Navigation Links
Tropical forest CO2 emissions tied to nutrient increases

Extra helpings of key nutrients given to tropical rain forest soils caused them to release substantially more carbon dioxide into the atmosphere, a concern to scientists monitoring global change, says a new University of Colorado at Boulder study.

The study showed when either phosphorus or nitrogen -- both of which occur naturally in the rain forest soils -- were added to forest plots in Costa Rica, they caused soil microbes to increase their CO2 emissions to the atmosphere by about 20 percent annually, said Cory Cleveland of CU's Institute of Arctic and Alpine Research.

The study is important because human activities are changing the amount of phosphorus and nitrogen in ecosystems all over the globe, including the tropics, Cleveland said. Tropical rain forests play a dominant role on Earth in regulating atmospheric CO2, the primary greenhouse gas that has increased by roughly 33 percent since the Industrial Revolution began about 1760.

A paper on the subject by Cleveland and CU-Boulder Associate Professor Alan Townsend of INSTAAR is being published the week of June 19 in the Proceedings of the National Academy of Sciences. The National Science Foundation funded the study.

"One big question is how tropical rain forests are responding to climate change," said Cleveland, an INSTAAR research associate who led the study. "What we have demonstrated is that even small changes in nutrients could have a similarly profound impact on the release of CO2 from tropical forest soils."

Tropical forests contain up to 40 percent of the carbon stored on Earth's continents and account for at least one-third of the annual exchange of CO2 between the biosphere and the atmosphere, said Cleveland. Earth's soils are believed to store several times more carbon than all of the planet's vegetation.

"This is the first time anyone has taken a close look at how changes in key nutrients may alter soil CO2 emissions in tropical forests," said Clevela nd. "Processes in the tropics affect what is happening around the globe, so this study has some big implications."

Phosphorus is known as a "limiting nutrient" because its availability can govern the growth rate of many organisms, said Cleveland. While slash-and-burn agriculture in the tropics often reduces soil phosphorus in the long run, the practice can initially make more phosphorus available to tropical soil microbes, increasing their metabolism and the amounts of CO2 they emit, he said.

Phosphorus and many other nutrients are regularly transported around the Earth by global wind patterns, sometimes riding on huge transcontinental dust clouds, said Townsend, who also is associated with CU-Boulder's ecology and evolutionary biology department. "There is strong evidence that humans are increasing the size of these dust clouds as both land-use patterns and climate change, which in turn can change the availability of nutrients to forests," he said.

Nitrogen pollution also is increasing around the world, including in tropical forests, a result of fossil-fuel combustion and crop fertilization activities, said Townsend. "Human activity has changed the availability of nitrogen all over the world, especially in the last 50 years," he said. "This study was surprising because of the large effect both of these nutrients had on the release of CO2 to the atmosphere."

About three-quarters of anthropogenic emissions of CO2 to the atmosphere during the past 20 years are thought to be due to fossil-fuel burning, the researchers said. The rest is predominantly due to land-use changes like deforestation.

The new study, which took place in 2004 and 2005 in Costa Rica's Golfo Dulce Forest Reserve, included a series of 25 meter-square plots that were fertilized with phosphorus, nitrogen, or a combination of the two, said Cleveland. Soil respiration was measured using plastic tubes in the ground running into vented, closed chambers.

According to the National Academy of Sciences, temperatures on Earth have risen by more than 1 degree F in the past century due to build-up of greenhouse gases in the atmosphere, primarily CO2. According to the academy, the warming process has intensified in the past 20 years has been accompanied by retreating glaciers, thinning arctic ice, rising sea levels and longer growing seasons in many regions.


Source:University of Colorado at Boulder

Related biology news :

1. Finding Cures For Tropical Diseases: Is Open Source An Answer?
2. Tropical Deforestation affects rainfall in the U.S. and around the globe
3. Tropical dry forests receive international recognition
4. Tropical Atlantic cooling and African deforestation correlate to drought, report scientists
5. Tropical forests -- Earths air conditioner
6. Essential mangrove forest threatened by cryptic ecological degradation
7. Falling ants glide back to trunk to avoid dangers of forest floor
8. Worlds largest rainforest drying experiment completes first phase
9. Live fast, die young true for forests too
10. Shift of weather patterns necessitates rethinking of reforestation methods
11. Finding hidden invaders in a Hawaiian rain forest
Post Your Comments:

(Date:4/15/2016)... 15, 2016 Research and ... Biometrics Market 2016-2020,"  report to their offering.  , ... , ,The global gait biometrics market is expected ... the period 2016-2020. Gait analysis generates ... be used to compute factors that are not ...
(Date:4/13/2016)... 13, 2016  IMPOWER physicians supporting Medicaid patients in ... new clinical standard in telehealth thanks to a new ... higi platform, IMPOWER patients can routinely track key health ... mass index, and, when they opt in, share them ... to a local retail location at no cost. By ...
(Date:3/31/2016)... , March 31, 2016  Genomics firm Nabsys has ... CEO, Barrett Bready , M.D., who returned to ... the original technical leadership team, including Chief Technology Officer, ... Product Development, Steve Nurnberg and Vice President of Software ... the company. Dr. Bready served as CEO ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... , June 27, 2016   Ginkgo Bioworks ... to industrial engineering, was today awarded as one ... selection of the world,s most innovative companies. Ginkgo ... scale for the real world in the nutrition, ... engineers work directly with customers including Fortune 500 ...
(Date:6/23/2016)... ... June 23, 2016 , ... Mosio, ... second eBook, “Clinical Trials Patient Recruitment and Retention Tips.” Partnering with experienced clinical ... eBook by providing practical tips, tools, and strategies for clinical researchers. , “The ...
(Date:6/23/2016)... -- Houston Methodist Willowbrook Hospital has signed a ... serve as their official health care provider. As ... provide sponsorship support, athletic training services, and most ... athletes and families. "We are excited ... to bring Houston Methodist quality services and programs ...
(Date:6/23/2016)... ... ... Supplyframe, the Industry Network for electronics hardware design and ... in Pasadena, Calif., the Design Lab’s mission is to bring together inventors and ... brought to market. , The Design Lab is Supplyframe’s physical representation of one ...
Breaking Biology Technology: