IODP Exp. 382 Week 8: Our encounter with stormy seas

Seeing the Southern Ocean in action from the bridge. Photo credit: Thomas Ronge

Michelle writes…

Exp. 382 is quickly coming to an end. We’ve ended drilling at out last site, Site U1538, and we’re now in transit north across the Scotia Sea and heading toward the Straits of Magellan. It’s been slow going the past couple of days because we have hit several storms coming out of the west. Storms are both exciting and terrifying. It’s exhilarating to see waves crashing across the bow and to feel the wind blowing with enough force to knock me backwards. On the other hand, I can’t help but imagine a scenario in which we are stranded in a storm with nothing but miles of ocean between the ship and a safe port. Whatever the storm churns up in the imagination, one thing became very clear to me as I was standing on the bridge watching the swells roll by: we are at the mercy of the weather.

Weathering the storm through a long austral winter night. Photo credit: Thomas Ronge

I rarely find myself in a scenario where I think that I’m at the mercy of the weather. There have been many times where I have felt uncomfortable in the current outside temperature, but I can usually adjust how many layers I am wearing or find shelter inside. Even though I can put on an extra jacket or cozy up in my cabin, I find that I can never truly escape the elements out here. I always feel the waves, I always hear the wind, and I always see the approaching storm.

My current situation is not surprising. After all, I did voluntarily board a ship headed to one of the windiest, stormiest regions on Earth… in late (austral) autumn, no less! The JR is sailing across latitudes infamously dubbed the Roaring Forties and the Furious Fifties. At these high southern latitudes, the westerly winds flow nearly uninterrupted around the world with few landmasses to get in their way. With such a large fetch (stretch of ocean), the winds are able to generate enormous waves and storms. But that’s not even the most amazing part. What’s truly incredible is that even the mighty westerly winds are not constant. Think of the westerlies like a river. A river can contract and flow faster, or it can spread out and become more like a lazy stream. A river can meander. Over time, the westerlies have contracted and increased in strength; conversely, they have expanded and relaxed. They have also migrated north and south. Their position is related to Earth’s climate state, which also encompasses global atmospheric and ocean temperature, as well as the amount of ice locked up in ice caps and glaciers.

The many aspects of the Earth’s climate can be so clearly felt and seen in Antarctica and the Southern Ocean. We have seen the icebergs that have calved off the continent, felt the icy temperatures of a polar climate, and heard the westerly winds as they rip across the ocean. Even though I am climate scientist, I often forget about how the climate and weather affect my everyday life. It’s impossible to ignore this fact while living two months at sea in harsh weather conditions. Ultimately, I am glad to be reminded of it because it puts my science and my choices back home into a clearer perspective. Whether on a ship in Antarctica, or back home in sunny Florida, I am at the mercy of the weather. It’s just that, back home, I have the conveniences of modern society to shield me from a summer that is getting warmer and a climate that is changing. It’s important to remember, however, that not everyone has access to modern conveniences; moreover, our technology won’t always be able to shield us from a climate increasingly defined by drought, flood, and storms. This is why climate science and Exp. 382 are so important. In coming down to the Scotia Sea, we hope to gain a better understanding of a continent that plays a major role in Earth’s climate and global sea level. I hope that we can use that knowledge to better understand our planet and better care for it.

Stormy weather can be as beautiful as it scary. Here, we’re greeted by a spectacular sunrise. Photo credit: Marlo Garnsworthy

IODP Exp. 382 Week 7: Our work has just begun


What will this collection of ice-rafted debris have to tell us once we get back to the lab? Photo credit: Marlo Garnsworthy

Michelle writes…

The JR has now moved north, and we are currently drilling sediments at Site U1538 in the Pirie Basin. Site U1538 succeeds U1537, which was drilled in the Dove Basin. Thinking back to our first site, U1534, on the Falkland/Malvinas Slope, it occurs to me that we have now made our way through five separate sites. That’s five stratigraphic sequences characterized by their own interesting lithologies, microfossils, magnetostratigraphy, and drilling complications. It’s almost as if each site has developed its own personality, with each scientist looking at the sequence in their own way. What does each site have to offer? Can the project that I proposed be addressed in one sequence, but not another? What are the potential complications in this core? With whom can I collaborate?

