlessly photogenic, I spent the last week capturing images of the smaller under-sea animals to show you how amazing the little things in Antarctica are as well.
To capture images of the smaller animals in McMurdo, I used macro photography, which uses a magnified lens to show very small living organisms. As someone who studies microbiology, I appreciate any chance to show small, yet incredibly important life. Although not microbes, these creatures are fascinating and beautiful.
An anemone of the Clavularia genus. These anemones are an average of 8 mm tall, and were probably around that size in this picture. Antarctica has an abundance of anemones, including Edwardsia beds at our very own Cinder Cones Seep!
A sabellid polychaete, or feather duster worm (yes, it’s a worm!) filter feeding with its feathery radioles. The radioles of a feather duster worm have combs that pick up food from the environment. Sabellids are tubeworms, using the substrate from the environment to encase itself.
Likely an isopod from the Arcturid genus. Arcturid isopods are commonly found on sponges of the Homaxonella genus, which is exactly what you’re seeing here! They perch and filter feed on detritus passing by.
A little sea spider hiding in the crook of an anchor ice bed. This sea spider was small, but sea spiders in Antarctica can be bigger than a dinner plate!
Last week, we took leave of McMurdo Station by helicopter, to New Harbor, an additional research site about 50 miles away. We stayed for three nights at an established field camp there.
Approaching our field camp.
Our flight was entirely over sea ice, which extends beyond the horizon. The sea ice has been endlessly fascinating to me and it was such a joy to be able to see it from the air. I found this area strikingly beautiful:
An area of drift icefrom last summer that refroze this past winter. Drift ice is composed of many ice floes, individual plates of sea ice.
Arrival at New Harbor. We were lucky to have had such a clear day for our flight.
After unloading gear into our hut, we got right to work creating a dive hole in the ice. The first step was to use a battery-powered 10″ diameter auger to remove the first 3 feet of ice. Then a hole was drilled all the way through to the water, 9 feet below the surface. A metal coil through which a hot fluid was circulated (known as a hot finger) was inserted into that hole to melt the ice until the hole was wide enough to dive. We all took turns refueling the hot finger every three hours for about 22 hours.
Andrew working on drilling out the diving hole
As the hot finger ran, we had time for some cards…
and exploration.
An iceberg can be seen on the horizon which appears as a sharp white line. One sometimes feels as if they are on an alien planet here. On land, there are absolutely no detectable signs of life- no lichens or moss growing on the rocks, let alone some sort of little shrub, no birds in the sky, no burrows of little animals, nothing. The only living things are the microbes that live in the perpetually parched and frozen soil.
A pressure ridge created by the sea ice being shove against the shore.
The next afternoon, the dive hole was ready and the divers got to work.
Steve keeps a watchful eye on Jacob and Rowan as they prepare for their first dive here. Diving without the warmth of a dive hut at about 0F (-18 C) presents special challenges. Moisture from the divers’ breath can easily ice over their masks and clog the lines that supply the air from their tanks and are used to inflate their dry suits.
After sleeping in the warmth of the hut on the first night, several of us moved our cots and sleeping bags into the shelter we had set up near the dive hole for a night of sleep on the ice. As we all settled down and got quiet to fall asleep, we were alarmed to hear continuous cracking and popping sounds coming from the ice below us. Reassuring ourselves that the ice was 9 feet thick, we managed to drift off.
Beautiful blue light was transmitted into our shelter through the ice. (At this time of year, the sun does not set, of course.)
Early the next morning, we were awakened by the sound of repeated, deep exhalations. A Weddell seal had discovered the dive hole and was using it to breathe. It returned repeatedly over the course of several hours, taking about 1-1/2 minutes to complete its breathing exercises each time.
Weddell seal, breathing. They breathe through their nostrils which open and close like valves, allowing them to keep water out while they are diving.
After making our way across the ice to the hut for breakfast, we later returned to find our friend laying comfortably nearby. He spent the next 8 hours there.
In contrast, to the land, the sea below the ice is teaming with life, some of which makes an occasional trip to the surface.
The next day, the divers continued their work below, collecting samples and completing other tasks for their research.
