Discovery

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Archive for the ‘Geology’ Category

The Slime that Saves the Planet

Washington State University researchers have received half a million dollars to study a microscopic slime that they believe plays an outsized role in life on the planet.

The slime, also known as biofilm, forms a super-thin layer gluing the roots of plants to mineral surfaces and serves as a reactor in which a plant can break down the rock for vital nutrients. The process, says Kent Keller, was central to the start of land-based plant life as plants invaded the continents 350 million years ago. It continues to take place on modern volcanic ground and receding glaciers—anywhere a plant can’t get enough to eat.

A special root slime helps plants like this pine tree pull nutrients from bare rock. Flickr photo courtesy of eviltomthai.

“The magic of all of this is plants come in that are adapted to make the slime,” says Keller, co-director of the Center for Environmental Research, Education, and Outreach (CEREO) and professor in the School of Earth and Environmental Sciences. “Within 100 years, you’ve got soil. That’s an amazing thing. And it’s these slimes that are a key part of the mechanism.”

Wait, there’s more: The biofilm reactor also facilitates the most fundamental process on the planet for packing away carbon, as seen in the greenhouse gas carbon dioxide. As the plant dissolves minerals, the plant’s natural carbonic acids, made from CO2 through photosynthesis, are transformed into bicarbonate that is carried in runoff to the oceans. There it precipitates as calcium carbonate.

In other words, the biofilm acts as an intermediary between carbon from the atmosphere and its storage in the earth’s crust. Absent that process, carbon dioxide would continue building up in the atmosphere until oxygen-dependent life forms suffocated in a “runaway greenhouse.”

“Without that we wouldn’t be here,” says Keller. “We’d be Venus, because Venus has no mechanism to sequester volcanic CO2.”

But there’s a mystery to the process, which Keller and a group of colleagues will explore with $492,000 from the National Science Foundation. Somehow plants employ biofilms to build up nutrients for plants to use while also releasing them for long-term storage, and they’ve done this in a way in which plants thrive and the chemistry of oceans and the atmosphere is kept in balance.

The researchers—a team of earth, life, and soil scientists—plan to grow trees in different nutrient conditions, including pure sand, to see which are best at inducing the formation of biofilm. One indicator of that will be microbial communities, which essentially generate the biofilms for shelter. The researchers hypothesize that plants in the worst conditions will be predisposed to hosting the most diverse microbial communities, the better to generate slime and nutrients.

One experiment will rely entirely on fertilized irrigation as a proxy for conventional agriculture, which is less reliant on large microbial communities for nutrients. Comparing this system with those generating their own nutrients could help open the door to agricultural systems that can use fewer artificial fertilizers.

WSU Geochemist Filing Far-flung Dispatches for The New York Times

In Evelyn Waugh’s Scoop, pretty much the greatest novel ever written about journalism, William Boot is sent to cover an African civil war with a ton of baggage, including a canoe and a cleft stick to carry his dispatches. The cleft stick has since become a metaphor for far-flung journalistic enterprise and the lengths a reporter will go to get a story back to the home office.

Cold and scenic: WSU geologist Jeff Vervoort took in this view recently on a trip to the striking Koettlitz Glacier.

Instead of a cleft stick, Jeff Vervoort has a laptop and a “very, very small bandwidth,” text-only connection from the Central Trans Antarctica Mountain field camp at Antarctica’s Beardmore Glacier field station. That’s about halfway between the McMurdo Station, the continent’s largest community, and the South Pole.

Where William Boot sent brief, easily misinterpreted telegrams to the Beast, Vervoort is filing for the New York Times’ “Scientist at Work” blog. Times editor James Gorman launched this modern version of the old field journal earlier this year “to give scientists in the field a chance to describe what they do as they are doing it.”

“I am obviously thrilled,” says Vervoort, who majored in English as an undergraduate and now specializes in dating rocks by their chemical signatures.

