A tale of RICE

When is RICE not small, white and delicious? When it is an acronym used to stand for Ice Coring in the Antarctic. The Roosevelt Island Climate Evolution project

is an international collaboration between New Zealand, USA, Denmark, United Kingdom, Germany, Australia, Italy, China, and Sweden. The aim of the project is to recover a 750 m deep ice core from Roosevelt Island in Antarctica to determine the stability of the Ross Ice Shelf and West Antarctica in a warming world.” – VUW RICE Project

The ice cores extracted come back to NZ’s very own capital city, Wellington, for processing and safe keeping. Last week I went for a tour of the GNS science facilities where the science-ing takes place, as part of the VUWAE symposium. I came out with chilled toes, a huge smile, and a far better understanding of how an ice drilling project actually works, from start to finish.

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The starting point that is so often overlooked in these ice coring projects begins far before any logistics are settled for actually getting to the Ice. Before you can contemplate drilling, you need a drill. The Antarctic Research Centre at Victoria University are fortunate to have their very own engineer as part of the team: Darcy Mandeno is the man in charge of creating the equipment that allows the project to go ahead. He gave a most insightful presentation on the first day of the symposium, explaining how computer modelling (CAD) helps him to hone his concepts, before the fine task of machining comes into play. Antarctica is such an isolated environment, and the field season is relatively short, so it is imperative that all the equipment used in an operation like RICE works well, and works the first time. There is no hardware store or handy milling machine just up the road to make modification at the field site!

Once the field coring site has been finalised and the team have been dropped there, there is still plenty to do before the coring itself can start. Dr Nancy Bertler gave us an introduction to the process. Digging is the order of the day, for the first few days at least: a makeshift lab needs to be created in which to process the cores as they come up from below. Then it’s time to actually drill into the ice. Down in Antarctica, as much lubricating fluid as possible is wiped off as each core comes to the surface, before they are carefully labelled and stored. The cores are actually stored in a freezer, which may sound counter-intuitive, but they need to be kept below -18 degrees Celsius at all times in order to keep the gasses intact for later analysis.

Screen Shot 2014-11-05 at 10.48.45 AMThat analysis takes place at the National Isotope Centre in Wellington, and at a range of other labs around the world once the cores have been cut into sections vertically and processed. Of course, they actually have to get to Wellington first; come the end of the season, it’s time for the epic journey north. First, the cores are airlifted to Scott Base, where they are packed into refrigerated containers to be shipped to Lyttelton. The containers are chilled to well below 30 degrees to create a buffer in case of any power failure – they must not reach the 18 degree threshold, even if the roughest Southern ocean storms take out the power on board the ship. Once on NZ soil, the ice cores still need to be driven up the coast of the South Island, enjoy a trip on the Cook Strait ferry, and then make one final drive up to Lower Hutt. Darcy was happy to serve as the official chauffeur on the last scenic leg through NZ!

During our visit, the cores were safe in the GNS Science cold store facility. The ‘warm’ cold room is kept at -20 degrees, and that is where the cores are cut into cross sections and put in the ‘cheese grater’ machine to release the ancient gasses trapped within air bubbles in the ice. The ‘cold’ cold room is a brisk -35 degrees; while I was assured that bunny boots and parkas make all the difference, Nancy did admit that there is little you can do about your fingers get cold – colder than in Antarctica itself! RICE went as deep as 750m down and as far back as 30,000 years, so it was a marathon effort, spanning 3 field seasons, with another 2 years of analytical measurements and synthesis to follow. When we visited, the grad students in Nancy’s lab had just finished processing the core the day before, which was a temporary relief, but they still have plenty of analysis ahead of them.

Screen Shot 2014-11-05 at 10.48.12 AMIt’s all for a good cause though, as the ice cores collected provide a wealth of data about past climate and conditions. They’re an archive that stretches back hundreds of thousands of years, and as they are analysed they unlock more and more information about the world we live in.

Having heard the story of how an ice core is planned, extracted, analysed and stored, and having risked frozen toes to learn more from the experts in their freezer, ‘rice’ will never seem the same again.

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