Tropical Biofuels Getting Less and Less Green

Picture of rainforest

Knockdown fight. New research suggests that using tropical rainforests to grow biofuels could be even trickier than previously estimated.

A new analysis suggests that biofuels grown in the tropics are not a much greener source of energy than drilling for oil–at least in the short term. The research paints an even gloomier picture of biofuels than previous studies, which have begun to cast doubts on the greenhouse gas benefits that these alternatives to petroleum might provide.

Proponents see plant-based biofuels as a carbon-friendly alternative to fossil fuels. That’s because plants that produce, say, palm oil or corn ethanol recycle carbon dioxide from the atmosphere as they grow. In contrast, petroleum production introduces new carbon into the air that was previously sequestered deep within Earth.

Two studies published earlier this year in Science, however, suggest that the carbon benefits from biofuels are delayed for centuries when farmers knock down carbon-absorbing forests in order to grow the plants. One paper, for example, estimated that cutting down Brazilian rainforest to grow soybeans for diesel fuel would result in a so-called carbon debt that would take 319 years to repay–essentially rendering the fuel as carbon-unfriendly as gasoline in the short term.

But critics, including the U.S. Department of Energy, have charged that such analyses underestimate the yield of biofuel crops, especially those grown in the tropics.

To get a better sense of just how green biofuels are, Holly Gibbs, a tropical land-use scientist at the University of Wisconsin, Madison, and colleagues used newly available data on the yields of 10 crops in various seasons and ecosystems within South American, African, and Asian rainforests. Even when Gibbs assumed that the plants would perform in the top 10% of all global varieties–with corn ethanol varieties, for example, producing more than seven times as much ethanol as current species in Africa–the picture remained gloomy. For example, corn grown with high yields in tropical forests (thanks to fertilizer, irrigation, and sophisticated farming) repaid its carbon debt in 100 years: five times faster than corn grown at normal yields. But the improvement is still a "losing proposition," Gibbs says, given the goal of stemming carbon emissions immediately. What’s more, she notes, such yields would be hard to achieve throughout the developing world anyway given the cost of world-class agriculture.

To make biofuels more efficient, Gibbs suggests growing biofuel crops in places where trees wouldn’t have to be cut down, such as in West African scrublands where cocoa plantations once grew. Otherwise, growing, say, oil palm trees on land that was previously carbon-rich peatland forests in Southeast Asia can create a nearly millennium-long carbon debt, the team reports online today in Environmental Research Letters. The paper highlights the short-term risk of ramping up production of tropical biofuels and cutting down carbon-rich forests to grow them, says Gibbs.

The new studies offer a set of estimates more precise than before for the carbon tradeoff that biofuels entail, says Princeton University agricultural expert Timothy Searchinger, an author of one of the Science papers. "Forests and grasslands have a lot of carbon, so there is really no way to transform those lands into biofuel crops that produce net benefits," he says.

 

 

A Trickle on the Moon

Picture of volcanic glass bits

Beady clues. Water molecules lurk in these volcanic glass bits from the moon’s surface.

Credit: NASA

A team of researchers has discovered the first evidence of water on the moon. A new type of chemical analysis has spotted the telltale signs of water molecules inside tiny beads of volcanic glass brought to Earth decades ago by the Apollo astronauts. The find may force astronomers to rethink their theories of how the moon formed, and it might mean that future missions could mine water from the lunar soil, helping to sustain colonists and fuel voyages to other planets.

Soon after it coalesced, about 4.5 billion years ago, Earth took at hit from a Mars-sized object. The resulting cloud of debris eventually condensed to form the moon–or so the current thinking goes. But if the moon came from Earth, and Earth is awash with water, where is the lunar water?

Many planetary scientists think any water blown away from Earth by the impact would have been instantly vaporized by the high temperatures of the collision. Nevertheless, some researchers continue to believe that the moon does contain some water, perhaps locked deep within its interior. Over the years, they’ve intensely scanned tiny glass beads–brought back by the Apollo missions in the 1960s and 1970s–that had been ejected from inside the moon by volcanic eruptions about 3 billion years ago. Up to now, however, these samples have shown no evidence that the liquid ever existed on the moon.

A team led by geochemist Alberto Saal of Brown University decided to use a more sensitive method. The technique, called secondary ion mass spectrometry, was developed to detect trace amounts of volatile gases such as chlorine and fluorine in Earth soil samples. Applying it to the lunar samples, the team found trace amounts of water–about 46 parts per million–in the volcanic beads. Because the water was embedded in the beads, it can’t be a contaminant picked up since the samples arrived on Earth, the researchers report tomorrow in Nature.

