Scientists discover 'rain-making' bacteria - implications for agriculture, climate

A team of American and French scientists has found evidence that rain-making bacteria are widely distributed in the atmosphere. The remarkable findings shed an entirely new light on how rain is formed. The biological particles they discovered could factor heavily into the precipitation cycle, affecting climate, agricultural productivity and even global warming. What is more, the research findings could potentially supply knowledge that could help reduce drought from America to Africa. The team published their results in Science today.

Brent Christner, Louisiana State University (LSU) professor of biological sciences in partnership with David Sands, Montana State University (MSU) professor of plant sciences and plant pathology, and colleagues Christine Foreman (MSU) professor of land resources and environmental sciences, Rongman Cai (LSU) and Cindi Morris of the Institut Nationale de la Recherche Agronomique, examined precipitation from locations across the world to show that the most active ice nuclei are actually biological in origin.

Nuclei are the seeds around which ice is formed. Snow and most rain begins with the formation of ice in clouds. Dust and soot can also serve as ice nuclei. But biological ice nuclei are different from dust and soot nuclei because only these biological nuclei can cause freezing at warmer temperatures.

Biological precipitation, or the 'bio-precipitation' cycle, is basically is this: bacteria form little groups on the surface of plants. Wind then sweeps the bacteria into the atmosphere, and ice crystals form around them. Water clumps on to the crystals, making them bigger and bigger (picture, click to enlarge). The ice crystals turn into rain and fall to the ground. When precipitation occurs, then, the bacteria have the opportunity to make it back down to the ground. If even one bacterium lands on a plant, it can multiply and form groups, thus causing the cycle to repeat itself.

The team's work is far-reaching. Professor Sands and his colleagues have found the bacteria all over the world, including Montana, California, the eastern U.S., Australia, South Africa, Morocco, France and Russia.

The role that biological particles play in atmospheric processes has been largely overlooked. However, we have found biological ice nuclei in precipitation samples from Antarctica to Louisiana - they're ubiquitous. Our results provide an impetus for atmospheric scientists to start thinking about the role these particles play in precipitation. This work is truly multi-disciplinary, bridging the disciplines of ecology, microbiology, plant pathology and climatology. It represents a completely new avenue of research and clearly demonstrates that we are just beginning to understand the intricate interplay between the planet's climate and biosphere. - Brent Christner, LSU professor of biological sciences

The team's research shows that most known ice-nucleating bacteria are associated with plants and some are capable of causing disease.

Bacteria have probably been around for a million years. They live on the surface of plants, and may occasionally cause plant disease. But their role in rain-making may be more important. - David Sands, MSU professor of plant sciences and plant pathology

Indeed, the implications of a relationship between rain and bacteria could be enormous, though they are yet to be proven, Sands said. For example, a reduced amount of bacteria on crops could affect the climate. Because of the bio-precipitation cycle, overgrazing in a dry year could actually decrease rainfall, which could then make the next year even dryer. Drought could be less of a problem once we understand all of this:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: agriculture :: drought :: precipitation :: rain :: bacteria :: microbiology ::biosphere :: atmosphere ::

Professor Sands (pictured), who earned a doctorate in pathology and bacteriology from the University of California Berkeley, proposed the concept of bio-precipitation approximately 25 years ago, but few people believed him.

Since that time, he said, better tools have changed the research climate, because new DNA technology allows researchers to distinguish the bacteria, and giant computers allow people to do meteorological studies with satellites. Time and technology proved him right and the concept of 'bio-precipitation' is now a reality.

More studies must be done, though, because questions remain. For example, since the bacteria do not grow above 84 degrees, precipitation could be affected if the world's weather creeps up and reaches a cut-off point. The researchers are also examining the bacteria to find out if they vary by region.

A diverse group of people should be interested in the research, because bio-precipitation could affect many things, from agriculture and water availability to local climate and even global warming.

Top picture: Cells of ice nucleating bacteria (green dots) entrapped in ice crystals. Credit: Brent Christner.

