Wastewater, tourism, and trade are moving microbes around the globe at an unprecedented scale. As we travel the world we leave billions of bacteria at every stop.
As with rats, foxes, tigers and pandas, some microbes are winners, spreading around the world into new ecological niches we've created. Others are losing, and might face extinction. These changes are invisible, so why should we care?
"Yes, our survival may depend on these microbial winner and losers," say a team of Australian, Chinese, French, British and Spanish researchers in a paper published in Science today.
"The oxygen we breathe is largely made by photosynthetic bacteria in the oceans (and not by rainforests, as is commonly believed)," says Macquarie University biologist Michael Gillings.
"Over 95 per cent of the poo in the world comes from humans and the animals we farm. And our poo is travelling around the world with a billion tourists, spreading microbes and antibiotic resistance genes."
"Until 100 years ago all the nitrogen in our food came from bacteria we nurtured in our crops. Now more than half comes from artificial fertilisers."
"And we're moving trillions of ocean microbes around the world in ballast water. Some one hundred million tonnes of ballast water are dumped in US waters each year. We know they're introducing foreign starfish, sea snails, and seaweed. But we don't know what invisible changes they're making to ocean microbes."
The team is calling for urgent action to:
- Monitor and model the changes we're making to the microbial world
- Improve waste water and manure treatments to reduce the spread of microbes and resistance genes.
"Microbes usually perform their essential ecosystem services invisibly, but we ignore them at our peril," they say. The international research team is from Macquarie University, Australia; the Chinese Academy of Sciences; Universite de Lyon, France; University of Nottingham and University of Leeds, UK; and CSIC/CREAF, Barcelona, Spain.