Just a few days ago, we wrote that laughing gas, or nitrous oxide, has become today’s biggest threat to the ozone layer. So what’s the greatest source of nitrous oxide? Manure, according to new research published in Nature Geoscience.
Nitrous oxide, which also contributes to global warming, is produced naturally and through human activities like agriculture. Fertilizer is a recognized source of the gas, but until now, manure had been largely overlooked. Says researcher Eric Davidson: “[Fertilisers] are extremely important, but that’s only part of the story.” … He says nitrous oxide levels started increasing in the late 19th century “long before we started using nitrogen fertilisers in the 1960′s” [ABC Science]. And as a growing number of people around the globe consume meat, the manure that is an inevitable byproduct of meat production could pump an increasing amount of nitrous oxide into the atmosphere–or we could harness the power-producing potential of the waste.
Watermelons could do more than grace the tables at picnics across the land: They could also serve as a source of biofuel. Researchers fermented watermelon juice to produce ethanol, according to a study published in Biotechnology for Biofuels, and while the melons aren’t likely to become a primary biofuel crop, the process could help out farmers.
Nearly one-fifth of the watermelon crop grown in the United States is left in the fields after harvest because of defects on the melons’ rinds. “It’s not that there’s anything wrong with the melon on the inside, but our only method of judgment is the outside,” said [lead author] Wayne Fish [Greenwire]. Although farmers often till the abandoned melons into the soil, the value of the nutrients provided by this practice is much less than the overall cost to farmers of losing so much of their crop.
Scientists have long wondered what exactly is killing bees in hives afflicted by colony collapse disorder (CCD), and now they may have found a clue. Bees in collapsing hives showed evidence of damaged ribosomes, which are crucial to protein production, according to a study published in the journal Proceedings of the National Academy of Science. The researchers suggest that an onslaught of viruses may be responsible for the cellular damage.
The findings suggest that CCD, which has been blamed on everything from viruses to fungi to pesticides, may be linked to problems with protein production that could make bees more susceptible to these threats. “If your ribosome is compromised, then you can’t respond to pesticides, you can’t respond to fungal infections or bacteria or inadequate nutrition because the ribosome is central to the survival of any organism. You need proteins to survive” [AP], said lead researcher May Berenbaum.
The discovery of a pair of genes that prompt rice plants to grow extra-tall when submerged in water could potentially lead to new hardier varieties of rice that yield food even in flooded conditions, and could help out farmers in flood-prone nations like Thailand and Cambodia, according to a study published in Nature.
Researchers discovered a pair of genes known as SNORKEL, which spurs growth among the plants when they are completely submerged, allowing the plants to survive by keeping their leaf tops above the water. As water levels rise, accumulation of the plant hormone ethylene activates the SNORKEL genes, making stem growth more rapid. When the researchers introduced the genes into rice that does not normally survive in deep water, they were able to rescue the plants from drowning [AP].
The groundwater of northern India is being drained away by irrigation faster than it can be replenished by the annual monsoon rains, and new satellite data shows that the process is accelerating. In an area that’s home to about 10 percent of the world’s people, that could be a recipe for disaster, policy experts say. A growing population with an increasing standard of living will only boost the demand for groundwater, a trend that could eventually lead to a reduction in agricultural yields, shortages of potable water and an increase in societal unrest [Science News].
The Gravity Recovery and Climate Experiment (GRACE) is comprised of a pair of satellites that measure subtle variations in the Earth’s gravity, caused by the movement of water either in the oceans or under the ground. Most famously, GRACE has recorded the shrinking of ice sheets; it has also detected shifting ocean currents, the desiccation of droughts, and the draining of large lakes [ScienceNOW Daily News]. Now two new studies of GRACE’s data have revealed the loss of groundwater from northern India; once water is pumped up from the aquifers for use in irrigation, it either flows away from the region or evaporates.
Scientists have created genetically engineered corn plants that resist a root-destroying larvae by emitting a chemical call for help, summoning a parasite that preys on the larvae.
The larvae of the western corn rootworm (actually a beetle) is considered the most destructive corn pest in the United States and plagues parts of Europe as well. Known as the billion-dollar bug, the rootworm is said to be responsible for crop damage and pest-control spending valued at more than nine figures [National Geographic News]. To fight the larvae without the use of synthetic pesticides, researchers created corn plants that release a chemical compound into the soil, which calls forth parasitic nematodes to come and infest the beetle larvae.
An ancient Roman city that was the predecessor of Venice has been rediscovered beneath croplands near the Venetian lagoon using sophisticated aerial imagery and some clever analysis. Researchers say they’ve found the harbor city of Altinum, which was once one of the richest cities of the Roman empire. But terrified by the impending invasion of the fearsome Germanic Emperor Attila the Hun, its inhabitants cut their losses and fled in AD452, leaving behind a ghost town of theatres, temples and basilicas [Times Online].
