It is now time to say goodbye!! We have been transiting for the last few days and just reached Reykjavík, Iceland. Next, we will take all our science gear off the boat (a process called demobilization), thereby concluding the expedition. Over the past couple of days, we have been frantically packing and cleaning the labs that have been our workplace for the last month. Now that the science is done, scientists are trying to get back to their regular sleep schedule (no more 24-hour work schedule) and are also playing board games and watching a movie or two (including Lord of the Rings). This has been a wonderful research expedition with excellent weather and a great team of scientists. We are particularly thankful to the Captain of the boat and all the wonderful crew members and science support partners (Andrew, Amber, Bowman, Jeremiah, and Justin) who helped make the science happen. Many, many thanks to Stephanie and Ryan, who cooked wonderful meals throughout the expedition and helped celebrate all the birthdays. Last but not least, we are thankful to the U.S. National Science Foundation for supporting this research. Just like every good thing comes to an end, so should this. This expedition is as much about science as it is about helping train the next generation of scientists and making science accessible to everybody who is interested. We tried our best to bring the excitement of discovery through blogs, photos, and ship-to-shore sessions. We appreciate your support and involvement, and we hope that you will continue to support science moving forward. AuthorsPrincipal investigators (in alphabetical order): What is a gravity core and why do we use them? We love mud! Seafloor mud stores vast amounts of information about the present and the past and it’s the whole reason we are on this voyage. We have two main ways of collecting it from the depths of the sea; the multicorer and the gravity core. The multicorer collects eight short tubes of seafloor surface mud, but we need to take a longer core to get a glimpse of the past that is hidden deeper in the sediment. This is where the gravity corer shines! The gravity corer is just what it sounds like, it uses gravity to plunge a long PVC tube into the seafloor to recover sediments that were buried long ago. The length of gravity core tube that we can use depends on its overall weight when filled with sediment and the grade of wire cable used to pull the tube out of the sediment. With the type of gravity corer we have, the wire we are using, and the type and thickness of sediment we are encountering, we decided to use a 10 ft (~3 m) tube on the gravity corer. After making our careful decision on the length of core, we then got to assemble them! How it’s assembled Step one was to label the long PVC tubes and cut them to size with a specialized tool called, no surprise, a core cutter! A small round blade, like a pizza cutter, follows the circumference of the tube and is tightened as it cuts through the PVC. This allows for a clean cut, so no plastic gets shredded into the sample or onto the deck (like it would with a hacksaw)! Step two was to attach the top and bottom gravity core parts to the PVC tube to officially make it a gravity core. The top part is a metal tube with a plunger in the top to allow for water to escape. It also creates a seal with suction at the top, like a finger on the top of a straw when you trap liquid. The bottom addition is actually two parts! There is a metal cone like piece that is made of flexible metal fingers that is inserted into the tube so that sediment can get into the tube but can’t fall out when we haul it back onboard, like a lobster pot. The second piece, the actual cutting piece, is added over the core catcher. This cutter is exactly what it sounds like, it is angled in and bevelled so that when the tube encounters the sediment it can slice into it. Now the gravity core tube is assembled! Step three was to attach the weights to it because a PVC tube with a few metal bits attached is not going to travel fast enough to the seafloor over 3000 m away, let alone be able to plunge straight into the sediment! These weights are attached at the top of the gravity core and need to be drilled into place so that everything is sturdy. The weights are circular lead weights that weigh 25 lbs (11 kg) each and total around 600 lbs. (272 kg)! Step four was to attach the top of the corer to the wire cable (on a spool attached to a winch) and deploy the whole thing overboard and hope that the bottom of the ocean that we surveyed will yield a good core sample! We will only know when it is back onboard how much we were able to recover, or if we recovered anything at all. Sometimes the surface of the seafloor is too hard and sometimes the sediment is sandy, and does not stay in the core, even with the core catcher. Both these scenarios can result in an empty gravity core. So how did we do? We were able get several great cores! We recovered up to 6-8 ft (1.8-2.4 m) of sediment in most of the successful cores. Once the core was back onboard and we determined that the recovery was successful, we processed the core for storage. We apply a strict labelling scheme and cut the tube in half carefully, packing any gaps in the end with foam to maintain the core shape of the sediment. Unfortunately, some of our