Saal declines to speculate about how much water the moon contains or if any of it is still present in liquid form. Extrapolating the results to estimate the amount of lunar water would be like predicting "the final score of the game after we saw the first touchdown in the first 5 minutes of the first quarter," he says. Meanwhile, he and his team will be studying as many lunar glass beads as possible to refine their analysis.

Planetary scientist David Stevenson of the California Institute of Technology in Pasadena calls the findings important and says they open up a new possibility. "It is likely that at the time of the giant impact, Earth had water and the impacting body had water," he says, so some of that water might still be trapped in the moon.

Rain on the Martian Plain?

 

 

Picture of channels

Before the rains came. Martian water may have carved out channels like these early in its history, but eventually the torrents were replaced by light rain.

Martian soil data collected by five robotic missions indicates that rain fell on the Red Planet billions of years ago. The findings provide no new insight into the possibility of martian life, but they do suggest that further clues to Mars’s past could be found right here on Earth.

There’s little doubt now that Mars once was wet. The twin Mars Exploration rovers–Spirit and Opportunity–have been finding signs of water-associated minerals for 4 years now. And less than 2 weeks ago, the Phoenix Mars Lander struck water ice while digging at the north polar region (ScienceNOW, 20 June). What remains to be determined is where this wetness came from and how long it lasted. Preliminary investigations by Mars mission scientists, as well as high-resolution images taken by orbiters, have suggested that water on Mars surged up from deep below the surface, sometimes carving extensive channels and gullies (see photo).

Now, a team led by geologist Ronald Amundson of the University of California, Berkeley, has found indications of rain by studying our own planet’s geochemistry. Analyzing soil samples collected by five previous missions, including the 1976 Viking and 1997 Pathfinder landers, the researchers found a distinctive pattern of chloride and sulfate deposits. In all of the samples, the data show that the sulfates tend to stay nearer to the surface, whereas chloride concentrations increase with depth. That’s the same pattern found in extremely arid places on Earth such as Antarctica’s dry-valley regions and Chile’s Atacama Desert. In these areas, rain is light and infrequent, but over millions of years it can change the chemical makeup of soil by depositing sulfates near the surface and by transporting the more soluble chlorides farther into the soil.

So the picture emerging is that by about 3 billion years ago, the biggest bodies of water on the martian surface, which were derived from groundwater, had mostly frozen or evaporated, the researchers report online this month in Geochimica et Cosmochimica Acta. Then a prolonged period of intermittent drizzle and dew began. That climate apparently continued long enough to alter the chemistry of surface minerals, creating the pattern detected by the analyses.

It’s a convincing argument, says planetary scientist Itay Halevy of Harvard University: "Atmospherically delivered water and downward migration of salts, both common processes on Earth, played a part in the formation of martian soils, too." Moreover, the results "provide further chemical support for what previous studies have found: that during early parts of Mars’s history, liquid water existed on the surface for geologically significant periods of time."

Pollutants in the deep-ocean food web

Scientists say the concentrations of pollutants they documented in deep-sea squid are surprising?

Research published online May 22 in Marine Pollution Bulletin presents new evidence that human-made contaminants are finding their way into the deepest parts of the ocean. The paper is one of the first reports of persistent organic pollutant uptake by deep-sea mollusks, an important part of the marine food chain.

This deep-sea mollusk, <em>Histioteuthis reversa</em>, is called the jewel squid because of its many photophores, or light-producing organs, which appear as dark dots on its skin.

MICHAEL VECCHIONE, NOAA/NMFS
This deep-sea mollusk, Histioteuthis reversa, is called the jewel squid because of its many photophores, or light-producing organs, which appear as dark dots on its skin.

A team of researchers from the Virginia Institute of Marine Science and the National Marine Fisheries Service (NMFS) collected nine species of cephalopods, a class of organisms that includes octopods, squids, cuttlefish, and nautiluses, from depths between 1000 and 2000 meters (about 3300 to 6600 feet) in 2003 in the western North Atlantic Ocean. The team selected species for chemical analysis on the basis of their importance as prey and analyzed specimens for 11 classes of anthropogenic chemical contaminants. The compounds the researchers detected include DDT, PAHs, PCBs, PBDEs, tributyltin, and toxaphene.

