Research links soil mineral surfaces to key atmospheric processes

Pictured are, from left, are David Bish, Melissa Donaldson and Jonathan Raff. -  Indiana University
Pictured are, from left, are David Bish, Melissa Donaldson and Jonathan Raff. – Indiana University

Research by Indiana University scientists finds that soil may be a significant and underappreciated source of nitrous acid, a chemical that plays a pivotal role in atmospheric processes such as the formation of smog and determining the lifetime of greenhouse gases.

The study shows for the first time that the surface acidity of common minerals found in soil determines whether the gas nitrous acid will be released into the atmosphere. The finding could contribute to improved models for understanding and controlling air pollution, a significant public health concern.

“We find that the surfaces of minerals in the soil can be much more acidic than the overall pH of the soil would suggest,” said Jonathan Raff, assistant professor in the School of Public and Environmental Affairs and Department of Chemistry. “It’s the acidity of the soil minerals that acts as a knob or a control lever, and that determines whether nitrous acid outgasses from soil or remains as nitrite.”

The article, “Soil surface acidity plays a determining role in the atmospheric-terrestrial exchange of nitrous acid,” will be published this week in the journal Proceedings of the National Academy of Sciences. Melissa A. Donaldson, a Ph.D. student in the School of Public and Environmental Affairs, is the lead author. Co-authors are Raff and David L. Bish, the Haydn Murray Chair of Applied Clay Mineralogy in the Department of Geological Sciences.

Nitrous acid, or HONO, plays a key role in regulating atmospheric processes. Sunlight causes it to break down into nitric oxide and the hydroxyl radical, OH. The latter controls the atmospheric lifetime of gases important to air quality and climate change and initiates the chemistry leading to the formation of ground-level ozone, a primary component of smog.

Scientists have known about the nitrous acid’s role in air pollution for 40 years, but they haven’t fully understood how it is produced and destroyed or how it interacts with other substances, because HONO is unstable and difficult to measure.

“Only in the last 10 years have we had the technology to study nitrous acid under environmentally relevant conditions,” Raff said.

Recent studies have shown nitrous acid to be emitted from soil in many locations. But this was unexpected because, according to basic chemistry, the reactions that release nitrous acid should take place only in extremely acidic soils, typically found in rain forests or the taiga of North America and Eurasia.

The standard method to determine the acidity of soil is to mix bulk soil with water and measure the overall pH. But the IU researchers show that the crucial factor is not overall pH but the acidity at the surface of soil minerals, especially iron oxides and aluminum oxides. At the molecular level, the water adsorbed directly to these minerals is unusually acidic and facilitates the conversion of nitrite in the soil to nitrous acid, which then volatilizes.

“With the traditional approach of calculating soil pH, we were severely underestimating nitrous acid emissions from soil,” Raff said. “I think the source is going to turn out to be more important than was previously imagined.”

The research was carried out using soil from a farm field near Columbus, Ind. But aluminum and iron oxides are ubiquitous in soil, and the researchers say the results suggest that about 70 percent of Earth’s soils could be sources of nitrous acid.

Ultimately, the research will contribute to a better understanding of how nitrous acid is produced and how it affects atmospheric processes. That in turn will improve the computer models used by the U.S. Environmental Protection Agency and other regulatory agencies to control air pollution, which the World Health Organization estimates contributes to 7 million premature deaths annually.

“With improved models, policymakers can make better judgments about the costs and benefits of regulations,” Raff said. “If we don’t get the chemistry right, we’re not going to get the right answers to our policy questions regarding air pollution.”

Technology-dependent emissions of gas extraction in the US

The KIT measurement instrument on board of a minivan directly measures atmospheric emissions on site with a high temporal resolution. -  Photo: F. Geiger/KIT
The KIT measurement instrument on board of a minivan directly measures atmospheric emissions on site with a high temporal resolution. – Photo: F. Geiger/KIT

Not all boreholes are the same. Scientists of the Karlsruhe Institute of Technology (KIT) used mobile measurement equipment to analyze gaseous compounds emitted by the extraction of oil and natural gas in the USA. For the first time, organic pollutants emitted during a fracking process were measured at a high temporal resolution. The highest values measured exceeded typical mean values in urban air by a factor of one thousand, as was reported in ACP journal. (DOI 10.5194/acp-14-10977-2014)

Emission of trace gases by oil and gas fields was studied by the KIT researchers in the USA (Utah and Colorado) together with US institutes. Background concentrations and the waste gas plumes of single extraction plants and fracking facilities were analyzed. The air quality measurements of several weeks duration took place under the “Uintah Basin Winter Ozone Study” coordinated by the National Oceanic and Atmospheric Administration (NOAA).

The KIT measurements focused on health-damaging aromatic hydrocarbons in air, such as carcinogenic benzene. Maximum concentrations were determined in the waste gas plumes of boreholes. Some extraction plants emitted up to about a hundred times more benzene than others. The highest values of some milligrams of benzene per cubic meter air were measured downstream of an open fracking facility, where returning drilling fluid is stored in open tanks and basins. Much better results were reached by oil and gas extraction plants and plants with closed production processes. In Germany, benzene concentration at the workplace is subject to strict limits: The Federal Emission Control Ordinance gives an annual benzene limit of five micrograms per cubic meter for the protection of human health, which is smaller than the values now measured at the open fracking facility in the US by a factor of about one thousand. The researchers published the results measured in the journal Atmospheric Chemistry and Physics ACP.

