Key microbial species, also known as microbial ‘Old Friends’, play essential roles in training and developing our immune system. They help build immune memory by stimulating the creation of antibodies and are part of healthy immune signalling—for example, triggering inflammation to defend against pathogens, or supressing immune response to more mild or harmless pathogens that are in our air, food or body.
In this way, environmental microbes underpin many aspects of our health. Those who don’t have high exposure to microbes tend to have higher rates of non-communicable and chronic inflammatory diseases, such as autoimmunity, allergy and inflammatory bowel diseases.
Soil is arguably the richest source of microbes, but while microbes are incredibly light and become airborne easily, they are much less diverse in urban areas—where chronic inflammatory diseases and childhood allergies are steadily on the rise.
Currently, 50 per cent of the population lives in urban areas, and by 2030 this will have increased to 70 per cent, with dwindling urban green spaces also reducing our all-important exposure to the natural environment.
“Essentially, the aim of our project was to find out what we are exposed to, from a microbial perspective, when we walk around normally in our urban daily lives,” says Martin. “And whether this was different for children and adults, based on their proximity to the ground.”
“We deliberately selected sports fields for the project, as being a commonly accessed type of urban green space. The first part of the study quantified the microbes occurring in the air at locations such as Belair National Park, for example, which has a lot of different plant species, compared to metropolitan ovals that have many fewer plant species.”
“To answer the second question, we took air samples at different levels, from the ground, up to two metres above the ground. Then we used DNA sequencing to look at the microbial diversity in those samples.”
What the team discovered was that the complexity of vegetation surrounding sports fields has a significant impact on the microbiomes that people are exposed to when participating on these sports fields.
“This means we can actually shape the microbial communities on sports ovals by tending more plants. In addition to painting lines and cleaning the club rooms, sports clubs could use their working bees to also increase the diversity of plants around their sports fields to improve the health and immunity of their community,” Martin says.
“Secondly, with regard to vertical stratification, we discovered that air that is higher from the ground has lower diversity aerobiomes. The closer to the ground we looked, the more similar – from a microbe perspective – the aerobiome was to the soil, so small children are getting exposure to greater microbial diversity than adults.
“Therefore, we should not only be thinking about regularly visiting biodiverse green spaces, but also participating in activities that get us closer to the ground and its rich microbial diversity,” says Martin.
“My six-month old son is exposed to a much greater number of microbes than I am, so I’m better off getting down to his level.”
The Impact Seed Funding supported the purchase of equipment for the projects (including the apparatus for sampling the microbes in the air), the cost of conducting DNA sequencing—the same kind of high throughput sequencing researchers are currently applying to COVID—and the field and laboratory experiments undertaken by Martin’s student team.
Funded in 2020, after just over 12 months, the project is 90 per cent complete. As well as supporting both Daphne to complete her honours degree and Jake to publish several articles as part of his PhD research, the project is of high interest to many organisations, locally, nationally and internationally.
“If we can strongly tie the diversity of plants to our health and wellbeing, then the value of these green spaces is much, much higher,” says Martin.
“A large number of councils supported this work by providing access, and we’ve also worked on this closely with SA Health, Green Adelaide and the Department for Environment and Water (DEW), aligning with the Healthy Parks Healthy People framework.”
The state’s Healthy Parks Healthy People Framework 2021-2026 is focused on building understanding about the multiple benefits of South Australia’s parks, not only for protecting and restoring natural habitat, but for community health and wellbeing—physically, psychologically, socially and spiritually. It is connected with a larger ambition for Adelaide to increase its biodiversity, recreation and interaction with nature, to become the world’s second National Park City after Greater London (UK), where almost 50 per cent of green cover makes this metropolis one of the world’s most vegetated cities.
“It’s about biodiversity, conservation, sustainability and liveability, and the triple bottom line benefits are that it improves our health, benefits the environment and saves us money by reducing public health spending.”
Martin says international environmental non-governmental organisations are also very interested in this research, because they often take the lead in increasing urban biodiversity.
For Martin, whose research passion is intersection between genomics, ecosystem health and restoration ecology, this project is an aspect of his internationally recognised leadership in two key initiatives: the Frontiers of Restoration Ecology (FORE) and the Healthy Urban Microbiome Initiative (HUMI).
“Both of these are about the state of the world’s biodiversity and human health, and where those two areas meet—repairing and restoring microbial diversity and how vegetation is managed is key to human health”.
“We are increasingly discovering just how important biodiversity is—for human health, for climate change resilience, as part of the WHO’s manifesto for a healthy recovery from COVID-19, etcetera. The links between ecosystem degradation and the spill-over of COVID from bats to humans, and the long history of human and wildlife conflict have been very strongly and clearly articulated. But also, what we need to do now to help our recovery is use ecosystem restoration to reduce the risk of the next COVID from happening, as well as improving people’s physical and mental health and biodiversity of course.”
Martin says one of the great gifts of the Impact Seed Funding his research team received is that it is “not tied to a contract, but to discovery”.
“It allows us to follow our curiosity, to take greater risks—including working with students, who may be asking basic research questions but actually uncovering exciting outcomes.”
“It’s a kernel upon which a larger project can be built, gaining traction until it becomes a boulder of momentum towards other major types of research funding, such as that provided by the Australian Research Council.”
“This is especially important for Early Career Researchers in Australia, who fall through a gap between the hugely competitive research funds available to established researchers, and the many opportunities for students. They don’t yet have the track record to compete with the ‘big guns’. But it’s a good return on investment supporting researchers early in their career, because it makes a real difference in enabling the next generation of academics.”
Martin is a member of the World Health Organisation (WHO)’s Biodiversity Climate One Health and Nature-Based Solutions Expert Working Group and is supporting both WHO and the United Nations to help develop an evidence-based narrative that unites the health and environment sectors in a shared purpose.
