Drought may threaten much of globe within decades

These four maps illustrate the potential for future drought worldwide over the decades indicated, based on current projections of future greenhouse gas emissions. These maps are not intended as forecasts, since the actual course of projected greenhouse gas emissions as well as natural climate variations could alter the drought patterns.

The maps use a common measure, the Palmer Drought Severity Index, which assigns positive numbers when conditions are unusually wet for a particular region, and negative numbers when conditions are unusually dry. A reading of -4 or below is considered extreme drought. Regions that are blue or green will likely be at lower risk of drought, while those in the red and purple spectrum could face more unusually extreme drought conditions. -  Courtesy Wiley Interdisciplinary Reviews, redrawn by UCAR. This image is freely available for media use. Please credit the University Corporation for Atmospheric Research.
These four maps illustrate the potential for future drought worldwide over the decades indicated, based on current projections of future greenhouse gas emissions. These maps are not intended as forecasts, since the actual course of projected greenhouse gas emissions as well as natural climate variations could alter the drought patterns.

The maps use a common measure, the Palmer Drought Severity Index, which assigns positive numbers when conditions are unusually wet for a particular region, and negative numbers when conditions are unusually dry. A reading of -4 or below is considered extreme drought. Regions that are blue or green will likely be at lower risk of drought, while those in the red and purple spectrum could face more unusually extreme drought conditions. – Courtesy Wiley Interdisciplinary Reviews, redrawn by UCAR. This image is freely available for media use. Please credit the University Corporation for Atmospheric Research.


The United States and many other heavily populated countries face a growing threat of severe and prolonged drought in coming decades, according to a new study by National Center for Atmospheric Research (NCAR) scientist Aiguo Dai. The analysis concludes that warming temperatures associated with climate change will likely create increasingly dry conditions across much of the globe in the next 30 years, possibly reaching a scale in some regions by the end of the century that has rarely, if ever, been observed in modern times.

Using an ensemble of 22 computer climate models and a comprehensive index of drought conditions, as well as analyses of previously published studies, the paper finds that most of the Western Hemisphere, along with large parts of Eurasia, Africa, and Australia, will be at risk of extreme drought this century.

In contrast, higher-latitude regions from Alaska to Scandinavia are likely to become more moist.

Dai cautioned that the findings are based on the best current projections of greenhouse gas emissions. What actually happens in coming decades will depend on many factors, including actual future emissions of greenhouse gases as well as natural climate cycles such as El Niño.

The new findings appear this week as part of a longer review article in Wiley Interdisciplinary Reviews: Climate Change. The study was supported by the National Science Foundation, NCAR’s sponsor.

“We are facing the possibility of widespread drought in the coming decades, but this has yet to be fully recognized by both the public and the climate change research community,” Dai says. “If the projections in this study come even close to being realized, the consequences for society worldwide will be enormous.”

While regional climate projections are less certain than those for the globe as a whole, Dai’s study indicates that most of the western two-thirds of the United States will be significantly drier by the 2030s. Large parts of the nation may face an increasing risk of extreme drought during the century.

Other countries and continents that could face significant drying include:

  • Much of Latin America, including large sections of Mexico and Brazil
  • Regions bordering the Mediterranean Sea, which could become especially dry
  • Large parts of Southwest Asia
  • Most of Africa and Australia, with particularly dry conditions in regions of Africa
  • Southeast Asia, including parts of China and neighboring countries

The study also finds that drought risk can be expected to decrease this century across much of Northern Europe, Russia, Canada, and Alaska, as well as some areas in the Southern Hemisphere. However, the globe’s land areas should be drier overall.

“The increased wetness over the northern, sparsely populated high latitudes can’t match the drying over the more densely populated temperate and tropical areas,” Dai says.

A climate change expert not associated with the study, Richard Seager of Columbia University’s Lamont Doherty Earth Observatory, adds:

“As Dai emphasizes here, vast swaths of the subtropics and the midlatitude continents face a future with drier soils and less surface water as a result of reducing rainfall and increasing evaporation driven by a warming atmosphere. The term ‘global warming’ does not do justice to the climatic changes the world will experience in coming decades. Some of the worst disruptions we face will involve water, not just temperature.”