Steve and Andrew preparing for a dive.
After diving was complete, everyone warmed up, had some snacks, and then set off on a hike to Commonwealth Glacier.
Explorers of a remote and alien world
Commonwealth Glacier is at the edge of the McMurdo Dry Valleys, a vast part of Antarctica that receives 1-4 inches of precipitation (water equivalent) per year, classifying it as a desert. This is the front edge of the glacier.
We returned back to our hut at 10 p.m. One thing you do not have to worry about here at this time of the year is the sun setting while you are on your way back from somewhere.
After dinner, I decided to spend another night on the ice rather than drag my stuff back to the hut. I was awoken once again, early the next morning, by deep exhalations. As I stood near the dive/breathing hole, I could hear the other-worldly liquidy-sounding clicking and whistling calls of the seal as it swam below the ice before emerging to breathe.
After just two days, the dive hole had already begun to freeze over. Weddell seals scrape the ice with their teeth to keep their breathing holes open.
The next day, we packed up and made our return trip to McMurdo Station. It was a great privilege and joy to visit such a remote and beautiful place that few others have ever seen.
Jacob and Rowan enjoying our beautiful return flight
Because it is dangerous for divers to fly immediately after diving because the change in altitude can cause decompression sickness (the bends), we flew back below 500′ altitude, giving us a beautiful, low angle view of the landscape.
While conducting our research, we dive at a number of different spots in the Ross Sea. The site that we most commonly dive is known as Cinder Cones Seep. Cinder Cones Seep is particularly special because it was observed to begin seeping methane in 2011. This was a first for Antarctica! There were previous studies suggesting that the Antarctic region may have a large amount of methane reserves, but no eyes had ever been laid on an active seep. Being able to study this site will tell us a huge amount about the methane cycle in both Antarctica and the earth as a whole.
The white mats in the above picture are microbial mats, or biofilms filled with bacteria and archaea that are associated with the seeping methane. Photo credit: Andrew Thurber
Above the ice, the Cinder Cones Seep area has a lot of wind funneled onto it, causing most of the snow to blow away. The lack of snow on top of the ice makes the dive site extremely light, and when diving, we don’t even have to use lights! This is in sharp contrast to the other sites that I’ve visited here.
Andrew conducts a transect along the seep, filming the animals near the measuring tape to later be counted and analyzed.
The site has sea stars, nemertean worms, and anemones as far as the eye can see. There are so many of them everywhere that they’re often on top of each other.
A fish sits on top of a sea star, which sits on top of a nemertean worm, which sits on top of a bed of anemones!
Every time I dive at Cinder Cones, I get excited thinking about the implications of our research and the importance of learning more about this system. The samples collected from this site have been and will be a huge part of my research in the coming years, and I couldn’t be happier to see it with my own eyes and take samples of it with my own hands.
A seal swims towards a crack in the sea ice at Cinder Cones Seep, providing an easy access point for the marine mammals and incredible overhead features for us
Ice is as far as the eye can see in Antarctica. It varies in age from million-year-old ice sheets that are miles thick, to annual sea ice that is measured in meters. One incredible form of ice in Antarctica is anchor ice, which resides on the seafloor down to a maximum of 90 feet deep. Anchor ice typically forms plate-like crystals that overlap each other to form jagged structures on the seafloor that are resoundingly beautiful.
Ice and life come to a head in the McMurdo sound. As the anchor ice takes hold, it covers the seafloor and the animals residing on it. This makes for an odd life for the animals subject to the freeze and changes the ecology of the seafloor. Because ice has a lower density than water, Anchor ice can actually pick up the organisms it freezes around and float them to the sea ice ceiling, incorporating them and causing them to eventually die.
An example of a seafloor brimming with both life and anchor ice
With that said, the combination of life mingling with ice is amazing to witness. Most evidence points to anchor ice as damaging to many species, but I have to wonder: In all this time of life and ice intertwined, are there adaptations to life in anchor ice? Are there organisms and ecosystems that require anchor ice?
The sponge Homaxinella Balfourensis encased in anchor ice. Anchor ice can almost entirely eliminate this species from an area, evident to researchers by discolored sponge skeletons.