“Characteristic emissions of trace gases are encountered everywhere. These are symptomatic of gas and gas extraction. But the values measured for different technologies differ considerably,” Felix Geiger of the Institute of Meteorology and Climate Research (IMK) of KIT explains. He is one of the first authors of the study. By means of closed collection tanks and so-called vapor capture systems, for instance, the gases released during operation can be collected and reduced significantly.

“The gas fields in the sparsely populated areas of North America are a good showcase for estimating the range of impacts of different extraction and fracking technologies,” explains Professor Johannes Orphal, Head of IMK. “In the densely populated Germany, framework conditions are much stricter and much more attention is paid to reducing and monitoring emissions.”

Fracking is increasingly discussed as a technology to extract fossil resources from unconventional deposits. Hydraulic breaking of suitable shale stone layers opens up the fossil fuels stored there and makes them accessible for economically efficient use. For this purpose, boreholes are drilled into these rock formations. Then, they are subjected to high pressure using large amounts of water and auxiliary materials, such as sand, cement, and chemicals. The oil or gas can flow to the surface through the opened microstructures in the rock. Typically, the return flow of the aqueous fracking liquid with the dissolved oil and gas constituents to the surface lasts several days until the production phase proper of purer oil or natural gas. This return flow is collected and then reused until it finally has to be disposed of. Air pollution mainly depends on the treatment of this return flow at the extraction plant. In this respect, currently practiced fracking technologies differ considerably. For the first time now, the resulting local atmospheric emissions were studied at a high temporary resolution. Based on the results, emissions can be assigned directly to the different plant sections of an extraction plant. For measurement, the newly developed, compact, and highly sensitive instrument, a so-called proton transfer reaction mass spectrometer (PTR-MS), of KIT was installed on board of a minivan and driven closer to the different extraction points, the distances being a few tens of meters. In this way, the waste gas plumes of individual extraction sources and fracking processes were studied in detail.

Warneke, C., Geiger, F., Edwards, P. M., Dube, W., Pétron, G., Kofler, J., Zahn, A., Brown, S. S., Graus, M., Gilman, J. B., Lerner, B. M., Peischl, J., Ryerson, T. B., de Gouw, J. A., and Roberts, J. M.: Volatile organic compound emissions from the oil and natural gas industry in the Uintah Basin, Utah: oil and gas well pad emissions compared to ambient air composition, Atmos. Chem. Phys., 14, 10977-10988, doi:10.5194/acp-14-10977-2014, 2014.

A new look at what’s in ‘fracking’ fluids raises red flags

Scientists are getting to the bottom of what's in fracking fluids — with some troubling results. -  Doug Duncan/U.S. Geological Survey
Scientists are getting to the bottom of what’s in fracking fluids — with some troubling results. – Doug Duncan/U.S. Geological Survey

As the oil and gas drilling technique called hydraulic fracturing (or “fracking”) proliferates, a new study on the contents of the fluids involved in the process raises concerns about several ingredients. The scientists presenting the work today at the 248th National Meeting & Exposition of the American Chemical Society (ACS) say that out of nearly 200 commonly used compounds, there’s very little known about the potential health risks of about one-third, and eight are toxic to mammals.

The meeting features nearly 12,000 presentations on a wide range of science topics and is being held here through Thursday by ACS, the world’s largest scientific society.

William Stringfellow, Ph.D., says he conducted the review of fracking contents to help resolve the public debate over the controversial drilling practice. Fracking involves injecting water with a mix of chemical additives into rock formations deep underground to promote the release of oil and gas. It has led to a natural gas boom in the U.S., but it has also stimulated major opposition and troubling reports of contaminated well water, as well as increased air pollution near drill sites.

“The industrial side was saying, ‘We’re just using food additives, basically making ice cream here,'” Stringfellow says. “On the other side, there’s talk about the injection of thousands of toxic chemicals. As scientists, we looked at the debate and asked, ‘What’s the real story?'”

To find out, Stringfellow’s team at Lawrence Berkeley National Laboratory and University of the Pacific scoured databases and reports to compile a list of substances commonly used in fracking. They include gelling agents to thicken the fluids, biocides to keep microbes from growing, sand to prop open tiny cracks in the rocks and compounds to prevent pipe corrosion.

What their analysis revealed was a little truth to both sides’ stories – with big caveats. Fracking fluids do contain many nontoxic and food-grade materials, as the industry asserts. But if something is edible or biodegradable, it doesn’t automatically mean it can be easily disposed of, Stringfellow notes.

“You can’t take a truckload of ice cream and dump it down the storm drain,” he says, building on the industry’s analogy. “Even ice cream manufacturers have to treat dairy wastes, which are natural and biodegradable. They must break them down rather than releasing them directly into the environment.”

His team found that most fracking compounds will require treatment before being released. And, although not in the thousands as some critics suggest, the scientists identified eight substances, including biocides, that raised red flags. These eight compounds were identified as being particularly toxic to mammals.

“There are a number of chemicals, like corrosion inhibitors and biocides in particular, that are being used in reasonably high concentrations that potentially could have adverse effects,” Stringfellow says. “Biocides, for example, are designed to kill bacteria – it’s not a benign material.”

They’re also looking at the environmental impact of the fracking fluids, and they are finding that some have toxic effects on aquatic life.

In addition, for about one-third of the approximately 190 compounds the scientists identified as ingredients in various fracking formulas, the scientists found very little information about toxicity and physical and chemical properties.

“It should be a priority to try to close that data gap,” Stringfellow says.

