2/19/2014 – Marine Mammal Observations

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Tasha writes:

When you think about Antarctica, what first comes to mind? I’ve had quite a few people ask me about penguins and polar bears when I first told them I was traveling to Antarctica. Truth be told, polar bears only roam around the Arctic, and penguins only frolic here in the south. The penguins find company with the seals and whales that also live in the Antarctic, or sometimes become dinner for them. These guys are the token mascots for every image that most people conjure of Antarctica. They are also heavily protected under the Marine Mammal Protection Act so part of our job when we conduct science is to ensure our science minimally impacts wildlife.

Adelie penguins in "flight"

Adelie penguins in “flight”

We worry most about our impact on marine wildlife when we conduct seismic surveys. The seismic guns deliver a low energy pulse into the water column, which may have the potential to negatively affect marine mammals if they are exposed to 180 decibels or more in the water. For that reason we have two qualified marine mammal observers, Andrea Walters and me, on-board to ensure we do not injure wildlife during our seismic gun operations. Our science party must also conduct marine mammal observations (MMO) when the ship is breaking ice in order to record how many marine mammals we might be exposing to our operations and to record how icebreaking may alter their behaviors. Icebreaking potentially produces quite a racket that can expose animals within 12 nautical miles to 120 decibels underwater. MMO during icebreaking is a new practice so the data we record will be extremely helpful in understanding how icebreaking impacts the animals. Continue reading

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2/3/2014 – Mertz Glacier Science Plan

Tasha writes:

Today marks the beginning of our sixth day underway and the crossing into the beginning of an entirely new world. We crossed 60 degrees south and have committed to continuing our travel directly south to the Mertz glacier; we expect to make it to the edge of the continental shelf on the morning of the 4th. To prepare us for our arrival in East Antarctica and for the beginning of a flurry of science that will be taking place, we listened to a couple of brief science talks about past science and our current objectives at the Mertz glacier.

And after that, we didn't let the penguins drive the boat any more...

And after that, we didn’t let the penguins drive the boat any more…

One of our objectives will be to acquire geophysical (seismic) survey data that will satisfy the requirements for future deep sediment drilling in the area. Seismic surveys will be conducted using two air guns that transmit sound pulses to the sea floor. This energy is powerful enough to penetrate 1 or 2 kilometers down into the sediment and underlying bedrock basement. When the sound waves encounter density changes in the stratigraphic layers (e.g. transitions from clay to bedrock), some of the energy reflects back up to the surface of the ocean where we have a seismic streamer (array of hydrophone receivers) that will detect the sound and record it.

Vessel telemetry, 3.5 kHz sub-bottom profiler, multibeam sonar, and other assorted toys

Vessel telemetry, 3.5 kHz sub-bottom profiler, multibeam sonar, and other assorted toys

We then translate the recorded sound to an image that will be used to create a map of the sediment layers below the seafloor. The map is based solely on the time it took for the sound to travel from the guns into the sediment and back to the receivers. These maps of the sub-bottom have many applications. Continue reading

1/28/2014 – Cruise Preparations

Tasha writes: 1-P1010284 Excitement is building now that we’re almost ready to sail. By the time you read this, in fact, we’ll probably be well underway. Research time during this cruise will be split evenly between three groups: physical oceanography, seismics, and marine geology and geophysics (MG&G). Our group, the MG&G group, is comprised of the following people. Principal Investigators:

  • Chief scientist, Dr. Amy Leventer (Colgate University)
  • Dr. Amelia Shevenell and Dr. Eugene Domack (USF) 

Graduate students:

  • Michelle Guitard, Katy Smith, and Tasha Snow (USF)
  • Kelsey Winsor (OSU)

Undergraduate students:

  • Mikhaila Redovian and Kara Vadman (Colgate University)
  • David Morgan (Hamilton College)
Gene Domack shares with the students some insights gleaned from three decades of Antarctic research. Number one: Look around. This is not Antarctica.

