In the morning the alarm goes off. Breakfast is served from 7.30 to 8.30 am. Only half awake, I stumble into the breakfast hall, where you always receive a warm welcome from the friendly stewardesses. The breakfast menu offers everything the heart desires: from pancakes to scrambled eggs, to freshly baked rolls. And when you have a day on the ice ahead of you, you need every calorie. For me, an ROV day means having my lunch out on the ice. So I quickly pack my lunchbox and fill my thermos, then head for the winch room. Once there, it takes me about 10 minutes to put on all my polar gear: thermal underwear, thick socks, a fleece jumper, balaclava and parka, snow pants and snow boots. Then it’s finally time to go outdoors. Out on the working deck, the others are already waiting: our polar bear lookout and two additional members of the ICE Team. Before we can leave, we quickly check in with the gangway watch and the ship’s bridge, to make sure everyone knows where we’ll be.
Since the ROV site is fairly close by, we go by foot, and after five minutes, we reach the ROV cabin and ROV tent. Though the temperature is roughly -30 °C, our polar bear lookout remains outside, keeping vigilant watch. There is a ‘changing of the guard’ every three hours. We first make our way to the ROV tent. ROV stands for Remotely Operated Vehicle; in other words, a small underwater robot packed to the gills with cameras and various scientific instruments. Our ROV, which has been dubbed the BEAST, is based at the ROV tent, and is piloted from the ROV cabin. The tent is heated, which keeps the ca. 1.5 x 1.5 metre hole in the ice from freezing over. ROV work is by far the warmest type of work that our team does out on the ice; otherwise we work, mostly without any protection from the elements, at temperatures that can reach -50 °C wind-chill (air temperature + the effects of the wind) and gather snow profiles, ice-thickness measurements, test the ice mechanics, or scan the surface with a laser. When it’s time to collect ice cores, which usually takes from 9 am to 4 pm, we sometimes put up a tent to give us a bit of shelter from the frigid wind.
But back to the ROV. Once inside the ROV tent, we immediately get to work, preparing the cameras on the BEAST for today’s mission and going through the checklist of essential steps before today’s first dive. Once the BEAST is ready, we boot up the three computers and launch the software needed for the dive. The computers are in the ROV cabin, which is also heated in order to protect them. Saturdays are our cross-team ROV days, and just in time for the first dive, two members of the ECO Team join us. For the first five dives of the day, nets will be attached to the BEAST: a five-five-metre-long net with a sweeper of sorts on its upper edge and a collecting container at its end; and within the first net, a second, finer-mesh net with its own collecting container. We use this combination to catch phytoplankton, zooplankton and other small life-forms, which can by analysed further right on the ship.
The group splits up: the majority go to the ROV cabin, to watch the pilot and co-pilot at work, and to enjoy the fascinating view of the underwater world below the ice through the cameras installed on the ROV. First the BEAST will traverse a horizontal line right below the ice; then it will repeat its course, but at depths of two metres and ten metres. In this way, we can measure the microorganisms, their numbers, frequency and food sources at different water depths. Each time it fills its net, the ROV resurfaces, and the team members are eager to empty the containers, inspect and clean the contents. Up to this point, I’ve been working in the tent, making sure the robot has enough cable, and alternately lowering it into the water and winching it back out so the net could be emptied.
Now it’s time for me to switch to the cabin and relieve our veteran pilots. Though I’m still a fairly inexperienced pilot, today I finally get to try my hand at diving with a net, which is a tricky business: the long net can easily get tangled in the ROV’s propellers and damage them. Our pilot starts feeding me instructions and I take the ROV down to run a V-shaped dive pattern at a depth of 50 metres; this run will provide us with data we can compare with the other zooplankton nets, gathered directly below the ice and at ten metres below. I start by letting the BEAST descend to 50 metres at roughly a 45° angle; after running a sweep, I take it back to the surface at the same angle. When an experience pilot does this, it always looks easy. But in reality, you not only have to know how the BEAST moves, but also take into account the current and the added weight of the nets. Plus, we’re so close to the North Pole that our compass can’t be relied on to find north, which can make travelling in a straight line into a real challenge. But all goes well, and I manage to find the hole in the ice quite quickly. The ECO Team members are satisfied, and head back to the ship to start their analyses.
Our next task is to film the underside of the ice, marine life-forms, and instruments hanging in the water for the MEDIA Team. It’s now 1 pm and I switch over to the ROV cabin full-time, to pilot the BEAST together with my more experienced colleagues. One of my teammates stays in the tent to keep an eye on the cable winch, and to lower / retrieve the ROV. Before starting the next dive, five GoPro cameras are mounted on the BEAST, and a few of its lights are also reconfigured for better illumination; then it’s time to hit the water. First I take the ROV down to Ocean City, a station on the ice where the OCEAN Team takes many of its readings. There we film a device that measures the current at various depths being hauled out of the water. Soon it will be put back in the water to resume its work. Since I don’t want to risk getting tangled in its cable once it’s put back in service, I pilot the BEAST to the underside of a nearby pack ice hummock. Hummocks are formed when winds and currents cause the floe to break up at certain points, and the sheets of ice are then crushed together. When this happens, hummocks measuring seven metres thick can be created in just a few hours. Part of the hummock is above water, and part is underwater. Using the ROV, we can observe the different types of ice underwater. In some places the ice is very smooth and even; in others it’s very rough. We get some good footage of jellyfish, fish (Arctic cod) and marine microorganisms, not to mention the underside of the ice, shimmering a beautiful blue. Pack ice hummocks often contain small cavities, and I pilot the ROV into a roughly 1.5-metre-high one, where I find sediment inclusions in the ice, and several clumps of algae. On the way back out, I bump into a patch of delicate platelet ice, and a few tiny platelets break off and drift in the water: a beautiful sight. Other forms of ice, reminiscent of the stalactites you’d find in a flowstone cave – but made of ice – can also be found here; here and there, we see these branched icicles hanging from the underside of the ice.
Our next stop is another pack ice hummock, where we’ve installed a whole range of monitoring instruments. We lovingly refer to it as Fort Ridge, and have even decorated it with a homemade flag. Yesterday we took readings on the hummock’s thickness, and measured the hollow cavities within it, created by the overlapping sheets of ice. We also left hooks and marker rods in the holes drilled for the measurements; these markers will help us take visual readings once the sun has returned to the Arctic. Part of our job today is to use the ROV to check the hooks’ positions from below and make sure that all of them are hanging in the water. But of the five installed, we only find two. From below you can see how irregularly shaped the hummock is. It looks like we drilled right into a thick sheet of ice. The holes we drilled weren’t deep enough, which explains why we can’t see all the hooks … and means we’ll have to install them again.
By now it’s almost suppertime. The ROV has to be switched back to its original configuration, the GoPro cameras have to be removed, the propellers retightened, and the data copied; then it’s time to head back to the ship. A successful ROV day has now come to an end; one on which I, the ROV rookie, had the chance to gather a few more hours at the helm. While navigating the cavities in the pack ice hummocks, I only got the cable tangled in the craggy underside of the ice once, and our seasoned pilot quickly solved the problem. Thanks so much for the wonderful impressions and the experience I had the chance to gain today. There’s another meeting scheduled after supper, followed by data work. After that, a quick trip to the sauna, which is terrifically relaxing, and a few chats in the Zillertal, Polarstern’s onboard bar, which the scientists run themselves on Saturday nights. Then I hit the sack, tired but happy. Tomorrow may be Sunday, but my next meeting is at 10.45 am. After that, it will be time to pack my instruments and lunch, and head back out on the ice.
Daniela Krampe, ICE Team, Alfred Wegener Institute