EARTH: Source code: The methane race

What is the lifespan of a natural gas deposit? How quickly is our planet’s permafrost melting? And does life exist on other planets? Although seemingly unrelated issues, the answers to these questions are linked. And in this month’s issue of EARTH Magazine, scientists show that we may be closer to answering them than we think.

Ten years ago, John Eiler, a geochemist at Caltech, couldn’t convince anyone to build him his dream machine. He wanted a mass spectrometer that could measure the mass of common gases with extreme precision and sensitivity. Using methane, this instrument could potentially unlock the answers to many unsolved questions and provide us with a whole new perspective on paleoclimate and ancient temperatures.

Eiler has already been successful in modifying a standard mass spectrometer to use isotopologues (chemically identical, but isotopically different molecules) of carbon dioxide as a time-traveling thermometer. So far, this technology has discovered the body temperature of woolly mammoths and dinosaurs, and has even pinned down highly disputed ocean temperatures hundreds of millions of years old. Now, as EARTH explores in Source Code: The Methane Race, available at http://www.earthmagazine.org/earth/article/5eb-7dc-1-a, the race is on to use methane as a proxy to identify and solve new mysteries.

Crack the methane source code and read other great stories in the January of issue of EARTH Magazine, available online now at http://www.earthmagazine.org/. Discover what gives dinoflagellates their glow; find India’s missing ground; and view the latest bolide strike models in the most recent issue of EARTH.

Could Siberian volcanism have caused the Earth’s largest extinction event?

Around 250 million years ago, at the end of the Permian geologic period, there was a mass extinction so severe that it remains the most traumatic known species die-off in Earth’s history. Although the cause of this event is a mystery, it has been speculated that the eruption of a large swath of volcanic rock in Russia called the Siberian Traps was a trigger for the extinction. New research from Carnegie’s Linda Elkins-Tanton and her co-authors offers insight into how this volcanism could have contributed to drastic deterioration in the global environment of the period. Their work is published January 9 in Earth and Planetary Science Letters.

The end-Permian mass extinction saw the sudden loss of more than 90 percent of marine species and more than 70 percent of terrestrial species. The fossil record suggests that ecological diversity did not fully recover until several million years after the main pulse of the extinction. This suggests that environmental conditions remained inhospitable for an extended period of time.

Volcanic activity in the Siberian Traps has been proposed as one of the mechanisms that may have triggered the mass extinction. Gases released as a result of Siberian magmatism could have caused environmental damage. For example, perhaps sulfur particles in the atmosphere reflected the sun’s heat back into space, cooling the planet; or maybe chlorine and other chemically similar nonmetal elements called halogens significantly damaged the ozone layer in the stratosphere.

The team designed experiments to examine these possibilities.

Led by Benjamin Black of the Massachusetts Institute of Technology, the group included Elkins-Tanton, formerly of MIT and now director of Carnegie’s Department of Terrestrial Magnetism, Michael C. Rowe of Washington State University, and Ingrid Ukstins Peate of the University of Iowa.

The geology of the Siberian Traps is comprised of flood basalts, which form when giant lava eruptions coat large swaths of land or ocean floor with basaltic lava. This lava hardens into rock formations. The team investigated concentrations of sulfur, chlorine and fluorine (another halogen) that were dissolved in tiny samples of ancient magma found within basalt samples from the Siberian Traps. These small frozen droplets, which preserve a record of volcanic gases from the time of the eruption 250 million years ago, are called melt inclusions.

Sulfur, chlorine, and fluorine gasses could have been released into the atmosphere from eruptions spewing out of large fissures, which is common in basalt flood formation. Plumes escaping from these cracks could have reached the stratosphere. If sulfur, chlorine, and fluorine made it to the upper atmosphere, these gasses could have cause a wide array of adverse climate events, including temperature change and acid rain.

Based on their findings, the team estimated that between 6,300 and 7,800 gigatonnes of sulfur, between 3,400 and 8,700 gigatonnes of chlorine, and between 7,100 and 13,700 gigatonnes of fluorine were released from magma in the Siberian Traps during the end of the Permian period.

They say more research on atmospheric chemistry and climate modeling is urgently needed to determine whether these gasses could have been responsible for the mass extinction.

