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Fall 2013 Expedition to Antarctica

Monday, November 4

By Isabelle "Izzy" Weisman '15

It’s 12 p.m., and I’ve just finished my first shift. For the past 12 or so hours I, and two other scientists, have been tirelessly processing our first core, JKC 1 (Jumbo Kasting Core 1). This core spans an impressive 430 cm, and was taken from about 1000m below sea level. In the near future, scientists and researchers at the University of South Florida will be running a multitude of tests, ranging from radiocarbon dating to foraminifera, to DNA, and magnetic susceptibility. Interestingly, this unique sediment archive extends back about 3000 thousand years. Physical properties, as well as carefully prescribed sampling, will give scientists valuable information regarding the paleoclimate and biology from the past to present day. For example, Chief Scientist Amelia Shevenell will use an advanced geochemical procedure that will enable her to reconstruct the sea surface temperature hundreds to thousands of years ago.

While core logging and sampling took up much of my shift, our chief scientist was occupied with the performance of the “yo-yo cam.” A yo-yo cam is a contraption, with a waterproof camera, that is lowered to the sea floor and then brought up and down as the vessel drifts at about five knots. The apparatus moves slowly across the sea floor, bouncing along like a yo-yo. Each time the machine is raised, the camera is programmed to take a flash photograph of the sea floor.

While the concept of this machine is not overly complex, it is highly sensitive and requires constant attention. The up and down motion of the camera is controlled by a crane operator on the ship. Each time the camera hits the sea floor the operator hears a beep, and seconds later is slightly raised to trigger the flash photograph. Once we completed a calculated path, we then retrieved the camera to see the pictures. Throughout the trial our team believed that 175 photos were taken. However, when we recovered the images, 30 or so impressive images resulted. We will consult with the Electronic Technicians to see if we can remedy this fault for our next try.

Tuesday, November 5 – midnight to noon

By Isabelle "Izzy" Weisman '15

The past 12 hours have been an incredible learning experience. During my shift, I was exposed to an important laboratory technique and observed the chief scientist make a pivotal decision.

Using the 436 cm Jumbo Kasting Core we took U-channels and archive sediment for testing. We took three U-channels that spanned the entire length of the core; 0-135 cm, 135-285 cm, and 285-436 cm. We then ran a magnetic susceptibility test on this sediment.

Before we could begin this arduous process, we had to first set up a contraption that would allow us to slowly track the u-channels through the sensor. We drilled the sensor into the wooden table and then carefully aligned wooden support blocks on either side of the sensor. Once we were satisfied we made sure that the track of the u-channel was perfectly centered in the censor. This was a crucial step. The magnetic susceptibility (MS) test requires us to measure how magnetic the sediment is at centimeter intervals. Therefore, we had to carefully mark lines one centimeter at a time on the u-channel. After this was done, we were ready to run our samples. This process was relatively painless…just repetitive.

Once we gathered accurate data, it was my job to translate our raw data into a scatter plot in the electronics lab. After some maneuvering and manipulation, I was successful in this task. Our chief scientist found this plot especially important because she will compare the results from this core with others on which she has previously published papers. All the while I was working in the electronics lab, Chief Scientist Shevenell was carefully monitoring seafloor sediment thickness.

As we surveyed south through the Hugo Island Trough, Shevenell watched the sub bottom reflectors in search of the “toothpaste” layer of interpreted post-glacial till. Several prime coring locations were noted in our logbook in the deeper waters. As we moved to shallow waters, however, apparent iceberg scouring disrupted the sediment layers below. This proposed a problem for our chief scientist. The prime locations, of long and flat sediment, were now about 30 minutes back the way we had just traveled. Considering the science with our highest priority, Shevenell directed the vessel back to the great coring location. Although we did lose some time during this process, Shevenell stuck to her high standards and did not settle for mediocre data. Just as this conclusion was made, my shift was over, and it was time to Alex Hare and his crew to pick up where we left off.

Tuesday, November 5, noon – midnight

By Alexander Hare '14

We are day two into the science portion of our trip and have successfully retreived a Jumbo Kasten Core from the Palmer Deep. There is a lot of lab work to do, and the crew is scheduled to work on two different 12-hour shifts to prepare and sample the cores.

We took u-channel samples of the core to capture the stratigraphy, and once the seas are more calm, these samples will be analyzed on the ship using the magnetic susceptibility machine.

The final samples we took were the archive sampling, which are composed of u-shaped channels but on a much larger scale. These samples will be taken back to the labs in the States to be further analyzed.