A portrait of worsening drought

Previous climate studies have indicated that global warming will probably alter precipitation patterns as the subtropics expand. The 2007 assessment by the Intergovernmental Panel on Climate Change (IPCC) concluded that subtropical areas will likely have precipitation declines, with high-latitude areas getting more precipitation.

In addition, previous studies by Dai have indicated that climate change may already be having a drying effect on parts of the world. In a much-cited 2004 study, he and colleagues found that the percentage of Earth’s land area stricken by serious drought more than doubled from the 1970s to the early 2000s. Last year, he headed up a research team that found that some of the world’s major rivers are losing water.

In his new study, Dai turned from rain and snow amounts to drought itself, and posed a basic question: how will climate change affect future droughts? If rainfall runs short by a given amount, it may or may not produce drought conditions, depending on how warm it is, how quickly the moisture evaporates, and other factors.

Droughts are complex events that can be associated with significantly reduced precipitation, dry soils that fail to sustain crops, and reduced levels in reservoirs and other bodies of water that can imperil drinking supplies. A common measure called the Palmer Drought Severity Index classifies the strength of a drought by tracking precipitation and evaporation over time and comparing them to the usual variability one would expect at a given location.

Dai turned to results from the 22 computer models used by the IPCC in its 2007 report to gather projections about temperature, precipitation, humidity, wind speed, and Earth’s radiative balance, based on current projections of greenhouse gas emissions. He then fed the information into the Palmer model to calculate the PDSI number. A reading of +0.5 to -0.5 on the index indicates normal conditions, while a reading at or below -4 indicates extreme drought.

By the 2030s, the results indicated that some regions in the United States and overseas could experience particularly severe conditions, with average readings over the course of a decade potentially dropping to -4 to -6 in much of the central and western United States as well as several regions overseas, and -8 or lower in parts of the Mediterranean. By the end of the century, many populated areas, including parts of the United States, could face readings in the range of -8 to -10, and much of the Mediterranean could fall to -15 to -20. Such readings would be almost unprecedented.

Dai cautions that global climate models remain inconsistent in capturing precipitation changes and other atmospheric factors, especially at the regional scale. However, the 2007 IPCC models were in stronger agreement on high- and low-latitude precipitation than those used in previous reports, says Dai.

There are also uncertainties in how well the Palmer index captures the range of conditions that future climate may produce. The index could be overestimating drought intensity in the more extreme cases, says Dai. On the other hand, the index may be underestimating the loss of soil moisture should rain and snow fall in shorter, heavier bursts and run off more quickly. Such precipitation trends have already been diagnosed in the United States and several other areas over recent years, says Dai.

“The fact that the current drought index may not work for the 21st century climate is itself a troubling sign,” Dai says.

Shaping the future of the High Plains’ water supply

The Ogallala Aquifer is one of the largest in the world, spanning from South Dakota to Texas. Image by Anthony Kendall
The Ogallala Aquifer is one of the largest in the world, spanning from South Dakota to Texas. Image by Anthony Kendall

Researchers at Michigan State University are helping shape the future of the High Plains’ water supply.

The Ogallala Aquifer is a vast underground system that spans from South Dakota to Texas with smaller portions in Colorado, New Mexico and Wyoming. It is one of the world’s largest aquifer systems, storing nearly as much water as Lake Erie and Lake Huron combined. Yet this seemingly limitless water supply, a key component supporting the Great Plains’ bountiful agriculture production, is shrinking.

The National Science Foundation has awarded MSU $1.2 million to help shape a course to better manage this important natural resource. The multidisciplinary team of researchers, led by hydrogeologist David Hyndman, will use the four-year grant to develop a sustainability plan based on economic, sociological and geographic issues affecting the aquifer.

“For more than 80 years, the Ogallala Aquifer has been used for irrigation, and the withdrawals far exceed its ability to replenish itself,” said Hyndman, who worked with the Kansas Geological Survey on this project. “We are on an unsustainable course and must make difficult changes if we are to keep using some of the best agricultural land in the country.”

Researchers will review decades of scientific data. They also will study the interactions between the region’s landscape, atmosphere and socioeconomic systems and link this data with climate, hydrology, vegetation and economic models.

The end result will produce predictions and impact assessments covering a range of potential solutions. Community and government leaders will be able to implement the team’s forecasts to adjust land management policies and to make strides toward sustainable water-use practices.

