A pair of papers in the Dec. 9 issue of the journal Nature, one focused on bacteria and another on a microbial fungi, shows that the number of species present the diversity increases as the area they occupy increases.
"The results suggest that this relationship may be a universal law common to all domains of life," say Claire Horner-Devine, University of Washington assistant professor of aquatic and fishery sciences and lead author of the paper concerning bacteria. Jessica Green, University of California, Merced, assistant professor of natural sciences, is lead author of the other.
If true of other microbes, the work will give ecologists new ways of understanding the ecology and biodiversity of these tiny organisms, most of which are too small to see even with microscopes, Horner-Devine and Green say. Bacteria and fungi may well comprise the bulk of species on Earth and, despite their small size, play roles in everything from global climate change to water purification to recycling of dead plants, animals and other matter.
"Bacteria, for example, decompose organic material that, among other things, provides the majority of nitrogen needed by the plants we eat," Horner-Devine says. "So understanding the distribution and basic ecology of one of the most abundant and diverse groups of organisms on Earth is crucial."
The idea that the number of species increases as the area increases - referred to as the "species-area relationship" - may seem obvious to anyone who has, say, compared a garden-size patch of wildflowers to an entire meadow and realized how many more kinds of flowers there are in the latter, Horner-Devine says. Still, some scientists thought microbes might be different.