References:
Brent C. Christner, Cindy E. Morris, Christine M. Foreman, Rongman Cai, David C. Sands, "Ubiquity of Biological Ice Nucleators in Snowfall", Science 29 February 2008: Vol. 319. no. 5867, p. 1214, DOI: 10.1126/science.1149757

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Bernanke favors lower tariffs on Brazilian ethanol

U.S. Federal Reserve Chairman Ben Bernanke has said he favors cutting high tariffs on Brazilian ethanol. He thereby joins a growing rank of world leading economists, energy experts, social scientists, international development institutions (like the IMF and the World Bank), economic think tanks (like the OECD), key food and agriculture analysts (like the FAO and the IFPRI) and development organisations, who have all spoken out in favor of international free trade in biofuels. Many of these analysts have said current high food prices are partly the result of protectionism in the biofuels market.

Biomass based fuels can be made in a far more efficient, environmentally friendly and cost effective way in countries like Brazil and other nations in the Global South. Countries in the North should import these fuels, which would end pressures on food markets and benefit consumers. But both the EU and the US levy high tariffs on these biofuels, to protect their own inefficient, subsidized producers.

Speaking before the Senate Banking Committee, Bernanke said in this context:

As you know, I favor open trade and I think allowing Brazilian ethanol, for example, would reduce costs in the United States.

Most of the ethanol made in the United States comes from corn, and domestic production is protected from much more efficient and cost-effective sugar-based Brazilian ethanol by a steep, US$0.54 per gallon tariff. This uncompetitive reliance on corn has distorted global food markets. Bernanke said it was hard to say how much current strong demand for ethanol was boosting food prices.

But it is the case that a significant portion of the corn crop is being diverted to ethanol, which raises corn prices. And there's some knock-on effects. For example, some soybean acreage has been moved to corn production, which probably has some effect on soybean prices. So there is some price effect on foodstuffs coming through the conversion to energy use.

Promoting free trade in biofuels combined with a framework that ensures environmental and social sustainability, will unlock a large and efficient biofuel potential that benefits consumers everywhere. According to researchers, such a global 'biopact' between the North and the South may help alleviate poverty in developing countries, where large rural populations can benefit from the new biofuels opportunity (previous post). Some analysts, like the WorldWatch Institute have even concluded that, with good policies, biofuels can help end hunger [entry ends here]
energy :: sustainability :: biomass :: bioenergy :: biofuels :: ethanol :: biodiesel :: subsidies :: tariffs :: trade :: Bernanke :: Brazil ::

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NSF releases report on next-generation hydrocarbon biofuels; finds large potential

The National Science Foundation (NSF) of the United States has published an extensive roadmap for the production of next generation hydrocarbon biofuels derived from lignocellulosic biomass that are close analogs for their petroleum-derived hydrocarbon counterparts. Whereas the U.S. has made a significant investment in technologies focusing on breaking the biological barriers to biofuels, principally cellulosic ethanol, this is only one of many biofuel production pathways. There has not been a commensurate investment in the research needed to break the chemical barriers to make bio-based hydrocarbon fuels. According to the roadmap, chemical pathways hold many advantages over bioconversion of biomass into cellulosic alcohols and can generate a much wider range of fuels that can replace gasoline, diesel, and jet fuel (schematic, click to enlarge).

The comprehensive report entitled Breaking the Chemical and Engineering Barriers to Lignocellulosic Biofuels: Next Generation Hydrocarbon Biorefineries [*.pdf 8.8Mb] is one of the outcomes of a workshop on the topic held last June with more than 70 leading biofuels scientists and engineers from America's leading laboratories and research organisations. The workshop was sponsored by NSF, the U.S. Department of Energy (DOE) and the American Chemical Society; it was chaired by George W. Huber, University of Massachusetts-Amherst.

