Antarctic ice kept with chips and peas in Bourne
How does Antarctic ice destined for vital climate research end up in a massive fridge in Lincolnshire - next to bags of frozen peas and oven chips?
Scientists at the Cambridge-based British Antarctic Survey (BAS) have been shipping back samples from the Antarctic Peninsula for 35 years, but with limited space in their own chilled laboratories the best option for halting the melting process is a cold storage warehouse.
Here, samples share space with groceries destined for supermarket freezers.
The warehouse on an industrial estate in Bourne, Lincolnshire, marks the end of a journey that begins about 15,000km (9,300 miles) away.
BAS scientists drill up to 1,000m (3,300ft) deep into the Antarctic ice, recovering cores - cylindrical samples of ice - some of which fell as snow more than 150,000 years ago.
These are packed in polythene tubes in insulated boxes, and stored in underground caverns cut into the ice before being flown to Rothera or Halley, two BAS Antarctic research stations accessible by ship.
Here they are kept in refrigerated containers at about -22C (-7.5F).
They are sent back to the UK in April on the final ship to sail before the winter weather sets in and makes access impossible.
The RRS Ernest Shackleton brings them back, usually docking at Immingham, in North East Lincolnshire.
The refrigerated container then travels by lorry to the cold storage warehouse in Bourne.
About 550 boxes the size of tea chests, containing about 4,000m (13,000ft) of ice cores, are currently stored with frozen food there.
Samples are regularly sent from there to BAS's Cambridge laboratories.
"Each one metre-long, 10cm diameter core is measured electronically to count the number of annual layers in the ice to date it, and also to see how much snow falls each year," said BAS's ice-coring chemist Dr Robert Mulvaney.
"This helps us understand how the climate has been changing over the whole region in the last 100 years."
The cores, collected mainly from the Antarctic Peninsula, the West Antarctic Ice Sheet and in Dronning Maud Land, can help show scientists "how the local climate responds to the global change in climate", Dr Mulvaney said.
"We are recording the warming in temperature and an increase in annual snowfall as a warmer atmosphere holds more water vapour."
Part of each sample, known as the "archive half" is then sent back to the Bourne unit.
'Chicken, chips and peas'
"At some point in the future we'll make other measurements on those. We don't know what yet, but we like to store some of the ice from each core for the future," Dr Mulvaney said.
Laboratory manager Emily Ludlow said: "Bourne is storing all our ice at the moment. We're definitely sharing it with frozen chips, frozen chicken, frozen peas and all sorts of ice cream.
"Occasionally they don't bring back quite what we want."
Dr Mulvaney added: "One box of ice cores came back accompanied by a load of ice cream.
Not every part of every core sample is used for research or put in storage, however.
"It's quite hard work collecting all of this ice, so sometimes if we reach some kind of milestone we might all just sit back, and have a whisky with a tiny fragment of ice that's broken off the core," Dr Mulvaney admitted.