SNIPPETS - Clouds help amplify El Nino effect

SNIPPETS - Clouds help amplify El Nino effect

Clouds help amplify El Nino effect

Clouds help amplify El Nino’s effect on the atmosphere to a greater degree than once thought, a new study reports. In El Nino conditions, sea surface temperatures in the Pacific Ocean become unusually warm and tall thunderheads, known as cumulonimbus clouds, form over the water. Above them, a layer of colder cirrus clouds also appears. The cirrus clouds trap heat.

“They act as a blanket and further warm the atmosphere,” said Thorsten Mauritsen, a meteorologist at the Max Planck Institute for Meteorology in Germany and one of the study’s authors. In the areas that surround El Nino, cumulonimbus clouds are rarer and the sea is more often covered by lower clouds, which cool the air. Thorsten and his colleagues compared climate model simulations that accounted for the role of clouds with models that did not. They found that if clouds are not factored in, the strength of an El Nino event is underestimated by about two-thirds. “This phenomenon has a big impact on life around the Pacific and I can see how it could help us anticipate climates of the future,” he said. The study appears in the journal, Nature Geoscience.


Ants can change roles
Among Florida carpenter ants there are the so-called majors, brawny soldiers that guard the colony, and the smaller minors that act as foragers. But membership in these castes is not set in stone, a new study found.

By treating ants with chemical compounds, researchers were able to make young majors behave like minors. The compound manipulates the ants’ epigenetic makeup, which governs which genes are turned on and off but does not alter their DNA. “These are long-term, permanent changes that occur when we inject the brain with these chemicals,” said Shelley Berger, an epigeneticist at the University of Pennsylvania and one of the study’s authors.

However, the treatment did not alter the physical appearance of the ants; majors were still larger than minors. The study appeared in the journal Science. The researchers found that certain compounds could modify proteins called histones, which affect how tightly DNA is coiled and whether certain other proteins are able to gain access to it. But they also found that the majors’ behaviour could be changed only in the first few days of life. “This was surprising, and we still don’t understand why,” said Danny Reinberg, a biochemist at New York University and another author of the study.


Romans were affected by parasitic infections
Two thousand years ago, the ancient Romans introduced public multiseat toilets, hand-washing stations, sewage systems, aqueducts for drinking water and heated public baths. A new study finds that despite these sanitation advances, Romans of the time suffered just as many, if not more, parasites and ectoparasites, like lice and fleas, as their counterparts in the preceding Iron Age. This may have been the indirect result of laws that required residents to remove excrement and rubbish from their towns, said Piers Mitchell, a palaeopathologist at the University of Cambridge in Britain and one of the study’s authors. “The excrement was used to fertilise crops and the feces would have contaminated the crops,” he said. Mitchell and his colleagues reported their findings in the journal Parasitology.

His study is the first to use archaeological evidence to assess how Roman practices affected health. Piers looked for evidence of parasites in ancient latrines, human burial sites, fossilised feces, and in combs and textiles from excavation sites across Europe. The study found that fish tapeworm eggs in particular were very widespread in Europe during the Roman Empire as compared with the Iron Age. Romans were fond of a fish sauce called garum, Piers said. The sauce was not cooked, which might have destroyed the tapeworms, but fermented in the sun. “They used it to dip bread into, and it was traded across the empire,” Piers said.


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