‘Fracking’ in the dark: Biological fallout of shale-gas production still largely unknown

Eight conservation biologists from various organizations and institutions, including Princeton University, found that shale-gas extraction in the United States has vastly outpaced scientists' understanding of the industry's environmental impact. With shale-gas production projected to surge during the next 30 years, determining and minimizing the industry's effects on nature and wildlife must become a top priority for scientists, industry and policymakers, the researchers said. The photo above shows extensive natural-gas operations at Jonah Field in Wyoming. -  Photo courtesy of EcoFlight.
Eight conservation biologists from various organizations and institutions, including Princeton University, found that shale-gas extraction in the United States has vastly outpaced scientists’ understanding of the industry’s environmental impact. With shale-gas production projected to surge during the next 30 years, determining and minimizing the industry’s effects on nature and wildlife must become a top priority for scientists, industry and policymakers, the researchers said. The photo above shows extensive natural-gas operations at Jonah Field in Wyoming. – Photo courtesy of EcoFlight.

In the United States, natural-gas production from shale rock has increased by more than 700 percent since 2007. Yet scientists still do not fully understand the industry’s effects on nature and wildlife, according to a report in the journal Frontiers in Ecology and the Environment.

As gas extraction continues to vastly outpace scientific examination, a team of eight conservation biologists from various organizations and institutions, including Princeton University, concluded that determining the environmental impact of gas-drilling sites – such as chemical contamination from spills, well-casing failures and other accidents – must be a top research priority.

With shale-gas production projected to surge during the next 30 years, the authors call on scientists, industry representatives and policymakers to cooperate on determining – and minimizing – the damage inflicted on the natural world by gas operations such as hydraulic fracturing, or “fracking.” A major environmental concern, hydraulic fracturing releases natural gas from shale by breaking the rock up with a high-pressure blend of water, sand and other chemicals, which can include carcinogens and radioactive substances.

“We can’t let shale development outpace our understanding of its environmental impacts,” said co-author Morgan Tingley, a postdoctoral research associate in the Program in Science, Technology and Environmental Policy in Princeton’s Woodrow Wilson School of Public and International Affairs.

“The past has taught us that environmental impacts of large-scale development and resource extraction, whether coal plants, large dams or biofuel monocultures, are more than the sum of their parts,” Tingley said.

The researchers found that there are significant “knowledge gaps” when it comes to direct and quantifiable evidence of how the natural world responds to shale-gas operations. A major impediment to research has been the lack of accessible and reliable information on spills, wastewater disposal and the composition of fracturing fluids. Of the 24 American states with active shale-gas reservoirs, only five – Pennsylvania, Colorado, New Mexico, Wyoming and Texas – maintain public records of spills and accidents, the researchers report.

“The Pennsylvania Department of Environmental Protection’s website is one of the best sources of publicly available information on shale-gas spills and accidents in the nation. Even so, gas companies failed to report more than one-third of spills in the last year,” said first author Sara Souther, a postdoctoral research associate at the University of Wisconsin-Madison.

“How many more unreported spills occurred, but were not detected during well inspections?” Souther asked. “We need accurate data on the release of fracturing chemicals into the environment before we can understand impacts to plants and animals.”

One of the greatest threats to animal and plant life identified in the study is the impact of rapid and widespread shale development, which has disproportionately affected rural and natural areas. A single gas well results in the clearance of 3.7 to 7.6 acres (1.5 to 3.1 hectares) of vegetation, and each well contributes to a collective mass of air, water, noise and light pollution that has or can interfere with wild animal health, habitats and reproduction, the researchers report.

“If you look down on a heavily ‘fracked’ landscape, you see a web of well pads, access roads and pipelines that create islands out of what was, in some cases, contiguous habitat,” Souther said. “What are the combined effects of numerous wells and their supporting infrastructure on wide-ranging or sensitive species, like the pronghorn antelope or the hellbender salamander?”

The chemical makeup of fracturing fluid and wastewater is often unknown. The authors reviewed chemical-disclosure statements for 150 wells in three of the top gas-producing states and found that an average of two out of every three wells were fractured with at least one undisclosed chemical. The exact effect of fracturing fluid on natural water systems as well as drinking water supplies remains unclear even though improper wastewater disposal and pollution-prevention measures are among the top state-recorded violations at drilling sites, the researchers found.

“Some of the wells in the chemical disclosure registry were fractured with fluid containing 20 or more undisclosed chemicals,” said senior author Kimberly Terrell, a researcher at the Smithsonian Conservation Biology Institute. “This is an arbitrary and inconsistent standard of chemical disclosure.”

Modern ocean acidification is outpacing ancient upheaval, study suggests

<IMG SRC="/Images/964394569.jpg" WIDTH="350" HEIGHT="237" BORDER="0" ALT="The deep-sea benthic foram Aragonia velascoensis went extinct about 56 million years ago as the oceans rapidly acidified. – Ellen Thomas/Yale University”>
The deep-sea benthic foram Aragonia velascoensis went extinct about 56 million years ago as the oceans rapidly acidified. – Ellen Thomas/Yale University

Some 56 million years ago, a massive pulse of carbon dioxide into the atmosphere sent global temperatures soaring. In the oceans, carbonate sediments dissolved, some organisms went extinct and others evolved.

Scientists have long suspected that ocean acidification played a part in the crisis-similar to today, as manmade CO2 combines with seawater to change its chemistry. Now, for the first time, scientists have quantified the extent of surface acidification from those ancient days, and the news is not good: the oceans are on track to acidify at least as much as they did then, only at a much faster rate.

