One of the questions you may have asked yourself when reading this blog is an obvious one. Why would you go to Antarctica to do research on soils? Well, there are many interesting scientific questions to explore here, but I’ll explain a couple of key reasons why we choose Antarctica. First of all, because of the harsh climate in Antarctica—it is the coldest and driest continent—the number of life forms that can survive here is very limited. This means that we are actually able to study all the major players and their interactions in the soil here. This is very difficult in other places around the world, where soils contain many different species that not only interact with each other but also with the plants that are rooted in those soils, extracting water and nutrients from it and returning leaf litter that is in turn decomposed and converted back into nutrients. By studying these relatively “simple” soil ecosystems we hope to get a better understanding of some of the fundamental processes in soils. This in turn will help scientists to get a better insight into more complex soil communities’ functions. The fact that Antarctic soils are a simple ecosystem also makes them very suitable to test the effects of disturbance on the soil food web.

Taylor Valley

Taylor Valley, Antarctica. Image courtesy of NASA.

This brings us to a second reason why we choose Antarctica as a place of study. Here in the Dry Valleys the short Antarctic summer brings temperatures that are above freezing. This means that the life forms that live here are very well adapted to cold and drought, but also have to deal with the short warmer summer period. If the temperature increases by even one degree celsius, this immediately translates into the melt of a large amount of ice from glaciers and permafrost, which can cause drastic changes in the landscape. All this makes the Dry Valleys an ideal place to study the effects of climate change on the life in soils. By studying a system that potentially shows large reactions to small changes, we can learn about the general mechanisms by which climate change affects ecosystems.

The edges of Lake Fryxell are melting as the summer reaches its peak. In the distance the Canada Glacier comes down from the Asgard Range.

The edges of Lake Fryxell are melting as the summer reaches its peak. In the distance the Canada Glacier comes down from the Asgard Range.

In addition, the wetting of the landscape can occur by two different methods that will influence other processes in the valleys. Aboveground water flow from glaciers and snowpack can carry surface soils, their salts and nutrients and the organisms within them from higher up in the valley to lower elevations and the lake margins. Melting permafrost can cause large seep areas, with moisture connecting large patches of the soil system together and permitting movement of the soil organisms across the area more easily than normal. If these conditions persist over time, we may also see portions of the valley shift from their normally dry state into one which includes more surface algae and patches of moss. This increase in productivity may result in shifts in the animal distributions across the valley, and being able to capture these shifts as they occur will provide us with insights into landscape-level process changes due to climate change.

A female Scottnema lindsayae as seen through the microscope. Photo: Ashley Shaw

So which organisms live in such an inhospitable place? When you arrive in the Dry Valleys, you would initially think that there is really no life at all. You see no plants, you see no animals running around. But underneath the soil surface life abounds. Most of this life is represented by the very smallest forms such as bacteria and protozoa. In places where melt provides a source of water some algae and mosses can be found. Different multicellular animals live here also; nematodes such as Eudorylaimus and Plectus, rotifers and tardigrades (also called water bears). But these wet, algal habitats are relatively scarce, and the vast majority of Dry Valley soil is very dry and salty, rendering it unsuitable most organisms. Here, one very hardy creature thrives. Its name is Scottnema lindsayae, a nematode named after the British explorer Robert Falcon Scott, and is only found in the Dry Valleys. One of the questions we are trying to answer is what happens to Scottnema when soils get warmer and wetter. Will we one day lose this unique Antarctic nematode, the “lion of the Dry Valleys”, altogether when the climate keeps changing?

This tardigrade or water bear was observed piercing the body of a nematode. However, we currently do not know how general this sort of interaction is in the field. Photo: Martijn Vandegehuchte

Written by: Ashley Shaw