Amazon is a desert
biodiversity-rich Amazon is more like a desert when it comes to soil microbes, while an arid desert is a teeming microbial Amazon, two us researchers have found.
Noah Fierer and Robert Jackson of Duke University studied the diversity of soil bacteria in 98 locations in South and North America and found that the acidic soils of Amazon rain forests harbour fewer bacterial species than the neutral soils of deserts. "Qualitatively, there was no clear relationship between soil bacterial diversity and plant diversity at the continental scale,' they said in a paper that appeared in the early online edition of the Proceedings of the National Academy of Sciences on January 9, 2006.
While temperature and latitude of an area largely determine its plant and animal diversity, this cannot be said to be true of soil bacteria, the scientists said. Their studies revealed that the primary factor governing the diversity of soil bacteria is soil p h, which is a measure of acidity/alkalinity. The p h scale ranges from 0 (very acidic) to 14 (very alkaline or basic). A p h value of 7 indicates the neutral state.
Unanswered questions "Although soil bacteria have been studied for centuries, fundamental questions (about their existence and diversity) remain unanswered,' said Fierer. "We probably know more about the organisms in the deepest ocean trenches than we know about the organisms living in soil in our backyards. We step on soil every day, but few people realise that