‘Core is on the floor’ is the what we hear through the intercom system on the ship, every time when a new piece of sediment floor comes up from the seafloor. What happens after the announcement is a highly streamlined sequence of steps. First the IODP technicians go out on the catwalk (see picture), where they put the core on racks, label it, and cut it in pieces.
The catwalk is where the core first arrives. Normally it is an open space, but since it is quite cold down here off Antarctica, they put up a nice little wall to give the technicians some shelter from the cold wind.
From there it goes inside the ship and is left alone for some hours to equilibrate. Then it gets put through a series of so-called track systems, where the physical properties of the sediment are measured. After this, the core is split into two halves – a working half and an archive half. The archive half goes to the sedimentologists, who take pictures of it and describe what type of sediment we found, what colour it has, and what the likely depositional environment was. The working half is used by the palaeomagnetists to measure the magnetic field, which helps us to figure out the age of the core. A complimentary way to find out about the age is to look at the palaeontology in the core (diatoms, radiolarian, dynoflagellates, foraminifera, nannofossil). This is done by another group of people on the ship. They prepare slides and then look at them through the microscope. Finally we, the geochemists, take a sample for determining the amount of carbonate in the core, as well as the elemental composition of the sediment. All this sampling happens on the ‘sampling table’ (see picture). Afterwards the cores are wrapped and stored away.
James Bendle (organic geochemist, Glasgow) during his sampling shift, taking samples for all other scientists from the core on the sampling table (photo credit: Christina Riesselmann).
We are currently drilling our last Site for this expedition. We are recovering a very nice looking record of the more recent past of Antarctica (i.e., the past few million years). Our last attempt to go to the shelf failed yesterday, as the ice is moving in for the winter. Hence the only thing left to do is to drill a bit further offshore. Soon we will start wrapping up all our analyses, finalize the reports we have to write, and pack things away for our return to shore. It has been a long cruise, but I could still stay out for longer. It is simply amazing how much cool science you can get done on the Joides Resolution with all its analytical capabilities, the drilling crew, the IODP technician, and thirty scientist, focusing on one single goal: to make this expedition a scientific success. And we succeeded big time!
Below you can see a picture of our ship track on the Antarctic shelf over the past few days. The curly line is the result of quite difficult ice conditions with huge icebergs and some sea ice in the area where our targeted drill sites are. Earlier this week we had to sit out a storm, caused by a significant low pressure system going through the area. This was done away from the shelf, where there is only very little ice, making it a safer place to be in rough seas. On Tuesday we started the journey back to the continental shelf, to drill some more material that tells us about the transition from the Greenhouse world into the icehouse world. On the shelf this transition can be found in only a few hundred meters depth below the seafloor (ice advances and retreats over the past ~34 million years have scraped off the younger deposits from the shallow ocean floor). In contrast, at the deep water site where we drilled first, the Greenhouse-icehouse transition was down at ~900m below the seafloor.
Ship's track over the last few days.
Our ship’s track is such a wiggly line, as we had to find our way through a lot of ice. The captain and the ship’s crew are doing a fantastic job, in trying to get us back on site, but drilling on the shelf of Antarctica is not a trivial task. We are lucky that we recovered some amazing cores already, and we still hope to get some more. However, the weather window (it is summer down here at the moment) will close eventually, and most of our targeted drill sites will be covered with ice for the winter. But we have about two weeks of science time left before we will return to Hobart (Tasmania). Keep your fingers crossed that we not only get more wonderful sunny days with gorgeous icebergs, but that the icebergs stay far enough away from us so that we can continue our scientific mission and get more spectacular core material!
My colleagues Masao Iwai (Japan, paleontologist) and Masako Yamane (Japan, sedimentologist) enjoy the nice weather today. In the background you can see icebergs, which are grounded on the continental shelf, as well as the Antarctic ice sheet.
I have been writing a lot about the excitement of being at sea. This post will be dedicated to giving you some impression on how life aboard the ship (the Joides Resolution) feels like.