It may seem like a lot to think about at the end of a two-month cruise, but the fact is that the work is just beginning. When we leave the ship in just under two weeks, we will head back to the lab and begin preparations for post-cruise activities. For some, these include a pilot study to test the feasibility of a proposed method. For others, they include plans to write proposals for student funding. Now, don’t walk away from the post just yet! I know lab work and proposals may seem tedious and dull, but let me convince you that they are equally as interesting and as important as the expedition itself.

Once we return to our institutions, we will begin working up pilot samples collected from both the working and archive half of the cores. There are X-ray images to be analyzed, ice-rafted debris to be sieved, microfossils to be picked, and biomarkers (organic material leftover from organisms) to be extracted. Samples for individual analyses are not usually taken during an expedition, but our timeline dictates that we should begin working up material before our sampling party at the end of the year at the Bremen Core Repository in Bremen, Germany. It’s not a party in the normal sense of the word, but it is an event we are looking forward to.


Our future plans include finding out where these beautiful rocks come from to understand more about ice mass loss in Antarctica. But for now, we just get to enjoy their colors. Photo credit: Marlo Garnsworthy.

At the sampling party, we will once again come together as a science team to do more extensive sampling of the cores. Each person will have a plan for collecting individual samples that will be influenced by many different variables: sediment deposition rate, analytical methods, our shipboard collaborations, etc. The data we will eventually produce will be analyzed and the results written up. Drafts will become papers, which will become manuscripts submitted to scientific journals. Some of these data may be needed as a proof-of-concept in a proposal being written to fund future projects and expeditions. And so the cycle begins anew.

This is the part of science that I find so exciting: being part of a collaborative, iterative process designed to address questions and solve problems that we observe in the world around us. Not that living on ship in the Southern Ocean for two months isn’t exciting, but it’s just one small part of the job we’ve signed up to do. Even as the end of the cruise draws closer and I think about how much I will miss living on the JR, I find that I am not so sad as I am anxious to begin the next phase of the journey. As they say, the best is yet to come.

IODP Exp. 382 Week 6: Our two selves

Specially prescribed medicine to treat the Week 6 blues

Michelle writes…

We’re now at the start of Week 6 and steadily working through cores that are coming up from ~3800 m water depth in the Dove Basin. We’re old pros at this point, which is to be expected after doing the same thing for 12 hours a day, seven days a week for six weeks. That’s roughly 500 hours of work in a little over a month… on a ship… in the middle of the ocean… Umm, is it just me, or are the walls closing in?!

Just kidding.

Scientists Yuji Kato, Mutsumi Iizuka, Fabricio Cardillo, and Ji-Hwan Hwang (left to right) take time to soak up some sun. Photo credit: Mutsumi Iizuka.


But on a more serious note, we’ve reached the point of the expedition appropriately named Week 6. Appropriately named, not just as a marker of time, but also as a marker of emotion. Week 6 means more than halfway done with the cruise, but not so close to Week 8 that we can see the light at the end of the tunnel. Week 6 is dutifully going about our work, but not without moments of weary monotony. Week 6 is calls to our loved ones with messages like, “It’s going so fast, I’ll see you soon,” but not soon enough to keep the homesickness at bay. The feeling of Week 6 is so prevalent on each expedition that our staff scientist, Trevor, gave a specially prepared presentation to help us recognize signs of stress and to find ways to combat them.

Scientist Brendan Reilly, outreach officer Lee Stevens, scientist Linda Armbrecht, technician Sarah Kachovich, and scientist Jonathan Warnock (left to right) catching the last of a beautiful southern sunset. Photo credit: Brendan Reilly.