Gene Domack shares with the students some insights gleaned from three decades of Antarctic research. Number one: Look around. This is not Antarctica.

Since our arrival in Hobart, Tasmania, we have been steadily working together to prepare the ship for the six-week research cruise. When we first stepped onto the R/V Palmer for the cruise, we found the labs completely bare; they had just been stripped down by the outgoing science crew and were ready for the incoming group of scientists to set them up in a way that best facilitates the new research demands. That would be our primary focus for the four days before the cruise.

Core lab ready for transit. The calm before the storm.

Aft dry lab ready for transit. The calm before the storm.

We began transforming the lab on Saturday, Jan 25th, by unpacking all of our supplies: sediment sampling tools, vials and bags for carrying samples, and a cornucopia of other odds and ends that together make scientific research possible. We strategically arranged lab benches to accommodate 6-meter (20ft) long jumbo kasten cores and leaving space to move around the core in the limited lab space; the process became more of a game of Tetris than lab setup.Next, we built jumbo piston core racks as well as our magnetic susceptibility (MS) system with core tracks and electronics that will be used to measure the amount of magnetic material in the cores (like magnetite). We secured all equipment and boxes for sea by bolting down all loose tables, using ropes and bungees to tie any loose items to the table legs, and fixing any drawers that do not latch properly. This will prevent drawers from ceaselessly banging open and closed, boxes sliding around the room dumping their contents, and objects becoming missiles during heavy seas.

To wrap up our preparations for the transit south, we cleaned all of the lab benches and cabinet doors for radiocarbon, first with soap and then ethanol. Cleaning will help to prevent the radiocarbon contamination of our sediment samples that would artificially alter our radiocarbon dating measurements. After being cleaned, lab benches were covered with bench paper and our facility preparations complete. Now as we set sail on our long voyage to the East Antarctic, the lab will be ready for any sort of event we might encounter. Continue reading

11/10/2013 – Cruise Progress: Sitting Still

Tasha writes:

Like I have said before, geologists love to have their hands on rocks and sediment especially when it has come from a site with a well-recorded and fascinating geologic past. We had quite a bit of sediment to work with up until three days ago. Now our hands, nails, and faces are clean and we are left feeling a little upset. Our plan had been to go into Palmer Deep, near Palmer Station, to get some water samples then steam over to Palmer Station to pick up five scientists who would be ready to go home after a long stay in Antarctica. Then we would head to Boyd Strait to get one last core on our way home. However, our plans were thwarted.

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“So, anyone know any good chanteys?”

The wind can be unpredictably troublesome this time of year, moving large expanses of brash sea ice around the Antarctic Peninsula like a chess player moves a queen around a chess board. One day there is no sea ice, the next day the wind pushes sea ice in from a distant location and packs it in so tight it may as well be a solid sheet of impassable sea ice. That is what happened since we last pulled in and has now stopped us from making it into Palmer Deep or Palmer Station. When we began pushing through the ice yesterday morning, we made a little over a mile of progress in about six hours (pushing into the ice until it halted us, backing, then getting a little speed to push a little farther through the ice) before we just couldn’t go any farther. Continue reading

11/7/2013 – Neck Deep in Sediment, Part 1

Tasha writes:

When you are a geologist, there is no greater happiness than when you are neck deep in the mud of a well-taken core. That’s how I’ve felt for the last couple days. Alex and I have been standing 12-hour watches together from noon to midnight each day. The science party has been working non-stop, as we have few people and a whole ton of work to do.

Alex Hare (Hamilton College) at the helm

Alex Hare (Hamilton College) at the helm

In total so far, we have taken three jumbo gravity cores, a jumbo kasten core, and three regular sized kasten cores. The gravity core differs from the kasten core in having a liner within the pipe that stays around the sediments until the core is cut open in a core repository like the one we will use at Florida State University (check my last blog to learn about kasten cores). The gravity core is round, not square like the kasten, and can go much deeper into sediments because it is heavily weighted and dropped rapidly to the bottom of the ocean. It blows past the soft upper layer of sediments usually, so we take the kasten core in the same location to get a continuous sediment record.