Below you can see a picture of the cabin I am sharing with one of my female colleagues. We are lucky in that we scored one of the biggest cabins with a private bathroom. For most other scientists the cabins are significantly smaller and the bathroom is shared with another cabin. I am sleeping in the lower bunk and find it quite comfortable. The only downside of our cabin is that we do not have a window! From the beginning of the expedition on I started getting into a routine of visiting the gym every other day. It is good enough equipped that everybody can find some of their favorite machines for workout. Moreover, we are very fortunate that we have a great Yoga teacher on board (Paleomagnetist Lisa Tauxe). She gives Yoga classes every other night at 1am, which is right after the end of my shift. I am not going every time, but it is the best thing to do after a tiring shift, and Lisa is simply fantastic in monitoring the different levels of abilities in the group and adjusting her program accordingly.
Our cabin - quite a lot of space for a ship!
The first trip after waking up in the morning is usually to the mess. The mess on a ship is the place where people eat – just like a cafeteria back home. Our mess is quite spacious and offers place for about 40 people to eat at the same time. There is a coffee machine, an ice machine, a fridge, a toaster, a microwave, soda machines, and a constant supply of cereals and deserts. Food is served four times a day by the galley (kitchen) personal: 5 – 7 am/pm and 11 – 1 am/pm. During these times the mess becomes the social hot spot of the ship, where besides eating also a lot of information exchange happens (just like in the real world). The quality of the food is reasonable, but by now we are out of fresh stuff, and the same dishes tend to reappear on the menu…
Mess hall - this is where we take all our meals.
Arguably one of the best thing about life on the ship is that we do not have to do our own laundry or cleaning of the cabins! We can leave laundry bags with dirty laundry outside our cabin, and some 12 hours later the bag comes back with clean and folded laundry – heaven for people like me who hate doing laundry. A big thank you to the stewards doing the work on the ship.
This week we finished our first drill site, which was Site WLRIS07 on the map. The primary science objective for this site was to recover a distal record of the first arrival of glaciers to the eastern Wilkes Land margin. This is thought to represent the Earth’s transition from a ‘Greenhouse world’ to an ‘Icehouse world’ some 33 million years ago. We drilled the seafloor in 4000m water depth and recovered sediments from down to about 1000m. The material is truly spectacular: we recovered sediments from about ten different lithostratigraphic units ranging from very biogenic material over glacial deposits to very clay-rich material. We also found layers which were very rich in ice-rafted debris. Most of the material is of Miocene age (~5 to 23 million years), but we also found some older material (Oligocene and Eocene). Stay tuned and follow all the science results to come out over the next years – I am sure they will bring our understanding on Antarctic glaciation to a new level!
Map with locations where we plan to drill during the Wilkes Land IODP expedition.
After completion of drilling at Site WLRIS07 we collected all the drill pipe and moved over to the continental shelf. Under bright blue sky we arrived at Site ADEL01B, where we are currently drilling in a place where a lot of sediment was deposited very fast over the past ~10,000 years. This project was an add on to the original drilling proposal, and has the objective to recover a high-resolution record of the Holocene (the past 10,000 years). So far things are going well.
My personal highlight was that for the past two days we could see the Antarctic ice sheet. We are only about 30 miles off the coast of the continent. Due to the spectacular weather we can actually see the continent, and a large number of icebergs grounded right in front of it (see picture) – I will remember this view for a long time to come …
View on the Antarctic ice sheet with icebergs in front of it - what a day! Photo credit: Dan Brinkhuis.
The wildlife highlight of the last days was the sighting of my first penguin (see picture).
I had seen penguins before, sitting on icebergs in the distance, but with cheap cameras (like mine) these penguins only show up as black dots on a white berg. This penguin however was different. He was swimming very close by the ship, and thanks to an announcement of the captain, everybody who was awake got a chance to run outside and see it. The little guy was swimming up and down the side the ship, giving us a proper show – very cute!
Lonely penguin. Photo credit: Ursula Röhl.
