ABOARD THE JOIDES RESOLUTION, IN TRANSIT TO HOBART, TASMANIA– The work of the ship ended as quickly as it started nearly two months ago. We finished drilling Site 1361 and logged the hole. The drillers tripped 3500 meters of pipe and prepped it for storage as the ship will not drill again until July – off the coast of British Columbia. Everyone on board is absolutely brain dead from the non-stop grind of 12-hour shifts day after day. But all are happy as well. We’ve completed most of our objectives and made some exciting discoveries. When we did not meet with complete success it was always because of weather and ice, either encroaching sea ice or fields of icebergs so thick that we had no chance to pass.

Relaxing with some music after the work is done.

Now we have some days in transit. These days are filled with meetings to design our post-cruise research. We will all spend much more time at home working on the cores than our actual days at sea on this expedition. Some of the methods we will employ are expensive and difficult and we have recovered nearly 2000 meters of core. This means that we must carefully select the intervals we will study, so that we can answer the most important questions about Antarctic climate change as quickly as we can. For some of us, the analytical work will extend over the next 4 years. Then other scientists will work on these cores for decades to come. They will be stored in a vast library of ocean cores in College Station, Texas, at the IODP core repository where they are available to scientists from all over the world.

What I like most about these days in transit is going off shift. I no longer set my alarm to awake at 11PM. The two shifts mingle at meals and in the labs, almost as strangers at first as they have not seen much of each other for more than 7 weeks.

The whole team for Expedition 318. Photo courtesy of John Beck, IODP.

Working groups between the shifts assemble to design research strategies and timetables. I will lead a group that will make oxygen isotopic measurements of the small shells of amoeba-like organisms called foraminifera. Forams, as we call them, live for about 4 weeks during the brief Antarctic summer. They build their tiny shells out of calcium carbonate, the main mineral that makes up limestone. By measuring the ratios of two types of oxygen in the carbonate we can tell the temperature of the water in which the forams grew. We will make these analyses on forams that were living in Antarctic surface waters hundreds, thousands, and even millions of years ago to see how warm the water was next to the Wilkes Land coast. We already know from our microscope work on board that this part of Antarctica has been very warm at times, maybe 10 to 15 degrees centigrade warmer when we go back 35 million years. The foram work will help tell us exactly how warm the waters may have been during more recent periods when we know the ice sheet became much smaller. The results will help us predict the behavior of Antarctic ice in the future.

What a trip it’s been! I hope you’ve enjoyed these blogs. If you live in the Bay Area, please look for a notice about a talk I’ll likely give on this expedition in 6 months or so, after we’ve had a chance to start the shore-based part of the work. As we pull ever closer to Hobart we are very much aware that we are simply reaching the end of the beginning.

Christina and Joerg at the bow at sunset. Photo courtesy of John Beck, IODP.

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.

Position: 66º 33’ 39’’S, 136º 59’E
Water Depth: 1000 meters
Exact Location: The Antarctic Circle

ABOARD THE JOIDES RESOLUTION, OFF THE COAST OF WILKES LAND, ANTARCTICA– Yes, we crossed the Antarctic Circle today! It is perhaps only the 3rd time this ship has ever done so. All points south of the Antarctic Circle experience at least one day every year of total darkness and likewise one day every year when the sun never completely sets. We are now in early February so the sun does set but only for 4 hours and it never gets really dark. As a member of the night shift out here, I love this…I get up at 11PM, come on shift at midnight. The sun sets around 1 AM and rises again around 5 AM. I get to see both and when the weather is good, the colors are spectacular.

Moon set behind our drilling derrick.

Dawn at 0330 in the AM.

We are now working at one of our shallow continental shelf sites, called U1358. We just finished the major site for which I am the lead scientist. This site was cored very successfully. The water is a 1000 meters deep and the spot we cored is like a big dish at the seafloor, with lots of small sediment particles drifting into it.

Here you can see the annual layers in the sediment cores we collected.

The sediments accumulate at a rate of 2 cm every year and leave an annual layer – a summer deposit made up of microscopic plants and a winter layer made up of dust and silts carried by the wind and the ice. We can see each layer and each layer represents one year. It looks as though we can count these layers back over 10,000 years. The record may not be perfectly continuous, we don’t know yet, but we do know that we have 470 meters of layered mud to work on and that it will tell how the sea ice and temperature of Antarctic surface and deep waters has changed on a year-to-year basis for many thousands of years…..

The core sampling table where this bag holds the last of more than 2300 samples taken from one Hole.

We save EVERYTHING There are more boxes on this ship than you would believe.

Everyone on board worked long hours to get this site completed, many for 18 to 20 hours each day. So, when we have a transit day to another site we get to rest, but we also have a chance to cross the Antarctic Circle. Everyone is excited and a bit relaxed, both at the same time! The weather is sunny and warm today but tonight we expect a big storm to begin, one with winds gusting to over 60 kts and waves as high as 25 feet. It might last 2 to 3 days, a problem for us as it is difficult to work in such stormy conditions. I’ll let you know how it turns out!

