Monday, 7 July 2014

Life above the subduction zone... by Sev Kender

A quick photo opportunity after a nice meal in the sun. From top left:
Gemma Maxwell, Kathie Marsaglia, Cees van der Land, Clara Sena
Da Silva, Tony Morris, Frank Tepley III, Vincent Percuoco, Me,
Martin Neuhaus, Philipp Brandl, Adam Bogus, and Alissa Stephens.
Off the coast of Japan, in the Philippine Sea, a team of researchers are exploring the great subduction zones in the western Pacific, specifically that of the Izu-Bonin-Mariana (IBM) system. Here Sev Kender, from BGS and the University of Nottingham, tells us what life is like aboard ship (as a storm approaches!) and what they are working to achieve...

Big science, big questions

I have been travelling on the IODP drillship JOIDES Resolution for five weeks out of a two-month expedition to the Philippine Sea. We are drilling one deep hole into the Earth’s crust underneath a layer of sediments more than 1 km thick. Our aims are to understand the age of the crust, and the evolution of this crust since it formed. So far, estimates of the age of the crust vary hugely, from about 55 to 100 million years old, so we are hoping to solve that one soon. As it happens, this location is fairly near to the fossilized remnants of the early Mariana Trench, an oceanic trench system in the west Pacific where one plate is being subducted to the core underneath the other. The trench is incredibly large, and contains the deepest point on Earth – the Challenger Deep. The big science question is how did the subduction zone form, and we are going to analyse the sedimentological characteristics during the subduction initiation which occurred much nearer to this site than today (further details of the science can be found here.)


Me sitting at a microscope desk during IODP Expedition 351
Some of us on board, including myself, are also really interested in what happened to the oceanography and climate back through time, and I am hoping for some interesting sediment records passing through critical boundaries in earth’s climate in the past.
As part of the palaeontology team, my job on the ship is to tell the age of the sediments as we drill through them, by identifying key species that only lived at certain times in the past. My microfossil group is the foraminifera, which are single-celled protists living both on the sea floor, and making up the floating plankton in the ocean. They secrete shells that are usually well-preserved in sediments. Each time a core barrel of sediment is brought up on deck, it measures something less than 10 m depending on the recovery, which relies on the sediment hardness and consolidation. At the bottom of each core, a metal device that holds the core from falling out – a ‘core catcher’ – is filled with some sediment and it is this that the palaeontologists analyse as quickly as possible. 

Two micropalaeontologists Alex Bandini and myself taking
in the view of the Philippine Sea

The sediment is analysed for three fossil groups on this ship, by the four micropalaeontologists on board. These are the foraminifera (me), the radiolarians (Alex Bandini), and the calcareous nannofossils (Rodrigo Guerra and Mohammed Aljahdali) (see scientists profiles here). Each time the driller broadcasts “core on deck, core on deck”, one of us (there are two on each 12 hour shift) goes outside to receive the sample and brings it straight into the Palaeo Lab. I process my part of the sample by washing it over a sieve to retain the sand-sized fraction, put it in the oven, and search through it under a binocular microscope. The hard work comes when there are lots of species that I haven’t seen before, and I’m frantically searching the large collection of literature here on the ship, or Google, to tie down the designation and age determination. It is inevitable that I won’t have seen all the species before, as we are traversing at least 50 million years of sediment and a LOT of evolution has happened in that time. For perspective, there are over a quarter of a million species of foraminifera recognized since their Precambrian emergence.


A view of the JOIDES Resolution drill floor, where
roughnecks and roustabouts work very hard to set
up the drilling equipment
The excitement comes when we hit significant sedimentological and time boundaries. For instance, when we finally passed into the Eocene, the Co-chief Scientist was in the Palaeo Lab waiting to hear. It didn’t take long for the buzz to pass around the ship, and there was a round of applause at the cross-over meeting. I am hoping there will be cheers (and not crying) when (if?) we hit the crust.