The first dispatch, by colleague and University of Minnesota-Duluth geoscientist John Goodge, went up on the Times site yesterday. Vervoort and Goodge are now scheduled to have alternate posts as their team spends the next five weeks gathering rock samples over about 1,000 miles.

Logistical challenges aside, it’s not hard to interest people in Antarctic science, Vervoort says in a recent email to Pullman:

“This place appeals to many people on so many levels for many reasons. It is the land of extremes (they  like to call Antarctica the coldest, windiest, and driest place on Earth) as well as unknowns.”

The continent also has an ancient story to tell about climate change, he says.

“Many people think of Antarctica as an ice covered continent and couldn’t imagine it any other way.  But 40 million years ago or so there were not permanent ice sheets on Antarctica, during a period of extreme global warming.  The best guess is that these started forming 35-40 million years ago. Sitting up here at the edge of the polar plateau in the austral summer with temperatures a little below zero degrees F and a stiff wind blowing, however, it is hard to imagine that Antarctica warming up any time soon.”

Blogger/researchers Jeff Vervoort, left, and John Goodge enjoy t-shirt temperatures before heading out on the ice.

The research can also tell an even older story about the earth’s crust, says Goodge in the first “Scientist at Work” post:

“Antarctica was a key piece in Pangea, Gondwana and Rodinia (huge supercontinents formed by the assembly of many of today’s familiar continents at roughly 250, 500 and 1,000 million years ago), and knowing more about its geologic architecture can help to refine the picture of global paleogeography as far back as 1 billion years ago.”

For more on Vervoort’s trip, see our previous post, “Journey to the Bottom of the Earth.”

Update–A few hours after this was posted, Vervoort’s first blog went up on the Times site. Here’s an excerpt:

It is probably impossible to prepare yourself before getting here for what to expect from this large ice-covered continent at the bottom of the world. Like many people, I have seen pictures and videos of Antarctica. I am also familiar with different scientific aspects of Antarctica’s oceans, climate and geology, and I had talked about this trip extensively with John Goodge, the leader of the current expedition, before coming down here. But nothing completely prepares you for this place.

Read more…

Journey to the Bottom of the Earth

Jeff Vervoort’s research is running hot and cold, in a good way.

Last week, he contributed to a paper in Science showing tropical rain forest biological diversity went up, not down, during a period of global warming 56.3 million years ago. Vervoort, an associate professor in the School of Earth and Environmental Sciences, was one of nearly two dozen contributors to the paper and played a key role in dating the materials studied.

Now he’s going on an extended expedition on the bottom of the earth to put a finer point on the age and origin of the Antarctic continent. He and fellow researchers from the U.S. and Australia will face sub-zero temperatures, crevasses, and 30 mph katabatic winds flowing off the ice cap. But in the samples of rock they collect, they might confirm that Antarctica used to be our neighbor on the supercontinent Rodinia, about 1 billion years ago. (Read more in the winter 2008 Washington State Magazine.)

“This will be quite an adventure and I am quite excited,” says Vervoort. “I am originally from northern Minnesota and have gone winter camping in temperatures colder than this, but haven’t been out in tents for six weeks before at these temperatures.”

Image courtesy of Michael Studinger, Lamont Doherty Earth Observatory

The mountains of Antarctica are difficult to study, lying for the most part several thousand feet beneath a sheet of ice. Radar has given researchers some idea of their contours, as seen in the exaggerated image above. Researchers on this trip, which is being led by the University of Minnesota-Duluth’s John Goodge, will collect rock from exposed areas and boulders encased in the ice. Vervoort will use his expertise in radiogenic isotopes and geochronology to date the rock and get a better idea about its origin.

Previous work on glacial rocks by Goodge, Vervoort, and an Australian colleague showed the materials were different from those found in outcrops near the surface. Moreover, the chemistry of the rocks was similar to those seen in North America, buttressing thinking from the early 1990s that Antarctica, Australia and North America were once next-door neighbors in Rodinia. The team on this trip hopes to clarify the geological composition for a large part of Antarctica and further test ideas about how the supercontinent puzzle fits together.