“Navigating a patchwork of state laws, regulations and economics means any change will require complex solutions,” Hyndman said. “And since scientific solutions don’t exist in a vacuum, our plan will also address social and economic variables.”

Geophysicists claim conventional understanding of Earth’s deep water cycle needs revision

Harry Green is a distinguished professor of geology and geophysics in the Department of Earth Sciences. -  Green lab, UC Riverside.
Harry Green is a distinguished professor of geology and geophysics in the Department of Earth Sciences. – Green lab, UC Riverside.

A popular view among geophysicists is that large amounts of water are carried from the oceans to the deep mantle in “subduction zones,” which are boundaries where the Earth’s crustal plates converge, with one plate riding over the other.

But now geophysicists led by the University of California, Riverside’s Harry Green, a distinguished professor of geology and geophysics, present results that contradict this view. They compare seismic and experimental evidence to argue that subducting slabs do not carry water deeper than about 400 kilometers.

“The importance of this work is two-fold,” Green said. “Firstly, if deep slabs are dry, it implies that they are strong, a major current question in geophysics that has implications for plate tectonic models. Secondly, even small amounts of water greatly reduce the viscosity of rocks; if water is not cycled deep into Earth, it means that mantle convection has not been as vigorous over time as it would have been with significant water.”

Study results appear in the current issue of Nature.

The Earth’s lithosphere is formed at mid-ocean ridges where magma upwells and freezes to form new oceanic crust. Interaction between cold water of the deep ocean and the extreme heat of magma results in widespread cracking of rocks and a hydrothermal circulation that drives sea water several kilometers below the surface.

Away from the mid-ocean ridges, the lithosphere moves along under the ocean until it reaches an oceanic trench, long topographic depressions of the sea floor. Here, the lithosphere bends sharply and descends back into the mantle. Near the trench, numerous faults are created that provide a pathway for additional water to enter the down-going lithosphere. Subsequent dehydration results in large amounts of this water leaving the subducting slab and migrating upwards. The ensuing instability leads to seismic activity.

Geophysicists have long suspected but only recently established that at depths less than about 250 kilometers earthquakes occur through dehydration of minerals like serpentine. But when Green and his colleagues studied the data for deeper earthquakes, they found that the subducting slabs are essentially dry, providing no pathway for significant amounts of water to enter the Earth’s lower mantle.

Further, the researchers cite evidence for olivine in the slabs at these depths, despite the fact that it is not stable below about 350 km.

“At these depths, olivine should transform to the stable phase, spinel,” Green said. “The very cold temperatures deep in the downgoing slabs inhibit this transformation. Experiments show that even extremely small amounts of water, if present, would cause the olivine-to-spinel transformation to run. But we see no spinel here, just olivine, which confirms that the slabs are dry.”

Green explained that the olivine found below 400 kilometers is “metastable,” meaning it is physically present as a mineral phase even though this is not its “right phase” at such depths – akin to a diamond, which forms only at the kind of high temperatures and pressures found very deep in the Earth’s crust, being brought to the Earth’s surface.

“At such depths, the olivine should undergo a phase transformation,” he said. “A different crystal structure should nucleate, grow and eat up the olivine. If it is very cold in the center of subducting slabs, the reaction won’t run. This is exactly what is happening here.”

According to Green, the presence of the metastable olivine provides an alternative mechanism to initiate deep earthquakes – a mechanism he discovered 20 years ago – and also to cause them to stop at around 680 kilometers, where they are seen to stop.

“Does this mean that Earth’s deep interior must be dry? Not necessarily,” he said. “It is possible there are other ways – let’s call them back roads – for water to penetrate the lower mantle, but our work shows that the ‘super highway,’ the subducting slabs, as a means for water to enter the lower mantle can now be ruled out.”

Green and his colleagues cite the evidence for the existence of metastable olivine west of and within the subducting Tonga slab in the South Pacific and also in three other subduction zones – the Mariannas, Izu-Bonin and Japan.