Scientifically we are making great progress. We are still on our first site, drilling deeper and deeper into the ocean floor. We passed today the depth of 700 meter below the seafloor. Our target for this drill site is to get all the way down to the Eocene-Oligocene boundary, which happened some 33 million years ago. This was when ice first covered the entire Antarctic continent. Before than there was a so-called greenhouse world with lots of vegetation on the continent and very warm temperatures in the ocean around Antarctica. If we are lucky we may see this transition tomorrow in >800 m below the seafloor.
But since nobody has drilled that deep in this location we just won’t know until we get there. Things are going very well and we have been recovering some amazing core material. Everybody is very excited and in a good mood.
The first hole we tried to drill off Antarctica did not like us too much and we had to abandon it. After collecting the pipes going down from the ship to about 3700m water depths, we moved to another Site not too far away, but in a different depositional environment. We tripped the pipes again (to about 3900m; see video for one piece of pipe going down), and got our first core on deck at 2 am tonight. It seems that conditions at this new location are much more favorable for successful drilling, and we are making fast progress down the hole! The routine operation is now rolling and the ship’s crew is just amazing in doing all the hard work for us.
When a core comes on deck, it is cut by the IODP technician in pieces (sections). Each of these pieces is sealed with end caps, labeled carefully, and carried inside the ship. After a four hour period of equilibration (waiting) the core is taken through the various machines to measure its physical properties, and cut in two halves. One of these halves (the archive half) is used to describe the material; a job done by the sedimentologists. The other half (working half) is then subjected to sampling for palaeomagnetics, palaeontology, and geochemistry. Everybody from the science team has to help for two hours per day to do the sampling for everybody else. It is a fun moment when all the different groups of scientists are gathered around the sampling table and decide where to take the samples for the shipboard analyses we want to carry out. Palaeomagnetics and palaeontology will tell us about the age of the sediment and geochemistry and sedimentology will give us a first idea on the composition of the material, how it was deposited, and where it was coming from.
After the sampling is completed, the core is packed up and stored away. We will only see it again at our post-cruise sampling party. This is a meeting, which takes place typically a few months after the end of the cruise at one of the three IODP core repository in the US, Germany or Japan. All scientists meet again to take personal samples for individual research projects. Sometimes this sampling already happens on the ship, but in our case we will postpone it to a later point. The material we are recovering from off Antarctica is very precious, and we want to carefully think about our subsamples, before taking them.
The most used quote on the ship: ‘We are currently drilling where no drill bit has gone before.’ Exciting times …
When I got up yesterday morning the labs were emptied out – everybody seemed to be outside. Soon I learned that we were passing by some quite spectacular icebergs. In the photo you can see just one of those bergs. According to our ice specialist Diego Mello we saw bergs of every possible shape, and the excitement hold up for most of the day. If you check out other blogs on the expedition (www.joidesresolution.org) you will see more bergs. The sea has been very calm over the last few days, but the fog prevented more spectacular pictures. Unfortunately the massive presence of icebergs around our first targeted drill site (‘bergy water’ is the term Diego uses) forced the captain to make the decision that drilling on the shelf was not feasible at this point. So the ship turned around and we started heading towards another drill site, more distal from the ice margin, where we arrived this morning. The crew is working very hard to get all ready for drilling and if things go well we should have the first core on deck tonight!
Talking about icebergs is a good starting point to fold in some exciting science we are going to do out here. Icebergs are pretty picture objects, especially when they are all white and shiny. The bergs that I am interested in however are ‘dirty’ icebergs. They carry ice-rafted debris (IRD), picked up from the continents where the icebergs break off the ice shield or outlet glaciers (see schematic drawing).
