It’s a microbial world

When the International Census of Marine Microbes (ICoMM) kicked off in 2003, microbiologists had identified 6,000 kinds of microbe and predicted that they might find as many as 600,000.

After collecting samples at more than 1,200 sites around the world, ICoMM researchers compiled a database of 18 million microbial DNA sequences and identified hundreds of thousands of different microbes. They conservatively estimate that there must be at least 20 million kinds of microbe in the oceans. The true number may even be billions or trillions.

Some of the microbial habitats discovered in the oceans by the census are astounding. A patch of microbes identified on the sea floor off the west coast of South America covers an area roughly the size of Greece.

Meanwhile, even the deepest mud brought to the surface by the project, from more than 1,600 meters below the sea floor off Newfoundland in Canada, still teemed with microbes.

Ecological wild cards

The surprising wealth of species presents researchers with fresh questions, says Mitch Sogin of the Marine Biological Laboratory at Woods Hole, Mass., who leads the ICoMM.

The future of those microbes in a warming world is unclear. “They are basically wild cards,” says Sogin. “We don’t know what they do or how they are going to respond, but they could have an enormous impact.”

As a major constituent of marine biomass, microbes continue to serve as the primary engine of Earth's biosphere, driving biogeochemical cycles that shape our planetary atmosphere and environment.

Despite this, “we know very little of the microbial world in the oceans”, says Ian Poiner, chief executive of the Australian Institute of Marine Science at Cape Ferguson in Queensland.
Jane Qiu

Debate over burning grasslands and forests

The mist-shrouded mountains rising out of the forest here form one of the world’s most beguiling frontiers of exploration and research, inspiring Arthur Conan Doyle’s 1912 fantasy novel ‘The Lost World’ and teams of biologists who still mount expeditions to remote escarpments in hopes of finding species new to science.

But in the savannas below, the tendrils of smoke hanging over the landscape attest to a custom that has set off a fierce debate among scientists in Venezuela and beyond: the Pemon Indian tradition of repeatedly burning grassland and forest to hunt for animals and grow food.

The drought that afflicted Venezuela this year is intensifying claims that the Pemon have unleashed a surge in fires that rains would normally extinguish.

But many Pemon, along with some of the scholars who study them, say the fires help prevent grasses from building into biomass for much larger fires that could tear through the region, in the way vast wildfires devastated parts of Indonesia in 1997.
Simon Romero
New York Times News Service