Opah the first deep warm-blooded fish ever discovered
New research by NOAA Fisheries has revealed the opah, or moonfish, as the first fully warm-blooded fish that circulates heated blood throughout its body much like mammals and birds, giving it a competitive advantage in the cold ocean depths. The silvery fish, roughly the size of a large automobile tire, is known from oceans around the world and dwells hundreds of feet beneath the surface in chilly, dimly lit waters. It swims by rapidly flapping its large, red pectoral fins like wings through the water. Fish that typically inhabit such cold depths tend to be slow and sluggish, conserving energy by ambushing prey instead of chasing it. But the opah’s constant flapping of its fins heats its body, speeding its metabolism, movement and reaction times, scientists report in the journal Science. That warm-blooded advantage turns the opah into a high-performance predator that swims faster, reacts more quickly and sees more…
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Ice ages in the Southern Hemisphere are influenced primarily by sea surface temperature and atmospheric carbon dioxide rather than changes in the Earth’s orbit
A new international study casts doubt on the leading theory of what causes ice ages around the world — changes in the way the Earth orbits the sun. The researchers found that glacier movement in the Southern Hemisphere is influenced primarily by sea surface temperature and atmospheric carbon dioxide rather than changes in the Earth’s orbit, which are thought to drive the advance and retreat of ice sheets in the Northern Hemisphere. The findings appear in the journal Geology. The study raises questions about the Milankovitch theory of climate, which says the expansion and contraction of Northern Hemisphere continental ice sheets are influenced by cyclic fluctuations in solar radiation intensity due to wobbles in the Earth’s orbit; those orbital fluctuations should have an opposite effect on Southern Hemisphere glaciers. “Records of past climatic changes are the only reason scientists are able to predict how the world will change in the…
Convergent evolution in land to sea transitions in marine predators across major mass extinctions
For more than 250 million years, four-limbed land animals known as tetrapods have repeatedly conquered the Earth’s oceans. These creatures–such as plesiosaurs, penguins and sea turtles–descended from separate groups of terrestrial vertebrates that convergently evolved to thrive in aquatic environments. In a new scientific review, a team of Smithsonian scientists synthesized decades of scientific discoveries to illuminate the common and unique patterns driving the extraordinary transitions that whales, dolphins, seals and other species underwent as they moved from land to sea. Drawing on recent breakthroughs in diverse fields such as paleontology, molecular biology and conservation ecology, their findings offer a comprehensive look at how life in the ocean has responded to environmental change over time. The paper also highlights how evolutionary history informs an understanding of the impact of human activities on marine species today. More information is available in the April 17 issue of Science. Marine tetrapods represent a…
New meltwater is not likely to further lubricate the Greenland Ice Sheet waterslide
Surface meltwater regularly travels to the bottom of the Greenland Ice Sheet and lubricates the flow of the ice into the ocean, but new research indicates that future increasing volumes of this meltwater are unlikely to speed the flow of the ice sheet. How is the Greenland Ice Sheet like an oil drill site? They both host the process of fracking, which is the use of high-pressure fluid to enhance existing cracks. In an oil field, high-pressure drilling fluid widens and deepens cracks in oil-bearing rocks, opening access to more deeply buried fossil fuels. On the Greenland Ice Sheet surface, meltwater fills cracks in the ice. Water is more dense than ice, which creates pressure that pries the cracks open. If there is enough water, a crack can reach the bottom of the ice sheet, opening a path for surface water to flow down to the bottom of the ice…
Abnormally high plume observed above surface of Mars
Plumes seen reaching high above the surface of Mars are causing a stir among scientists studying the atmosphere on the Red Planet On two separate occasions in March and April 2012, amateur astronomers reported definite plume-like features developing on the planet. The plumes were seen rising to altitudes of over 250 km above the same region of Mars on both occasions. By comparison, similar features seen in the past have not exceeded 100 km. “At about 250 km, the division between the atmosphere and outer space is very thin, so the reported plumes are extremely unexpected,” says Agustin Sanchez-Lavega of the Universidad del País Vasco in Spain, lead author of the paper reporting the results in the journal Nature. The features developed in less than 10 hours, covering an area of up to 1000 x 500 km, and remained visible for around 10 days, changing their structure from day to…
Is the mind algorithmic? Confusing science speak with layman language
“Evolution is just a theory.” This claim, often made by creationists, is clearly based on a confusion of the scientific meaning of the word “theory” with its meaning in common language. We can forgive confused creationists, though, as most of them unfortunately know very little about science (all the more important it is for us to explain our research in a clear way). However, when scientists themselves make such mistakes, perhaps we should be less forgiving. In science, a theory is a well-established body of knowledge about a certain subject, supported by observable facts, repeatable experiments, and logical reasoning. However, in common language the word “theory” is often used to mean “hypothesis”, “proposition”, or even “speculation” (indeed, these synonyms are all listed in the dictionary). Darwin’s theory of evolution is scientifically well-established (it has been so for more than a century), and is definitely more than “just a hypothesis.” It…
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