In a study published in the latest issue of Paleoceanography, the scientists estimate that surface ocean acidity increased by about 100 percent in a few thousand years or more, and stayed that way for the next 70,000 years. In this radically changed environment, some creatures died out while others adapted and evolved. The study is the first to use the chemical composition of fossils to reconstruct surface ocean acidity at the Paleocene-Eocene Thermal Maximum (PETM), a period of intense warming on land and throughout the oceans due to high CO2.

“This could be the closest geological analog to modern ocean acidification,” said study coauthor Bärbel Hönisch, a paleoceanographer at Columbia University’s Lamont-Doherty Earth Observatory. “As massive as it was, it still happened about 10 times more slowly than what we are doing today.”

The oceans have absorbed about a third of the carbon humans have pumped into the air since industrialization, helping to keep temperatures lower than they would be otherwise. But that uptake of carbon has come at a price. Chemical reactions caused by that excess CO2 have made seawater grow more acidic, depleting it of the carbonate ions that corals, mollusks and calcifying plankton need to build their shells and skeletons.

In the last 150 years or so, the pH of the oceans has dropped substantially, from 8.2 to 8.1–equivalent to a 25 percent increase in acidity. By the end of the century, ocean pH is projected to fall another 0.3 pH units, to 7.8. While the researchers found a comparable pH drop during the PETM–0.3 units–the shift happened over a few thousand years.

“We are dumping carbon in the atmosphere and ocean at a much higher rate today-within centuries,” said study coauthor Richard Zeebe, a paleoceanographer at the University of Hawaii. “If we continue on the emissions path we are on right now, acidification of the surface ocean will be way more dramatic than during the PETM.”

Ocean acidification in the modern ocean may already be affecting some marine life, as shown by the partly dissolved shell of this planktic snail, or pteropod, caught off the Pacific Northwest.


The study confirms that the acidified conditions lasted for 70,000 years or more, consistent with previous model-based estimates.

“It didn’t bounce back right away,” said Timothy Bralower, a researcher at Penn State who was not involved in the study. “It took tens of thousands of years to recover.”

From seafloor sediments drilled off Japan, the researchers analyzed the shells of plankton that lived at the surface of the ocean during the PETM. Two different methods for measuring ocean chemistry at the time-the ratio of boron isotopes in their shells, and the amount of boron –arrived at similar estimates of acidification. “It’s really showing us clear evidence of a change in pH for the first time,” said Bralower.

What caused the burst of carbon at the PETM is still unclear. One popular explanation is that an overall warming trend may have sent a pulse of methane from the seafloor into the air, setting off events that released more earth-warming gases into the air and oceans. Up to half of the tiny animals that live in mud on the seafloor-benthic foraminifera-died out during the PETM, possibly along with life further up the food chain.

Other species thrived in this changed environment and new ones evolved. In the oceans, dinoflagellates extended their range from the tropics to the Arctic, while on land, hoofed animals and primates appeared for the first time. Eventually, the oceans and atmosphere recovered as elements from eroded rocks washed into the sea and neutralized the acid.

Today, signs are already emerging that some marine life may be in trouble. In a recent study led by Nina Bednarsek at the U.S. National Oceanic and Atmospheric Administration, more than half of the tiny planktic snails, or pteropods, that she and her team studied off the coast of Washington, Oregon and California showed badly dissolved shells. Ocean acidification has been linked to the widespread death of baby oysters off Washington and Oregon since 2005, and may also pose a threat to coral reefs, which are under additional pressure from pollution and warming ocean temperatures.

“Seawater carbonate chemistry is complex but the mechanism underlying ocean acidification is very simple,” said study lead author Donald Penman, a graduate student at University of California at Santa Cruz. “We can make accurate predictions about how carbonate chemistry will respond to increasing carbon dioxide levels. The real unknown is how individual organisms will respond and how that cascades through ecosystems.”

Forest emissions, wildfires explain why ancient Earth was so hot

This photo shows Nadine Unger with Yale University's omega supercomputer. -  Photo by Matthew Garrett/Yale School of Forestry & Environmental Studies
This photo shows Nadine Unger with Yale University’s omega supercomputer. – Photo by Matthew Garrett/Yale School of Forestry & Environmental Studies

The release of volatile organic compounds from Earth’s forests and smoke from wildfires 3 million years ago had a far greater impact on global warming than ancient atmospheric levels of carbon dioxide, a new Yale study finds.

The research provides evidence that dynamic atmospheric chemistry played an important role in past warm climates, underscoring the complexity of climate change and the relevance of natural components, according to the authors. They do not address or dispute the significant role in climate change of human-generated CO2 emissions.

Using sophisticated Earth system modeling, a team led by Nadine Unger of the Yale School of Forestry & Environmental Studies (F&ES) calculated that concentrations of tropospheric ozone, aerosol particles, and methane during the mid-Pliocene epoch were twice the levels observed in the pre-industrial era – largely because so much more of the planet was covered in forest.

Those reactive compounds altered Earth’s radiation balance, contributing a net global warming as much as two to three times greater than the effect of carbon dioxide, according to the study, published in the journal Geophysical Research Letters.

These findings help explain why the Pliocene was two to three degrees C warmer than the pre-industrial era despite atmospheric levels of carbon dioxide that were approximately the same as today, Unger said.

