Scientist’s ‘dramatic’ first trip to Antarctica

As a researcher, Joshu Mountjoy​ knew going to the frozen continent was a unique and privileged experience, but seeing first-hand the “lowest sea ice coverage on record, overall for the whole of Antarctica” left him with a sense of unease.

Mountjoy, who was a Niwa scientist, has lived for the past six weeks on the research vessel Tangaroa, and his “dramatic” first trip to Antarctica found lower summer sea ice levels than expected.

During the missions, the Tangaroa travelled for 11,500km with 20 scientists and 18 crew members aboard, reaching the world’s largest marine protected area, the Ross Sea.

“We were still dealing with quite a lot of sea ice. What the guys who have been going down there for a long time were seeing is that at the entrance of the Ross Sea there used to be a sea ice bridge – that was no longer there,” Mountjoy said.

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“There is an obviously dramatic reduction in summer sea ice that seems more apparent every year. Many of the ship’s crew have been coming to the Ross Sea for over 20 years and are seeing big changes.”

The scientists aboard the vessel have been trying to establish whether the unique Antarctic ecosystem was impacted by climate change and human activities.

Mountjoy, who had never been before to Antarctica, spent most of the time on the Tangaroa, but did have one trip ashore to get samples.

“What are we measuring in Antarctica is the water that is coming out of the Ross Sea and the water that is coming back to replace it. It’s a critical engine of the ocean circulation,” he said.

As 90% of the heat on Earth was trapped in the ocean, shifts in the oceanic currents could change the climate on land, he said.

So, the melting ice sheet which would contribute to rising sea levels was not the only change happening in Antarctica.

“Climate shift could happen within countries like New Zealand as we see changes in the ocean circulation.”

However, Mountjoy said it was an “amazing” experience working around glaciers and 4000m-high peaks.

“The air is so clean. On a nice day, you can just see right into the heart of the mountain range.”

With temperatures falling to -7.5C as the Tangaroa reached Cape Wheatstone and the “freezing wind” coming down from the glacier, “pancake ice” formed on the surface of the ocean – an event that occurred as temperatures dropped below 0C and the surface of the sea started to freeze.

“When you get waves you can see through it, it’s like someone is shaking a carpet. But because you are in the ocean instead of ripples going through it, it’s an ice sheet and the waves transfer through it.

“And that just looks absolutely incredible,” he said.

But his best memory was from the last, “dead calm” morning.

“It was a beautiful blue morning, icebergs all around us and just as we are finishing a pod of orcas came past, and then as we started to move away to get back to Wellington, there were like five or six pods of each of them with a dozen orcas.

“The boat was basically surrounded by orcas everywhere. It was a once-in-a-lifetime type of stuff,” he said.

Over the six weeks, the team processed 15,000 litres of seawater, took 25 hours of video footage of the sea floor, and collected over 5000 biological specimens.

On Thursday afternoon, the Tangaroa was docked in Wellington and from Friday Mountjoy and the other scientiss will start analysing the samples and data collected, while further monitoring will provide extra information over the next two years.