“It was surprising to find measurable and sometimes high amounts of toxic pollutants in such a deep and remote environment,” says coauthor Michael Vecchione of NMFS.

Although scientists have previously looked for persistent organic pollutants in deep-sea fish, there is little information on such chemicals in deep-sea cephalopods. The large variety of contaminants that the scientists reported in the new paper makes it “apparent that contamination of the deep-sea oceanic food web is occurring,” they write.

“The cephalopod species we analyzed span a wide range of sizes and represent an important component of the oceanic food web,” Vecchione says. He explains that he and his colleagues initiated the study in response to recent reports documenting the accumulation of persistent organic pollutants in the blubber and tissues of whales and other predatory marine mammals as well as in some deep-sea fish. The researchers set out to determine whether whales have a unique capacity to accumulate pollutants or are simply one of the top predators in a contaminated deep-sea food web. The finding that cephalopod tissues contained some of the same compounds that have been reported to bioaccumulate in marine mammals points to the latter hypothesis.

“Contamination of the deep-sea food web is happening, and it is a real concern,” Vecchione concludes.

ScienceShots

ScienceShots

  • Antarctic iceCrash! In one doomsday scenario, global warming triggers titanic chunks of ice to break and slide off the Antarctic landmass, causing sea levels to rise by meters. The surrounding Antarctic ice shelf has been splitting over the past 2 decades–but is this a harbinger of doom or just part of some natural cycle? Researchers using underwater acoustic sensors originally designed to detect nuclear explosions have listened to the grinding and cracking of the ice, and they have now determined that–at least over the past 7 years–there has been no increase in Antarctic ice shelf break-up. The results, reported this week at the Acoustics 2008 meeting in Paris, France, provide a baseline for the rate of Antarctic splitting. The question now is whether it will increase as the temperature rises.

江苏省政府安排专项经费技术攻关污水处理厂提标改造

一项为江苏省太湖流域169座城镇污水处理厂“提标”改造提供技术支撑的技术攻关及示范科研项目,近日,正在紧锣密鼓全面铺开。这项由江苏省政府专项安排2000多万元专项经费进行的除磷脱氮技术攻关,共设10个课题项目,项目大半“花落无锡”。今年6月底之前,完成的攻关成果,将对现有的污水厂和新建污水厂“提标升级”,起到实实在在的指导作用。
  根据国家和省太湖流域水污染防治工作的要求,在2008年底之前,江苏省需完成对太湖流域139个已投运、30个在建的城镇污水处理厂全面进行除磷脱氮改造,总规模365万吨/日,约需投资27亿元。据悉,这次太湖流域所有城镇污水处理厂都将要执行的最为严格的排放标准,与原先的排放标准相比,COD排放标准限值将由原先的60~120毫克/升,提高到50~60毫克/升;氨氮排放标准限值将由原先的15毫克/升,提高到5毫克/升;总磷排放标准限值将由原先的1毫克/升,提高到0.5毫克/升。通过这次“提标升级”,将进一步压减太湖流域的排污总量。尤其是169座污水处理厂全面除磷脱氮“提标”后,有助于改善太湖湖体的富营养化程度。
  由于江苏省太湖流域这项除磷脱氮“提标”工作走在全国前列,加上现有的污水厂的处理工艺不尽相同。为确保这次大规模除磷脱氮改造技术和设备的经济适用,并在规定时间内完成污水厂“提标升级”,江苏省政府拨出专项资金开展10个课题的技术攻关,课题框架中还考虑了城镇污水厂进水中的氮、磷污染物来源研究以及后续把关的生态处理技术研究等。
  无锡市在污水除磷脱氮及生态处理方面已进行了大量的实验,积累了相当经验,人工湿地项目更是先行一步,因此,有6个招投标项目“花落无锡”。目前6个课题已全部进入开题报告阶段,攻关成果将为下半年太湖流域众多污水厂改造,提供多种方案及成本、耗能方面的数据,可供污水处理厂自行选择改造方案。

业务

* 水处理技术开发及工程设计(给排水乙级资质)

* 环境规划与影响评价(环境影响评价甲级资质);

* 水资源论证(水文、水资源调查评价甲级资质);

* 污染环境修复以及资源综合利用;

* 清洁生产与风险评价;

* 环境质量监测、检测;

* 环境保护科技咨询;

* 环境保护相关领域专业翻译;

* 环境保护教育与培训。

 