cores (4 out of the 12 we attempted) came up completely empty! We think that two misses were because the surface of the seafloor was too hard and the other two were mostly sand. This still gives us information about the area but in far less detail! Where do they go after the voyage? To fully finish our gravity core process, we need to trace the label, that we initially did in sharpie, with an engraving tool to permanently etch the essential information into the core tubes. These cores will be sent to, and kept cool in, the Oregon State University Marine Repository for safe keeping until we are ready to sample them. The gravity core has been such an amazing tool for us, and we look forward to opening the core tubes up, sampling the muds, and discovering what ancient ocean sediments have to tell us about the history of environmental changes in the regions we visited. AuthorKira Sirois When I have gone to sea in the past, we have always been far enough offshore that we never see land until arriving back at port. On these trips, you get used to the more subtle array of views the open ocean has to offer—sometimes stormy, sometimes foggy, sometimes calm. When you are lucky you see a whale or dolphin. On this trip we got close to the coast twice in the mouth of fjords off the coast of southwest Greenland. Both times, we arrived in the early morning, only seeing glimpses of land through dense fog. Slowly the fog lifted, and by early afternoon we got better views of the steep, rocky coast and icebergs around us. The Greenland ice sheet (and all glaciers for that matter) slowly grinds up the rock beneath it and deposits fine “glacial flour” at the glacier terminus. One of our scientific goals on this cruise is to understand the impact of these processes on elemental cycles—particularly iron and neodymium—in the ocean. Because glaciers produce a lot of sediment, the mouths of fjords have lots of soft, soupy mud. This makes for easy coring, but we have to modify the multicore so it doesn’t overpenetrate. Ideally, all the multicore tubes will come up half filled with water and half filled with mud, but if the mud is too soft, the whole coring device can sink, which can cause us to lose the sediment-water interface—a critical part of the core. To rectify this problem, we take weight off the multicore and bring out the “snowshoes”. The snowshoes are planks of wood that we attach to the feet of the multicore. Just like snowshoes that you might wear on a winter hike, these planks of wood increase the surface area that is supporting the weight of the multicore and help it float on top of the sediments. The geochemistry of glacial fjords provided a great excuse to get close to shore, but seeing Greenland like this will be a once-in-a-lifetime experience for most of us. As we have come close to the coast, I have been reading about the nearby villages. The town of Paamiut, with a population of 1,300, was at the end of the first fjord we went to. About a week later, we went further south to a second fjord near Qaqortoq, population 3,050, capital of the southern Kujalleq municipality, and the 5th largest town in Greenland. The weather was clearer near Qaqortoq, and we got views not only of the mountains surrounding the fjord, but of the Greenland ice sheet itself—which at first looks like low clouds hanging over the mountain top. Even when we left the fjord mouth, we had great visibility for the rest of that day and into the next. It was hard to stop looking at the views that surrounded us as we continued to take multicores and seawater samples. Mostly it left me with a sense of awe, but it was hard not to feel the vulnerability of the ice sheet when you actually see it up close. As with all the research cruises I have been on in the past, there will be lots of memorable moments, but I think seeing Greenland will be close to the top of the list for a very long time. AuthorSophie Hines One of the most exciting aspects of our work at sea is that when we bring up small sections of the seafloor onto the ship, we are able to see small areas of the planet that no one has ever seen before. Viewing tiny creatures and the tracks and trails that they make on micro-landscapes brings deep seafloor and its strange ecosystems into light. Collecting and transporting these small, circular patches of seafloor up from thousands of feet to the surface takes specialized equipment. The largest habitat The deep sea, the largest habitat on the planet, is a mostly unexplored, perpetually dark environment, with crushing pressures and temperatures only a few degrees above freezing. As scientists, we seek to explore this remote, foreboding realm of our planet for many reasons. One of the primary motivations for our quest for deep sea mud on this trip lies in the fact that deep sea sediments archive valuable clues to the history of changes in ocean conditions and climate. The average depth of the ocean is about 3700 meters (over 12,000 feet), which is about 3670 meters deeper than most scuba divers can go. Obtaining samples from this remote and extreme environment requires specially designed equipment. There are several devices that can be used to collect seafloor sediments (including manned submersibles and remotely operated vehicles), but the most commonly used methods send sampling gear to the depths using a