Focusing on next-generation hydrocarbon liquid biofuels based on chemical conversion technologies similar to those found in the petrochemical industry, the study finds them to have many important advantages:

• First, green hydrocarbon fuels are essentially the same as those currently derived from petroleum, except that they are made from biomass. Therefore, it will not be necessary to modify existing infrastructure (e.g. pipelines, engines) and hydrocarbon biorefining processes can be tied into the fuel production systems of existing petroleum refineries.
• Second, biomass-based hydrocarbon fuels are energy equivalent to fuels derived from petroleum. In contrast to the lower energy density of E85 flex fuel, there will be no penalty in gas mileage with biomass-based hydrocarbon fuels.
• Third, hydrocarbons produced from lignocellulosic biomass are immiscible in water; they self-separate, which eliminates the need for an expensive, energy-consuming distillation step.
• Fourth, biomassbased hydrocarbon fuels are produced at high temperatures, which allows for faster conversion reactions in smaller reactors. Thus, processing units can be placed close to the biomass source or even transported on truck trailers.
• Fifth, the amount of water needed for processing hydrocarbon fuels from biomass can be greatly reduced, compared with the dilute sugar solutions to which enzymes are constrained. This is because organic or heterogeneous catalysts work well in concentrated water solutions or even in the absence of water if ionic liquids are used.
• Finally, heterogeneous catalysts are inherently recyclable. So they can be used over the course of months and even years, which significantly reduces costs compared to biological catalysts. The elimination of energy-intensive distillation, the higher reaction rates, and the much smaller process footprints can also lead to lower biofuel costs than are possible using currently available biological pathways for producing cellulosic ethanol.

According to the study, advances in agriculture and biotechnology have made it possible to inexpensively produce lignocellulosic biomass at costs that are significantly lower - about $15 per barrel of oil energy equivalent - than crude oil [note, this cost was calculated with at oil prices of $80 pb].

Availability of domestic lignocellulosic biomass is not a limitation to making the U.S. oil independent. In fact, non-food biomass, including trees, grasses and agricultural residues, constitutes more than 80% of the total biomass in the U.S. Significant amounts of lignocellulosic biomass can thus be sustainably produced on US agriculture and forestry land with an energy content of 60% of the current US petroleum consumption, the report finds:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: cellulosic ethanol :: biological conversion :: chemical conversion :: catalysts :: gasification :: pyrolysis :: Fischert-Tropsch :: synthetic biofuels :: nanotechnology :: hydrocarbons :: biorefineries ::

However, the key bottleneck for lignocellulosic-derived biofuels is the current lack of technology for the efficient conversion of this large biomass resource into liquid fuels. The report therefor illuminates the principal technological barriers and the underlying scientific limitations associated with efficient processing of biomass resources into finished hydrocarbon fuels.

It identifies the basic research needs and opportunities in catalytic chemistry and materials science that underpin biomass conversion and fuel utilization, with a focus on new, emerging and scientifically challenging areas that have the potential for significant impact.

The report focuses on six primary areas:

• Selective thermal processing of lignocellulosic biomass to produce liquid fuels (bio-oils) in distributed biorefineries.
• Utilization of petroleum refining technology for conversion of biomass-derived oxygenates within existing petroleum refineries.
• Hydrocarbon production by liquid phase processing of sugars to a heretofore “sleeping giant” intermediate, hydroxymethylfurfural (HMF), followed by HMF conversion to “green” diesel and jet fuel.
• Process intensification for diesel and gasoline production from synthesis gas (CO and H2) by Fisher-Tropsch synthesis (FTS), which dramatically decreases the economically viable size compared to traditional FTS processes with petroleum derived feedstocks.
• Conceptual design of biorefining processes in conjunction with experimental studies at the beginning of research projects to allow rapid development of commercial biofuel technologies.
• Design of recyclable, highly active and selective heterogeneous catalysts for biofuel production using advanced nanotechnology, synthesis methods and quantum chemical calculations.

According to the scientists, the benefits of moving toward fuel from lignocellulosic biomass sources will yield valuable benefits for national security, the economy, and the environment.

These benefits can be summarised as follows:

National Security Benefits of Biofuels: Achieving independence from foreign oil, and thereby making the country less vulnerable to political instability in the oil producing regions of the Middle East, is perhaps our foremost energy issue. America’s oil consumption accounts for approximately 25 percent of the global total, yet America holds only 3 percent of the world’s known oil reserves. Roughly 60% of the 319 billion gallons of petroleum consumed in the U.S. annually is imported, with about 13% (~42 billion gallons) coming from Persian Gulf countries.

The United States primarily imports crude oil but also imports petroleum products including gasoline, aviation fuel, and fuel oil. A concerted effort to develop the chemical and engineering methods for costeffective production of biomass-derived alternatives to conventional transportation fuels could significantly reduce our dependence on foreign oil.

