Sheer size is one of the few things we know for sure about the Weddell Sea. It's vast. A proposed sanctuary area alone is five times the area of Germany.

And in winter, 75 percent of the sea's entire surface is covered in ice. It's hard to get to and hard to get about once you're there. As a result, scientific research is thin on the ground.

It is the realm of the penguin and myriad marine species but it is not yet the realm of man, and many want to keep it that way.

The more information the team can gather, the better the chances of winning protection for these unique waters.

So relief all round when on the second attempt, after three days of negotiating the encroaching sea ice, the Arctic Sunrise found a way through and reached the beginning of the proposed marine protected area.

One of the global stories of the moment is plastics in the world's oceans, and the team wants to find out if any plastic microfibres have found their way into the frozen south.

Samples of water

In the evening sun, the wave crests glint gold and red as we jump on board one the ship's rigid inflatable boats (RIBS) to begin taking samples of water.

"These are some of the remotest waters on earth, so it will be very interesting to see what we find," said Grant Oakes, the ship's logistics officer.

"Plastic microfibres can be found in all manner of clothing and other household items - even carpets. So we're just sampling the sea surface, basically filling jars of water."

These samples will be taken back to Exeter University in the UK for further analysis.

Scoops of snow are also bottled from different locations.

"The irony is there's a lot of plastic involved in the production of Gortex and outdoor clothing," said Grant.

"And, of course, the Antarctic is awash with Gortex, from all the tourists and expedition personnel, including our own. So we have to be very careful not contaminate the samples."

And it is of crucial importance to fully understand the level of human impact here.

The Weddell Sea is bursting with life but these ecosystems are extremely fragile.

Small submarine

During the first leg of the expedition, the team launched a small submarine down to a previously unexplored part of the seabed.

They found an abundance of rare and vulnerable species from starfish to corals.

Susanne Lockhart, an Antarctic specialist, was on board. "There was 100 percent coverage of the sea floor of organisms," she said.

"It has great 3D structure, which allows other organisms to come and live. And really interesting species composition.

"All of these factors make it really difficult for a community to recover after a disturbance such as bottom fishing. We call these areas vulnerable marine ecosystems."

Experts say climate change has already affected the seas around Antarctica, warming some coastal waters.

The research data will help form a base of knowledge about how resilient, or not, these unique species may be in a time of ocean change.

And it will form a significant part of the case when the sanctuary proposal will be assessed by the governing body of Antarctic nations in October this year.