winch and a very long wire cable. The primary device that we chose for sampling the top few inches of the seafloor on this expedition is the “multicorer”. Just a little off the top The Ocean Instruments multicorer MC800 that we are using is designed to collect just the very surface of the seafloor, keeping intact the fluffy, dust-like materials that often lie on top of denser mud. We are interested in the chemistry, sediment characteristics and microscopic life of these seafloor surface sediments. An understanding of these surface muds will help us interpret clues about ancient oceans hidden in deeper muds. Essentially, for this project we get to play with mud! The multifaceted multicorer With a 12-foot-high metal teepee frame, and a 9-foot diameter base, the multicorer looks like a lunar lander. A circular arrangement of eight (28-inch long, 4-inch diameter) clear tubes held in metal harnesses are visible in the center of the teepee. These harnessed tubes are attached to a central metal “spider” that includes heavy lead bricks. The multicorer is typically lowered through the ocean using a 9/16 inch diameter wire cable from a very large spool of cable attached to a winch housed within the ship. We are using a different cable to accommodate the camera system on the multicorer. ![]() Three, two, one.. lift off! Josh Barnes, CSU Bakersfield (Left) is operating the A-frame that extends the multicorer over the water and into the fog. Ryan Tengelsen, CSU Bakersfield, and Kira Sirois, University of Tasmania (far left) hold tag lines to keep the multicorer steady during deployment. Andrew Naslund, Research Technician, Scripps Institution of Oceanography (center), directs the operation. Ocean views On this trip we have added a state-of-the-art camera system to the protected inner area of the teepee. The Multidisciplinary Instrumentation in Support of Oceanography (MISO) camera system developed at Woods Hole Oceanographic Institution provides live views of the seafloor, and also enables us to watch part of the mud collection process. Like the multicorer, this camera system is designed to function in the harsh conditions of the deep sea. With this unique camera system, we can view the seafloor several feet away before we decide to take a sample (sometimes there are just too many large rocks and not enough mud). When we find a good spot, we send the multicorer down the rest of the way to the seafloor. Eight is enough Once the “feet” of the metal teepee touches the seafloor, the cable begins to go slack, and the eight tubes are slowly pushed into the sediment by the lead weights. A “slow-down” cylinder on the multicorer ensures that the tubes go into the seafloor slowly, keeping the sediment-water interface as intact as possible. Under ideal conditions, the tubes are about half-filled with sediment and half filled with water when the process stops. At this point, the winch starts bringing the multicorer back. Discovery The multicorer typically travels back to the surface at 130 feet/minute, and depending on the water depth, it can take a while to get the multicorer’s sediment cargo up to the ship. Excitement builds as the multicorer reaches the surface. We all can’t wait to see what the deep seafloor at this site looks like up close. There is a strong sense of discovery and wonder when we look through the clear tubes to gaze at small patches of unexplored ocean bottom landscape. AuthorAnthony Rathburn Picking forams on a rolling ship One of the most delicate parts of our job at sea happens at the microscope—something that sounds routine, until the ocean decides otherwise. Out here, we’ve been collecting tiny marine organisms called foraminifera—single-celled protists that build shells (called tests)—from the surface of seafloor sediments. While microscopic, these organisms are incredibly important in paleoceanographic research, as their shells preserve information about past ocean conditions. In the upper layers of the cores we recover, foraminifera are not just buried in the mud, they also often cluster on hard materials like rocks, sponges, bryozoans, and other seafloor debris. These tiny specialists seem to prefer something solid to latch onto—living right at the sediment–water interface, where the bottom of the ocean meets the overlying water column. Seasick scopes and foggy views After retrieving these hard substrates from the top few centimeters of each core, we bring them to the microscope for picking. But picking forams at sea presents challenges you might not expect. Even when the waves aren’t dramatic, the motion of the ship is amplified in the microscope, causing the image to sway and bounce. Looking into the scope under these conditions can quickly bring on seasickness—especially when the ship is pitching enough to send all the swivel chairs rotating around the lab. We learned early on that picking sessions have to be timed carefully. If the ocean is too rough or a storm system is passing through, it’s better to wait. We’ve even had to tie down the microscope with line and metal braces to keep it steady on the table. Everything in the lab has to be secured, including our trays, vials, and tools—one rogue wave and you risk losing hours of work. We originally struggled with an awkward scope setup that we endured for hours each day, but after so long at sea some