Current Affairs 2013 Current Affairs

Study: Mangroves in Florida expanding poleward

According to a study published in the Proceedings of the National Academy of Sciences (PNAS) journal, Mangrove trees, which are highly sensitive to cold, have expanded extremely on the pole ward side or on the Atlantic coast of Florida as the frequency of frosts has diminished.

Mangroves are restricted to the tropical areas as they cannot tolerate the extreme cold events that are so very typical of the temperate zone. Thus, the massive expansion of mangroves in the temperate zone of Florida during the last three decades is a proof of climate change’s role.

  • Over 28 years, the Florida coast, from Miami northwards, gained more than 3,000 acres of Mangroves.
  • The reason for this strange expansion/reduction in mangrove coverage boils down to extreme cold events — days colder than -4o C. The -4o C is the physiological temperature limit of mangrove survival.
Usefulness of Mangrove trees
  • They form a biomass of trees that tolerate salt in tidal areas near freshwater estuaries on tropical coastlines.
  • Support great biological diversity, including numerous species of crustaceans, fish, birds and molluscs.
  • Both salt marshes and mangroves help contain flooding, store atmospheric carbon and contribute to the expansion of the land mass.

Note: At present, Mangrove forests face deforestation from carbon production, aquaculture and urbanization, and are threatened by drainage from sewers, while salt marshes are threatened by waste-water pollution and rising sea levels.

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Marijuana becomes legal in Colorado

The US State of Colorado became the first state to legally sell marijuana and open the retail spots for pot.

About Marijuana
  • Marijuana is a greenish-gray mixture of the dried, shredded leaves, stems, seeds and flowers of Cannabis sativa – the hemp plant. Most people smoke marijuana, though it can also be used in other forms such as edibles, powders and oils.
  • In Colorado, both medical and recreational marijuana are legal. The drug used for controlling pain for medical issues, like cancer, nervous system diseases, glaucoma, migraines, etc and also used to treat nausea and improve appetites for people with HIV or other chronic illnesses.
  • Research shows that daily use of marijuana during adolescent years results in impaired learning, memory and decreased IQ.
The health effects of marijuana use
  • Short term effect – it can lead to a rapid heart rate, increase blood pressure, red eyes, dry mouth, increased appetite and slowed reaction time.

Long-term effect- impaired thinking, memory problems, panic attacks and other psychological issues. There have also been studies showing a weakened immune system and, for those who smoke the drug, impaired lung function.

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