Amelia and Tasha get ready to inspect a fresh kasten core. Gravity core in the foreground, with till on the outer barrel.

Amelia and Tasha get ready to inspect a fresh kasten core. Gravity core in the foreground, with till on the outer barrel.

Like the kasten core, there is a trick to taking a great gravity core especially in Antarctica. Here there are layers of sediment, called glacial till. Glacial till comes directly from an ice sheet that is grinding up rocks and sediments then spitting them out from the edge of the ice sheet onto the ocean floor, creating what is called a glacial fan deposit. Glacial till can be very dense sediment and may as well be concrete to a gravity core trying to penetrate into it. If the gravity core penetrates too far into the till, the core barrel will bend as if it has hit a concrete wall. Continue reading

11/3-11/4/2013 – Trials of Sea Ice and Coring

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[Check out the Facebook page for more photos that we couldn’t squeeze into the blog entry. This link to the album will work even for those without a Facebook account.]

Tasha writes:

We were at Palmer Station for almost two days. It was nice to visit the store to buy Antarctica garb, meet the Palmer occupants, and hike the glacier. Views from the top of the glacier were breathtaking: snow draped islands fringing the station; glacier scoured rock outcrops littering the island; a giant, bright blue cave leading to glacial melt under the glacier; and….large expanses of sea ice!

Blue holes are little different here than back in Florida

Blue holes are little different here than back in Florida

While at Palmer, wind blew a ton of sea ice in around our mooring and into some of the locations we planned to visit to core. This included our first stop, Palmer Deep, which is an area where an ice stream carved out a basin over 1,000 meters deep. As we soon found out, the ice would make our voyage to Palmer Deep a bit more difficult than we had hoped. Continue reading

10/31/2013 – How to Open a Research Station

[Check out the Facebook page for more photos that we couldn’t squeeze into the blog entry. This link to the album will work even for those without a Facebook account.]

Tasha writes:

Last night we completed our crossing of the Drake Passage and arrived at Livingston Island. Our purpose for being here: reopen Cape Shirreff research station for the new field season. (Amelia wrote about the similar experience of reopening the field camp at Copacabana on King George Island around this time last year.) After the briefing from yesterday, most scientists were very excited to get on land and help out. Those running the show were a little worried about the sea state and weather but decided it was good enough to get things started just after breakfast. So we all dressed down in our cold weather gear for the first time.

"Guys, this is embarrassing, but I think we all wore the same Halloween costume."

“Guys, this is embarrassing, but I think we all wore the same Halloween costume.”

We were expecting to get cold and wet in the zodiac ride to shore and get relatively warm and sweaty moving all of the supplies from the zodiac to the station. So we layer on the clothes with the water resistant Gore-tex pants and orange float coat over everything to keep dry. After dressing, we have to step through a series of decontamination rinse buckets to clean off any dirt or organisms that could be hitchhiking so that we don’t introduce new species to Antarctica.

“Non-essential” personnel were allowed onto the third trip to shore. Getting into and off of the zodiac from the ship is the largest safety hazard for us, especially with the large swells we were in. The zodiac is so much lighter than the Gould that the zodiac was rising and falling 2-4 feet more than the mother ship with each swell. That made it pretty hard to come down the ladder without getting squished between the ship and the zodiac or falling off into the water or the boat. Luckily the techs on the zodiacs were great at instructing us on when to get in safely and there were no problems.

"Okay, everybody remember: we parked the ship in the Blue Lot, Row C."

“Okay, everybody remember: we parked the ship in the Blue Lot, Row C.”

The trip from ship to shore was pretty far and took about five minutes. Being on the small zodiac, the large swells and high winds did a great job of soaking us, but with our float coats and pants we all stayed relatively dry underneath. I can, however, say that I have tasted my fair share of Antarctic seawater now. Continue reading