End of the first season of SWAIS2C Project (ICDP 5072_1)
The first SWAIS2C field season at the 5072_1 (KIS-3) drill site on the Ross Ice Shelf is over and our on-ice team is heading home with some cool new data and invaluable on-site experience as we continue our efforts to recover long sediment cores at our two study locations.
Twelve scientists, 10 drillers and 4 camp staff deployed to the ICDP 5072_1 site in late November through early December 2023 and set up an efficient camp comprising many sleeping tents, a mess tent, three science facilities (tents and container), and a large drilling tent.
Hot water drilling through ~580 m of ice went exceptionally well and we broke through the base of the ice shelf into the ocean cavity just before Christmas. Our first science activities through the open hole began immediately. Over a twelve-hour period we were able to collect several sediment cores using a gravity corer, acquired oceanographic data during several CTD casts, and collect video camera footage from the seafloor and the bottom of the ice shelf.
On December 23rd the Antarctic Intermediate Depth Drill (AIDD) was moved into place. Our drillers had deployed ~80 m of drill string, including the heavy steel bottom hole assembly and many lengths of sea riser made of glass reinforced epoxy, when we had to halt operations due to technical challenges. After careful consideration of all options and risks involved our leadership team decided to end drilling operations for the season. Our drillers were able to safely retrieve all drill string and we have very clear options to modify our operations to mitigate the technical challenges we experienced this year.
Once the ice shelf hole was clear of drill pipe, we started another phase of open hole science activity. These included additional gravity coring and a series of continuous CTD casts over a 24-hour period.
On December 28th we deployed a hammer corer and recovered of a 1.92 m long core, a record for the Siple Coast. This success was due to several innovative modifications to the core catcher and our deployment technique that were suggested and implemented by members of our drilling team.
We finished our borehole science operations with a successful deployment of an oceanographic mooring that will collect important data from the ice shelf cavity over years to come. These new data add to a sparse but growing body of measurements that are key to understand if warming of the Southern Ocean will cause the Ross ice shelf to melt.
Several of our team members also took time to uncover GPS equipment and ice penetrating radar (ApRES) that had been buried by several years’ worth of snow at two sites close to 5072_1 (KIS-3) site, which were occupied by New Zealand colleagues at previous science campaigns in preparation for SWAIS2C ICDP project. Data have been downloaded and we are looking to redeploy the equipment prior to final camp pull-out. We also moved some consumables that will be used for seismic experiments at Crary Ice Rise, the second drill site of SWAIS2C, now targeted for drilling in the 2025/2026 season.
We have achieved much this season and have learned a large amount about our challenging drilling process and environment. This new knowledge can only be gained through a field-based ‘shakedown’ and will ultimately help us achieve our goal to drill deep below the sea floor in this poorly understood region of Antarctica. We were thrilled when the almost two-meter-long sediment core arrived ‘on-deck’. In all we return from the Ross Ice Shelf with 8 gravity cores and 3 hammer cores and a total 7.6 m of sediment.
Obviously, we want more, but the cores we did recover provide a new record of recent ice sheet and ice shelf retreat; a climate and environmental record that will be studied in detail over the coming months. We also have lots of sediment samples that will be studied for their microbiological content so that we can reveal more about the communities living in the extreme environment below the cold and dark ice shelf cavity.
And finally, we now know that the sediments below the seafloor at site 5072_1 are relatively soft and that we can use our hydraulic piston corer with confidence – a big step forward as we sort important details for our drilling campaign. As the calendar crosses from 2023 to 2024, our team is already preparing to return to 5072_1 (KIS-3) in November to complete our sediment drilling objectives. We can address the technical issue encountered with the AIDD system this season. Our drillers, engineers and scientists have gained significant hands-on field-experience with both the hot water drill and the AIDD system, and how they ‘connect’. We can’t wait to return for the 2024/25 season!
Sediment deposited below the seafloor often contains a lot of water, which is called interstitial water or porewater (because it is found in the spaces between grains in the sediment). Geochemists can study the composition of the water to learn about processes happening in the sediment after deposition. For instance, changes in pH (acidity) of the water can dissolve some particles. Microbes also interact with the sediment and water as they use different compounds energy, which can also result in changes to the sediment composition after deposition. For scientists who want to use sediment to understand past climate, it is important to be able to figure out if our sediment records represent conditions at the time of deposition, or if these processes after deposition have changed the record. Geomicrobiologist Alex Michaud studies the interactions of microbes, porewater, and sediment. To do this with the sediment cores we’re collecting here at the ICDP SWAIS 2C drill site, he has extracted porewater using a tool called a rhizon, which is similar to a small syringe that is inserted into the sediment at different places to remove the water from the sediment core.