Many of the city’s ancient buildings were dismantled and the stones were carted away in the Middle Ages. The remaining foundations sunk back into the marsh, which was drained and turned into agricultural land in the 19th century. The new study, published in Science, is a result of aerial images taken in unusually dry summer of 2007, when the crops were suffering from drought. When the visible light and near-infrared images were processed to tease out subtle variations in plant water stress, a buried metropolis emerged. The researchers discovered that the crops planted on the land were in different stages of ripening, thanks to differences in the amount of water in the soil [ScienceNOW Daily News].
The region today known as Iraq was once known as Mesopotamia, which means “Land Between the Rivers,” and since that ancient time the land between the Euphrates and Tigris rivers has been renowned for its fecund soil and thriving farms. But now the Mesopotamian cradle of civilisation seems to be returning to desert [New Scientist].
Decades of war and mismanagement, compounded by two years of drought, are wreaking havoc on Iraq’s ecosystem, drying up riverbeds and marshes, turning arable land into desert, killing trees and plants, and generally transforming what was once the region’s most fertile area into a wasteland…. “We’re talking about something that’s making the breadbasket of Iraq look like the Dust Bowl of Oklahoma in the early part of the 20th century” [Los Angeles Times], said Adam L. Silverman, a social scientist with the U.S. military.
The ancient civilization known as the Incan empire, which at its peak reached a population of 8 million people spread throughout South America, may owe its success at least in part to a warming climate, according to a study in the journal Climate of the Past. A rise in temperatures would have melted glaciers and allowed crops to grow further into the Andes mountains, fostering agricultural growth.
The study found that between 1100 and 1533 AD, temperatures increased several degrees, making it possible for the Incas to use new mountain land for agriculture. It also expanded the swath of land the empire occupied which, at its peak, spanned from the middle of Chile to the border shared by Ecuador and Colombia. This climate information came from an analysis of deeply buried sediment samples in the region the Incans once occupied. The researchers examined pollen and seeds buried in layers of mud on the floor of Lake Marcacocha in the Cuzco region of the Peruvian Andes. Similar to the rings in the trunk of a tree, each layer of sediment represents a fixed period of time. In the case of Lake Marcacocha, the researchers were able to analyze a 1,200-year-old sediment record [Discovery News].
The fungus that caused the notorious Irish potato famine of the 1840s and 1850s is spreading among tomato and potato plants in the northeastern United States. Known as late blight, the fungus spreads easily among plants by airborne spores. This year’s epidemic has taken root at major garden retailers, eventually invading not only home gardens but also major commercial and organic farms.
The disease causes dark lesions on the plant’s leaves and stems; tomatoes then turn brown and decay, emitting a rotten odor. Although the fungus is not dangerous to people, its effects render infected plants inedible. “Late blight has never occurred this early and this widespread in the United States,” said Meg McGrath, a plant pathologist [Reuters]. Its spread has been facilitated by the cool, wet weather the Northeast has experienced this summer, along with an increased number of home gardeners looking to grow their own food as a result of the recession. This year’s blight also is particularly dangerous because of how early it appeared in the growing season; usually, the blight hits plants late, after most of the fruit has been harvested [The Baltimore Sun].
Archaeologists have found granaries that were used to store wild cereals near the Dead Sea in Jordan more than 11,000 years ago. The structures predate agriculture in the Middle East by at least a millennium, according to a report published by the scientists in the journal Proceedings of the National Academy of Sciences.
The findings suggest that it took awhile to establish domesticated farming. In other words, the agricultural revolution likely spanned an appreciable period of time, during which our ancestors switched from hunting and gathering to growing their own food. The earliest definitive traces of domesticated grains, wheat, barley, and oats have been found in the Near East and date back about 10,500 years. Yet much recent research suggests that plant domestication was preceded by a long period–perhaps thousands of years–during which prehistoric peoples cultivated wild plants without visibly changing their appearance or altering their genetic makeup [ScienceNOW]. In archaeological digs of early villages in Israel, Jordan, Syria, and Turkey researchers have found large quantities of wild barley and wild oats, now the new findings provide evidence that the gatherers carefully stored these wild cereals.
Leaving the rainforest of the Amazon standing has obvious benefits to the environment, as the living forests absorb and store carbon dioxide that would otherwise contribute to global warming. But cutting down the forests has been assumed to be the only route to economic development for the local people, as it provides work in the timber industry and then clears the way for farming and cattle raising. Now, a new study has found that deforestation brings only short-term and temporary economic benefits, in what researchers call a boom-and-bust cycle.
The researchers say the boom is probably due to a number of factors, including better roads and therefore better access to healthcare and schools. For a short while, the community benefits from the natural resources of the forest, and makes money off the timber and the farms that are set up in the cleared lands. But the soil is rapidly degraded making farming and cattle ranching unsustainable. “A lot of that land ends up being abandoned” [New Scientist], says study coauthor Robert Ewers.
