Drilling at Site U1361
Position: 64º 24.6’S, 143º 53.2’E
Water Depth: 3470 meters
11 more days!

ABOARD THE JOIDES RESOLUTION, OFF THE COAST OF WILKES LAND, ANTARCTICA– Hi folks! We’ve been busy the past 9 days. We are coming to the end of our work window here in Antarctic. Summer has ended, the nights are much longer, and next Tuesday we must begin our transit back to Hobart, Australia.

We made our last attempt to get into one of our continental shelf drilling sites but were stopped once more by sea ice. All of the ice here is frozen seawater as opposed to glacial ice.

The sea ice is porous and inside the pores are salty brines that support plant and bacterial life. Here we are trying to collect so ice, but it’s a long way down to the water for this little bucket, especially when working from a moving ship.

We finished drilling deep into the seabed at Site U1359, encountering sediments and rocks that span much of the last 13 million years. For several hundred meters we found layers of rock that alternated between green and brown over distances of 2 to 4 meters. The green parts of the cycle showed evidence of intense mixing of the sediments by animals living at the seafloor while the brown parts showed something quite different – very well-developed laminations that could not have survived if the sediments were mixed. There were different materials in the layers too – some contain more shells of diatoms, the main plant in the surface waters of the ocean. We don’t yet know what these cycles of green and brown represent but we think they reflect the continued glacial-interglacial cycling of the Earth’s climate many millions of years ago.

Today we are in a very cold period in the long-term history of the Earth, and have been for most of the past several million years. Because the Earth is already quite cold, when we have glacial-interglacial cycles, we see large ice sheets coming and going at both poles – in Antarctica, Greenland, and over large parts of North America and Scandinavia. This waxing and waning of polar ice is driven by small changes in the shape of the Earth’s orbit around the sun (it changes from an ellipse to more circular and back again over about 120,000 years), the tilt of the Earth’s axis (it wobbles a bit over 40,000 years), and the exact seasonal timing of when the Earth is at its closest approach to the sun. All of these “orbital” changes impact how much sunlight reaches the Earth as well as when and where it warms the Earth seasonally. Sometimes, the Earth is in an orbital configuration that produces warm winters and cool summers – a combination that usually allows ice sheets to form and grow. Some 10’s of thousands of years later, the opposite occurs – warm summers and cool winters – which can cause ice sheets to rapidly melt. In today’s cold world, these small changes have big effects as the Polar Regions are cold enough to allow large ice sheets to form and last through the warmer periods. Antarctica has been covered in a large ice sheet for many millions of years because of this overall cooling. It still waxes and wanes along its margins but it is always present in the continent’s interior. But prior to about 2.5 million years ago, there was no permanent ice sheet in the north polar regions – it was simply too warm. Further back in time, the Antarctic ice sheet was much smaller than it is today but it was still dancing to the rhythms set by the Earth’s orbit.

What we were seeing at our last drill site and what we are looking for at our latest site is evidence of how these glacial-interglacial cycles affected the Southern Ocean and how they in turn may have been different because the planet was a little bit warmer than today. By studying this we can learn more about how small changes in the planet’s temperature can affect things like ice volume, sea ice extent, and the productivity of the ocean. This is directly relevant to understanding our Greenhouse future. Although all the climate variability that occurred millions of years ago was “natural” (in other words, not caused by people), the strength of the signal that caused these past changes (the orbital changes in this case) is not very different from the strength of the signal we expect from the man-induced increase in carbon dioxide levels in the atmosphere.

The poles are a great place to study both natural and man-induced changes in Earth’s climate because of a phenomenon called polar amplification. We know from many hundreds of studies of the past 50 million years of climate change that whenever the Earth warms up, the poles warm up more than the planet’s average. The converse is true for times of cooling. We don’t yet fully understand the reasons why but based on these studies of the past we shouldn’t be surprised that the poles are warming up very quickly today, at a rate greater than what we see in the tropics or the temperate belts. The cores we collect on this trip have the potential to tell us more about when and why polar amplification occurs.

I’ll send one more blog from this trip once we have cleared our last hole and are heading for Hobart. Sixty days is a long time to be as sea and working every day for 14 hours or more. We are all excited to get home.

I had a chance to get off the JOIDES Resolution a couple of days ago when we were running a “man overboard” drill. We recovered the dummy and then I was able to take these shots. It was our warmest, sunniest, calmest day by far. You’d never know we were in Antarctic waters.

