On ice: part one

An unexpected threat to Antarctica’s unique species (9 minute read)

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I’m trudging along a narrow path, stones crunching beneath my heavy boots. To my right, the land falls steeply away, so I’m taking care where I place my steps. If I lift my head, I see bare rock all around me. At the base of the slope, there’s an expanse of ice, stretching in an unbroken plain until it reaches distant mountains. I can see no signs of life.

If I look long enough, I might spot something which looks like a tiny black slug on the ice – a distant Weddell seal. Perhaps I might hear the call of a skua, lower pitched than a seagull but higher than an albatross. I’m too far south for penguins to be a common sight, and there’s no chance of spotting a green leaf anywhere around here.

But I know where to look for signs of life. As I trudge along the path (there’s no other pace in these boots), I keep my eyes on the rocks to my left. There it is – a flash of yellow among grey and red rock. It’s a lichen, a delicate crust of living tissue on the rocks, and it must have been growing here for hundreds, perhaps thousands, of years to reach this size. I call to Jana, my colleague from Antarctica New Zealand, who has been showing me the workings of Scott Base and McMurdo Station. We both crouch down and peer at it, amazed that a lichen so large has survived so close to a track. If someone had kicked over the rocks it was living on, they could easily have destroyed it.

The main patch of yellow here is about 10cm across and is the Antarctic equivalent of one of Northland’s giant kauri trees (image credit: Melanie Newfield)

Less than 1% of Antarctica’s land area is permanently free of ice. However, the ice-free areas are home to almost all of Antarctica’s land species (marine life is another matter, but that is a story for another time). They are also areas which humans like to occupy, because it’s much easier to build on rock than it is on ice, which compresses under the weight of buildings and tends to move.

The end of the Hut Point Peninsula, on Ross Island in Antarctica, is one such ice free area. It juts out at precisely the point where the Ross Ice Shelf meets the sea ice. Robert Falcon Scott made his base there, on his first expedition. Both the USA and New Zealand established permanent bases there in the 1950s. The hill where Jana and I spotted the lichen, known as Observation Hill, sits between the two bases.

When people first began visiting Antarctica, there wasn’t much concern for the protection of lichens and other living things surviving as crusts or in cracks among rocks. While the scientists on the first expeditions might have observed and collected specimens, protecting Antarctica’s living things was a low priority – they were struggling enough to survive themselves. Their priority was exploration and planting a flag in the snow as close as possible to the South Pole.

As far as I can tell – and I’ve read many original accounts of these expeditions – they never gave any thought to where they were putting their feet, as long as they weren’t stepping into a crevasse.

These explorers brought staggering quantities of supplies. They brought dogs, ponies and the occasional cat. They brought hay and oats for the ponies, although they shot seals and penguins to feed the dogs. They brought canned and frozen meat, flour, milk powder, butter in wooden boxes, bottled fruit, dried vegetables, pemiccan (a mixture of dried meat and rendered fat), tea, cocoa, whiskey and many other types of food and drink. They brought tobacco, matches, massive stocks of coal, coal-ranges, acetylene lights, portable cookers, prefabricated huts in pieces, skis, sledges, fur boots and mittens, woollen and wind-proof clothing, reindeer hide sleeping bags, ice axes, bamboo poles, ropes, scientific instruments, pistols, books, cameras, sewing machines, typewriters, footballs and all manner of other items deemed essential to the expeditions¹.

All of this sounds like a lot, but it seems quite modest compared with what began arriving in the 1950s, when the permanent bases were established. Not only were there buildings – McMurdo even has a chapel – but there were vehicles, from buses and tractors down to small snowmobiles and dog sleds (dogs were present until the 1990s). They brought many more people than Scott and Shackleton, and so brought much more food and other supplies. The bases were powered by diesel generators, although during the 1960s and early 1970s, McMurdo’s electricity was supplied by a nuclear power plant. While I was there, in 2009, massive wind turbines, in pieces, arrived on a ship.

As human activities in Antarctica widened in scale, our knowledge of Antarctic life grew. As well as the seals and penguins, scientists catalogued species of lichen, moss and liverwort, as well as tiny bugs living among them². They described microbes living in all sorts of places, including inside cracks in rocks and in thin layers of soil in some of the ice-free areas. On the Antarctic peninsula, there are even two species of flowering plant, although there’s nothing of that kind on Ross Island, which is further south and much colder.