rearranging was required and we now have a much more ergonomic space. We also use special picking trays with narrow grooves, which help stabilize the sample as we carefully tease apart the materials and extract the tiny foraminifera. And while most days a thick fog blankets the view outside, the microscope reveals a whole hidden landscape of life clinging to fragments of the seafloor. Tiny victories Despite the motion, the fog, and the challenge of working at sea, we’ve had great success. So far, we’ve filled nearly 100 cryovials with foraminifera and have several more stations to go! These samples will allow us to explore foraminiferal communities at the sediment surface, complementing the geochemical and micropaleontological studies focused on the deeper parts of the cores. Pairing foraminiferal ecology with geochemical profiles collected by collaborating teams on this expedition will help build a more detailed and dynamic picture of ocean change—linking what lives on the seafloor today to past environmental conditions. We may not see much of Greenland’s dramatic coastline past the fog, but each core we recover brings the seafloor right to our fingertips. There’s something exhilarating about that first look—even after 40 multicore recoveries, it never gets old. And when that material goes under the microscope, that sense of wonder only grows. For me, it’s a chance to see an entire hidden world, magnified. AuthorAshley Burkett Lately, it has been super busy as we had back-to-back stations with lots of science operations running round the clock. Now that we have wrapped up our operations in the Labrador shelf and have also completed our station in the center of the Labrador Sea, our next series of stations will be close to Greenland and inside some of the Greenland Fjords. Over the last few weeks, the ship has become our home. During this time, we also experienced things that are quite unique, and today’s blog is about a few of them. Also, please enjoy a video of pilot whales below! Foghorn! It is not uncommon to have dense fog in the middle of the ocean. The fog reduces visibility and therefore the ship needs to use sound to warn other nearby vessels of its presence and to avoid collision. So, this is like a car horn in some respect. However, there is a lot more to it than just letting other vessels know of its presence. For example, a small vessel will have a higher-frequency foghorn sound, and a larger vessel will have a lower-frequency sound. So, another vessel in the vicinity that cannot see us would not only know about the presence of another vessel but would know about the size too. These are the technical aspects of the foghorn, now let’s talk about our experience of trying to sleep with the foghorn, which is blown every two minutes. Boy, it is loud!! Some of us scientists are in rooms that are close to the foghorn by the bridge (from where the captain and mates drive the boat), and the foghorn has been a revelation. The foghorn rattles the walls every time it blows, and it goes on as long as there is fog around (which can be for days). After a day or so, we got used to the rhythmic blowing of the horn and then it stopped as the fog cleared. Now the absence of the foghorn is difficult to bear. Survey sound As part of our work, we use sound to survey the ocean bottom. These instruments produce periodic sound pulses, which travel to the bottom of the ocean and come back to a receiver on the boat. The two-way time of sound allows us to estimate the depth at a point. We do this over and over and when all of these depths are put together, we can create a map of the ocean floor. One of these sound sources (3.5 kilohertz) can also penetrate a little bit into the ocean bottom, allowing us to gauge what type of materials are at the bottom. We heavily depend on this type of survey to decide where to collect sediment versus when to move on. Scientists whose living quarters (called state rooms) are close to these sound sources hear periodic ‘chirps’ as we survey along. Time changes Since we left Woods Hole, we have had three time changes. The last two time changes were within one week. We are currently three hours ahead of the US eastern time. Every time there is an impending time change, the crew would put signs all around the vessel and come change the clocks. All time changes happen at night and as a result the night shift worked one hour less, and the day shift had one less hour of sleep. Sorry, day shift! AuthorChandranath Basak We have been transiting for last several days and we are about to reach our next station. Things are going to be busy real fast. We encountered a little choppy weather here and there, so at times we had to slow down. Many of us saw our first iceberg, which was extremely exciting. During this long transit, we have been talking to a lot of students from a range of classrooms on shore. So far we have connected with thousands of students - elementary, middle-school and high-school - in the USA and Switzerland (find resources for educators here). It has been super fun to see people interested in the work we are doing and we are equally happy to show them around the ship and explain what we are doing. Students submitted a range of questions that our scientists have answered - see the FAQ below! How does your research help with climate change?