Today we took a little time to make our camp feel a bit more festive in preparation for Christmas! Although we won’t have our official Christmas dinner until we can all celebrate together (after we are finished working different shifts), we still had some special treats prepared by our chef Rayanna including Christmas sugar cookies, fruit cake, and white Christmas, an Australian Christmas treat made of puffed rice, dried coconut, powdered sugar, dried milk, and mixed fruit. We also voted and since most of the camp considers the movie “Die Hard” a Christmas movie, we had a showing of it in the mess tent! Amongst the festivities, we continued with initial characterization of the gravity cores, which included X-ray imaging, smear slide observations to look at microscopic composition, and analysis of the microfossil assemblages for an initial assessment of age.
Since it is currently summer in the Southern Hemisphere, field work in Antarctica often occurs across the holiday season and start of the new year. Since we can’t celebrate with our family and friends at home, we do our best to celebrate together on the ice. This year, Elf on the Shelf decided to join us for some holiday fun! What is Elf getting up to on the Ross Ice Shelf? A bit of mischief but he also tries to help out with a bit of light mechanical work!
The larger hole (~35 cm) through the Ross Ice Shelf was completed today! We then had a short window to collect some data and samples from below the ice shelf before the start of drilling operations. This included deployment of the CTD and cameras to collect information about the seawater cavity below the ice shelf, and we also took several gravity cores to collect surface seafloor sediments. Gravity cores enable scientists to sample and study sediments from the seafloor reliably and at relatively little cost. They get their name because they use the force of gravity to help the instrument sink into the seafloor. The gravity corer we are using here is a relatively simple device with a short (~1 m long) plastic tube that attaches to a holder topped with heavy weights. The gravity corer is lowered down the ice hole on a cable. As it nears the seafloor we increase the speed of the winch lowering the cable as much as possible so that the gravity corer is “falling”, allowing the plastic tube to sink into the seafloor sediment. We then pull the device back to the seafloor with the sediment held in the tube by piston action. Our drillers are particularly interested in the surface sediment to help with positioning the sea riser in preparation for drilling.
Remote field work in Antarctica often involves going weeks without a shower or clean clothes. Fortunately for us at the SWAIS 2C field camp, hot water drilling operations mean that we can take the occasional hot shower! We also have a very small washing machine that we use to wash clothing that sits next to the skin. There are several ways to dry the clothes: freeze drying, hanging them on one of the hot water lines, or hanging them next to one of the heaters in the various tents. Regardless of method, having a hot shower and putting on clean clothes after a couple of weeks without feels magical! The shower and washing machine are set up in the corner of the drill tent, so currently doing some laundry is a great way to interact with the hot-water drilling team to find out more about how it works and see the progress! The drillers have successfully made the small pilot hole through the ice shelf (total thickness ~586 m) and are now “reaming” the hole to increase the diameter to 35 cm so that the tools we will deploy can fit through it.
After a beautiful day on Tuesday with sunny skies and very little windy, today started out grey and windy and it kept getting windier and colder throughout the day. By early afternoon, those of us working in the “warm” science tent had decided that it was very poorly named as the heat generated by the stove was not enough to keep the cold at bay! What to do then? Move to the mess tent, which has a larger heater and plenty of hot water and warm drinks to help us get through the day! We also learned a technique to warm up our hands from oceanographer Ollie Twigge, who has spent several seasons on the sea ice. It involved flexing our hands (to help increase blood flow) and then rapidly shrugging our arms up and down. We might have looked a little silly but it seemed to help! The wind blew quite a bit of snow around, so after it died down, Ollie and Jim Marschalek shoveled some back around the base of the science tent to provide us with better insolation. We were also visited by 3 skua, who seemed quite interested in the drill tent, where good progress is being made on the hole through the ice shelf.
Once the hot water hole is completed through the Ross Ice Shelf, we will have about 12 hours for science operations before the drilling team begins deploying the riser pipe. We will use this time to get a water sample, one or more gravity cores, and a CTD. But what is a CTD? It stands for conductivity, temperature, and depth and it refers to a set of instruments that can measure these properties in the ocean. A CTD is deployed through the water column (often from an oceanographic research vessel) and collects this information with depth. Conductivity measures how well a solution conducts electricity. By measuring conductivity through the water column below the ice shelf, our oceanography team will be able to determine the salinity using the conductivity measurement along with the temperature and the pressure. In addition to the CTD instruments, oceanographer Ollie Twigge has attached a camera and lights to the frame that will be deployed into the ocean through the ice hole in order to image the base of the ice and the seafloor.
Hot water drilling operations started today! The first step was to drill the pilot hole to 82 m and install the well pump, which was completed by the end of the day. The well pump is used to re-circulate water for making the main hole all the way to the seafloor. During the day, the scientists continued preparations for the start of our initial science activities prior to AIDD drilling, which will include collecting a water column sample, deploying a CTD, and collecting one or more gravity cores after the hot water hole through the ice shelf is completed. For inspiration, one of our scientists shared photos of some of the gravity cores collected during the KIS-2 campaign in 2021! (more photos see Gallery)
The Antarctic Intermediate Depth Drill (AIDD) has three coring systems that we can use: a hydraulic piston corer, a push corer, and a rotary corer. Piston and push cores are collected in plastic PVC core liners, whereas the rotary corer collects the core directly in the core barrel, which is then extruded onto core liner that has been split in half. The other half of the liner is placed on top and then the core is wrapped to hold it in place during shipping. We will split the cores during our core description workshop early next year.