This is mainly the night shift at the bow of the Joides Resolution as we cross the Antarctic Circle.

Your correspondents Rob and Christina on the Antarctic Circle.

At Site U1356, Hole U1356A,
Position: 63º 18.6139’S, 135º 59.9397’E
Water Depth: 4003 meters
Core Depth (penetration into the seabed): 1004 meters
Total weight of over 3 miles of pipe hanging from the ship: >650,000 pounds!

ABOARD THE JOIDES RESOLUTION, OFF THE COAST OF WILKES LAND, ANTARCTICA– Wow! What a week! We just finished retrieving our final core from the bottom of a drill hole more than 1 km in length. We’ve now recovered and described sediments that range in age from a few million to more than 36 million years old, all in the span of about 9 days.

The first sediments that came up told us what Antarctica was like when the ice sheet was like it is today. Then we saw evidence of a much warmer time and then a colder time before that – a time when flotillas of icebergs carried rocks and debris from the Antarctic continent out over our drill site, dropping this debris as they slowly melted. Even further back in time, more than 30 million years ago, we began to find evidence of much warmer waters…and for the first time no evidence of large ice sheets.

Yours truly wearing a shirt to match the core: muds from Tasmania. Photo by Christina Riesselman.

We also began to see sediments that may have come from Tasmania or other parts of Australia. Even though we are now thousands of kilometers away from Australia, back in time, 30 million years ago, Tasmania and Antarctica were much closer, perhaps only 100’s of kilometers apart. Plate tectonics since that time has carried Australia to the north while Antarctica has remained more or less anchored at the South Pole. So, not only do our sediment cores tell us tales of past warm climates (and perhaps give us hints as to what lies ahead in our greenhouse future), they also tell us new things about the science of plate tectonics.

The weather here changes fast! Yesterday, we had a warm (well…..maybe 4°C) and sunny day – our first sunshine in over 3 weeks. After shift, EVERYONE went outside to feel the warmth of the sun and to see blue skies and blue water.

Our first sunny day on Leg 318. Vitamin D the natural way.

I was up for shift at midnight. It was calm and cloudy with snow at 4AM but by 9 AM it was blowing 35 kts and we now have waves over 20 feet high. The change in weather happened while we were retrieving our very last core.

The night shift sedimentology team working on 30 million year old sediments.

Moon set on the JOIDES Resolution, 31 Jan 2010.

Now we will spend another 2 days here doing something called “logging”. Logging the hole is when we send instruments down to the very bottom of the drill hole after we remove the metal pipe that now supports it. These instruments measure the properties of the rocks we drilled through. By doing so we can piece together the sections of sediment we actually saw and described, even across breaks in our core that may have been caused by problems with the drilling. Altogether, we usually recover about 50% of the rocks we drill through. Some of the softer or stony units just can’t be cored and recovered very easily so this kind of work, logging, is very important for us.

So, back to writing up our results and making a short video clip for you about the work in the lab – I’ll send that off tomorrow. It’s great fun out here and the time is going by very quickly, just about as fast as the short Antarctic summer…..

ABOARD THE JOIDES RESOLUTION, OFF THE COAST OF WILKES LAND, ANTARCTICA– Finally, after 11 days of transit, we are spudding into our first drill site off the coast of Antarctica. It’s 3AM and we have just finished putting nearly 4 km of drill pipe together and hanging it from the derrick in the photo. The pipe is suspended only 5 meters above the seabed. We are getting ready to retrieve the first section of a sediment core ever taken from of this site, Wilkes Land!

The JR derrick. Currently, it’s supporting nearly 4 km of drill pipe.

The whole ship is abuzz with excitement. Everyone is awake to see what we will get. We will drill up to 1400 meters below the seafloor here over the next 18 days. Will we get back to sediments deposited when Antarctica was lush and green? It seems likely at this point, but first we will examine the age and makeup of the sediments right at the seabed. They should reflect the current glacial nature of Antarctica and maybe even tell us about changes in Antarctica in the recent past, the past few thousand years. We use special tools to collect these soft upper sediments – an advanced piston corer that shoots into the mud in 10 meter sections. This very first core will be on deck in only 30 minutes. We’ll send a special 2 minute video clip for the blog to capture this historic moment. Leg 318 begins in earnest today!

Chief Scientist Ken Taylor and science tech Anais Orsi looking at layers in backlit snowpit.

A one-meter long piece of ice core illuminated with a light. The green netting on the core is used to help hold the ice together in case it spontaneously fractures.

The bubbles visible in this piece from an Antarctic ice core sample contain carbon dioxide and other gases that were trapped in the ice when formed thousands of years ago. Researchers carefully crush the piece and capture the gases that escape when the bubbles break. This allows them to better understand what carbon dioxide levels were over time.