“The discovery is important for better understanding climate change throughout Earth’s history, and has enormous implications for the impacts of deforestation and the role of forests in climate protection strategies,” said Unger, an assistant professor of atmospheric chemistry at F&ES.

“The traditional view,” she said, “is that forests affect climate through carbon storage and by altering the color of the planet’s surface, thus influencing the albedo effect. But as we are learning, there are other ways that forest ecosystems can impact the climate.”

The albedo effect refers to the amount of radiation reflected by the surface of the planet. Light-colored snowy surfaces, for instance, reflect more light and heat back into space than darker forests.

Climate scientists have suggested that the Pliocene epoch might provide a glimpse of the planet’s future if humankind is unable to curb carbon dioxide emissions. During the Pliocene, the two main factors believed to influence the climate – atmospheric CO2 concentrations and the geographic position of the continents – were nearly identical to modern times. But scientists have long wondered why the Pliocene’s global surface air temperatures were so much warmer than Earth’s pre-industrial climate.

The answer might be found in highly reactive compounds that existed long before humans lived on the planet, Unger says. Terrestrial vegetation naturally emits vast quantities of volatile organic compounds, for instance. These are critical precursors for organic aerosols and ozone, a potent greenhouse gas. Wildfires, meanwhile, are a major source of black carbon and primary organic carbon.

Forest cover was vastly greater during the Pliocene, a period marked not just by warmer temperatures but also by greater precipitation. At the time, most of the arid and semi-arid regions of Africa, Australia, and the Arabian peninsula were covered with savanna and grassland. Even the Arctic had extensive forests. Notably, Unger says, there were no humans to cut the forests down.

Using the NASA Goddard Institute for Space Studies Model-E2 global Earth system model, the researchers were able to simulate the terrestrial ecosystem emissions and atmospheric chemical composition of the Pliocene and the pre-industrial era.

According to their findings, the increase in global vegetation was the dominant driver of emissions during the Pliocene – and the subsequent effects on climate.

Previous studies have dismissed such feedbacks, suggesting that these compounds would have had limited impact since they would have been washed from the atmosphere by frequent rainfall in the warmer climate. The new study argues otherwise, saying that the particles lingered about the same length of time – one to two weeks – in the Pliocene atmosphere compared to the pre-industrial.

Unger says her findings imply a higher climate sensitivity than if the system was simply affected by CO2 levels and the albedo effect.

“We might do a lot of work to reduce air pollution from road vehicle and industrial emissions, but in a warmer future world the natural ecosystems are just going to bring the ozone and aerosol particles right back,” she said. “Reducing and preventing the accumulation of fossil-fuel CO2 is the only way to ensure a safe climate future now.”

The modeling calculations were performed on Yale University’s omega supercomputer, a 704-node cluster capable of processing more than 52 trillion calculations per second.

The biggest mass extinction and Pangea integration

Relationships between geosphere disturbances and mass extinction during the Late Permian and Early Triassic are shown. -  ©Science China Press
Relationships between geosphere disturbances and mass extinction during the Late Permian and Early Triassic are shown. – ©Science China Press

The mysterious relationship between Pangea integration and the biggest mass extinction happened 250 million years ago was tackled by Professor YIN Hongfu and Dr. SONG Haijun from State Key Laboratory of Geobiology and Environmental Geology, China University of Geosciences (Wuhan). Their study shows that Pangea integration resulted in environmental deterioration which further caused that extinction. Their work, entitled “Mass extinction and Pangea integration during the Paleozoic-Mesozoic transition”, was published in SCIENCE CHINA Earth Sciences.2013, Vol 56(7).

The Pangea was integrated at about the beginning of Permian, and reached its acme during Late Permian to Early Triassic. Formation of the Pangea means that the scattered continents of the world gathered into one integrated continent with an area of nearly 200 million km2. Average thickness of such a giant continental lithosphere should be remarkably greater than that of each scattered continent. Equilibrium principle implies that the thicker the lithosphere, the higher its portion over the equilibrium level, hence the average altitude of the Pangea should be much higher than the separated modern continents. Correspondingly, all oceans gathered to form the Panthalassa, which should be much deeper than modern oceans. The acme of Pangea and Panthalassa was thus a period of high continent and deep ocean, which should inevitably induce great regression and influence the earth’s surface system, especially climate.

The Tunguss Trap of Siberia, the Emeishan Basalt erupted during the Pangea integration. Such global-scale volcanism should be evoked by mantle plume and related with integration of the Pangea. Volcanic activities would result in a series of extinction effects, including emission of large volume of CO2, CH4, NO2 and cyanides which would have caused green house effects, pollution by poisonous gases, damage of the ozone layer in the stratosphere, and enhancement the ultra-violet radiation.

Increase of CO2 concentration and other green house gases would have led to global warming, oxygen depletion and carbon cycle anomaly; physical and chemical anomalies in ocean (acidification, euxinia, low sulfate concentration, isotopic anomaly of organic nitrogen) and great regression would have caused marine extinction due to unadaptable environments, selective death and hypercapnia; continental aridity, disappearance of monsoon system and wild fire would have devastated the land vegetation, esp. the tropical rain forest.

The great global changes and mass extinction were the results of interaction among earth’s spheres. Deteriorated relations among lithosphere, atmosphere, hydrosphere, and biosphere (including internal factors of organism evolution itself) accumulated until they exceeded the threshold, and exploded at the Permian-Triassic transition time. Interaction among bio- and geospheres is an important theme. However, the processes from inner geospheres to earth’s surface system and further to organism evolution necessitate retardation in time and yields many uncertainties in causation. Most of the processes are now at a hypothetic stage and need more scientific examinations.