Researchers identify molecular ‘culprit’ in rise of planetary oxygen

University of Illinois crop sciences and Institute for Genomic Biology professor Gustavo Caetano-Anollés and his colleagues identified an oxygen-generating enzyme that likely was a key contributor to the rise of molecular oxygen on earth. -  L. Brian Stauffer
University of Illinois crop sciences and Institute for Genomic Biology professor Gustavo Caetano-Anollés and his colleagues identified an oxygen-generating enzyme that likely was a key contributor to the rise of molecular oxygen on earth. – L. Brian Stauffer

A turning point in the history of life occurred 2 to 3 billion years ago with the unprecedented appearance and dramatic rise of molecular oxygen. Now researchers report they have identified an enzyme that was the first – or among the first – to generate molecular oxygen on Earth.

The new findings, reported in the journal Structure, build on more than a dozen previous studies that aim to track the molecular evolution of life by looking for evidence of that history in present-day protein structures. These studies, led by University of Illinois crop sciences and Institute for Genomic Biology professor Gustavo Caetano-Anollés, focus on structurally and functionally distinct regions of proteins – called folds – that are part of the universal toolkit of living cells.

Protein folds are much more stable than the sequences of amino acids that compose them, Caetano-Anollés said. Mutations or other changes in sequence often occur without disrupting fold structure or function. This makes folds much more reliable markers of long-term evolutionary patterns, he said.

In the new study, Caetano-Anollés, working with colleagues in China and Korea, tackled an ancient mystery: Why did some of the earliest organisms begin to generate oxygen, and why?

“There is a consensus from earth scientists that about 2.4 billion years ago there was a big spike in oxygen on Earth,” Caetano-Anollés said. They generally agree that this rise in oxygen, called the Great Oxygenation Event, was tied to the emergence of photosynthetic organisms.

“But the problem now comes with the following question,” he said. “Oxygen is toxic, so why would a living organism generate oxygen? Something must have triggered this.”

The researchers looked for answers in the “molecular fossils” that still reside in living cells. They analyzed protein folds in nearly a thousand organisms representing every domain of life to assemble a timeline of protein history. Their timeline for this study was limited to single-fold proteins (which the researchers believe are the most ancient), and was calibrated using microbial fossils that appeared in the geologic record at specific dates.

The analysis revealed that the most ancient reaction of aerobic metabolism involved synthesis of pyridoxal (the active form of vitamin B6, which is essential to the activity of many protein enzymes) and occurred about 2.9 billion years ago. An oxygen-generating enzyme, manganese catalase, appeared at the same time.

Other recent studies also suggest that aerobic (oxygen-based) respiration began on Earth 300 to 400 million years before the Great Oxidation Event, Caetano-Anollés said. This would make sense, since oxygen production was probably going on for a while before the spike in oxygen occurred.

Catalases convert hydrogen peroxide to water and oxygen. The researchers hypothesize that primordial organisms “discovered” this enzyme when trying to cope with an abundance of hydrogen peroxide in the environment. Some geochemists believe that hydrogen peroxide was abundant at this time as a result of intensive solar radiation on glaciers that covered much of Earth.

“In the glacial melt waters you would have a high concentration of hydrogen peroxide and that would be gradually exposing a number of the primitive organisms (alive at that time),” Caetano-Anollés said. The appearance of manganese catalase, an enzyme that degrades hydrogen peroxide and generates oxygen as a byproduct, makes it a likely “molecular culprit for the rise of oxygen on the planet,” he said.

New cores from glacier in the Eastern European Alps may yield new climate clues

Researchers are beginning their analysis of what are probably the first successful ice cores drilled to bedrock from a glacier in the eastern European Alps.

With luck, that analysis will yield a record of past climate and environmental changes in the region for several centuries, and perhaps even covering the last 1,000 years. Scientists also hope that the core contains the remnants of early human activity in the region, such as the atmospheric byproducts of smelting metals.

The project, led by a team of Ohio State University scientists and their European colleagues, retrieved four cores from a glacier high atop Mount Ortles, a 3,905-meter (12,812-feet) peak in northeastern Italy. Three were 75 meters long (246-feet) and one was 60 meters (197 feet). They are significant in two ways:

First, scientists had previously believed that the glacier was at too low an altitude to contain ice cold enough to have preserved a clear climate record.

While the top one-third of the cores do show that melt water had percolated downwards, possibly affecting the record, the remaining two-thirds of the cores contained unaltered ice from which the research team should be able to retrieve a climate history.