We’ve been seeing lots of whales at our continental rise sites. The whales come to Antarctic waters in summer because of the abundance of food.

At dawn one day, we had more than 35 Humpback whales around the ship. From a distance you usually first see their spout, which you can make out here.

More storms and more icebergs. This seems to be the story around here now. Once each week we get a major blow and the seas kick up.

Then when we are near the continental shelf we see more icebergs…..

Transiting back to Site U1359
Position: 64º 34’S, 140º 30’E
Water Depth: 3700 meters
The scene outside: 2 days of storms and lots of icebergs

ABOARD THE JOIDES RESOLUTION, OFF THE COAST OF WILKES LAND, ANTARCTICA– Our latest drilling target is in an area where sediments that document the transition of Antarctica from the “Hothouse” to the “Icehouse” can be easily reached at shallow depth beneath the seafloor. We drilled for 18 hours and then had to pull the drill pipe up out of the hole and reposition the ship to avoid a large iceberg that was heading straight for us. When the iceberg had passed the weather started to deteriorate. Our forecast was for 60 kt winds and big seas so we headed north out of “iceberg city” to ride the storm out in deep water away from icebergs and sea ice. The forecast was true to its word – we had waves up to 30 feet and winds over 60 kts for more than 24 hours. But we had great iceberg viewing on the way to our WOW (Waiting On Weather) point so I’ll write something about them and how they fit in with our project.

The Antarctic ice sheet is always accumulating new snow that gradually turns to ice. For the ice sheet to remain the same size it must either melt or release ice to the ocean as icebergs. In parts of Antarctica some of the ice is in fact melting but most of the ice loss that maintains the continent at its present state occurs through the calving of icebergs. Most icebergs calve off of ice tongues and ice shelves – areas of concentrated ice flow at the coast. Imagine that the ice is draining off of the high parts of the continent by flowing down small ice drainages to form mighty rivers – but rivers of ice in this case. These vast rivers move slowly, only a few 10’s to 1000’s of meters each year. When they reach the coast, the ice flows out into the ocean where it begins to float wherever the water is deep enough. In some cases, this is where the water is over 500 meters deep and the ice is over 560 meters thick. Floating ice shelves or ice tongues are influenced by winds and ocean currents. They begin to melt if the water is warm enough but they mostly breakup to form icebergs.

Many of the icebergs here off Wilkes Land came from the Ross Ice Shelf – the world’s largest ice shelf. It is over 1500 km away in the Ross Sea but icebergs travel great distances in the Southern Ocean. The water is cold and they drift with the ocean currents, for decades in some cases. As they drift, they melt a bit below the waterline and become rounded. Sometimes they flip over and this rounded part is then visible. Icebergs often collide and gouge away at each other or they list over at an angle and slowly fall apart. This means that icebergs come in all shapes, sizes, and textures.

The biggest iceberg we’ve seen was over 20 km long.

Icebergs come in all colors, from the pure white of fresh snow to the deepest blue of pure crystalline ice from far below the surface of the ice sheet.

Icebergs come in all shapes, sizes, and textures.

A penguin on a growler (a small iceberg).

The ice at the base of the ice sheet often carries sediments: boulders, gravels, cobbles, and sands. When these parts break off and begin to float they form “dirty” bergs with dark rocky layers intermixed with the clear blue ice. The debris that falls from these dirty bergs accumulates in sediments at the seabed. When we see gravels or sands in otherwise fine-grained sediments, we know this debris was transported out over the ocean by ice. In fact, the presence or absence of ice-rafted debris is something we keep close track of in the cores we are collecting on this trip – this tells us whether Antarctica was generating lots of icebergs and therefore had at least some kind of ice sheet in the past. Conversely, when we see sediments that do not contain this debris we know we are looking at a record from a time when Antarctica was much warmer.

In the foreground, a dirty iceberg.

We’ve seen over 400 icebergs in the past 2 days.

As I write, the storm has abated and we are transiting back to our drill site.

Dawn at 4:30.