Gold mining ravages Peru

The Carnegie Airborne Observatory flies over the Madre De Dios region of Peru, where vast deforested and polluted areas result from gold mining. -  Image courtesy Carnegie Airborne Observatory
The Carnegie Airborne Observatory flies over the Madre De Dios region of Peru, where vast deforested and polluted areas result from gold mining. – Image courtesy Carnegie Airborne Observatory

For the first time, researchers have been able to map the true extent of gold mining in the biologically diverse region of Madre De Dios in the Peruvian Amazon. The team combined field surveys with airborne mapping and high-resolution satellite monitoring to show that the geographic extent of mining has increased 400% from 1999 to 2012 and that the average annual rate of forest loss has tripled since the Great Recession of 2008. Until this study, thousands of small, clandestine mines that have boomed since the economic crisis have gone unmonitored. The research is published in the online early edition of the Proceedings of the National Academy of Sciences the week of October 28, 2013.

The team, led by Carnegie’s Greg Asner in close collaboration with officials from the Peruvian Ministry of Environment, used the Carnegie Landsat Analysis System-lite (CLASlite) to detect and map both large and small mining operations. CLASlite differs from other satellite mapping methods. It uses algorithms to detect changes to the forest in areas as small as 10 square meters, about 100 square feet, allowing scientists to find small-scale disturbances that cannot be detected by traditional satellite methods.

The team corroborated the satellite results with on-ground field surveys and Carnegie Airborne Observatory (CAO) data. The CAO uses Light Detection and Ranging (LiDAR), a technology that sweeps laser light across the vegetation canopy to image it in 3-D. It can determine the location of single standing trees at 3.5 feet (1.1 meter) resolution. This level of detail was used to assess how well CLASlite determined forest conditions in the mining areas. The CAO data were also used to evaluate the accuracy of the CLASlite maps along the edges of large mines, as well as the inaccessible small mines that are set back from roads and rivers to avoid detection. The field and CAO data confirmed up to 94% of the CLASlite mine detections.

Lead author Asner commented: “Our results reveal far more rainforest damage than previously reported by the government, NGOs, or other researchers. In all, we found that the rate of forest loss from gold mining accelerated from 5,350 acres (2,166 hectares) per year before 2008 to15,180 acres (6,145 hectares) each year after the 2008 global financial crisis that rocketed gold prices.”

In addition to wreaking direct havoc on tropical forests, gold mining releases sediment into rivers, with severe effects on aquatic life. Other recent work has shown that Perú’s gold mining has contributed to widespread mercury pollution affecting the entire food chain, including the food ingested by people throughout the region. Miners also hunt wild game, depleting the rainforest fauna around mining areas, and disrupting the ecological balance for centuries to come.

Co-author Ernesto Raez Luna, Senior Advisor to the Minister, Peruvian Ministry of the Environment, remarked: “Obtaining good information on illegal gold mining, to guide sound policy and enforcement decisions, has been particularly difficult so far. Finally, we have very detailed and accurate data that we can turn into government action. We are using this study to warn Peruvians on the terrible impact of illegal mining in one of the most important enclaves of biodiversity in the world, a place that we have vowed, as a nation, to protect for all humanity. Nobody should buy one gram of this jungle gold. The mining must be stopped.”

As of 2012, small illicit mines accounted for more than half of all mining operations in the region. Large mines of previous focus are heavy polluters but are taking on a subordinate role to thousands of small mines in degrading the tropical forest throughout the region. This trend highlights the importance of using this newer, high-resolution monitoring system for keeping tabs on this growing cause of forest loss.

Asner emphasized: “The gold rush in Madre de Dios, Perú, exceeds the combined effects of all other causes of forest loss in the region, including from logging, ranching and agriculture. This is really important because we’re talking about a global biodiversity hotspot. The region’s incredible flora and fauna is being lost to gold fever. “

Technical reports examine hydraulic fracturing in Michigan

University of Michigan researchers today released seven technical reports that together form the most comprehensive Michigan-focused resource on hydraulic fracturing, the controversial natural gas and oil extraction process commonly known as fracking.

The studies, totaling nearly 200 pages, examine seven critical topics related to the use of hydraulic fracturing in Michigan, with an emphasis on high-volume methods: technology, geology and hydrogeology, environment and ecology, public health, policy and law, economics, and public perceptions.

While considerable natural gas reserves are believed to exist in the state and high-volume hydraulic fracturing has the potential to help access them, possible impacts to the environment and to public health must be addressed, the U-M researchers concluded.

Though modern high-volume hydraulic fracturing is not widely used in Michigan today, a main premise of the U-M study is that the technique could become more widespread due to a desire for job creation, economic growth, energy independence and cleaner fuels.

“There’s a lot of interest in high-volume hydraulic fracturing, but there really isn’t much activity at the moment in Michigan,” said John Callewaert, project director and director of integrated assessment at U-M’s Graham Sustainability Institute, which is overseeing the project. “That’s why now is a good time to do this assessment.”

These reports conclude the first phase of a two-year U-M project known formally as the Hydraulic Fracturing in Michigan Integrated Assessment. The seven documents-which should not be characterized or cited as final products of the integrated assessment-provide a solid informational foundation for the project’s next phase, an analysis of various hydraulic fracturing policy options. That analysis is expected to be completed in mid-2014 and will be shared with government officials, industry experts, other academics, advocacy groups and the general public.