I am not writing about this to complain or to publicly declare my decision to leave science. In fact, this cruise has reaffirmed my love for Antarctic Paleoceanography, and I feel incredibly privileged to work with such a competent, intelligent, enthusiastic group of scientists, technicians, and crew.  I am sharing this on Expedition Antarctica to highlight the human side of a scientific research cruise.

Since the beginning of graduate school, I have noticed that institutions and people outside of science tend to reduce scientists to talking heads. Even within science, I see our initial perceptions of each other mostly defined by the data we produce or the papers we write. I am guilty of this, too. But living and working on the JR over the past six weeks has emphasized the fact that we can’t separate the scientist from the person, both within ourselves and in others. We’re all dedicated researchers here to work and contribute to the understanding of Antarctica and the Southern Ocean, but it’s impossible to be professional 24/7.

Scientists Frida Hoem (left), Anna Glueder (right), and myself let our creativity shine in the time honored tradition of decorating styrofoam cups. Photo credit: Marlo Garsnworthy

Publications specialist Alyssa Stephens and scientist Gerson Fauth share some tea during a long midnight shift. Photo credit: Marlo Garnsworthy.

Running jokes about the best way to call scientists to the sampling table have developed into a friendly competition. Little rituals like sharing erva mate (a Brazilian tea) have become a daily mainstay. We sit outside watching icebergs float serenely by and chat about everything from science to hobbies to our families. Sunrises and sunsets become opportunities to stretch our legs, but also to reminisce about past fieldwork, ask after mutual friends, and scheme future expedition ideas. Friendships blossom to form the foundation of potential future collaborations.

My adviser likes to say that science doesn’t happen in a vacuum, meaning we can’t push the science forward without a healthy flow of ideas between individuals and working groups. In forming working relationships and fostering good communication, we move closer and closer to the goal of this cruise: understanding a changing Antarctica. Perhaps Week 6 is not a reminder of the things we have left behind, but rather a promise of the things to come.

IODP Exp. 382 Week 5: Our journey through time

Michelle writes…

A map of our journey through the ages. Read on to find out how the Paleomagnetics team uses it to help us find our way. Image credit: Brendan Reilly.

One of the things I have enjoyed most about this cruise is the high volume of stratigraphic data collected in real time. Many other coring platforms have instruments to collect navigational and bathymetric data (images describing the shape of the sea floor), but only a very preliminary assessment of lithology and some physical properties can usually be made on a ship. I briefly mentioned physical properties measurements in IODP Exp. 382 Week 2, but there are four other teams on the JR dedicated to collecting additional data: Sedimentology, Geochemistry, Biostratigraphy and Paleomagnetics. 

Each team produces new and pertinent information about each site and while I have a lot of love in my scientific heart for sedimentological and geochemical data, I find myself captivated by the information coming out of the Biostratigraphy and Paleomagnetics labs (Biostrat and Paleomag, for short), which is the focus of this week’s blog. What is so interesting about this work that it warrants an entire blog post? It’s the fact that these data let us travel through time!

Diatoms, radiolarians and dinoflagellates act as our guides through time. Photo credit: Frida Hoem.

It’s not exactly a science fiction jump to hyperspace; rather, the biostratigraphers and paleomagnetists give us the age of our sediment. Because age is a necessary component of any geologic investigation, our geology-minded readers might be wondering what is particularly special about these data. The shipboard work that Exp. 382 scientists do allows us to estimate the age of the cores as we collect them! I think this is amazing because I work mostly with radiocarbon, which requires special instrumentation and weeks of waiting time to get radiocarbon dates. But here on the JR, Biostrat and Paleomag teams work together to constrain ages using shipboard data, sometimes working out the sediment age before the other teams can make their own measurements.

Night shift Biostratigraphy team hard at work, but always ready with a smile. Photo credit: Marlo Garnsworthy.