Most of the Antarctic continent, an area larger than 50 x the UK, is covered by ice. This ice is divided in two distinct units: the East Antarctic Ice Sheet (EAIS) covering most of the continent, and the roughly eight times smaller West Antarctic Ice Sheet (WAIS). Both ice sheets are separated by the Transantarctic Mountains. Together a water mass is locked up on Antarctica that if melted would be equivalent to a sea level rise of ~60 m. From the study of marine sediments we know that today’s situation on Antarctica with ice cover all over the continent is just a snapshot in the geological history, which has been characterized by the transition from an ice-free “Greenhouse world” more than 40 million years ago, to the present “Icehouse world” with ice caps on both poles. While there is clear signs for present day melting of the WAIS, the EAIS may stay stable for a bit longer. If future temperatures however rise more than a few degrees centigrade from now, there is potential for the large EAIS to become unstable as well. We can study the behavior of this large ice sheet under warming conditions by looking into the record of the past. The most powerful way to do so is to study sediments deposited at the bottom of the ocean –exactly what we try to drill during IODP expedition 318 to Wilkes Land.
I am particularly interested in the record of Ice-Rafted Debris (IRD) around East Antarctica. Studying the layers of past IRD opens a window to explore which parts of the East Antarctic ice margin became unstable under certain environmental conditions. This can be done by matching the chemical signature of IRD from drilled sediment cores with known Antarctic geology. This work is done in collaboration with a team of researchers from Lamont-Doherty Earth Observatory and Imperial College London. If you want to know more, a paper about the topic is going to come out in the next few weeks in the journal Earth and Planetary Science Letters.
This morning at 9:20 am we past 60°S. We have been making very good progress on our transit and detailed planning for the first drill site on the shelf has began. We hope to arrive at site on Monday. This morning at 4 am the first iceberg was sighted. Unfortunately I was asleep, but there will be more to come…
IODP expedition 318 chemistry/microbiology team
By now everybody on the ship is eager to get started – a week of transit is a long time although we have been busy setting up the labs, working out our sampling strategies, and attending science talks. It is quite fascinating to see how diverse the background of all the scientists is. Focusing all these minds on one single science objective is what makes IODP expeditions quite unique. We are all part of a big ‘machinery’ that will guarantee that by the time we leave the ship there is a full science report and data documentation for every singly bit of core we will have drilled during this expedition. This of course also means that everybody has a designated position on board. There are two co-chief scientists, one expedition project manager (IODP staff scientist), ten sedimentologists, four paleontologists (expertise in diatoms, radiolaria, foraminifera), four experts in physical properties of sediments, three geochemists, two logging scientists, two paleomagnetists, two palynologists, and one microbiologists (on top of that there is 27 IODP staff who help us accomplish our science on board, 52 Transocean crew members to operate the ship and 15 catering crew members).
I am sailing as an inorganic geochemist, and my job will be to analyse and interpret interstitial waters we will squeeze out of the sediment, as well as looking at the geochemistry of sediment samples. My shift for the rest of the expedition will be from noon to midnight, and my colleague Francisco Jimenez-Espejo (Spain/Japan) will do the same job while I am asleep. Our geochemistry/microbiology team is completed by James Bendle (Organic Geochemistry, UK) and Stephanie Carr (Microbiology, US). Below you can see a picture of our floating laboratory geochemistry team, including the two IODP chemistry laboratory technicians (Chieh Peng and David Houpt). The analytical capabilities we have out here in our floating laboratory are really amazing – there are thirteen (13!) analytical instruments in our lab including gas chromatographs (GC), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and x-ray diffraction (XRD). The analyses we can make in the chemistry laboratory range from water chemistry over sediment and rock geochemistry to organic chemistry. The main reason however why the geochemistry lab must be staffed 24/7 is that we routinely do gas safety monitoring for the drilling operations.
A cool little detail is that we have balances in the lab which are specifically designed to make precise measurements on a moving ship. Two of them can carry out measurements down to 10 microgram precision (and wobble around all the time) and the other six are operated in pairs of two to yield weight differences with a precision of about 10 milligram (second video – explained by David Houpt).
After we left the ‘roaring fourties’ behind, we are currently making slow progress in the ‘screaming fifties’ to avoid the worst of a low pressure system to the south of us. Although the video looks quite nice, the waves are actually very high and the boat rolls around significantly (up to 60 knots winds and swells of 20 ft).