Secondly, since no other ice core analyses have been retrieved from the eastern side of the Alps, this work should paint a much clearer picture of climate change in this portion of Europe.

“This glacier is already changing from the top down in a very irreversible way,” explained expedition leader Paolo Gabrielli, a research scientist at Ohio State’s Byrd Polar Research Center. “It is changing from a ‘cold’ glacier where the ice is stable to a ‘temperate’ glacier where the ice can degrade.

“The entire glacier may transition to a temperate state within the next decade or so,” he said. That probable change made the retrieval of these cores now even more important so that the ice record won’t be lost for future research.

Gabrielli said that previous research has shown already that there is an increase in summer temperatures at high elevations in the region of up to 2 degrees C (3.6 degrees F) over the last three decades. In spite of the melting in the top parts of the cores, the researchers hope to find a record that begins in the 1980s and proceeds back several centuries, or perhaps more.

Based on weather patterns, ice in the cores that was formed during past summers will likely paint a picture of past climate in an area close to the mountain, perhaps only 10 to 100 kilometers (6.21 to 62.1 miles) away.

But ice formed during past winters should provide clues to a much wider area, Gabrielli said, perhaps as much as 1,000 kilometers (621 miles).

An analysis of the ice might also answer some important questions about the region, such as the climate change in the region during the transition between the Medieval Warm Period and the Little Ice Age.

The research team, with co-leader Lonnie Thompson, Distinguished Professor of Earth Sciences at Ohio State, spent two weeks on the glacier, drilling the four cores. Along with him, Victor Zagorodnov, also from Ohio State, worked on the project.

Other team members included researchers from the University of Venice, the Russian Academy of Sciences, the University of Innsbruck, the University of Padova, the University of Pavia and the Autonomous Province of Bolzano which provided logistical support to the project.

Afghanistan’s mineral resources laid bare

Geologists carrying rock hammers and accompanied by Marines traverse the rugged expanse of the Helmand Province in southern Afghanistan, searching for untold mineral wealth. Although the nature of Afghanistan’s mineral deposits is not unique in the world, the country’s deposits are largely untouched. Will Afghanistan be able to utilize these minerals to rebuild the war-torn nation? Join EARTH Magazine in our January issue as we examine Afghanistan’s mineral wealth and the implications it holds for the country’s future.

Since 2007, the Department of Defense, the U.S. Geological Survey and their partners have been working to identify, confirm and describe mineral resources in two dozen areas of interest in Afghanistan. In 2011, USGS issued its most recent report estimating that Afghanistan contained “world-class resources,” including most notably gold, high grade copper and iron deposits, and rare earth element minerals. Read more about this story online now at http://www.earthmagazine.org/earth/article/5e7-7db-c-1d.

Peru’s Misti volcano: Understanding the past to assess future hazards

This new special paper from the Geological Society of America looks at Peru's Misti volcano and its last Plinian eruption -- which emplaced voluminous tephra-fall, pyroclastic-flow, and lahar deposits ca. 2 ka. Arequipa, located at the foot of the volcano, has a population of over 800,000 people and growing.  Misti will erupt explosively again, and it is important to understand the past Plinian eruption. -  The Geological Society of America
This new special paper from the Geological Society of America looks at Peru’s Misti volcano and its last Plinian eruption — which emplaced voluminous tephra-fall, pyroclastic-flow, and lahar deposits ca. 2 ka. Arequipa, located at the foot of the volcano, has a population of over 800,000 people and growing. Misti will erupt explosively again, and it is important to understand the past Plinian eruption. – The Geological Society of America

Misti volcano’s last Plinian eruption happened ca. 2 ka, emplacing voluminous tephra-fall, pyroclastic-flow, and lahar deposits. Arequipa, located at the foot of the volcano, has a population of over 800,000 people and growing. Misti will erupt explosively again, and it is important to understand the past Plinian eruption.

This GSA Special Paper first provides a detailed description and analysis of the lahar deposits from the 2 ka eruption and the flows that emplaced them.

Because Misti is located in an arid region, the authors have also included a detailed discussion of the paleoclimate conditions that provided the water for voluminous mudflows. The authors further delineate the complete eruption sequence for the pyroclastic-flow and tephra-fall deposits, providing a narrative of the eruption progression and dynamics.

Finally, the book discusses the 2 ka eruption in the context of hazards from a future Plinian eruption and provides hazards maps for the different phenomena.