The secret life of soil

Did you know that there can be more organisms in one teaspoon of soil than there are people on the planet?  

If your answer is "No!”, you're not alone.  

These microorganisms make up a dynamic community known as the soil microbiome that includes bacteria, fungi and archaea (single-celled organisms thought to be one of the oldest living things on earth).

But while soil is critical to healthy ecosystems, it often gets overlooked. That's one of the reasons I chose to look into the role of soil microbes in restoration ecology as a PhD candidate with Flinders University. 

Soil microbes are crucial to the health of our environment – playing important roles in the survival of plants, carbon sequestration, nutrient cycling, and the decomposition of organic matter.

A healthy soil microbiome has even been linked to human health, yet there's still so much we don’t know about it. 

Through a fortuitous connection with Bush Heritage ecologist Angela Sanders, I became interested in the microbial biodiversity in the area between the Fitzgerald River and Stirling Ranges national parks in Western Australia’s Great Southern region, Noongar country.

Known as the Fitz-Stirling, this global biodiversity hotspot has been highly fragmented and as such has been the focus of much of Bush Heritage’s ecological restoration work in the area over the past two decades. 

My research focuses on figuring out how the soil microbiome responds following restoration as well as how we can actually use soil microbes to facilitate restoration, so these sites provide the perfect laboratory. 

With the help of Bush Heritage ecologist Ange Sanders, soil samples were taken from six reserves in the Fitz Stirling – Beringa, Red Moort, Chereninup, Chingarrup Sanctuary, Yarraweyah Falls, and Monjebup North. Three of these sites are owned by Bush Heritage, the others by Greening Australia and private landholders. 

The samples were snap frozen and sent to Perth’s Kings Park where they're currently sitting in a freezer at -80 degrees Celsius. Once they’ve made their way to me in Adelaide, I plan to extract DNA from the samples as soon as possible. 

Unlike monitoring for vegetation or wildlife, we can’t simply eyeball soil to know what species are present – we need to use DNA sequencing to identify what's there.

Remember – there are hundreds of thousands of different species in one soil sample! 

In the soil microbiome, health is subjective as there's no one gold standard for a healthy soil microbiome. So I’ll compare our samples from the restored sites with samples from intact, unimpacted bushland. 

I'll then use this data to examine how the soil microbiome changes following restoration and the impact of restoration efforts in restoring soil microbial biodiversity.

Additionally, my research will highlight associations between above-ground and below-ground biodiversity and, importantly, whether these microbes are performing the same ecological functions in their restored ecosystems. 

This will help Bush Heritage and other landholders determine if the success of above-ground restoration efforts is carrying through to the soil microbiome and restoring their crucial ecological roles. 

Soil has been overlooked in science for too long and I’m keen to contribute as much as I can to this fascinating field of research. 

This research project is made possible by the generous support of Peter and Maxine Wilshaw.