古力特心中历史最佳11人:超级锋线 球王非他莫属

古力特心中历史最佳11人:超级锋线球王非他莫属

  新浪体育讯 足坛巨星古力特接受英国《442》杂志邀请,评出了自己心中的历史最佳11人阵容。

  守门员:舒梅切尔

  他在球门前有着巨大的影响力,而且让人随时感到他的存在,这是他的优势。无论什么时候我和他交锋时,他都是一个很难击败的守门员。他不仅仅在曼联踢得好,1992年欧洲杯上他代表丹麦赢得了冠军,也展示出自己在国家队舞台上也是最好的。

  右后卫:曼弗雷德-卡尔茨

  在80年代他为汉堡踢球,因为香蕉球传中而闻名,他的传中有非常大的旋转,非常难防守,而前锋们利用这种传球可以很轻易的破门。他也是最早的攻击型边后卫之一,他几乎发明了进攻边后卫这个概念,远在卡福和卡洛斯之前。而且他还非常擅长主罚定位球。

  中后卫:巴雷西

  后防线上的领袖,非常强壮和迅捷,而且对比赛有着非凡的理解。作为一个后卫,他可以做到一切,很多时候,他对前锋们跑位的了解,就像他就是那个前锋一样!你怎么能越过这样的防守者呢?

  中后卫:德塞利

  一个非常强壮的后卫,在空中十分优秀,这是你所需要的。他还有速度和爆发力,能让前锋们慌乱的做动作从而犯错误。他不是一个绝对的领袖,但却是一个非常有经验的后卫,他能很好的和巴雷西合作。

  左后卫:马尔蒂尼

  历史上最好的球员之一,他现在还在比赛,这表明了他有着多么好的运动天赋。不过和其他的伟大边后卫不同,当他只防守或者只进攻时,都不是世界级的,可作为一个边后卫,他却能同时做到这两样,而且综合起来比其他多数人都好。他还是一个优秀的中后卫。

  右前卫:卡卡

  有着优秀的速度和天赋,是我见过不多的能在带球时比不带球还快的几个人之一。他还有很好的视野,能让队友也发挥的很好,而让对手很糟糕。目前,他绝对是世界上最好的选手之一。

  中前卫:里杰卡尔德

  一个有着视野和力量的优秀防守型中场,我在俱乐部和国家队和他一起效力了很多年,他是最好的之一。他靠着自己的影响力、力量和技术统治着中场,他会帮助球队发起进攻,而确保其他球队不对防线进行突击。他给所在的任何球队都带来了平衡。

  中前卫:马拉多纳

  我还需要给理由吗?有史以来最好的球员,比贝利更好。在意大利,我每周都近距离看他踢球,他比其他任何人都高一个档次,他做的一些动作令人难以置信。他可以不用看就能在脚下控球,这意味着他能比任何人都更快的预见到发生的一切,并且最快的做出决定。

  左前卫:戴维-库珀

  在欧洲冠军杯上我和他交锋过,当时他为格拉斯哥流浪者队效力,他是一个真正有技术的球员,令人难以置信的技术。他并没有太快的速度,但他的盘带太好了,能给队友创造大量机会,自己也打进了一些好球。前锋:克鲁伊夫

  他有着一切素质。视野、态度、影响力,而且很灵活。当对手试图踢他,他会总先预判到,然后及时的移动,后卫根本碰不到他。他可以成为中锋身后的活动者,但他本身也是一个非常高效的射手。

  前锋:巴斯滕

  在空中很强壮,而且能给自己创造进球机会。虽然他很高,但很灵活,可以很聪明的转身以及做一切动作。头球、倒勾、凌空、一切。他也是一个以牙还牙的球员,如果后卫们踢他,他会回敬踢他们。在场上,他知道怎么处理一切。

  主教练

  弗格森

  肯定是弗格森,因为他的经历、他的成就,无论是在球场上还是在生活中。

  替补

  齐达内

  最近十多年里最好的球员,他可以控制比赛,而且重要的是,他在关键时刻总会有所表现。

  罗纳尔迪尼奥

  又是一个灵活多变的球员,他的一些动作令人难以置信。我不知道他是否愿意和齐达内一起坐在板凳上。

  罗伊-基恩

  优秀的防守中场,在场上还是一个领袖,又一个我非常喜欢的球员。

  科曼

  一个好后卫,另外和其他一些优秀球员一样,是一个天生的领袖。靠着任意球,他能在关键时刻破门,这给球队带来了很大的便利。

  范德萨

  对一些人来说,我选他也许有点意外,但我非常喜欢他,一个优秀门将。