Heidi Roop, a science technician, worked with more than 100 scientists to recover a 2-mile-long (3.5-km-long) ice core from the West Antarctica Ice Sheet (WAIS) Divide. Imagine, that’s a column of ice twice as tall as the Grand Canyon is deep! The properties of each layer of an ice core reveal a slice of climate history. The WAIS team estimates that this ice core will reveal climate changes that have happened as far back as 100,000 years, a time when woolly mammoths still walked the earth.

During the 2009–2010 season, Heidi helped the WAIS team uncover new chapters of the climate story by drilling deeper into the ice. The WAIS scientists were able to decipher the climate year by year back approximately 40,000 years and at decadal (10-year) resolution from 40,000 to 100,000 years, making it the most detailed ice core record ever collected in the Southern Hemisphere. With the ability to extract annual (1-year) to decadal climate information such as past greenhouse gas concentrations, the climate record developed from WAIS can be directly related to ice cores from Greenland. By comparing records from the Southern and Northern hemispheres, our understanding of global climate change will be more complete. The earth’s climate history will be known in more detail than ever before—and it’s bound to be an interesting story!

Standing in a polygon trough on a snowy day in Beacon Valley.

Helicopter day trip away from our main camp in Beacon Valley.

Coring of the underlying glacial ice, Beacon Valley.

Beacon Valley: home for the next 7 weeks.

Taking orientation of sand veins within the buried ice.

A collapse of the Antarctic ice sheets would raise global sea levels approximately 180 feet (60 m) with devastating consequences for near-shore and low-elevation communities. To better understand the response of the Antarctic ice sheets to future changes in climate, quantitative geomophologist Doug Kowalewski and colleagues from Boston University are working to understand the ancient climate of Antarctica and the corresponding stability of the glaciers and ice sheets. Buried alpine glacier ice was discovered two decades ago in the McMurdo Dry Valleys, a predominantly ice-free region roughly the size of Rhode Island. The buried glacier is allegedly the oldest on earth with an age of more than 8 million years; that would be almost ten times older than ice currently being cored from the Antarctic ice sheets.

If the ice is indeed that old, gases trapped within the buried glacier ice represent a potential archive of climate data stretching back to the time of the earliest hominids. Doug Kowalewski (UMass, Amherst) along with colleagues from Boston University, Brown University and Colgate spent October to December camped in Beacon Valley (77.859 S, 160.574 E) coring the alpine glacier ice. The ice cores were shipped to Boston and Princeton universities where analysis of the trapped gases will provide a more robust chronology for the glacier and provide insight about past atmospheric temperatures and precipitation.

To establish further evidence that buried glaciers can persist for over 8 million years in the dry, albeit cold environment of Antarctica, Doug conducted in-situ experiments and modeling studies to calculate the existing rate of glacier ice sublimation (the change of state from solid directly to gas, a process that slowly reduces the size of glacier and over time may eliminate the glacier completely). Doug also ran regional climate model simulations at the UMass Amherst Climate System Research Center to resolve whether sustained cold climate conditions necessary for long-term ice preservation occurred during the lifetime of the glacier specifically during warmer times in Earth’s history (episodes of higher atmospheric CO2 and increased solar radiation due to Earth’s orbital changes). For model input, Doug and his colleagues monitored atmospheric temperatures, wind speed, amount of solar radiation received, and relative humidity. Glacier ice temperatures and overlying rock and soil temperatures were monitored in Beacon Valley. These modeling efforts provide increased evidence that buried ice and a super-arid, cold-polar climate have sustained in parts of Antarctica for millions of years.

Doug Kowalewski’s field site, Beacon Valley (yellow square), sits at 1500 m in elevation and is in close proximity to the East Antarctic Ice Sheet (left of image).

But for tonight let me leave you with a few more links to some videos I’ve made:

Another video tour of the JR. During the filming of the prior clip of the F-deck, we spotted a cargo ship off the port side. This is what happens any time something different happens, be it whale, seal, porpoise, cargo ship, sunset… anything.

A walking tour to the bridge deck from the F-deck. We had to ask a question of Captain Alex, and I’ll see if you can guess the answer: How far can you see out on the horizon from the main deck? From the Bridge deck? Maybe I’ll get the Captain to explain how he arrives at his answer to this question on video later! He got called away to important business. You may notice there is a lot of magic on this ship…

This is the place where the cores first enter the labs. Lots of testing, imaging, poking, prodding and sampling take place on this deck. I’ll get into more detail soon, and show some of the indigenous scientists in their natural habitat.

A quick interview with Ivano Aiello, one of the sedimentologists on board the JOIDES Resolution for Expedition 323. He explains a bit about one of the things we are looking at (micro fossils in the sediments), and how they help us understand paleoclimate.

Sedimentologist Beth Caissie shows off the Core imaging camera and explains a bit about cleaning up the cores before making these images. Taken on the JOIDES Resolution during Expedition 323 to the Bering Sea.