Each team derives an age differently. Biostrat uses the fossils of tiny phytoplankton and zooplankton preserved in the sediment. Each team member specializes in a specific plankton group. Biostrat uses their expertise to identify certain species and their knowledge of many different species allows them to determine when a species existed and how it relates to older or younger species. Ivan, our radiolarian specialist, says its like finding the father then looking for the grandfather and the son. I want to stress that these scientists do this just by looking at these organisms! Of course they have references and colleagues on land to help, but I always marvel at the encyclopedia-level of knowledge contained within the Biostrat team. I talked with Frida, our resident palynologist (one who studies dinoflagellates, pollen and spores) and Yuji, who specializes in diatoms, to help me understand their work. Each biostratigrapher spends hours on the microscope looking at specially prepared slides, but they each have different amounts of work to do before getting to the scope. This ranges from simply smearing sediment on a glass plate with a toothpick, to spending hours at the fume hood working with strong acids. The preparation and microscope time are well worth it when Yuji, Frida, and Ivan, together with their day shift counterparts, Linda and Jonathan, can compare their results to narrow down the age of a core section.

The Paleomag team provides the framework and confirmation for Biostrat. The paleomagnetists are responsible for identifying changes in Earth’s magnetic field through time using magnetic minerals preserved in the sediment. If that sounds more like magic than science, then you’ll be happy to hear that we sometimes refer to the Paleomag team as Paleomagicians! Stefanie, Paleomag team member and veteran Antarctic researcher, says that magnetic minerals act as compass needles as they are deposited at the sea floor, orienting themselves to the Earth’s magnetic field, which periodically flips upside down. Right now, Earth is in the “normal” phase and the magnetic field lines are pointing down at the magnetic north pole; reverse phase is just the opposite orientation with field lines pointing down at the magnetic south pole. A switch in orientation is called a reversal, and it leaves a characteristic signature in magnetic deposits everywhere on Earth. The pattern of reversals acts like a barcode, signifying the cores’ place in time to the paleomagnetists. Assuming surface sediments are zero age and therefore have “normal” orientation, the team can work back through time to match the known pattern reversals and determine the sediment age. The theory sounds straightforward; the practice is anything but. Discontinuous sediment sequences and the absence of magnetic magnetic minerals can complicate a reconstruction. It’s a good thing we have Stefanie and her team mates, Lisa (who literally wrote the book on Paleomagnetism) and Brendan, to do some next-level pattern recognition.

Samples for Paleomag all lined up and ready for analysis. Photo credit: Stefanie Brachfeld.

Both teams on both shifts provide the chronological framework for the cores we collect. I recognize that it’s not literal time travel, but it’s the best way to describe the feeling of looking at sediment and knowing that you’re staring ~8 million year old material in the face…or facies (I can’t resist a geology pun). With each age update, I feel like I am hurtling back through time back to a different Southern Ocean. If not a journey through time, then definitely a journey through imagination.

IODP Exp. 382 Week 4: Our best-laid plans

Drama is everything for these icebergs. Photo credit: Thomas Ronge

Michelle writes…

Who among our Expedition Antarctica readers likes to have their plans disrupted? I bet most people would rather not have the proverbial wrench thrown at them, but unfortunately disturbance is inevitable. It happens to everyone and in all types of situations despite our best efforts to avoid it. Like most people, I do not like to have my careful planning wrecked by happenstance. But this week, I am taking a different perspective and suggesting that a little disturbance isn’t always a bad thing.

Beautiful bergs floating by the site. Photo credit: Thomas Ronge


One example of disturbance that Exp. 382 is currently dealing is icebergs. This should not be totally surprising considering that we have ventured into Iceberg Alley. The problem is that the JR is not ice strengthened and therefore doesn’t have the added steel reinforcements required for polar vessels. Rather than risk a potentially danger situation of, um, titanic, proportions, the JR steers clear of icebergs. We do with this using radar and with the help of our ice observer, Diego Mello. Diego is the captain of the R/V Siquliak up in Alaska, so he has plenty of experience with ice. When Diego and our captain, Terry Skinner, say a berg is too close, all drilling operations cease: coring stops, the drill comes up, and the JR moves to a safer location. As you can imagine, this situation is not ideal for the science party. We have a limited amount of ship time, so the time lost waiting for icebergs to move away is time lost collecting cores. Still, it’s a special opportunity to see an iceberg up close. A couple nights ago, the night shift was treated to a close encounter. We trooped outside, tracking the ship’s light, and there it was: ~70 meters of visible ice above the surface and several hundred meters of invisible ice below! The very next day, the icebergs got even closer, with growlers (bergy bits ~5 m long that sound like they’re growling as they float in the water) passing within tens of meters of the ship. Despite the disruption to our operations, I think everyone watching the icebergs is glad to have witnessed one of Antarctica’s most famous sights.

