Secret ingredient for the health of tropical rainforests found

December 9, 2008

A team of researchers led by Princeton University scientists has found for the first time that tropical rainforests, a vital part of the Earth's ecosystem, rely on the rare trace element molybdenum to capture the nitrogen fertilizer needed to support their wildly productive growth. Most of the nitrogen that supports the rapid, lush growth of rainforests comes from tiny bacteria that can turn nitrogen in the air into fertilizer in the soil.

Until now, scientists had thought that phosphorus was the key element supporting the prodigious expansion of rainforests, according to Lars Hedin, a professor of ecology and evolutionary biology at Princeton University who led the research. But an experiment testing the effects of various elements on test plots in lowland rainforests on the Gigante Peninsula in the Barro Colorado Nature Monument in Panama showed that areas treated with molybdenum withdrew more nitrogen from the atmosphere than other elements.

"We were surprised," said Hedin, who is also a professor in the Princeton Environmental Institute. "It's not what we were expecting."

The report, detailed in the Dec. 7 online edition of Nature Geoscience, will be the journal's cover story in its print edition.

Molybdenum, the team found, is essential for controlling the biological conversion of nitrogen in the atmosphere into natural soil nitrogen fertilizer, which in turn spurs plant growth. "Just like trace amounts of vitamins are essential for human health, this exceedingly rare trace metal is indispensable for the vital function of tropical rainforests in the larger Earth system," Hedin said. Molybdenum is 10,000 times less abundant than phosphorus and other major nutrients in these ecosystems.

The discovery has implications for global climate change policy, the scientists said. Previously, researchers knew little about rainforests' capacity to absorb the greenhouse gas carbon dioxide. If molybdenum is central to the biochemical processes involved in the uptake of carbon dioxide, then there may be limits to how much carbon that tropical rainforests can absorb.

The biological enzyme, nitrogenase, which converts atmospheric nitrogen into soil fertilizer, feeds on molybdenum, the researchers found. "Nitrogenase without molybdenum is like a car engine without spark plugs," said Alexander Barron, the lead author on the paper, who was a graduate student in Hedin's laboratory and earned his Ph.D. in ecology and evolutionary biology from Princeton in 2007 and who now is working on climate legislation in Congress.

Source: Princeton University

4.8 /5 (22 votes)  

Filter


Move the slider to adjust rank threshold, so that you can hide some of the comments.


Display comments: newest first

holmstar
Dec 10, 2008

Rank: 5 / 5 (1)
This only proves that their test plots were deficient in molybdenum, ie: it was the limiting nutrient in *that area*. There is no reason to believe that this is the case in all rain forests. It could very well be that in most areas, phosphorus is indeed the limiting nutrient.
deepsand
Dec 10, 2008

Rank: 1 / 5 (1)
There is no claim here re. deficiencies and/or their locations.

The point of the work is that molybdenum acts as a catalyst for nitrogen fixation, a fact that was previously not known.
Rank 4.8 /5 (22 votes)
Relevant PhysicsForums posts
  • Discrepancy between oxygen and carbon-dioxide levels
    created21 hours ago
  • where gems are found in the world
    createdFeb 09, 2012
  • Wind Waves in Reservoir ~ Wind run-up and Wind set-up
    createdFeb 08, 2012
  • Balance of oxygen in the atmosphere
    createdFeb 01, 2012
  • The case for a methanol-based economy
    createdJan 30, 2012
  • Weather in a rotating cylinder
    createdJan 25, 2012
  • More from Physics Forums - Earth

More news stories

NASA sees wide-eyed cyclone Jasmine

Cyclone Jasmine's eye has opened wider on NASA satellite imagery, as it moves through the Southern Pacific Ocean.

Space & Earth / Earth Sciences

created 1 hour ago | popularity not rated yet | comments 0

NASA sees Giovanna reach cyclone strength, threaten Madagascar

Tropical Storm 12S built up steam and became a cyclone on February 10, 2012 as NASA's Terra satellite passed overhead. Residents of east-central Madagascar should prepare for this cyclone to make landfall ...

Space & Earth / Earth Sciences

created 1 hour ago | popularity not rated yet | comments 0

Humans may have helped the decline of African rainforests 3000 years ago

(PhysOrg.com) -- Large areas of rainforests in Central Africa mysteriously disappeared over three thousand years ago, to be replaced by savannas. The prevailing theory has been that the cause was a change ...

Space & Earth / Environment

created 13 hours ago | popularity 4.3 / 5 (8) | comments 10 | with audio podcast report

Could Venus be shifting gear?

(PhysOrg.com) -- ESA’s Venus Express spacecraft has discovered that our cloud-covered neighbour spins a little slower than previously measured. Peering through the dense atmosphere in the infrared, the ...

Space & Earth / Space Exploration

created 9 hours ago | popularity 5 / 5 (7) | comments 7 | with audio podcast

Mars Science Laboratory computer issue resolved

(PhysOrg.com) -- Engineers have found the root cause of a computer reset that occurred two months ago on NASA's Mars Science Laboratory and have determined how to correct it.

Space & Earth / Space Exploration

created 10 hours ago | popularity 4.7 / 5 (6) | comments 3 | with audio podcast


Google users warned of threat to smartphone wallets

Users of Google smartphone wallets were being warned on Friday that there is a way to crack pass codes intended to thwart thieves from going on illicit shopping sprees.

Anonymous knocks CIA website offline (Update)

The website of the Central Intelligence Agency was inaccessible on Friday after the hacker group Anonymous claimed to have knocked it offline.

Complex wiring of the nervous system may rely on a just a handful of genes and proteins

Researchers at the Salk Institute have discovered a startling feature of early brain development that helps to explain how complex neuron wiring patterns are programmed using just a handful of critical genes. ...

Putting the squeeze on planets outside our solar system

(PhysOrg.com) -- Using high-powered lasers, scientists at Lawrence Livermore National Laboratory and collaborators discovered that molten magnesium silicate undergoes a phase change in the liquid state, abruptly ...

The power of estrogen -- male snakes attract other males

A new study has shown that boosting the estrogen levels of male garter snakes causes them to secrete the same pheromones that females use to attract suitors, and turned the males into just about the sexiest ...

New error-correcting codes guarantee the fastest possible rate of data transmission

Error-correcting codes are one of the triumphs of the digital age. They’re a way of encoding information so that it can be transmitted across a communication channel — such as an optical fiber o ...