Life on the wind: Study reveals how microbes travel the Earth

Aug 17, 2011

Scientists from the UK and Switzerland have investigated the remarkable distance that microorganisms may be able to blow between continents, raising questions about their potential to colonise new lands and also potentially to spread diseases.

The researchers from Liverpool John Moores University (LJMU), Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) and the Ecole Polytechnique Fédérale de Lausanne (EPFL) the University of Neuchâtel published their results in the Journal of Biogeography this month. They used large computer models of the Earth's atmosphere to study how widely could be dispersed.

LJMU's Dr Dave Wilkinson led the team along with Symeon Koumoutsaris, from the International Space Science Institute in Bern, who modified computer models which were designed for studying the dispersal of dust particles. They looked at what would happen if they released virtual microbes from both the southern tip of South America and also from Mexico. Once airborne, microbes of 0.02mm in diameter and below can easily travel thousands of kilometres.

Dr Dave Wilkinson, LJMU School of Natural Science and Psychology, explained:

"Microbes less than 0.009 mm across went as far as Australia! These sizes would include microbes such as bacteria and many amoebae and also some fungal spores. We found that for smaller microbes, once airborne, dispersal is remarkably successful over a 1-year period. The most striking results are the extensive within-hemisphere distribution of small virtual microbes and the lack of dispersal between the Northern and Southern Hemispheres during the year-long time-scale of our simulations.

What our models show is that only the smallest microbes travel easily between continents. The larger ones (i.e. Larger than 20µm but still 500 times smaller than the 1mm threshold previously believed to separate the "cosmopolitan organisms" from those with potential biogeographies) cannot easily travel between on the time span of a single year. This is an important result as it very significantly increases the potential for microbial diversity."

Most microbes carried by wind are likely to be harmless, but outbreaks of certain disease such as meningitis in the Sahel region of Africa and foot and mouth disease have been linked to airborne microbes in the past.

"We stress that our model looks at only one aspect of microbial dispersal – namely airborne transport to a new site. Once a microbe arrives, it clearly needs to reproduce, including potentially competing with microbes already at that location," Dr Wilkinson concluded. "Given the ease with which the smaller microbes disperse in our model it is possible that this (rather than dispersal itself) may be the rate-limiting step in many cases of microbial range expansion and this topic should form the topic for future research in this area."

Explore further: At dusk and dawn: Scientists pinpoint biological clock's synchronicity

add to favorites email to friend print save as pdf

Related Stories

Cosmopolitan microbes -- hitchhikers on Darwin's dust

Dec 04, 2007

Scientists have analysed aerial dust samples collected by Charles Darwin and confirmed that microbes can travel across continents without the need for planes or trains - rather bacteria and fungi hitch-hike by attaching to ...

Microbes as climate engineers

Jan 29, 2008

We might think we control the climate but unless we harness the powers of our microbial co-habitants on this planet we might be fighting a losing battle, according to an article in the February 2008 issue of Microbiology To ...

House-sharing with microbes

Sep 09, 2010

Household dust contains up to 1000 different species of microbes, with tens of millions of individual bacterial cells in each gram. And these are just the ones that can be grown in the lab!

Researcher seeks 'missing piece' in climate change models

Feb 13, 2007

To most people, soil is just dirt. But to microbiologists, it is a veritable zoo of bacteria, fungi and nematodes. It's also a vast carbon dioxide factory. As these microorganisms consume carbon-based materials found in soil, ...

New Window Opens on the Secret Life of Microbes

Mar 13, 2008

Nowhere is the principle of "strength in numbers" more apparent than in the collective power of microbes: despite their simplicity, these one-cell organisms -- which number about 5 million trillion trillion ...

Microbial stowaways: Are ships spreading disease?

May 29, 2008

Ships are inadvertently carrying trillions of stowaways in the water held in their ballast tanks. When the water is pumped out, invasive species could be released into new environments. Disease-causing microbes could also ...

Recommended for you

Plants prepackage beneficial microbes in their seeds

23 hours ago

Plants have a symbiotic relationship with certain bacteria. These 'commensal' bacteria help the pants extract nutrients and defend against invaders – an important step in preventing pathogens from contaminating fruits and ...

User comments : 0