Bacteria are everywhere, of course, and biologically rich environments can exist in the middle of the densest cities on the planet. Just ask a team of soil scientists who went bacteria hunting the New York City's Central Park.
The scientists went on a digging spree in the sprawling park as part of a project known as The Global Soil Biodiversity Initiative.
They didn't have to dig too deep -- just a couple of inches down -- to unearth an astounding 167,000 kinds of microbes living in the park's soil, most of which had never been documented before.
"There are all these organisms and we don't know what they're doing, we don't have names for them or anything like that," said study co-author Noah Fierer of the University of Colorado at Boulder.
The dirt in Central Park turned out to be "a terra incognita in one of the most frequently visited urban parks in the world," the researchers reported in the Proceedings of the Royal Society B.
Despite being in the very heart of one of the world's great cities, the park's below-ground biological diversity is similar to what is found anywhere in the world, they said.
Because of the way the park has been managed and modified so many times over the years of its existence, it is home to hundreds of distinct microscopic biological communities, they added.
Samples taken from 500 separate subsurface locations, each around 50 feet apart, around the park showed it possessed as wide a range of microbial soil life as any tropical rainforest, grassland prairie, temperate forest or other wild area in the world, they revealed.
Among the 167,000 species of microbes found, around 2,000 are apparently unique to Central Park, they said.
It's not the first time scientists have mounted forays into the 843-acre park in search of life.
In 2003, 350 scientists assisted by volunteers made a sweep through the park, hoping the find and identify as many species of plants and animals as could be identified in the 24-hour effort.
The project, dubbed BioBlitz, eventually created a list of 836 species of animals and plants within the park's boundaries.
The recent microbe hunt showed just how healthy -- and vital to the city's health -- the soil of Central Park is, says Diana Wall, director of the School of Global Environmental Sustainability at the University of Colorado and a corresponding author on the study.
"The soil microbes in Central Park benefit us, benefit soil health, and are linked tightly to the beauty of the trees and other plants we see," she says. "The nation's food, cities, clean air and water and economy are all dependent on healthy, fertile soils and that motivates us to understand this fascinating hidden life beneath our feet."