Another disturbance that the science party has had to deal with is coring disturbance, which happens when the coring process disturbs the original depositional structure within the core. This can include flow-in, which occurs when water flows in with the sediment and mixes it up. Disturbance can also occur when something (e.g., a hard piece of sediment or a piece of core liner) gets trapped in the core liner with the sediment and acts like a blade in a blender. We have seen core disturbance in one form or another since drilling began, but a couple of days ago the cores really decided to show off.

Being a diatom ooze is simply not enough for this core section.

The greenish grey oozes and muds took on a marbled look, swirling and flowing to reflect the disturbances that shaped them*. Because these sections are useless for putting stratigraphic changes into context, our stratigraphic correlation team will direct us to an equivalent depth in the next hole to try to recapture these particular sections in their undisturbed form.

Now it’s just showing off!

I don’t think constant disruptions are a good thing, nor would I want to work around huge roadblocks in my everyday life. But since even the best-laid plans often go awry, especially on Antarctic expeditions, I figure we might as well sit back and enjoy a little disturbance.



*When this entry was first written, the cores in the above pictures were labeled “disturbed” by the Sedimentology team. Stratigraphic analyses in Hole B showed that the sediment had the same structure at an equivalent depth. The stratigraphic correlators and the sedimentologists therefore changed their interpretation to say that the sediment exhibited slumping, and that disturbance had not occurred. Just another example of why multiple holes are drilled at a single site!

IODP Exp. 382 Week 3: Our guest blog and a Southern Ocean connection

Michelle writes…

This week on Expedition Antarctica is a little different. Instead of writing a whole new post, I am going to direct readers to a recent guest blog that I wrote with Marlo Garnsworthy, outreach officer and artist extraordinaire! Marlo and her day-shift counterpart, Lee Stevens, make up a two-women super outreach team dedicated to sharing the science with the wider community. Head on over to the Exp. 382 blog page to read what they have to say.

Without spoiling too much, I will say that my guest blog reflects on our encounters with wildlife, a shared interest in polar waters, and the importance of taking time to appreciate the beauty in the science. Click here to read more about a Southern Ocean Connection.

We’re now at the Dove Basin, in the Scotia Sea. Cores are coming steadily up from more than 3000 m (!!) and the science team is ready to get their hands back on some sediment. We’ll be here awhile (~10 days), so check back soon to find out more.

IODP Exp. 382 Week 2: Our first cores and the chaos that ensued

Michelle writes…

I have been lucky enough in my graduate career to have traveled to Antarctica twice and  logged ~60 total days at sea. All of my previous ocean-going research experience has been with the U.S. Antarctic Program (USAP) aboard the R/V L.M. Gould and RV/IB N. B. Palmer. Sailing as a new IODP science party member, I can’t help but compare my experiences on the JOIDES Resolution to those with the USAP.

The main thing that stands out as different is the pace of the work. The working day on USAP vessels and the JR are the same: two shifts running 12 hours each, starting either at noon or midnight. This schedule maximizes the work that the science party can do with the available ship time. I began mentally preparing myself for 12-hour shifts before the cruise, but didn’t dwell on it too much. I had done this before. It would be fine… famous last words.