The sea urchin Sterechinus neumayeri, which sits on top of an anchor ice field. S. neumayeri is numerous in the shallows of McMurdo sound, causing it to inevitably live within and around anchor ice. This sea urchin is largely a grazer, living off of algae, diatoms and animals such as sponges. One interesting fact about S. neumayeri is that it co-opts items from the environment for camouflage! You’ll typically see these urchins with pieces of shells and other objects on their spines.
A fish of the Trematomus genus. These fish often have antifreeze compounds that bind to ice forming in their blood. This is a great example of animal adaptation to living at extreme cold conditions.
This past week, I’ve had the incredible opportunity to slip through the cold and dark portal into what can only be described as an alien realm. Sitting above the dive hole made my eyes widen and my heart pound. I had seen pictures, sure. But was I really up to the task of diving under sea ice? After a brief wave to Michael on the surface, I took the plunge.
The first time going through a dive hole is a strange experience. From above, you would think it would be cramped or claustrophobic sinking through 8 feet of ice. Once in the hole, however, it was an entirely different perspective. The visibility is so incredible in Antarctica that once your face is in the water, you can easily see the incredible wealth of life on the seafloor. Curiosity got the better of me, and I opened my drysuit valve to descend.
After a brief moment of pure white, I descended through the hole and the under-ice world opened up to me. Fine shards of brash ice hung from the ceiling, breaking and dancing with my air bubbles. The snowpack above made for incredibly dark yet beautiful conditions, lit only by the ambient blue of a crack in the ice above.
Brash ice is fine shards of ice crystals on the underside of sea ice
My tentative thoughts were immediately washed away by questions. The floor was covered in life!!! I knew this conceptually, but to see it with my own eyes was incredible. I looked down and thought all the five W’s: Who’s down there? What adaptations are needed to live in such a unique environment? When in Earth’s history did life become so special in Antarctic waters? Where does the anchor ice stop on the sea floor? Why does life thrive in such cold water?
I couldn’t believe my eyes!!! The sea floor was abundant in life!!
Unfortunately, humans are not amphibious, and my time was limited by the air in my scuba tank. I came to the surface and was helped out of the dive hole by Andrew. From that moment and every dive since, I have a stronger and stronger desire to jump back in the hole and witness the incredible life of Antarctica.
Andrew swimming up the dive hole and leaving the under-ice realm
By now, Jacob is a seasoned Antarctic diver. But just a week ago, he completed his first Antarctic dive. He was accompanied by Steve Rupp, a dive supervisor here at McMurdo. Steve is wearing the black and white dive suit. Steve is a highly experienced and skilled diver, having done about 1500 dives in Antarctica alone. And he is a heck of a nice person too.
The dive took place from a heated hut, the yellow structure, positioned over a dive hole.
As the plane touched ground on the ice and we slid to a stop, we donned our extreme cold weather (ECW) gear with electric excitement. We had landed in Antarctica. The loading port of the plane cracked, and an icy blast of air hit us. It was time to get moving.
Walking off the plane for the first time. The angle of the sun and the flatness of the ice makes shadows long and apparent here (Photo: Andrew Thurber)
We headed off the plane and down the runway in what I can only describe as a state of awe. Ice stretched endlessly, obscured only by untouched mountains and the transport vehicles we were walking to. We hustled onto “Ivan the Terra Bus,” the all-terrain vehicle for transporting first-arrivers and the engines roared to life. We were off to McMurdo.
Andrew and I on “Ivan the Terrabus” heading into McMurdo. Andrew was an expert, naming and describing the features of Antarctica as we drove (Photo: Andrew Thurber)
We arrived at McMurdo and were raring to go. It is an incredible privilege to do science here, and we can’t waste a minute of the time we have down here.
Standing in front of the sea ice is humbling. In this picture, the sun is about as low as it will ever get during our time here (Photo: Isaiah Reeves)
We worked to unpack all of our personal and science supplies that we brought. Clothes were put into dorms, and we headed over to the Crary lab building, the epicenter of Science here in McMurdo.
