Nature: Following the Deepwater Horizon oil spill in 2010, the US government concluded that one-fourth of the oil was unaccounted for. Scientists are now reporting that up to one-third of the spilled oil may have mixed with sediments and settled to the bottom of the Gulf of Mexico. A series of reports presented at the Gulf of Mexico Oil Spill and Ecosystem Science Conference show that surface material was deposited at 10 times the normal rate during and following the spill. That increased rate appears to have been caused by the oil creating clumps of plankton and sediment, which fell to the sea floor and formed a darker-than-normal layer. Observations during the spill recorded layers of water that would normally be full of plankton instead being clear—except for strings of material settling to the bottom. Why that occurred isn’t certain, though one report found that weathered oil may cause clumps to form more easily than clean oil. Another report suggests that the clumping material may have picked up even more oil as it reached lower levels before it settled and mixed with the sea-floor sediments. Although oil concentrations found in samples taken from the bottom of the Gulf have been low, the total volume of oil on the sea floor could be large if it was widely spread.
Science News: Waste heat from cars, power plants, and other fossil-fuel-burning machinery in the world’s largest urban areas can influence climate on a regional scale, and the “largest warming is not in the places where the energy is consumed.” This assessment comes from Ming Cai of Florida State University in Tallahassee and colleagues, in a study published online yesterday in Nature Climate Change. The researchers used computer simulations of 2006 energy use ifrom 86 of Earth’s largest cities and estimates of the waste heat emitted. Although the total amount of human-generated heat pales in comparison with that produced by the Sun, its influence on atmospheric circulation could raise temperatures by as much as 1 °C in northern Asia and North America, the researchers found.
BBC: What gives a molecule its odor is generally considered to be its shape. However, some researchers believe that quantum mechanics may play a role through the molecule’s quantized vibrations. Advocated by Luca Turin, now at the Alexander Fleming Biomedical Sciences Research Center in Greece, that theory has been tested by replacing hydrogen with its heavier isotope deuterium in various aromatic molecules. Deuteration lowers a molecule’s vibration frequency without changing its shape. Turin and his colleagues had previously showed that fruit flies could distinguish between normal and deuterated molecules, but an experiment with human subjects showed no difference. Turin’s team decided to repeat the experiment on humans, but this time using a much larger molecule in order to boost the effect of substituting deuterium for hydrogen. They found that the human subjects could distinguish the two molecules. The theory is still not widely accepted, however, with some scientists saying that only a microscopic look at the smell receptors’ structure and function will resolve the debate.
Science: A plane that crashed in Antarctica on 23 January has been located, and it has been determined that none of the three men onboard survived. The Twin Otter research plane had been traveling with its crew of two pilots and one mechanic, all Canadian, from a US base at the South Pole to an Italian research base. Rescue efforts were hampered by bad weather until Saturday, when two helicopter crews managed to survey the crash site from the air. The plane “appears to have made a direct impact that was not survivable,” said the Rescue Coordination Centre New Zealand, which has led the search, in a statement on its website. Because of the remote location of the crash in the Queen Alexandra mountain range, recovering the bodies may be difficult.