My advisor, Amelia Shevenell, and labmate, Imogen Browne, both previously sailed on the JR and told me how busy it was going to be. I believed them, but I didn’t fully appreciate their words of wisdom until I stepped into the core lab for my very first shift. Admittedly, the first day at our first site started out slow because we had to wait for the sediment cores to equilibrate. The cores at the first site were coming up from ~650 m below sea level, plus an additional ten to hundreds of meters below the seafloor, so they are quite a bit colder than the 20°C core lab temperature. After the cores equilibrate to room temperature, the Physical Properties team runs them through a series of multi-sensor logging instruments to measure various physical parameters. These include magnetic susceptibility (a proxy for the relative amount of terrestrial material), thermal conductivity (to help determine chemical composition, porosity, structure, and fabric of the sediment), and natural gamma radiation (to aid in identifying clay composition). These measurements, which we make on whole round (un-split) cores, require about 45 minutes per 10 m core. Although I am part of the Physical Properties lab, my main responsibility for the time being is to take individual samples to measure moisture and density (MAD), which happens after the cores are split. So I had a little down time that first shift, before things got crazy.

Scientists Lara Perez, Lisa Tauxe, Stefanie Brachfeld, and Anna Glueder take some time to inspect a newly split core. Photo credit: Marlo Garnsworthy











Boy, did things get crazy! The next half of the shift was a steady (and frequently chaotic) interval of taking samples for moisture and density, weighing them, and placing them in the oven to dry for 24 hours. It seemed like the work never ended. Night shift finished their time in the lab, briefed the day shifters, and we went to bed, and then returned to an even busier shift 12 hours later. Cores kept coming up, other cores kept being split, working halves for sampling made their way to the sampling table, archive halves went to the sedimentology team for core description. Over, and over, and over again. I am not exaggerating when I say I spent maybe 30 minutes sitting down during that second 12-hour shift.

The sampling table is where I live now. Photo credit: Marlo Garnsworthy











Shifts are not always so fast-paced, but I wanted to share this story so that readers get a sense of the scale of an IODP operation. The JR is essentially a floating island of laboratories with a drill rig attached, outfitted with more instruments and equipment than I can normally access in any given day on land. These capabilities allow an international team of scientists from different subspecialities to collect and process tons of data, all at the same time. I find it absolutely amazing that we are out here at all, let alone imaging sediment with an X-ray machine, identifying reversals in Earth’s magnetic field, or continuously providing age constraints using microscopic fossils preserved in the sediment. I hope whoever is reading this also finds this amazing and checks back periodically to learn more about the expedition over the next two months.

We’ve just left the Falkland/Malvinas sites and we’re heading south! Keep your eyes and ears open for more news about science, sediment, and sailing through the Southern Ocean.


IODP Expedition 382 Week 1: Our foray into Iceberg Alley and Subantarctic Ice and Ocean Dynamics

D2iDJ47X0AEEEq6.jpgMichelle writes…

The apparatus that the JR uses to drill sediment cores. The rig is 60 m high and will support our efforts to drill up to 600 m of sediment in ~3500 m of water

Well the Shevenell Lab is back at it again, this time in the Scotia Sea! If you had the opportunity to read about Imogen’s time in the Ross Sea aboard the JOIDES Resolution (JR), then you might already know about the International Ocean Discovery Program (IODP) and the work that scientists and crew do on the JR. For those who are unfamiliar with IODP, I have included some background in this blog post. IODP is committed to reconstructing Earth’s history through the collection and investigation of sea floor sediments and rocks. Scientists and organizations from member countries participate in the shore- and ship-based science. Some countries and consortiums also provide the platforms on which scientists sail. This includes the JR, which is operated by the United States. To sail aboard these vessels and take advantage of deep sea drilling capabilities, scientists must submit proposals to drill. The proposal process can take years or even decades (literal decades!) and often includes multiple revisions. Proposed projects that pass review then move to the planning and staffing stage. Scientists from all over the world are staffed to sail with IODP. On this cruise, Expedition 382, we have scientists from, and representing institutions in, the U.S., the U.K., Germany, Korea, Japan, Norway, China, Australia, Brazil, the Netherlands, India, and Spain. This means that at any one time I often hear about four languages spoken at once in the conference room!