In the 1970’s, an international effort to fly ice-penetrating radar over Antarctica resulted in the first rough maps of the sub-ice world.  A ski-equipped Navy LC-130 Hercules was outfitted with radar and flown for long distances.  This reconnaissance was invaluable, but the program went by the wayside after the specially modified airplane crashed doing other work.  The concept was largely put aside until the early 1990’s when glaciologists and geologists got together and tried again.  By this point, it was clear to some that critical additional information could be obtained by including other measurements, namely gravity and magnetics to help understand the geology beneath.  Incredibly, the scientists stuffed all these instruments and a laser altimeter (we didn’t have satellite laser altimeters then) into a much smaller aircraft, a deHavilland Twin Otter.  The Otter is much cheaper to operate and supportable at temporary field camps, so it was perfect for high-resolution studies of specific problems.  

A ski-equipped LC-130 Hercules with jet assisted takeoff (JATO).

Field camps were built each season and LC-130’s delivered fuel for the Twin Otter to use.  This went on until 2001 and then again in the 2004-05 season, and many discoveries were made; however, the Twin Otter just can’t reach the deep interior without heavy support, and this has become very expensive.  Such resources are also very limited.  LC-130’s are very costly to operate, are much larger than needed for this type of work, and require a huge ground crew to support.

The Twin Otter.

The Twin Otter flying over Thwaites Glacier Remote Field Camp.

Having outstripped the capacity of Twin Otters, what next? In my next dispatch, I’ll tell you about what might seem an unlikely platform for Antarctica research: a twin engine aircraft that first saw action during World War II.

AGAP-SOUTH CAMP, ANTARCTICA– There are finally planes in the airspace of AGAP-South! We flew our first survey lines during the transit of scientists from Pole to our main camp. With the first flight, came the first observation of peaked bedrock under relatively thin ice. Thus far the radar shows the bedrock to be about 1.8 miles below the ice sheet surface and its elevation varies in some regions by up to half a mile. Hard to believe that just under this endless expanse of ice there are mountains. It’s such a secretive part of the world.

While our research group is here doing an airborne survey, another group based out of Penn State University is installing and servicing seismometers. The airborne side is called GAMBIT while the seismic side is called GAMSEIS. Together we are the AGAP project and the occupants of AGAP-South.

View across AGAP-South at one of the rare times when both planes are grounded.

Unlike the work I am here to do, GAMSEIS is a multi-year project that began last year. Over the course of the project, whenever there is a large enough earthquake, waves of energy will pass through the earth and be recorded at the GAMSEIS seismic stations. The GAMSEIS group will return and collect their seismometers along with the record of seismic events. Using those data, they’ll be able to piece together the story underlying the Gamburtsev Subglacial Mountains. We’ll better understand how the mountains were built and the nature of the mantle, the molten layer of Earth, that lies below.

This is the inside of the Jamesway tent where the scientists sleep. It’s hot, crowded but somehow still a welcome change from being outdoors.

The weather on Christmas Day forced us to take a break and enjoy the holiday. Both science teams were grounded due to low visibility caused by blowing snow coming out of the South. Despite our 24-hour schedule, dinner at AGAP is the meal most of our population of 42 actually are awake and present to eat. It falls right between the morning flight and evening flight for both science groups and those working the night shift have usually just gotten up. Although one of the cooks is suffering a rib injury, Christmas Dinner was a meal to be reckoned with. It was also a great chance for the whole camp to relax and get to know each other individually rather than categorically as science, flight crew, or staff.

For me part of the holiday excitement was that those of us on the GAMBIT side got to share some of our first data products! We’ve waiting a long time to see these radar profiles with plenty of peaks! The days ahead hold a lot of the same, but there are still firsts and discoveries to be made. I wonder when we will find the biggest mountain peaks and the biggest lake!

We have completed the familiar routine of sorting through two large orange bags of clothes. I am glad I packed alternatives to the four pairs of wool tube socks I received. I am both groggy from the jet lag and concerned about delayed traverses missing aircraft certifications and dented fuel drums. My achy back makes me fidget. The feeling in my stomach is similar to what you feel in the hours before you cast off the lines from the dock to sail across an ocean. Your head is racing plans, alternative plans and worries but time is running out. Tomorrow morning the lines will be cast off and the focus will be on the here and now.

The Gamburtsev Mountains beneath the ice.