Oil boom possible but time is running out

There is potential for CO2 transfer from the industrial centers on the UK's eastern seaboard to the oilfields and saline aquifers of the North Sea. -  Professor Jon Gluyas, Durham University
There is potential for CO2 transfer from the industrial centers on the UK’s eastern seaboard to the oilfields and saline aquifers of the North Sea. – Professor Jon Gluyas, Durham University

Oil recovery using carbon dioxide could lead to a North Sea oil bonanza worth £150 billion ($ 240 billion) – but only if the current infrastructure is enhanced now, according to a new study published today by a world-leading energy expert.

A new calculation by Durham University of the net worth of the UK oil field shows that using carbon dioxide (CO2) to enhance the recovery from our existing North Sea oil fields could yield an extra three billion barrels of oil over the next 20 years. Three billion barrels of oil could power, heat and transport the UK for two years with every other form of energy switched off.

Importantly, at a time of rising CO2 emissions, the enhanced oil recovery process is just about carbon neutral with as much carbon being put back in the ground as will be taken out.

The technique could yield an enormous amount of oil revenue at a time of public service cuts and developing the infrastructure would put the UK in the driving seat for developing enhanced recovery off-shore oil production around the world. It would also allow the UK to develop its carbon storage techniques in line with the UK government’s commitments on emissions reductions.

The study, funded by DONG Energy (UK) Ltd. and Ikon Science Ltd., will be presented today, October 14th 2010, at a conference on Carbon Capture and Storage (CCS), at the Institution of Mechanical Engineers, London. The new figures are conservative estimates and extend a previous calculation that predicted a 2.7 billion barrel yield from selected fields in the North Sea.

The UK Government’s Energy Statement, published in April 2010, outlines the continued role that fossil fuels will have to play in the UK energy mix. CO2 enhanced oil recovery in the UK would secure supplies for the next 20 years.

Jon Gluyas, a Professor in CCS & Geo-Energy, Department of Earth Sciences, Durham University, who has calculated the new figures, said: “Time is running out to make best use of our precious remaining oil reserves because we’re losing vital infrastructure as the oil fields decline and are abandoned. Once the infrastructure is removed, we will never go back and the opportunity will be wasted.

“We need to act now to develop the capture and transportation infrastructure to take the CO2 to where it is needed. This would be a world-leading industry using new technology to deliver carbon dioxide to the North Sea oil fields. We must begin to do this as soon as possible before it becomes too expensive to do so.

“My figures are at the low end of expectations but they show that developing this technology could lead to a huge rejuvenation of the North Sea. The industrial CO2 output from Aberdeen to Hull is all you need to deliver this enhanced oil recovery.”

Carbon dioxide is emitted into the atmosphere when fossil fuels are burnt and the UK Government plans to collect it from power stations in the UK. Capturing and storing carbon dioxide is seen as a way to prevent global warming and ocean acidification. Old oil and gas fields, such as those in the North Sea, are considered to be likely stores.

Enhanced oil recovery using carbon dioxide (CO2 EOR) adds further value to the potential merits of CCS.

Oil is usually recovered by flushing oil wells through with water at pressure. Since the 1970s oil fields in West Texas, USA, have been successfully exploited using carbon dioxide. CO2 is pumped as a fluid into oil fields at elevated pressure and helps sweep the oil to the production wells by contacting parts of the reservoirs not accessed by water injection; the result is much greater oil production.

Experience from the USA shows that an extra four to twelve per cent of the oil in place can be extracted using CO2-EOR. Professor Gluyas calculated the total oil in place in the UK fields and the potential UK gain in barrels and revenue from existing reserves using the American model.

David Hanstock, a founding director of Progressive Energy and director of COOTS Ltd, which is developing an offshore CO2 transport and storage infrastructure in the North Sea, said: “The UK has significant storage capacity potential for captured carbon dioxide in North sea oil and gas fields.

“There is a unique opportunity to develop a new offshore industry using our considerable experience in offshore engineering. This would give us a technical lead on injecting and monitoring CO2 that we could then export to the wider world to establish the UK as a world leader in carbon capture and storage technology.”

Professor Gluyas added: “Enhanced recovery of oil in the North Sea oil fields can secure our energy supplies for the next fifty years. The extra 3 billion barrels of oil that could be produced by enhanced CO2 recovery would make us self sufficient and would add around £60bn in revenue to the Treasury.

“Priming the system now would mean we have 10-15 years to develop CO2 recycling and sufficient time to help us bridge to a future serviced by renewable energy.”