Our goal for Expedition 382, as an international team, is to uncover how Antarctica has changed over the past 14 million years, including how ice sheets responded to atmospheric CO2 changes, how ice sheets affected global sea level, and how the oceanography surrounding Antarctica evolved. To do this, the JR will be traveling to a site directly south of the Falklands/Malvinas, as well as to two sites in the Scotia Sea, which is located within the stretch of ocean between South America and the Antarctic Peninsula. The Scotia Sea sites were chosen because they are in the pathway of an iceberg armada. Dubbed Iceberg Alley, this stretch of ocean is the terminus of the counter clockwise-flowing Antarctic Coastal Current that transports icebergs around the continent. Once they leave the frigid waters of their icy birthplace and enter the relatively warm sub-Antarctic waters north of ~60°S, the icebergs melt and deposit debris that they have carried since they were glaciers sitting on the continent. The debris is a clue to how Antarctica evolved through time.

This figure shows the sites we will drill during the two month expedition.

Our co-chiefs, Michael (Mike) Weber and Maureen (Mo) Raymo, and lead-proponent, Victoria (Vicky) Peck, are anticipating hundreds of meters sediment that we can use to understand major changes in Antarctic history. Expedition 382 scientists are eager to collect the entire 14 million year sequence, but we are particularly interested in sediment that captures times of change in Antarctica. Many of our individual proposals focus on the glacial intensification throughout Antarctica at different times in its history, or times that represent higher-than-modern global temperature and CO2. Investigating these changes is very important for understanding the rapid retreat and thinning that we currently observe in Antarctic marine-terminating glacier systems. To better predict the response of modern glaciers to environmental stressors, we look to the past to understand ice-ocean-atmosphere dynamics. Our questions address various themes, such as ocean temperature, water mass distribution, and carbon cycling.

A presentation delivered by Co-chief Scientist, Mo Raymo, explaining the importance of understanding Antarctica’s past climate

So that’s an overview of who we are, what we’re doing, and how we plan to achieve our science objectives. We’ve had a bit of delay leaving port and now leaving the fueling station, but we should be on our way soon. Stay tuned for updates as we transit south.

Drilling on Antarctica’s continental shelf to uncover ice sheet history

We have finished drilling at our first site on the Ross Sea’s continental shelf, where we had overall excellent recovery for the method of drilling (rotary core barrel; RCB). The RCB is designed to cut through all types of sediment. Because we were targeting both hard diamictites (mixture of poorly-sorted clasts in a muddy/sandy matrix) and softer mudstones, the RCB method was the most appropriate for our site. The diamictites were likely deposited underneath or proximal to ice, and the mudstones which contain microfossils of phytoplankton (mainly diatoms in Antarctica) represent deposition in open marine conditions, far away from ice influence. We can use downcore changes in these sediment types to understand past advances and retreats of the West Antarctic Ice Sheet.

snnow drilling_kenny

Drilling in Antarctic conditions (Photo by Kim Kenny)

andrill graphic

Example of sediment core recovery from the Ross Sea from the ANDRILL program, and modeled ice sheet configuration as a result of this project (Gasson et al., 2016). When there are open water conditions, phytoplankton like diatoms thrive and are incorporated into the sedimentary record once they die, creating layers of diatomaceous sediment. At this time Antarctica’s ice sheets are retreated (bottom right model). As the ice sheet advances (top right model), rocks, mud, and sand carried by the ice sheet are deposited, creating layers of lithogenic sediment. Alternating layers of these two units through time tells us about the past environment used to infer ice sheet history.

excited_de zsantis

Some excited scientists: Imogen Browne, Tim van Peer, and Jeanine Ash (Photo by Laura de Santis)

Ice sheet models and paleoclimate data tell us that the Ross Sea is one of the last places on the continent to become glaciated, so drilling here helps us to constrain the biggest advances of the West Antarctic Ice Sheet over the past 20 million years or so. One of our main aims at this site is to constrain ice advance at a regional erosional surface, which we think happened around 16 million years ago during a period of Earth’s history called the Miocene. This surface represents regional advance and grounding of ice across the continental shelf of the Ross Sea, which only happens every few million years or so, and results in a fall in global sea level.


