Oil mats after BP spill pose long-term ecosystem threat: study

Auburn University researchers said oil mats submerged in the seabed more than a year after the biggest oil spill in U.S. history pose long-term threats to coastal ecosystems across the northern Gulf of Mexico. The study, released on Tuesday by the school's engineering department, showed that tarballs churned to the surface by Tropical Storm Lee and deposited along Alabama beaches this month had "essentially identical" chemical composition as samples taken from mats after the Deepwater Horizon oil spill. "Our interpretation of these observations is that submerged tar mats buried offshore of this coastline are breaking apart to yield these tar balls," the study reads, estimating the tarballs in question contained about 17 percent oil by mass. The civil engineering study -- conducted prior to, during and after the tropical storm's landfall on Alabama beaches -- indicated the spill's remnants remained largely unchanged 17 months after the Deepwater Horizon oil rig exploded and sank off the coast of Louisiana. The data directly linked the recently deposited tarballs to the 2010 event that resulted in more than 200 million gallons of oil spewing into the Gulf of Mexico from BP PLC's Macondo well. "The data question the validity of the widely held belief that submerged oil from the Deepwater Horizon accident is substantially weathered and thus depleted of most polycyclic aromatic hydrocarbons," the study said. "Also, it supports the hypothesis that submerged oil may continue to pose some level of long-term risk to nearshore ecosystems," it said.

Hydrogen fuel from just bacteria and water

Hydrogen, a potential clean energy source, can be sustainably generated using just seawater, river water and bacteria, according to new research. Hydrogen is a potentially valuable energy source, however environmental concerns about using fossil fuels to produce the gas, and about production costs, have limited its application so far. Previous studies have shown that hydrogen gas can be produced by harnessing the by-products of microbial organic matter metabolism in a device called a microbial electrolysis cell. But the process requires an additional input of electricity to make it work effectively. Now, according to a study published online in the Proceedings of the National Academy of Sciences, hydrogen can be produced in a single device by integrating a water-based power supply into the system. Exoelectrogenic bacteria are found in ponds, streams, sediments and soils, as well as in wastewater. As they metabolise organic matter they can transfer electrical energy to conductive materials such as metal or graphite. "[When they are used in Microbial Electrolysis Cells] bacteria produce electrical current, but not enough voltage to drive hydrogen gas production at the other electrode," says co-author of the new study Professor Bruce Logan, of Pennsylvania State University's Hydrogen Energy (H2E) Center.

Britain sees 'two autumns' as trees turn at different times

Autumn has come twice this year, according to the Woodland Trust, after the dry spring and invasive pests caused some trees to drop their leaves early. Traditionally the season of "mists and mellow fruitfulness" falls in late September as trees begin to turn gold and shed foliage. But this year many species lost their leaves early due to one of the warmest and driest springs on record. The Royal Horticultural Society recorded leaves turning yellow on hazelnut, acer and laburnum at the beginning of August. Horse chestnuts, or conker trees, lost their leaves early due to the leaf miner moth, from Turkey, that has been spreading across the country. Autumnal flowers like winter hellebores, viburnum and magnolia also came out early. But this was a "false autumn" caused by a lack of water rather than cold weather, explained Professor Tim Sparks, nature adviser to the Woodland Trust. Trees shed their leaves during a drought in order to retain water and survive. He said the real autumn is only just happening as native species like oak and ash, that are more used to the capricious British weather, begin turning. Prof Sparks urged the UK public to help record the "real autumn" by looking out for the vivid red, golds and browns of turning leaves. The study of the seasons, known as phenology, is important for measuring how the weather is changing in Britain with global warming.

Source: Green Times