All of the sampling and prepping took about eight hours to complete. We then cleaned out the Jumbo Kasten Core, so that it could be used again. Now we are headed out to the edge of the shelf in the hopes of repeating this process all over again.

Wednesday, November 6

By Isabelle "Izzy" Weisman '15

My past shift was incredibly productive. Just as my group replaced the day shifters, we became inundated with an array of new, unprocessed, cores.  As a result, I spent almost my entire shift preparing the cores and running the magnetic susceptibility test on them. As I’ve explained before, when running these tests, we need to accurately collect data every centimeter. Before we can gather any results, my group and I carefully marked our first Jumbo Gravity Core (JGC). This large core is extremely heavy, and usually weighs around 100 pounds, depending on the physical properties of the material inside. This added weight makes it much more difficult to move centimeter by centimeter through the Magnetic Susceptibility (MS) sensor. Despite this hurdle, we were able to complete around 6m of core…that means we collected 600 individual data points! After running the JGC’s, my partner and I then moved on to run MS on some u-channels from previously collected cores.

After working eight to ten hours on MS, I had the opportunity to get a crash course in the art of monitoring a coring event.  I had to pay close attention from the moment the empty core barrel went into the water to the moment the full core was back on deck. At my 10th hour of work, we had conveniently reached a particularly favorable coring location in the Hugo Island Trough Deep. At this location, named station 6, we could easily see the “toothpaste” sediment reflector that was remarkably constant at four meters. Our chief scientist alerted the crew and preparations for coring began immediately. Soon after, we were ready to core.

As an observer, I learned the important variables that our chief scientist was considering as the empty core barrel descended to the sea floor. For instance, the speed at which the core descends is extremely important. Lighter cores require less weight and heavier cores require more weight. This difference is crucial, as it controls how the core and sea floor interact when contact is made. Some other important variables are wire tension of the core on the way down and up, the “wire out” (length of wire attached to core), and maximum pull out tension. These values allow scientists and knowledgeable observers to have an idea of what is going on with the core, and whether or not the deployment was successful. Fortunately for our JGC, we were wildly successful.

I, along with my advisor Amy Leventer, walked out to the core, float coats and hard hats on, and witnessed the first viewing of the core. We saw some saw some sea water come out of the barrel, as well as a mud horizon below the top of the core. This confirmed that we had captured the crucial sediment water interface.

After some careful maneuvering, our new core, JGC6, was transported into the lab. It was then I realized my shift was indeed over, so I said goodbye to the core and passed on the analysis to Alex Hare and his team.

Thursday, November 7

By Alexander Hare '14

he past couple days aboard the Gould have been extremely busy for everyone on board. The ship crew members have been working non-stop to make sure everything runs smoothly while we move to different core sites. The technicians have been working around the clock making sure the coring equipment runs smoothly. Everyone in the labs has been working tirelessly to sample and prep the core for further analysis. Feeling tired is great because it is a sign of our success.

My last 12-hour shift moved by very quickly. The marine techs successfully launched and retrieved two Kasten cores, which were approximately 2.5 meters in length. The first core came on ship around 1 p.m. We gathered DNA samples, Foram samples, physical property samples, radiocarbon samples, archives and u-channels. This took us seven hours to complete because each sampling had to be taken from specific depths along the core. My group worked methodically and efficiently to clean and sample the first core. We were able to finish the sampling just as the second core was coming on deck. Without having time to clean the barrel we moved the first core on the ground.

We worked non-stop in order to finish sampling and to refrigerate the cores before they were altered by the temperature of the room. We were able to move through this process easily and efficiently because of the expertise of the techs aboard the ship. At the end of our 12-hour shift Tasha Snow and I were tired and satisfied with a successful day of work behind us.

The Marine techs getting the Kasten core aboard the ship.
The Marine techs getting the Kasten core aboard the ship.
Here we are sampling the Kasten Core, Amelia Shevenell ’96 back left, Christina Subt back right and me front left.
Here we are sampling the Kasten Core, Amelia Shevenell ’96 back left, Christina Subt back right and me front left.

Thursday, November 7

By Isabelle "Izzy" Weisman '15

The past shift went more smoothly than ever before. Finally my co-workers and I seemed accustomed to our night shift working hours, and we were able to work productively and alertly from beginning to end.

Our day began by cleaning the lab. The shift before us had spent hours sampling a jumbo gravity core in this room, but had not yet found a chance to clean the u-channels and archives and discard of the remaining, useless, mud. Therefore, Michelle and I spent our morning doing just that. As Michele cleaned, and I took the u-channels and began the inevitable process of labeling every centimeter. This preemptive work would prove to be very helpful later when we were ready to run MS testing. After about four hours we all took a brief break to meet up with the marine technicians on duty in the galley for “Tea Time.” During this break we typically grab a snack, a cup of tea or coffee and tell stories and joke around. It’s a great way to break up our long shift and build friendships along the way.

