Case study

How an army of microbes protects the Earth

We are investigating how a tiny army of microbes, moss and lichen do the job of plants in places in the world where plants cannot survive. They stabilise soil by gluing the surface together in a “biological soil crust” or “biocrust”.

‘Ecosystem services’

Plants play an important role in our environment. They deliver a host of “ecosystem services”. These include photosynthesis, stabilising soil, controlling water systems and providing habitat for animals.

But there are many places in the world where plants do not thrive – deserts, glaciers, and mountains for instance. These places are not devoid of life. Even if you can’t see it, there is a tiny army of microbes and non-vascular plants, such as moss and lichen, which deliver similar benefits to the larger and more obvious plants and trees.

This life is collectively called “biological soil crust” or “biocrust”. Collectively these biocrusts play a massive role but we know very little about them. What we do know is that they glue fine soil together to resist the erosive force of the wind, preventing dust storms. They also regulate transfers of energy and matter between the atmosphere and the soil.

A cut piece of biocrust standing vertically
The strength of this excavated biocrust comes partly from the microorganisms that glue the sand grains together

Focusing on dryland

Our biocrust research focuses on the microbes that live in the top few millimetres of desert soil and in the top few centimetres of upland peatlands.

Our current work is looking into how microbes stabilise dryland soils. Drylands cover over 40% of the Earth land surface. But there are very few studies identifying the structure and function of their microbial communities. Most soil research has focused on temperate and agricultural systems.

By addressing this knowledge gap, the Environmental Sustainability Research Centre contributes to informed land management relevant to sustainable goals, such as maximising carbon storage, minimising greenhouse gas emissions, enhancing soil fertility and preventing dust storms.

Dr David Elliott, Associate Professor in Microbiology, has been carrying out biocrust research at the Lake Constance Claypan in Diamantina National Park in Australia. This is an area that is prone to dust storms. Without the biocrust, its soil would be highly vulnerable to wind erosion, contributing more as a dust source.

Broad scope

Our approach is multi-disciplinary and collaborative. We work together with experts in different fields to ensure that all relevant aspects of complex dynamic systems are considered. This is challenging but also rewarding and interesting.

Dr Elliott, a microbial ecologist, works alongside geomorphologists, engineers, chemists and remote sensing experts for instance. Working together, each person contributes their part to the bigger picture of understanding Earth System functioning.

As such the scope of our work is also broad, for example:

Our research is also investigating the role of microbes in other environments where vascular plants are unable to dominate the landscape – such as peatlands and glaciers. These studies fall under the biocrusts research umbrella and the objectives are similar. We seek to explain and understand the role of microbes in the environment to support sustainable management of the environment.

Dr David Elliott sampling soil in central Australia
Associate Professor in Microbiology

Dr David Elliott is a microbial ecologist specialising in the roles of microbes in low productivity soils including drylands and the cryosphere. He leads the BSc (hons) Biology programme and teaches a variety of topics in Human and Environmental Sciences.

closeup of some coral in a fish tank

Environmental Sustainability Research Centre

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