SciTech

Intense farming of ‘Green Revolution’ heightens swings in atmosphere’s carbon dioxide

‘Green Revolution’ increasing carbon dioxide swing

Intense farming practices of the “Green Revolution” are powerful enough to alter Earth’s atmosphere at an ever-increasing rate, boosting the seasonal amplitude in atmospheric carbon dioxide to about 15 percent during the last five decades.

That’s the key finding of a new atmospheric model called VEGAS, according to a study of it published in the journal Nature .

“What we are seeing is the effect of the ‘Green Revolution’ on Earth’s metabolism,” said Ning Zeng, an atmospheric scientist at the University of Maryland and the lead developer of the VEGAS carbon-cycle model that, for the first time, factors in changes in 20th and 21st century farming practices. “Changes in the way we manage the land can literally alter the breathing of the biosphere.”

Scientists have known since the 1950s that carbon dioxide levels in the atmosphere hit an annual low during late summer and early fall in the Northern Hemisphere. The atmosphere’s carbon dioxide level falls in spring and summer as plants reach their maximum growth, taking in carbon dioxide and releasing oxygen. In the autumn, when plants are decomposing and releasing stored carbon, the atmosphere's carbon dioxide levels rapidly increase. nsf.gov

Tigers identified by photo, stripe-pattern software

Researchers from the Wildlife Conservation Society and its partners in India are using high-tech solutions to identify conflict-prone tigers and relocate them. In a pair of recent cases involving both a human fatality and the killing of livestock near two of India’s national parks, WCS scientists helped identify the problem tigers by using camera traps and stripe pattern-matching software. Both tigers were captured and relocated to a nearby zoo.

The system uses unique stripe patterns to identify and track individual animals; software programs have greatly improved the speed and accuracy of the process. Since its initiation, more than 750 tigers have been identified from six protected areas across India. A paper on this subject appears in the journal Oryx.

“The vast majority of tigers generally avoid humans and focus only on natural prey species,” said Ullas Karanth of WCS, lead author on the paper. He said the stripe-identification software “helps us to mitigate threats to people and prevent the capture of the wrong tigers, especially wherever tigers may venture beyond protected area borders.” wcs.org

Lower calcium levels in lakes favor jelly-clad organisms

A plague of “aquatic osteoporosis” is spreading throughout many North American lakes due to declining calcium levels in the water – and hindering the survival of some organisms, according to researchers at Canada’s Queen’s University, in Kingston, Ontario.

With collaborators from other universities, they have identified declining calcium levels after prolonged periods of acid rain and timber harvesting. The decline hinders the survival of aquatic organisms with high calcium requirements and also promotes the growth of nutrient-poor, jelly-clad invertebrates whose increase can have important implications for lake biology – altering food webs and also leading to clogged water intakes.

The study was published in Proceedings of the Royal Society B. queensu.ca

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