Co-chief Laura de Santis presenting an image of the sea floor during the middle Miocene (Photo by Jule Müller)

We rely on microfossils among other methods to tell us the age of erosional surfaces. Microfossils can be different types of phytoplankton, zooplankton, or pollen. In Antarctica, the dominant group of phytoplankton are called diatoms, which form discs and chains called ‘frustules’, composed of silica (glass). We know from regional studies of well-dated sedimentary sequences when different taxa of these groups appear and disappear through the geologic record due to evolution and extinction through time. These biological events are often associated with abrupt changes in the marine environment, such as initiation of new currents and warming or cooling of surface waters.


Diatoms collected from surface waters south of 70S (Photos by Expedition 374 Paleontology team)

During the Miocene Climate Optimum (~17-15 million years ago), climate was warm enough for plants to grow around the edges of the continent. During this time, Antarctica’s ice sheets were generally reduced in extent and global sea level was much lower. However, recent studies from the Ross Sea and the ANDRILL project indicate that both the West and East Antarctic Ice Sheets were dynamic and capable of modulating global sea level, even during warmer climates of the middle Miocene. By studying past ice sheet behavior and response to warm climates like the middle Miocene, we can better model and predict how Antarctica will respond to ongoing anthropogenic warming.


Crossing the Ross Sea Polynya and other antics

The JOIDES Resolution is now following RV/IB Nathaniel B Palmer into the Ross Sea Polynya, which is Earth’s largest ice making factory. Cool air temperatures encourage surface water freezing which creates sea ice. Strong winds then move this ice around, freeing up more space for sea ice formation. The Ross Sea is highly productive in the summer months, where sunlight, a stable water column, and abundant dissolved nutrients stimulate huge phytoplankton blooms. These blooms are consumed by krill, which are consumed by predators like penguins, seals, and whales.


The first iceberg spotted on our way down to greeting the RV/IB Nathaniel Palmer. Photograph by Bill Crawford


The JOIDES Resolution being escorted towards the Ross Sea polynya by the RV/IB Nathaniel Palmer. Photo by Gary Acton


First (Adélie) penguin spotting! Photo by Gary Acton

Before we arrive at our first site, all scientists need to adjust to their shift time. (day shift is from 12pm-12am and night shift is from 12am-12pm). Apparently, there is no ‘right’ way to do this, but some of us attempted to pull an all-nighter fueled with coffee and movie marathons. Others opted for short sleeps and an early start. Those of us night shifters who were bored yesterday decorated the conference room to celebrate Rob’s birthday (our co-chief) and the catering staff prepared a cake and cupcakes.

movie room

Some of the night shifters enjoyed the movie room (Molly Patterson; USA, Brian Romans; USA, Isabela de Sousa; Brazil, and Jeanine Ash; USA). Photo by Kim Kenny


Birthday celebrations for co-chief Rob McKay. Photo by Saki Ishino

During our transit, individual lab groups have practiced shipboard measurements and core descriptions on legacy cores recovered on previous Antarctic expeditions. The sedimentology team has discussed how to describe sediments from glaciomarine environments and practiced estimating grain size percentages and identifying minerals under the microscope. The physical properties group has reviewed methodologies for the required measurements. Kim Kenny, our on-board videographer has also been conducting short interviews with the science party- so stay tuned!

seds 2

Sedimentologists discuss legacy cores (Brian Romans; USA, Benjamin Kiesling; USA, Amelia Shevenell; USA, Saki Ishino; Japan, and Rob McKay; NZ). Photo by Mark Leckie

phys props

Physical properties night shift (Imogen Browne, USA; Francois Beny; France, Brian Romans; USA). Photo by Kim Kenny