This project to study the Gamburtsev Mountains is the biggest I have ever helped put together. For almost eight years we have been puzzling over the logistics of how to get to this hidden mountain range hidden beneath the largest ice sheet on our planet. They are completely covered with ice. Not a single craggy peak sticks up out of the ice sheet. They are tall – rising about 9000 feet above the surrounding terrain. This means the Gamburtsev Mountains tower over the Appalachians and are about as high as the Alps. They are wide – hundreds of miles wide. If a well-maintained highway cut across them it would take the better part of a day to cross them. But alas there is no highway.

The AGAP Project logo.

We have assembled a multinational team for the International Polar Year from six nations. We developed an expedition consisting of three small scientifically equipped aircraft with over 25 scientists and engineers. But we only have a very short seven weeks when the weather is warm enough to work in. Warm enough means the temperature is warmer than -50 degrees C.

Much has to happen before we can start “doing science”. The two field camps have to be constructed and the fuel to fly the aircraft and heat the buildings has to be delivered. Parts of the plan are beginning to change already. The British plans are delayed due to paperwork and the traverse has had trouble with the crevasses.

One of the partially built AGAP field camps.

The lines for this expedition have been cast from the dock. The here and now has arrived.

Cassandra and an Antarctic toothfish on 2006 AMLR fish cruise off the Antarctic Peninsula.

Yet over evolutionary time scales, spanning thousands to millions of years, Antarctic fish species have adapted to changes in their environment with success. During the second day of the SCAR conference, Karel Janko from the Czech Academy of Sciences and others demonstrated this fact during their talk entitled “Does the life history affect the ability of Antarctic fish to cope with climatic changes?” The team used population genetics to see the effect of past major climate shifts on fish populations and tried to predict what may happen in the future as we are in the midst of another major shift.

Over the past millennia, the ice sheets of Antarctica have advanced and retreated multiple times, each time drastically changing the available habitat for fish. Massive ice sheets originally form on the continent of Antarctica and grow outward toward and into the ocean. In times when the ice is expanding, it grows out over the continental shelf and due to its massive weight, it becomes grounded into the shelf. When this happens, all the benthic organisms that live on the continental shelf get pushed out and cease to thrive.

As Janko described, during glacial times when the ice shelf advances, benthic ecosystems, including fishes, are depleted whereas pelagic fishes, that don’t depend on the benthos, flourish. In contrast, during interglacial times, when there is little ice, the continental shelf is exposed and benthic ecosystems flourish, with little affect on the pelagic species. Since in the present, the ice has been retreating, we are currently in a time of benthic species expansion.

An Antarctic toothfish (Dissostichus mawsoni)

Of course, this is all on an evolutionary time scale, meaning that Antarctic fish will not likely disappear altogether. They will instead continue to evolve and adapt with some species flourishing and others dying out completely. Based on the work of Janko and others, we can guess that benthic species will have more available habitat as the ice continues to retreat, but we still don’t know the physiological effect of warming on their bodies which are adapted specifically for cold environments. Other IPY studies are looking at this and will reveal more information with regards to the future of Antarctic fish. For more information, visit http://www.ipy.org/ and click on OCEANS.

In this second video, Jeaime describes his own journey from computer technician to polar researcher and some of the outreach work he does with students in his local community of Elizabeth City, North Carolina. (Videos by Lisa Strong-Aufhauser.)

If you thought ice sheets were just large blocks of slowly melting frozen water, think again. They are dynamic, ever-changing seas of ice that grow from fallen snow at the top, move in ice streams, lurch suddenly in “ice quakes” and flow toward the ocean where they break off in calving events, both large and small.

Ice sheets are also one of the “black boxes” of climate change, because scientists don’t know how they will respond to global warming or even have detailed information about the normal range of their dynamic behavior. It’s important to understand how stable, or unstable, ice sheets are in a warming world because their loss could mean catastrophic sea level rise that would flood world-wide coastal communities.

CReSIS is an international, 10-year project funded by the National Science Foundation to gather data about ice sheet dynamics using an arsenal of tools from satellite imaging, to airplance instrument surveys, to research on the ground. The research in Ilulissat is centered on surface mapping and ice-mass balance using a suite of instruments on a twin-engine airplane, the Kenn Borek Twin Otter.

In this video, we talk with Earl Frederick of NASA about the ice-mapping flights over the Greenland Ice Sheet. Stay tuned for an interview with Jeaime Powell, a member of the data-analysis team from Elizabeth City State University, a partner with the University of Kansas. (Video by Lisa Strong-Aufhauser.)