“Nothing like this has been done before in Michigan,” Callewaert said. “Having this comprehensive, state-specific set of reports will be an invaluable resource that will help guide future decision-making on this issue-and hopefully will help Michigan avoid some of the pitfalls encountered in other states.”

Conclusions of the reports, which were written by faculty-led, student-staffed teams from various disciplines, include:

  • Technology. In view of the current low price of natural gas, the high cost of drilling deep shale formations and the absence of new oil discoveries, it is unlikely that there will be significant growth of the oil and gas industry in Michigan in the near-term future. However, considerable reserves of natural gas are believed to exist in deep shale formations such as the Utica-Collingwood, which underlies much of Michigan and eastern Lake Huron and extends into Ontario, Canada.

  • Geology/hydrogeology. A recent flurry of mineral rights acquisitions in the state associated with exploratory drilling suggests the potential for growth in natural gas production through high-volume hydraulic fracturing, though only a handful of such wells have been drilled to date. “Michigan is thus in a unique position to assess the future of high-volume hydraulic fracturing before the gas boom begins.”

  • Environment/ecology. Potential impacts of hydraulic fracturing on the environment are significant and include increased erosion and sedimentation, increased risk of aquatic contamination from chemical spills or equipment runoff, habitat fragmentation and resulting impacts on aquatic and terrestrial organisms, loss of stream riparian zones, and reduction of surface waters available to plants and animals due to the lowering of groundwater levels.

  • Public health. Possible hazards in the surrounding environment include impaired local and regional air quality, water pollution and degradation of ecosystems. Possible hazards in nearby communities include increased traffic and motor vehicle accidents, stress related to risk perception among residents, and boomtown-associated effects such as a strained health care system and road degradation.

  • Policy/law. The state is the primary source of law and policy governing hydraulic fracturing in Michigan. The operator of a high-volume hydraulically fractured well must disclose the hazardous constituents of chemical additives to the state Department of Environmental Quality for each additive within 60 days of well completion. Unlike most other states, DEQ does not require operators to report to FracFocus.org, a nationwide chemical disclosure registry.

  • Economics. The gas extraction industry creates employment and income for Michigan, but the employment effects are modest compared with other industries and not large enough to “make or break” the state’s economy. In the future, the number of technical jobs in the industry will likely increase, while less-skilled laborer positions will decline.

  • Public perceptions. A slight majority of Michigan residents believe the benefits of fracking outweigh the risks, but significant concerns remain about the potential impacts to human health, the environment and groundwater quality. The public tends to view the word “fracking” as the entirety of the natural gas development process, from leasing and permitting, to drilling and well completion, to transporting and storing wastewater and chemicals. Industry and regulatory agencies hold a much narrower definition that is limited to the process of injecting hydraulic fracturing fluids into a well. These differences in perceived meaning can lead to miscommunications that ultimately increase mistrust among stakeholders.

In fracking, water, sand and chemicals (in a mix known as hydraulic fracturing fluid) are injected under high pressure deep underground to crack sedimentary rocks, such as shale, and free trapped natural gas or oil. Though the process has been used for more than half a century to improve well production, recent technical advances have helped unlock vast stores of previously inaccessible natural gas and oil, resulting in a boom in some parts of the United States.

Chief among the technical advances are directional drilling and high-volume hydraulic fracturing, which are often used together. In directional drilling, the well operator bores vertically down to the rock formation, then follows the formation horizontally.
High-volume fracking-the focus of recent attention and public concern-is defined by the state of Michigan as a well that uses more than 100,000 gallons of hydraulic fracturing fluid. For reference, an Olympic-size swimming pool holds about 660,000 gallons of water.

Since the late 1940s, an estimated 12,000 gas and oil wells have been drilled in Michigan using hydraulic fracturing, without any reported contamination issues. Most of those wells have been relatively shallow vertical wells that each used about 50,000 gallons of water.

But recently, a small number of deep, directionally drilled, high-volume hydraulically fractured wells have been completed in the northern part of the Lower Peninsula. Those wells sometimes use several million gallons of water, and one Michigan well required more than 20 million gallons.

Since 2010, when the Petoskey Pioneer Well spurred interest in high-volume hydraulically fractured wells in Michigan, 19 such wells are known to have been completed in the state, according to Sara Gosman, a lecturer at the U-M Law School and author of the technical report on policy/law.

In the public perceptions report, authors Kim Wolske and Andrew Hoffman of the U-M Erb Institute for Global Sustainable Enterprise note that chemical additives in high-volume hydraulic fracturing fluids “remain a primary point of contention for many stakeholders in Michigan.” Many nonprofits and concerned citizens stress the point that operators of high-volume wells are not required to report the composition of those fluids to the state until 60 days after the hydraulic fracturing event.

The often-repeated concern is that if a spill were to occur, responders would not be as well-prepared as they would have been if the fluid composition had been known beforehand, Wolske and Hoffman note.

Though groundwater contamination is often cited as a top concern, surface contamination from spills and improper disposal of waste fluids likely carries the greatest risk for harmful water-quality impacts, due to proximity to potable water resources, according to the geology/hydrogeology report written by Brian Ellis, assistant professor in the Department of Civil and Environmental Engineering.

When a well is fracked, the fluid is injected into rock formations to create cracks and to prop them open. Of the total volume of hydraulic fracturing fluids injected into a well, amounts varying from 10 percent to 70 percent may return to the surface as “flowback water” after the pressure is reduced and gas or oil begin to flow toward the wellhead.