Having fun (keeping sane?) on the ship

Life on this ship is, well, different. It is hard to imagine what two months on a ship is like before you get here. There is, above all, a good sense of comradeship as everyone is away from loved ones and it is really easy to make friends. And there are a lot of people to talk to, 110 of us on board. For the most part, there is a mixture of work (lab, microscope) and food/tea breaks. We need to be on shift at 12 until 24 (or the opposite for the other half on the night shift). We eat before and after coming on shift, and also at 6 pm. Then there are tea breaks at 3 and 9 pm. So there is a lot of chatting and eating, and discussions include absolutely everything you can imagine, not just the science. All the food is made for us in a really nice mess area, and we eat outside every time the weather is nice which it has been for the last 3 weeks. My favorite meal is probably the slow roasted pork, but they also make an awesome burger.

After shift or before, there are just a couple of hours to fill and so there is a gym, a cinema room, and a lounge area with some musical instruments and books. The World Cup has been playing throughout the trip so far, which has been really exciting especially as there are so many nationalities on board. There are also deck chairs on the top deck, where we have spent a few evenings lately playing the guitar and watching the shooting stars and the Milky Way.


Frank Tepley III comes storming in for a famous victory,
in the great treasure hunt play-off final.

During the ‘casing’ of the hole (a way of stabilizing a hole before coring deeper), there was a two-week period of no new cores and so we had quite a bit of down time. Several things took place to fill the time, which included science seminars, photoshop and illustrator classes, and a treasure hunt organized by the Staff Scientist, Yeoperson, and Teacher at Sea. We spent hours hunting around areas of the ship we had never been to before, trying to collect stamps and answer questions related to the ship. It was a good way to speak to some of the drilling, support and catering staff that we rarely come into much contact with. The night and day shifts drew the contest, after something of a controversy that seemed quite important at the time, and so a play-off was sprung on us one morning. All personal belongings (and dignity?) were left in the lab, as we headed to the helideck for a series of childhood games including an egg-and-spoon race, ‘cookie-on-your-face’ contest and more. Other events that have occurred over the past few weeks include 2 dance parties, an Independence Day banquet, and two outside barbeques.

Forecast

‘Super’ typhoon Neoguri building in the southern Philippine Sea.
Our coring location (white circle) is just to the north of the green
outer margins of the typhoon, which is heading north-west,
as we are sailing directly east!
We are rapidly approaching the basement, and in the next week or so should have some understanding how successful this expedition has been. There is, however, a dirty great big storm (Typhoon Neoguri) heading directly at us as I write. We are currently taking a few days off, travelling east to avoid the worst of the storm. Let’s hope the storm doesn’t change direction unexpectedly…

Keeping in touch

It can be very tiring at times being away from friends and family for so long. Most days are great but you can become a little sensitive at times especially if you haven’t slept so well or something went wrong in the lab. So, luckily, we have limited connectivity to the internet and one machine with Skype on it for video calling. We also put up pictures around the lab to remind us of home, play our favorite music in the lab, and I have brought some things from including Marmite and Twinings tea.

Back to basics, why are we here?

A benthic foraminifera in thin section, collected from one of the
cores that contained coarse sands. This ‘giant’ single-celled
foraminifera (about 0.5 cm across) would have housed symbiotic
algae in the numerous chambers in its shell, and would therefore
have lived on a reef within the reaches of sunlight.
The International Ocean Discovery Program (IODP) is probably the largest international collaborative science project ever. Since the 1960’s, the organisation has sent ships and scientists circling the earth drilling ocean sediment cores throughout all the world’s oceans. The science that has emerged has revolutionized, amongst others, the fields of palaeoclimatology, palaeomagnetism, biostratigraphy and marine plankton evolution, our understanding of the oceanic crust, and microbiological activity within the ‘deep biosphere’. Despite this there is still much to do, and the international funding bodies (largely, but not exclusively, from the USA, Europe and Japan) have recently agreed the next 10-year plan. For instance, the Arctic and Antarctic are primary objectives now, as we know relatively little about their history and yet they are so vulnerable.
Scientists from each of the countries funding the project can apply to sail, and after a competitive assessment process the invitation letters are sent out about 12 months before sailing. Last minute calls are common though, as scientists commonly have to drop out for many reasons.

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