One of the ways we understand how our climate is changing is by looking at changes in climate throughout Earth's history. We do this by using something called "proxies" - a chemical measurement we can make in the modern day that reflects some geologic process in the past! Neodymium (Nd) is one of the key focuses of this research cruise and is often used as a proxy for water masses and ocean circulation throughout Earth's history. But we can only use proxies like Nd to reconstruct that past if we understand how these elements behave in the ocean: where do they come from, are they removed, and what other processes might impact them?
We use our understanding of how different Earth processes relate to each other to inform the models we use to project changes in our climate. By studying the past, we can better understand our present and what we think might happen in the future. How do you collect and analyze water samples from thousands of meters deep?
Some of the deepest water we're collecting on this cruise is 3600 m deep (that's about the length of 33 American Football fields)! At that depth, we can't swim down and simply collect the seawater in a bottle.
We use a special instrument called a CTD (which stands for Conductivity, Temperature, and Depth) that measures the salinity and temperature of the water. We lower it on a wire and get readings sent back to the ship. Attached to this instrument are 24 special bottles called Niskin Bottles, which are open as we send the CTD down. Sending the CTD to 3600 m can take over an hour! Once we have a profile of what the salinity and temperature is like, we decide which depths we want to sample seawater from. Then, we bring the CTD back up to each of those depths and "fire" the bottle to close it. Once all the bottles have been closed, we bring the CTD onto the deck of the ship and the scientists collect samples of the water depths they want to study. How do you use sediment to learn about what the ocean was like thousands of years ago?
There are multiple ways we can look at sediment to learn about what the ocean was like thousands of years ago, but on this cruise, we have people looking at microfossils within the sediment. These are super tiny creatures the size of a grain of sand called foraminifera that either live in the sediment (called benthic foraminifera) or live in the water column (planktonic foraminifera). These creatures build a shell out of a material called calcium carbonate, which is the same material seashells and coral are made of. They build these shells by taking calcium and carbonate dissolved in seawater and combine them into a hard shell. But while they build these shells, other elements dissolved in seawater (like magnesium or lithium) can enter the shell structure. Changes in the seawater can affect how much of these other elements enter the shell.
When these creatures die, they get buried in the sediment. Then, scientists can look at the chemistry of the foraminifera shells across thousands-of-years’ worth of sediment layers to learn about those changes the seawater chemistry. How do you make sure your samples aren't contaminated?
We are studying trace amounts of metals (like iron) in a big metal ship! Fortunately, there are ways to make sure our samples don't get contaminated. One of the ways we do this is by making something called a "clean bubble" on the ship. We put up plastic sheets to make a tent like room and filter the air that is pumped into the space. We affectionately call it "The Bubble" because it looks like a bubble in the middle of the main lab.
Anyone who works in The Bubble must change their shoes to special clean Crocs and wear clean clothes that won't shed fibers into the samples. We make sure to clean our sampling equipment with super clean water before using it and we store all our samples in pre-cleaned containers to ship back to our labs on land for analysis. Have you ever encountered any dangerous situations at sea?
One of the challenges of doing research at sea is making sure the ship, crew, and scientists are all safe. The Captain has been working with the crew and scientists to make sure we avoid situations that could be dangerous (such as extreme weather or sea ice). Things like sea ice can sometime interfere with our ability to collect samples, so we must stay flexible as the expedition progresses. But safety is a top priority!