Undertaking a drilling project of this scope in a remote area along the Siple Coast of the Ross Ice Shelf requires a lot of careful preparation and a well-designed camp! Sedimentologist Jae Il Lee put her creative talents to use to create a beautiful illustration of our SWAIS 2C camp layout! The main structures of the camp include the mess tent (kitchen/dining/gathering place), 3 science areas (warm science tent, warm blue container, and cold science tent), and the drill tent and staging area. Also critical are our two toilet facilities and “canvas town”, where our tents are set up. We also have several vehicles used during the traverse that are important for moving snow and large objects around the camp and a green container that serves as an office and emergency medical facility. (for more photos see Gallery)
An important part of the Antarctic Intermediate Depth Drill (AIDD) system is the sea riser, which helps to support the drill string when drilling from floating ice. The sea riser is made of glass reinforced epoxy (GRE), a type of fiberglass that is lighter weight than traditional steel casing. It is designed to provide drill string support for ice platform movement, including both lateral movement (from currents) and vertical movement (from tides). Each GRE sea riser pipe is approximately 3 m in length. Our drilling team has carefully measured each segment and then connected two segments together into 6 m lengths in preparation for deployment after the hot water hole has been drilled.
Preparations are gearing up to begin operations soon! Once all of the equipment is set up, tested, and ready to go, the first thing we will do is melt an ~30 cm wide hole through the Ross Ice Shelf, which is approximately 590 m thick at the location of our drill site. This operation uses hot water jets to melt the ice, so we need to have a lot of water at the surface for the start of this operation. Flubbers to the rescue! These large, yellow, collapsible containers hold 12,000 liters of water. To make the water, they are filled with snow that is melted with water from a much smaller container with heatng elements. With the flubbers full, we are almost ready to start!
A popular question from friends and family about life in the deep field in Antarctica is where do you go when you need to GO? With a total of 27 members now at the SWAIS2C KIS-3 drill site, we needed more than the “Turdis” (our blue “outhouse” toilet facility) to keep everyone comfortable. Fortunately, science team member Jason Coenen has excellent snow construction skills, and today he completed construction of our second facility, called the “Nautilus” due to its spiral shape. Each facility has a urinal for those that prefer standing up, as well as an “en-suite” for those that prefer to sit. Solid waste is collected in bags in a bucket so that it can be taken back to the mainland at the end of the field season!
Antarctica is the driest place on Earth, so even though it is cold, we have to drink a lot of water to stay hydrated here. As our water bottles remind us: hydrate or die! But where do we get water in the middle of a frozen ice shelf? We cut and retrieve blocks of snow with dedicated saw, shovel, and gloves (to avoid contamination). The snow blocks are brought to a large covered container with heating elements in the bottom that is positioned outside the mess tent. The heating elements melt the snow, providing us with fresh water that we can drink and cook with! The water is pumped into the mess tent, where it feeds a spigot to fill water bottles and pitchers, as well as a small sink that has both cold and hot water for cooking and doing dishes!
Today the science team members still at Scott Base got up early and waited for the go/no-go announcement for the flight to the drill site. At around 7:30, they got the good news that the flight was a go! The team helped get all of the gear into the vehicles for transport to Williams airfield, and then helped to load the gear onto the plane. After fueling, the team enjoyed a very smooth 2+ hour flight to the site, where the co-chiefs were waiting to greet them!
Today, those of us at Scott Base worked on entering the science party into the ICDP database system (mDIS) in preparation for drilling. In the afternoon, we geared up for a hike to the top of Observation Hill, where there is a memorial cross erected in January 1913 to commemorate Captain Scott and his party, who lost their lives on the return journey from the South Pole in March 1912. After descending, we walked along the trail that encircles Observation Hill, getting lots of nice views of the Transantarctic Mountains and some seals hanging out on the sea ice.
All of the camp structures are set up, connected to power, and working well! We also completed the food inventory and stored everything away. With camp set up, the science team has been working on plans for shifts and the core handling process once drilling begins. The most exciting thing that happened today was the return of the mini-traverse team, who traveled to the KIS-2 site to retrieve the hot water drilling system, which is the last of the gear needed before we can begin operations. Everyone pitched in to help offload the sledges and work has begun getting the equipment set up.
The rest of the KIS team underwent Advanced Field Techniques training, where you learn how to set up tents and generally survive outdoors in the Antarctic! The sky was blue but the wind picked up later in the evening, making for a bit chillier conditions but fortunately the gear issued by Antarctica New Zealand is up to the task! After spending a cozy night in our sleeping bags in the tents we set up, we got to take them back down again the next day. Meanwhile at the drill site, the team got both of the science tents set up!
