下一个碳捕获工具可能是新的,改进的草

(PhysOrg.com)——一个草叶注定要被转化成生物燃料可能加入能源效率和其他高价策略努力减少大气碳——但不是你想象的方式。除了抵消化石燃料的排放,一个潜在的生物能源植物如草芒草也可以网罗大气中的碳和陷阱的土壤。听起来让人充满希望。但科学家通过基因工程生物能源作物应该更好地消除大气的温室气体?和这种策略可以发生在缓解气候变化所需的规模?这些问题是框架在一个新的分析劳伦斯伯克利国家实验室的科学家Christer简颂和橡树岭国家实验室的研究人员。他们的研究发表在《生物科学》10月期,探讨生物能源作物的方法可以成为一个大的驱动控制大气中二氧化碳水平的上升。作者希望得到他人不仅考虑工程植物生产生物燃料,但也封存碳。“我们希望鼓励讨论和研究这个话题,“简颂说,高级职员科学家在伯克利实验室的地球科学部门和作者的分析。“我们需要探索植物的程度,特别是转基因植物,可以减少大气碳含量的。“科学家们分析的核心是生物能源作物可以对抗气候变化在两个方面。 There’s the obvious way, in which a plant’s cellulosic biomass is converted into a carbon-neutral transportation fuel that displaces fossil fuels. And the not-so obvious way: bioenergy crops also take in atmospheric carbon dioxide during photosynthesis and send a significant amount of the carbon to the soil via roots. Carbon from plant biomass can also be incorporated into soil as a type of charcoal called biochar. Either way, the captured carbon could be out of circulation for millennia. At stake is the urgent need to make a dent in the nine gigatons of carbon that human activities emit into the atmosphere each year (one gigaton is one billion tons). Natural processes such as plant photosynthesis annually capture about three gigatons of carbon from the atmosphere. “We could double that in the next several decades,” says Jansson. “By 2050, we could get to five or six gigatons of carbon removed from the atmosphere by plants, and I think a major part of that could come from bioenergy crops like grasses and trees. They could make a big contribution in sequestering carbon, but other strategies will have to be used.” As Jansson explains, to increase the capacity for plants to act as carbon sinks, scientists need to continue to develop bioenergy crops that are efficient in harvesting light energy and using the energy to convert carbon dioxide to biomass. Bioenergy crops should also have a high capacity to send the carbon it captures to its roots, where it has the best chance to be stored in soil for thousands of years. Fortunately, top bionergy crop candidates, such as Miscanthus, are already better-than-average carbon sinks. The large root systems in perennials such as grasses make them better at sequestering carbon in biomass and soil than annual plants. But can bioenergy crops become even better? Jansson and colleagues outline several possibilities in their analysis. A plant’s canopy can be altered to enhance its efficiency at intercepting sunlight. Another approach accelerates a plant’s photoprotection mechanisms, which would improve its ability to use light. And a plant’s tolerances to various stresses could be improved without compromising yield. A game-changing success, Jansson explains, could be the design of a bioenergy crop that can withstand drought and which utilizes brine, saline wastewater, or seawater for irrigation to avoid having to tap into freshwater supplies. Jansson suggests that genetic engineering can play a key role in introducing these traits into a plant. “Bionergy crops are likely to be engineered anyway,” he says. “It makes sense to also consider enhancing their ability to withstand stress and sequester carbon. This analysis will hopefully guide research and prompt people to think in new ways about bioenergy crops.”