SNIPPETS

SNIPPETS

Enough carbon talk, now it’s nitrogen’s turn

This element is essential to life and is the building block of proteins. Photosynthesis and plant growth is impossible without it. The element is nitrogen. Although the Earth’s atmosphere is an abundant source, it cannot be used by plants until it is ‘fixed’.

This means converting gaseous nitrogen into forms usable by living organisms. Usually cooperative bacteria that live in soils or in harmony with plants do the fixing. Life would not be possible if the nitrogen cycle was disrupted. And, global warming can disrupt this cycle.

Warmer climates could lead to a loss of nitrogen from desert soils in the form of gas. Over the years, scientists observed that nitrogen losses from arid zones could not be accounted for just by the biological mechanism of nitrogen gas production.
Ecologist Jed Sparks and evolutionary biologist Carmody McCalley from Cornell University in USA tried to trace the ways in which nitrogen is disappearing. They covered small patches of soil in the Mojave Desert with sealed containers to measure nitrogen gases that escape desert soils. “At 40 to 50°C, rapid increases in gases coming out of the soil was found. Any place that gets hot and dry in all parts of the world might exhibit this pattern,” concluded Sparks. The team warned that some climate models predict more summer rainfall for desert areas and the water, when combined with heat, would greatly increase nitrogen losses. The study was published by Science in November. The story of the escaped nitrogen takes a worse turn when it combines with the nitrogen pollutants released by human activities. The lower atmosphere replete with the pollutants is a second layer of ozone which does not protect from UV rays. It increases the greenhouse effect warming the planet.
Tiasa Adhya
Down To Earth Feature Service

New materials may aid in capturing carbon
To sequester carbon dioxide as part of any climate-change mitigation strategy, the gas first has to be captured from the flue at a power plant or other source. Then, CO2 has to be released from whatever captured it so that it can be stored for the long term.
That second step can be costly from an energy standpoint. Materials currently used to capture CO2 have to be heated to release the gas. But chemists at the University of California, Los Angeles, say that a new class of materials they developed called metal-organic frameworks, or MOFs, hold promise for carbon capture. In a paper in The Proceedings of the National Academy of Sciences, Omar M Yaghi and colleagues describe one MOF, which they say can release most of the CO2 it captures at room temperature.
Yaghi described an MOF as a “crystalline sponge,” a hybrid lattice of organic compounds and metal atoms that has a huge internal surface area where gas molecules can be absorbed. The MOF used in the study contains magnesium atoms,” he said. In experiments, the material separated out CO2 while allowing methane to pass. What was surprising, was that at room temperature, 87 pc of the CO2 could be released. And if desired, the remaining 13 pc could be liberated by heating to about 175 degrees Fahrenheit, lower than temperatures currently required.
Henry Fountain
NYT News Service

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