Antarctic biodiversity research

This video is called Destination Unknown South Orkney Islands.

From the Natural Environment Research Council in Britain, with photos:

How biodiverse is a polar archipelago?

It’s a simple question. How many species are there around the South Orkney Islands? David Barnes describes how the answer surprised almost everyone.

For half a century, textbooks have told us biodiversity falls as you move from the tropics to the poles. The idea seemed plausible – after all, how many species can you see on ice-covered land, or ice-scoured shore or shallows?

But nobody seemed to have any evidence for it, or even a good estimate of how many species lived in any particular polar area, except within a few single groups of animals. Even at a time when the International Polar Year and the first World Conference on Marine Biodiversity were approaching, we still didn’t know something as basic as this.

You may be thinking, so what? But there are several very good reasons to understand polar biodiversity. The poles are among the fastest-warming places on the planet, as well as the most vulnerable to ocean acidification, caused by CO2 dissolving in seawater. This is where the planet’s surface is changing most fundamentally – from white to blue.

Polar life may be the most sensitive anywhere to changes in temperature. Experiments have shown polar organisms are least able to cope with short-term warming, perhaps because they have lived for millions of years in an environment whose temperature varies less than anywhere else on Earth. Because of their sensitivity, these organisms can give us information about how life responded to environmental change in the past and so provide an early-warning system for how it will react to what are expected to be the most drastic changes since humans evolved.

Some of this information, such as changes in growth rate, comes from the skeletons of long-lived species. Other insights come from comparison of subfossil and fossil abundances over time and in current species distributions and genetics.

Polar life is clearly very important. So in 2008 a team from the British Antarctic Survey and Hamburg University set about estimating how much of it there is, as well as assessing how good this estimate was.

An isolated archipelago makes the job easier, as it has a definite boundary – the edge of the continental shelf. Confining ourselves to animals larger than a millimetre made it easier still; now all we needed to do was go through thousands of scientific papers, a century of Antarctic expeditions, tens of museums and several international databases, and then mount an expedition to sample across realms, habitats and animal types.

I had spent the early years of my career as a marine biologist continuously working in this archipelago. My boss had spent much of his working life there, and so had his boss. None of us knew what the answer would be – but it would not be 42. On land, in fresh water and on the shore, we quickly built up a picture from the literature; the animals were small and few.

Rich sea, poor land

With 100 species, the South Orkney Islands are rich in land animals compared to elsewhere in the Antarctic, but at the same time poor compared with similar-sized areas in the subantarctic or Arctic, and very poor compared with lower latitude places. Only very young, isolated islands might come close to having so few land species – even a modest garden would have more. Unlike anywhere else, though, just two of these 100 were known to be non-indigenous aliens. This is one of the few terrestrial communities on the planet that remains near its ‘natural’ state.

Lakes and streams were similarly impoverished, with just 65 species. But we found records of 43 known from the shore.

Some of the many marine animals near the South Orkney Islands:

1. A variety of brittlestars [see also here].
2. Sea spiders have more species than anywhere else in the world and are among the animals that grow far larger than their warm-water relatives.
3. Octopus seemed to be particularly common in the study area and were found in most trawls.
4. Feather stars are very mobile – both adults and larvae eat phytoplankton (marine algae) and as such may track the changing patterns of marine algae.
5. Ice fish have no red blood cells and have glycerol in their blood acting as antifreeze.
6. A basket star expanding its curly, branching arms outwards.

Changes in lichen diversity and community structure with fur seal population increase on Signy Island, South Orkney Islands: here.

How do Antarctic notothenioid fishes cope with internal ice? A novel function for antifreeze glycoproteins: here.

Biology of the Antarctic dragonfish Vomeridens infuscipinnis (Notothenioidei: Bathydraconidae): here.

New light on new species? a drill close to reaching 14-million-year-old Antarctic lake: here.

Antarctic crinoids: here.

What International Polar Year discovered: here.

Algae biodiversity cleans streams. The more species a habitat holds, the faster pollutants are removed from the water: here.