Close to where we found the lichens (image credit: Melanie Newfield)

By the 1960s, scientists were becoming concerned that humans could threaten Antarctica’s animals, plants and microbes. So, in 1964, they came to an agreement to protect Antarctic life. Removing or otherwise harming any species required a permit. They recognised that blundering around among ancient mosses and lichens could destroy them and so required permits to visit any particularly sensitive sites (although the ancient lichens of Observation Hill did not warrant special protection). But there was another clause in the agreement, and it might be surprising. They also placed restrictions on introducing any species which wasn’t native to Antarctica.

Why would introducing non-native species to Antarctica be a problem?

Wherever humans have travelled, we have brought species with us, both intentionally and unintentionally. Most of these species have proved to be benign and many have been beneficial to us. But a small proportion have got out of control, and they have had big impacts on agriculture, biodiversity and human health. These troublesome species include some mosquitoes, which I wrote about in January and various small mammals such as rats and stoats, which I wrote about in 2021.

But Antarctica is brutally cold. Would any introduced species actually survive?

It’s true that many species wouldn’t. But the 1964 agreement accounted for the possibility that some might. It didn’t forbid introductions, for example McMurdo Station once had a fairly extensive greenhouse, artificially lit, which grew herbs and vegetables such as basil, lettuce, chillies and tomatoes. But the agreement did require permits and encouraged countries operating in Antarctica to be aware of what they might carry along with their cargo.

In the early years when these rules applied, I’m not certain how seriously countries took them. I don’t know, for example, how careful they were about hitchhiking bugs on building materials, weed seeds stuck to the base of containers and microbes in clumps of soil on vehicle tracks. But, by the end of last century, people were definitely paying attention.

The first warning had come in 1987, when seals in Lake Baikal in Siberia began dying from canine distemper virus. Could the sled dogs still used in Antarctica infect seals there? Concern about the disease risk was one of the reasons why all countries operating in Antarctica agreed to remove their dogs.

Then, in 1997, scientists found signs that penguins near one of the Australian Antarctic bases had been exposed to a virus of poultry. Although the birds showed no signs of disease, it was a startling reminder that there might be unanticipated ways in which Antarctic life was at risk. Had people brought the poultry virus to Antarctica with chicken meat and eggs?

A further reminder came when small flies established in a couple of bases in the late 1990s. They were only surviving in the heated environments of the bases – the alcohol store in one and the sewage plant in another – so they should have been easy to eradicate. In reality, though, they were remarkably persistent. A few years later, Scott Base had its own fly outbreak which took some months to get under control.

Scientists were also becoming concerned about introduced grasses and daisies, which were turning up on the Antarctic Peninsula. One grass, in particular, seemed to be persisting. It probably didn’t help that the peninsula had already warmed by more than 3^oC by the end of the 20th century.

And that was another reason to be concerned about new species introduced to Antarctica. A warming climate was likely to mean that more species could survive.

There was one final reason for concern – numbers. More and more people were going to Antarctica. It wasn’t just scientists, either. Antarctic tourism was growing in popularity. While most tourist cruises kept to a limited route on the Antarctic Peninsula, visits to the Ross Sea region were increasing in number and in the range of sites visted. More people meant more cargo. And more cargo meant more opportunities for things to hitch a ride.

This is where I came in. At the time, I was working at Biosecurity New Zealand³, and I was particularly looking at how to understand and predict the types of pests associated with what we called “inanimate” cargo. By that, we meant things that weren’t animal or plant material, things like vehicles, bricks and television sets.

After Scott Base’s fly problems, Antarctica New Zealand was keen to avoid a similar situation happening again. So they came to Biosecurity New Zealand for help on what to do next. I was lucky enough to be the one to work on the problem.

What became clear, during our discussions, was that we needed to go back to the beginning. What were Antarctica New Zealand trying to protect? What was at risk from new species being introduced to Antactica? And what kind of species had the greatest chance of getting to Antarcica and surviving? The problem needed a systematic assessment, and that was the kind of thing I did.

But I’m going to save that for next week, because I’m passionate about this topic and I can’t cover everything in one article.

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1. My sources for this information are the original accounts from Scott and Shackleton. I haven’t included half of what they brought with them.

2. Scientifically speaking, they aren’t bugs, they’re invertebrates, and include insects, nematodes, rotifers, springtails and tardigrades. But bugs will do.

3. For those outside New Zealand, Biosecurity New Zealand is the agency responsible for assessing and managing the risk of inadvertently bringing pests and diseases of animals and plants into New Zealand, as well as responding if such pests and diseases are found here.