To make sure we're ready for any possible situation, we do safety drills about once a week, so we know what to do and where to go in case of an emergency. Since we're in the North Atlantic, we're keeping a close eye on both stormy weather and sea ice, and making sure everyone on the ship feels prepared for any possible situation. Thanks to all the scientists who helped organize and run these ship-to-shore sessions. We had fun during those sessions and I hope everybody who joined had fun too. We are about to reach our next station, so have to keep this short today. More to come, so stay tuned. AuthorChandranath Basak As I write this blog, we are leaving Station 1. Most of us have had only a few hours of sleep in the last 24 hours but we know we are ready for what is coming. Station 1 was intense and full of surprises and taught us how we should run our operations. In a research cruise, the first station is always very stressful and a bit chaotic, as scientists try to get all types of samples they want and at the same time try to find a rhythm so that things go smoothly. So, it becomes a bit difficult. Lucky for us, the weather was great, so we had one less challenge. Here is a quick summary of what happened at Station 1. One of the main goals of the expedition is to collect short cores from the ocean bottom. To do that, we need to make sure that our target locations have soft sediment. If we land our coring gear on a rock, it will simply break our equipment, which we absolutely want to avoid. So, about three nautical miles before we reached our Station 1, we started surveying the ocean bottom to locate soft sediments (lovingly called ‘mud’) so that we can deploy our coring device. The survey started a little after midnight, and we found the right kind of mud around 3 a.m. We also wanted to collect water samples at different depths, so we put out a series of bottles and some sensors first. As these sensors are lowered, they send real-time temperature, salinity, and pressure data to us. This helps us decide where to collect our water samples. This operation took about 4–5 hours, and then we deployed the ‘Multicore,’ which is the main coring device for this expedition. This device has 8 empty tubes. The top of the tubes is capped, and the bottoms are open. Once it reaches the bottom, we let the whole device sink into the soft mud, and as it is pulled out, there are contraptions that close the open end at the bottom and hold the mud. This time we also had a camera installed on the Multicore so that we could see what the ocean bottom looks like. The Multicore operation is complicated, but we have experts who have extensive experience in running these operations, which we are heavily relying on. The deployment was successful — the Multicore went down to a depth of 3,500 m (over 2 miles), penetrated the sediments successfully, and then, as it was time to pull it out of the mud, we lost camera feed on one of the cameras. For the next couple of hours, as the Multicore was being pulled up through the water column, we did not know what went wrong, and if we would get any sediment in the coring tubes. The whole science team was on deck, waiting to see what happened as the Multicore was being pulled out of the water. MIRACLE! The contraptions that close the tube bottoms and hold the mud had broken off on most tubes, yet the suction from the top cap was still holding the mud in the tube. Seems like the keepers of the ocean really want us to have mud. There were a lot of smiling faces as we did retrieve sediments, but also a lot of worried faces as the Multicore needed quite a bit of repair. We wanted to do another Multicore deployment at that location, but it was clear that it would take several hours to repair it. In these situations, scientists must decide whether they want to wait or rather conserve the time and move on. Since we could retrieve the most urgent samples from that one deployment, we decided to move on to the next station — which is three days away. AuthorChandranath Basak Since our last post, a lot has happened. Most of the science party has reported to the ship, and we’ve been moving all the science gear (which we worked so hard to clean, pack, and ship) onto the vessel. There are multiple science objectives to be investigated during this expedition, and each one requires something unique to be done in a specific way. For example, one project needs an extremely clean environment to handle its samples. So, the scientists have been busy building a clean bubble with specialized air filters attached, ensuring the air inside contains as little dust as possible. They’ll be wearing special shoes and gloves, and avoiding fleece—since it tends to shed fibers. Another project will be collecting particles from the air as the ship travels. For this, we installed a dust-collecting device on one of the top decks (which has an amazing view). There are many more similar operations we needed to sort out before leaving port. By and large, things have been coming along well, and we are ready to set sail. Bon voyage to us! AuthorChandranath Basak |