Economic Benefits of Biofuels: According to the U.S. Council on Competitiveness, energy security and sustainability are key U.S. competitiveness issues because of the direct impact they have on the productivity of U.S. companies and the standard of living of all Americans. A vibrant lignocellulosic biofuels industry would create a large amount of high paying domestic jobs in the agricultural, forest management, and oil/chemical industries.

The U.S. Bureau of Labor Statistics (BLS) has stated that production workers in chemical manufacturing, which would be similar to those in a biorefinery, earn more money ($820 weekly) than in all other manufacturing sectors ($659/week). The BLS has further stated that the median hourly wages in 2004 were more than $19/hour for plant operators, maintenance and repair workers, chemical technicians, and chemical equipment operators and tenders. Thus, jobs created in the biofuel industry are likely to be good-paying jobs for skilled workers.

Because of the variable nature of biomass resources, small-scale, geographically localized plants are likely to be prevalent in the biofuels production industry. In contrast to fossil fuels, the quantity of biomass is not confined to certain localities and the resource cost of biomass is much lower than that of crude oil. Therefore, conversion to fuels or fuel precursors must be done on a local level to eliminate the expense of transporting low-cost biomass, which would likely limit biomass harvest to a radius of 50-75 miles around the conversion plant; such a plant would produce the liquid fuel equivalent of 10,000-20,000 barrels of oil/day.µ

Distributed production of fuels from domestically grown biomass would reduce infrastructure vulnerability by not consolidating all extraction and production activities in single geographic area. This paradigm of distributed production will create good jobs in biorefineries and may offer the opportunity to found new bio-based industries that will benefit rural economies across the nation.

Biofuels and Food: Biofuels can and should be produced sustainably with food and animal feed as co-products. Ethical and moral questions arise when edible biomass products are converted into biofuels. Therefore, conversion of non-edible biomass is the preferred strategy for long-term, large-scale biofuels production in the U.S. However, the economics are currently more favorable for conversion of edible biomass (e.g. corn starch, soybeans) into fuels due to their chemical structure, which can be more efficiently processed.

Therefore, it is important to continue developing technologies for the cost-effective conversion of non-edible lignocellulosic biomass into fuels. Agricultural practices in the U.S. and other industrialized countries are very advanced, and most industrialized regions produce more than enough food for domestic consumption.

Farmers do not pick the crops based on how efficiently they produce edible food products. Instead farmers’ goals are to grow crops that maximize their income, even though more efficient crops can be grown. Therefore, to the extent that bioenergy crops can be produced economically and dependably command a good price, they can provide farmers another market for their products, which could improve the economic situation of agricultural communities.

Environmental Benefits of Biofuels: One of the biggest benefits of biofuels is the associated reduction in net emissions of CO2. The release of CO2 into the atmosphere is directly related to an increase in temperatures worldwide. According to a landmark report released by the United Nation’s Intergovernmental Panel on Climate Change (IPCC), an international body comprised of representatives from 113 world governments,“Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.” The IPCC report further states that burning fossil fuels is one of global warming's main drivers.

Projections of rising sea levels and more frequent episodes of severe weather have prompted policy makers and the general public to demand action to stabilize atmospheric CO2 concentrations. Over the long term, stabilizing CO2 concentrations in the atmosphere means reducing emissions close to zero. Fossil fuel combustion releases CO2 into the atmosphere. While the biofuels combustion also releases CO2, it is consumed during subsequent biomass re-growth. Thus, biofuels made from lignocellulosic biomass can be carbon-neutral transportation fuels if efficient processes for biomass conversion are developed (i.e. the amount of CO2 produced during fuel production and combustion is equal to the amount of CO2 consumed by the biomass during its growth).


References:
National Science Foundation: Breaking the Chemical and Engineering Barriers to Lignocellulosic Biofuels: Next Generation Hydrocarbon Biorefineries [*.pdf 8.8Mb], Ed. George W. Huber, University of Massachusetts Amherst. National Science Foundation. Chemical, Bioengineering, Environmental, and Transport Systems Division. Washington DC, 2008.

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