Pest control has never looked so sweet. Scientists have found that a simple derivative of sugar can shut down the immune defenses of ravaging termites, thus leaving the insects open to attacks from bacteria and fungus. Says lead researcher Ram Sasisekharan: “When you have an immune system that is compromised, you have a variety of opportunistic infections that take over…. You give these microbes sort of a leg up to attacking more seriously” [The Scientist].
As termites cause an estimated $30 billion in crop and building damages each year, and most current methods used to combat them rely on toxins that disrupt the termites’ nervous systems. These new findings could give rise to a whole new class of safer pest-control treatments, the authors say. “We wanted something environmentally friendly, biodegradable, and [that] does not play a toxic role” [National Geographic News], says Sasisekharan.
The oil-rich and weedy plant jatropha has been hailed as the most promising source of biofuel on the planet, and one airline has already begun testing a jatropha-derived fuel in its jumbo jets. But a new analysis suggests that the plant may not be a miracle crop destined to solve all our energy problems: Current jatropha plantations are not realising the oil yields that drove the “Jatropha euphoria” [EcoWorldly].
It was previously thought that the hardy jatropha plant would require less water than other biofuel crops like sugarcane and corn and could grow in marginal soil, so growers wouldn’t have to take fertile land out of agricultural use. But the new study rebuts that assumption. “The claim that jatropha doesn’t compete for water and land with food crops is complete nonsense,” says study coauthor Arjen Hoekstra. The researcher says it’s true that the plant can grow with little water and can survive through periods of drought, but to flourish, it needs good growing conditions just like any other plant. “If there isn’t sufficient water, you get a low amount of oil production,” Hoekstra says [Technology Review].
It’s not just humans who can take part in combating global warming–cows can play a role, too. Scientists say that the methane belched up by cows is a significant source of the greenhouse gas, and are searching for ways to reduce these burps. The digestive bacteria in the cows’ stomach produces the methane, which is the second-most significant gas (behind carbon dioxide) driving global warming. While methane is much less prevalent in the atmosphere than carbon dioxide, it traps heat 20 times more efficiently than carbon dioxide.
Researchers are examining a variety of tactics, including breeding or genetically engineering cows that belch less, or adjusting the bacterial mix in cows’ stomachs. But altering the cows’ feed has shown the most promise thus far. Since January, cows at 15 farms across Vermont have had their grain feed adjusted to include more plants like alfalfa and flaxseed — substances that, unlike corn or soy, mimic the spring grasses that the animals evolved long ago to eat. As of the last reading in mid-May, the methane output of [one test] herd had dropped 18 percent. Meanwhile, milk production has held its own [The New York Times].
80beats is DISCOVER's news aggregator, weaving together the choicest tidbits from the best articles on the day's most compelling topics.
80beats is written by Veronique Greenwood and Valerie Ross. This team darts through each day's science news faster than the ruby-throated hummingbird that beats its wings 80 times per second. Send ideas, tips, suggestions, and complaints to [azeeberg at discovermagazine dot com].
Just a few days ago, we wrote that laughing gas, or nitrous oxide, has become today’s biggest threat to the ozone layer. So what’s the greatest source of nitrous oxide? Manure, according to new research published in Nature Geoscience.
Watermelons could do more than grace the tables at picnics across the land: They could also serve as a source of 
Scientists have long wondered what exactly is killing 
The groundwater of northern India is being drained away by irrigation faster than it can be replenished by the annual monsoon rains, and new satellite data shows that the process is accelerating. In an area that’s home to about 10 percent of the world’s people, that could be a recipe for disaster, policy experts say. A growing population with an increasing standard of living will only boost the demand for groundwater, a trend that could eventually lead to a reduction in 
Scientists have created 
An ancient Roman city that was the predecessor of Venice has been rediscovered beneath croplands near the Venetian lagoon using sophisticated aerial imagery and some clever analysis. Researchers say they’ve found the harbor city of Altinum, which was once one of the richest cities of the Roman empire. But terrified by the impending invasion of the fearsome Germanic Emperor Attila the Hun, its inhabitants cut their losses and fled in AD452, leaving behind a ghost town of theatres, temples and basilicas [
The region today known as Iraq was once known as Mesopotamia, which means “Land Between the Rivers,” and since that ancient time the land between the Euphrates and Tigris 
The ancient civilization known as the Incan empire, which at its peak reached a population of 8 million people spread throughout South America, may owe its success at least in part to a warming climate, according to a 
The fungus that caused the notorious Irish potato famine of the 1840s and 1850s is spreading among tomato and potato plants in the northeastern United States. Known as late blight, the fungus spreads easily among plants by airborne spores. This year’s epidemic has taken root at major garden retailers, eventually invading not only home gardens but also major commercial and organic 
Leaving the 
Pest control has never looked so sweet. Scientists have found that a simple derivative of sugar can shut down the immune defenses of ravaging termites, thus leaving the 
The oil-rich and weedy plant jatropha has been hailed as the most promising source of 
It’s not just humans who can take part in combating 