After Tea Time, we headed back to the labs and began running MS on some unprocessed JGC’s and u-channels. All the while, we could see the sun rising from our porthole. Afraid to miss the outstanding view, my group and I quickly went to the 02 deck to grab a glimpse of the sunrise and take some pictures. The quietness and serenity I experienced on that deck is the reason I enjoyed working the night shift. While the views were outstanding, it also brought my attention to the heavy, consolidated pack ice that surrounded the ship.  Since I had not yet been on watch, I had no idea that we hadn’t moved in almost four hours.

To our dismay, the ice had become so thick overnight that our vessel was unable to break the ice and move forward. For now, we will maintain our position and wait for any opportunity to reach our destination. With time running out, this unpredictable variable is preventing us from reaching the Palmer Deep and Palmer Station. While it is unfortunate that we might not be able to finish our science and reach our last locations, we can only hope for the best and that things will change over the next couple of hours.

Friday, November 8

By Alexander Hare '14

Currently the Laurence M. Gould is waiting out a heavy ice flow that is surrounding Anvers Island. While we were out on the science portion of our cruise, a thick ice flow migrated towards Anvers Island and Palmer Station. The Gould was scheduled to travel back to Palmer Station this evening, but due to the lack of horsepower the ship cannot push apart the ice to make its way toward Palmer. Stuck roughly 5.9 nautical miles from the Palmer pier, we are hoping that overnight the winds might shift the ice flow.

Although we are sitting out in the water waiting for an ice shift it still has been a productive day because we were able to finish up the magnetic susceptibility tests on our cores. Once we completed our analysis, we packed up the lab and tied down our equipment in preparation for crossing the Drake Passage. We then moved to our samples making sure that they were safe and secure. These valuable pieces of sediments must be well protected. The marine techs built us large wooden crate where we could place our Jumbo Gravity Cores in order to keep them for moving when the seas get rough. After getting the labs and the samples squared away we geared up to spend time outside.

Later in the day we had a chance to take the Zodiac to examine some sea ice. The specific ice that we were hoping to obtain had a brownish tinge color, which is due to algae that grows within the sea ice in places called brine channels. These channels are created when salt water freezes. Here the channels are large enough for the algae to thrive when close to the surface so it can receive sunlight.

We boated around the Gould, going up to the ice fringe and hauling in ice samples. Bringing in pieces of the ice into the Zodiac was harder than expected. The ice chunks were often larger and awkward size to bring into the boat, but luckily we brought a hammer and chisel to break apart smaller pieces. After we finished our task, we returned to the Gould to see what we had retrieved.

To prepare the samples for anaylsis, we melted them down with filtered seawater. Once the samples are melted they will be taken to the University of Southern Florida where the samples will be analyzed to identify the type of algae and how it might relate to the algae in the sediment.

As we head off to bed we are optimistic that the Gould will make it to Palmer Station in the morning.

Saturday, November 9 and Sunday, November 10

By Isabelle "Izzy" Weisman '15

For the past two days we have been stuck in a heavy ice flow a mere two miles from our destination, Palmer Station. We are surrounded by thick pack ice that is overlain by about a foot of fresh snow. These types of conditions inhibit our vessel’s ability to make any progress. We will continue to try to push our way to Palmer Station until November 11. After that, we are ordered to turn back around and head towards Punta Arenas, Chile.

In the meantime we have spent a couple of hours in the lab filtering seawater for unique Antarctic algae. We are looking for micro-sized algae invisible to the naked eye. We are using a .2 nanometer size filter, which means that it takes about an hour and a half to filter a liter of our seawater and melted sea ice mixture. Once we have filtered out the algae, it is placed into a labeled vial and stored in the -80 degree Celsius freezer on board. So far we have collected around 15 samples that will be examined at University of South Florida.

This afternoon Alex and I spent some time out on the back deck helping the marine technicians prepare the ship for our upcoming voyage. We cleaned and replaced screws all the while listening to the crew’s favorite music. It proved to be a refreshing break from our daily science routine.

With snow covered mountains dominating the horizon, it seems as if our ship has attracted some curious visitors. During our time near Palmer Station, we have witnessed some amazing wildlife encounters. Last night we watched two whales surface just off the back of our ship. Today I spotted two different types of seals wandering around the fluffy snow-covered sea.

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