In Michigan high-volume hydraulically fractured wells, the average amount of flowback water returning to the surface is about 37 percent of injected volumes, according to the Ellis report.

The flowback water is highly saline and can contain elevated levels of heavy metals and naturally occurring radioactive elements, in addition to methane and the original chemical additives in the fracturing fluids. In Michigan, common hydraulic fracturing fluid additives include ethylene glycol, hydrochloric acid, isopropyl alcohol, methanol and ammonium persulfate, according to the Ellis report.

“However, since in Michigan all flowback is disposed of by deep-well injection and it is not allowed to sit in open pits, the risk of this type of contamination will be lower than in other states without such disposal opportunities and regulations,” Ellis wrote.

On the topic of potential water contamination, the environment/ecology report notes that Michigan’s dense, interconnected aquatic ecosystems (streams, rivers, lakes, inland and coastal wetlands) and the groundwater aquifers to which they are linked are of particular concern. The connectivity between surface and groundwater bodies “can lead to impacts distant from, as well as close to, drilling sites,” according to the report by G. Allen Burton, professor in the School of Natural Resources and Environment and director of the U-M Water Center, and Knute Nadelhoffer, professor of ecology and evolutionary biology and director of the U-M Biological Station.

The potential migration of methane, the main component of natural gas, into groundwater reservoirs has also received a lot of attention lately.

But the probability of significant methane leakage associated with deep-shale drilling involving hydraulic fracturing in Michigan “is quite low provided that best practices are adhered to,” according to the U-M report on hydraulic fracturing technologies written by John Wilson, a consultant to the U-M Energy Institute, and Johannes Schwank, professor of chemical engineering.

The greatest challenge to understanding the potential public health risks of hydraulic fracturing in Michigan is the lack of state-specific data, according to Niladri Basu, author of the public health technical report and a former faculty member at the U-M School of Public Health. While thousands of hydraulically fractured wells have been drilled in Michigan, the potential public health risks related to these facilities have been poorly documented, Basu wrote.

For example, while operators of high-volume fracking wells are required to disclose the contents of their hydraulic fracturing fluids, operators of the 12,000 or so low-volume wells in the state are not. “There needs to be much greater understanding of what chemicals are being used in every well, with information related to volumes, amounts, disposal plans, etc., made available,” Basu wrote.

The U-M hydraulic fracturing study is expected to cost at least $600,000 and is being funded by U-M through its Graham Sustainability Institute, Energy Institute and Risk Science Center. State regulators, oil and gas industry representatives, staffers from environmental nonprofits, and peer reviewers provided input to the technical reports, and more than 100 public comments were considered.

In addition to the study authors mentioned above, the technical report authors include Roland Zullo, assistant research scientist, U-M Institute for Research on Labor, Employment and the Economy (economics report).

Mountaintop mining pollution has distinct chemical signatures

Three elements commonly found at elevated levels in an Appalachian river polluted by runoff from mountaintop coal mining have distinctive chemistries that can be traced back to their source, according to a Duke University-led study.

The distinctive chemistries of sulfur, carbon and strontium provide scientists with new, more accurate ways to track pollution from mountaintop mining sites and to distinguish it from contamination from other sources.

“Essentially, we found that these elements have unique isotopic fingerprints, meaning we can use them as diagnostic tools to quantify mountaintop mining’s relative contribution to contamination in a watershed,” said Avner Vengosh, professor of geochemistry and water quality at Duke’s Nicholas School of the Environment.

The newly identified tracers will be especially useful in watersheds with more than one source of potential contamination, he said. “Because they allow us to distinguish if contaminants are coming from natural sources, fracking and shale gas development, coal mining, coal ash disposal, or other causes.”

Vengosh and his team’s findings were published today in the online edition of the peer-reviewed journal Environmental Science & Technology.

The researchers measured the chemical and isotopic compositions of water samples collected monthly from 23 locations along West Virginia’s Upper Mud River and its tributaries between May and December 2012.

They found that the isotopic signatures of sulfur (in sulfate), carbon (in dissolved inorganic carbon) and strontium from water samples collected from tributaries adjacent to mountaintop mining sites are distinguishable from those collected from unaffected upstream waters. They also found that the strontium isotope ratio is a sensitive tracer for selenium contamination, one of the major pollutants of mountaintop mining.

In mountaintop mining, companies use explosives and heavy machinery to clear away surface rocks and extract shallow deposits of high-quality coal. The companies typically dispose of the waste rock in adjacent valleys, where they bury existing headwater streams.

Previous studies by the Duke team and others have shown that runoff from these “valley fills” contains elevated levels of salts and selenium, a known fish toxin. The contamination can persist and accumulate in downstream waters for decades after active mining stops and the fills are reclaimed.

By conducting tests that simulated the natural leaching of contaminants from local rocks, Vengosh and his team were able to characterize the chemistry of the different geological formations that end up as waste rock in these fills. They found significant differences in strontium isotope ratios and selenium concentrations in streams flowing from reclaimed valley fills versus those flowing from active fills.

“This helps us further pinpoint the source of contamination by linking it directly to the type of rocks in the valley fills,” Vengosh said.

The Upper Mud River flows through sparsely populated areas of southern West Virginia as a headwater stream. For about 10 kilometers, the river passes through the Hobet 21 surface mining complex, which has been active since the 1970s and is among the largest in the Appalachian coalfields.