Boxes of supplies to be unpacked line the halls of the Crary lab building
We unpacked boxes full of science supplies into the lab. Syringes and petri dishes were placed above the bench, sea star cages and sediment corers were brought down to the aquarium room.
Supplies are unpacked in one of our lab spaces. This room has water piped in straight from under the sea ice in McMurdo Sound
Instruments vital to our research such as the cavity ringdown spectrometer, which is used to study methane in the seafloor, was assembled.
Andrew has been working tirelessly to assemble the Picarro instrument
This past week, we have been taking trainings that educate us on the intricacies of conducting research in Antarctica. This includes field safety, sea ice profiling, Pistenbully training and more! All of the trainers have been incredibly knowledgeable and are crucial to a safe field season here.
Michael is profiling the sea ice by probing, drilling, and measuring the thickness at a weak point
I am gearing up to do my first checkout dive tomorrow, to ensure that I can safely work under the sea ice. I am beyond excited to share my experience with you. Until then, we will be working on good science to share with the world.
Today Jacob and I learned all about sea ice and how to traverse it safely. Even though the ice is very thick overall, it is full of many different kinds of hazards.
Here are some of the types and features of sea ice we learned about:
pack ice
fast ice
floes
frazil ice
ice bergs
old ice
polynya
pressure ridge
The main hazards for traversing the ice for us are cracks and pressure ridges. Cracks form as different forces are exerted on the ice such as newly formed ice pressing into existing ice, currents, and rising and falling tides. After cracks form they can be shoved back together to form pressure ridges. They can also grow wider in repeated steps. When that happens the ice at the center of the crack can be very thin Today we learned how to evaluate whether these features can be safely crossed with the specialized vehicles called Pisten Bullys that are used to travel on the ice.
Here are some photos of our day.
Eleven scientists whose work requires them to travel on the ice did the training. We rode out onto the ice and vehicles called Hagelands.
These happy scientists in the Hageland are excited for their training.
Our instructor Mitch
The first step after finding a crack is to use a probe to determine the edges of the crack. Then a shovel is used to remove snow from a cross section of it. Then a hole is drilled in various places of the crack and the depth of the ice is measured through each hole. For this crack, the ice beyond the crack was well over a meter (3′) thick but the center of the crack was only 14 cm (6″) thick. However, the width of the thinnest ice was very narrow so this one was safe to drive across.
Shoveling snow out of a cross section of the crack.
Drilling a hole to measure the thickness of the ice.
Jacob and I celebrating the completion of all our training. Now we can get to work. Jacob’s first ever Antarctic dive is tomorrow! Check back to see how that goes!
One must receive many trainings here at McMurdo in order to conduct research. Tomorrow, we will be spending six ours on the sea ice learning how to be safe out there. Check back tomorrow to find out how that went.
For today, we did Global Positioning System(GPS) training field safety training; Pisten Bully training; and recreation training.
I neglected to take a photo of the GPS training today, but while we were route finding with our GPS devices, I had to pause and take a photo of the stunningly beautiful Royal Society Mountain Range. It is very difficult to judge distances here. They are about 25 miles away.
Those who will be traveling away from McMurdo must take the field safety course. In a few weeks we will be traveling by helicopter to a remote site. For such trips, research teams are provided with survival kits. Perhaps the biggest danger is that powerful storms can suddenly appear and last for days. This makes rescue impossible and can force you to hunker in your tent for days waiting for the storm to end. Some of the items include sleeping bags and pads, camp food, and a first aid kit.
The kits also include sturdy tents that we practiced pitching, and very long stakes and ice screws that can be hammered into the ice.
We also practiced lighting and repairing the stoves.
Our instructor Katy demonstrating how to operate the camp stove. She has extensive backcountry experience.
Next up was learning how to drive a Pisten Bully. What, you may be wondering, is a Pisten Bully? It is a very rugged tracked vehicle that is designed for hauling and pulling heavy loads on snow. Our team will be using them to haul ourselves and dive gear across the sea ice to our dive sites. They are loud, rumbling, cantankerous machines that travel up to about 8 mph.
Our last training ended at 7:45 pm, after which Jacob and I rewarded ourselves with a trip the dining hall to have a cookie. You can get them there any time of day or night!
