Eco/Env English
등록일 : 2018-04-11 14:18 | 최종 승인 : 2018-04-11 14:18
Cedric Dent

[리서치페이퍼=Cedric Dent 기자] NASA has announced that it has extended a grant to American aerospace to the tune of $2.85 million in order to study the gradual changes that happen over a set period of time in earth's atmosphere. The study is expected to focus on the ionosphere in particular and thereby supplement the two satellite missions that NASA is set to launch this year. There's a lot that can be gleaned from this atmospheric study, as is intended, but some of those things relate to global warming's effects where atmospheric science is especially pertinent. Researchers at the University of Miami are actually conducting a study that speaks to the carbon budget we can expect to have in the future, and another team at the University of California, Davis is conducting a study that points to a novel source of the world's nitrogen other than the atmosphere itself.

The gases in earth's atmosphere have a lot to do with what rains back down on us, the climate effects we're experiencing these days and the predictions we can make about future environmental conditions. Nitrogen is one gas that people are often most likely to look to the atmosphere to find, but the new University of California, Davis study suggests that we could significantly lift our spirits about climate change projections because as much as a quarter of that nitrogen apparently originates from bedrock on Earth according to the study. This upends centuries of scientific thought on the subject. Mind you, to a lesser extent than carbon dioxide, nitrogen is a chemically vital gas for plants.

The study was just published Friday in Science, and it found that 26 percent of the world's nitrogen — that of known natural ecosystems — comes from rocks, which originally was believed to come from the atmosphere like all the rest. It's a somewhat groundbreaking discovery because the global scientific community has long been under the impression that no such nitrogen contribution was reaching the global land system. Climate change predictions are predicated on our current analyses of the carbon cycle, and this changes that significantly because it represents a nitrous feedback loop that lets ecosystems pull greater emissions from the atmosphere according to the study.

"Our study shows that nitrogen weathering is a globally significant source of nutrition to soils and ecosystems worldwide," said Ben Houlton, a co-lead author on the UC Davis study as the director of the Muir Institute. "This runs counter the centuries-long paradigm that has laid the foundation for the environmental sciences. We think that this nitrogen may allow forests and grasslands to sequester more fossil fuel CO2 emissions than previously thought." Nitrogen's a necessary element for ecosystems to absorb CO2 pollution, and there's only so much of it coming from plants themselves or the soils in which they're rooted.

Natural ecosystems such as boreal forests, however, might be able to consume higher levels of carbon dioxide than we thought if this much nitrogen is coming from rocks. The fact remains, though, that not every rock can have this effect; it's an effect yielded by the weathering of said rocks, whether physical or chemical. Chemical weathering, for example, would be minerals reacting to rainwater, and physical weathering would be more like tectonic shifts. "Geology might have a huge control over which systems can take up carbon dioxide and which ones don't," Houlton explained. "When thinking about carbon sequestration, the geology of the planet can help guide our decisions about what we're conserving."

The University of Miami study, meanwhile, is being conducted in the School of Marine & Atmospheric Science. Researchers are looking at how the Black Sea's oxygen-deprived waters answer common inquiries about the utmost depths of the ocean as well as the global climate. The study found that both biological and chemical processes happening in the Black Sea are akin to those of the oxygenated deep ocean despite the lack of oxygen in the Black Sea. That bears the implication of new insights into the role deep oceans play in storing carbon, which facilitates the dampening of human-driven climate change.

"Understanding such processes is especially important today since oxygen in the ocean is decreasing, largely due to the warming of ocean waters driven by climate change," according to the lead author of the study, Andrew Margolin, who serves as a postdoctoral researcher at the College of William & Mary's Virginia Institute of Marine Science. He's also an alumnus of the Rosentiel School himself. In lieu of that oxygen dearth, scientists discovered that organic carbon respiration in the Black Sea isn't really so different from what happens in the deep ocean. One thought about how this is so has been that less oxygen in the deep ocean might assuage carbon respiration to CO2, thereby building up organic carbon.

That carbon buildup in the ocean would restrict carbon releases toward the atmosphere in the form of CO2, too, which is good for combating global warming. Comprehending the carbon exchange between the atmosphere and earth's oceans is requisite for comprehending the scope and nature of the global warming situation, including how it has varied in the past and might vary in the future. The oceans have taken in about a third of man's CO2 contributions, which mitigates CO2-based greenhouse effects. "Insights into oceanic carbon transformations — including the oxygen dependence of organic carbon respiration — can be gained by studying the anoxic Black Sea," Margolin explained.

[researchpaper 리서치페이퍼=Cedric Dent 기자]

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