Marcellus shale needs scientific study to set guidelines

The Academy of Natural Sciences is calling for a comprehensive research plan that would result in guidelines and an assessment tool for regulators and managers in order to minimize the environmental impact of Marcellus Shale gas drilling.

“At this time, there is very little information available as to the impacts of long-term exposure of a watershed to Marcellus Shale drilling activities,” said Dr. David Velinsky, vice president of the Academy’s Patrick Center for Environmental Research. “Nor do we know if there is a cumulative impact of drilling activity on the ecosystem services of a small watershed.”

Initial research by Academy scientists working with University of Pennsylvania graduate student Frank Anderson shows the environmental impact of drilling may be directly related to the amount of drilling in a specific area, referred to as the “density” of drilling. “The question that needs to be addressed is whether there is a threshold point past which a certain amount of drilling activity has an impact on the ecological health and services of the watershed-regardless of how carefully drilling is conducted,” Velinsky said.

Loss of salamanders signals ecological impact

In the preliminary research conducted this summer, scientists examined small watersheds in northeastern Pennsylvania-three in which there had been no drilling, three in which there had been some drilling and three in which there had been a high density of drilling. At each site, they tested the water, the abundance of certain sensitive insects, and the abundance of salamanders. The presence of salamanders is particularly important because amphibians are especially vulnerable to changes in the environment. The absence of amphibians is often an ecological early-warning system.

For each of the measures, there was a significant difference between high-density drilling locations and locations with no drilling or less drilling. The studies showed that water conductivity (which indicates the level of contamination) was almost twice as high in the high density sites as the other sites, and the number of both sensitive insects and salamanders were reduced by 25 percent.

“This suggests there is indeed a threshold at which drilling-regardless of how it is practiced-will have a significant impact on an ecosystem,” Velinsky said. “Conversely, it also suggests there may be lower densities of drilling at which ecological impact cannot be detected.”

Velinsky stressed that the data is preliminary and that a larger, more comprehensive study must be done before definitive conclusions can be drawn. The Academy has applied to the Pennsylvania Department of Environmental Protection’s Growing Greener Program to fund such a study.

“When this study has been completed we will be able to indicate with a much higher level of certainty what the ecological risks are of drilling in the shale and how they might be managed.”

Tsunami risk higher in Los Angeles, other major cities

The scientific team on board the RV Endeavor included (left to right): Cecilia McHugh (Lamont/Queens College), Leonardo Seeber (LDEO), Carol Prentice (USGS), Paul Mann (UTIG), Milene Cormier (University of Missouri), Matt Hornbach (UTIG), and Sean Gullick (UTIG). Photo: Marcy Davis
The scientific team on board the RV Endeavor included (left to right): Cecilia McHugh (Lamont/Queens College), Leonardo Seeber (LDEO), Carol Prentice (USGS), Paul Mann (UTIG), Milene Cormier (University of Missouri), Matt Hornbach (UTIG), and Sean Gullick (UTIG). Photo: Marcy Davis

Geologists studying the Jan. 12 Haiti earthquake say the risk of destructive tsunamis is higher than expected in places such as Kingston, Istanbul, and Los Angeles.

Like Haiti’s capital, these cities all lie near the coast and near an active geologic feature called a strike-slip fault where two tectonic plates slide past each other like two hands rubbing against each other.

Until now, geologists did not consider the tsunami risk to be very high in these places because when these faults rupture, they usually do not vertically displace the seafloor much, which is how most tsunamis are generated. This latest research suggests even a moderate earthquake on a strike-slip fault can generate tsunamis through submarine landslides, raising the overall tsunami risk in these places.

“The scary part about that is you do not need a large earthquake to trigger a large tsunami,” said Matt Hornbach, research associate at The University of Texas at Austin’s Institute for Geophysics and lead author on a paper describing the research in the Oct. 10 online edition of the journal Nature Geoscience.

“Organizations that issue tsunami warnings usually look for large earthquakes on thrust faults,” said Hornbach. “Now we see you don’t necessarily need those things. A moderate earthquake on a strike-slip fault can still be cause for alarm.”

Within minutes after the magnitude 7 Haiti earthquake, a series of tsunami waves, some as high as 9 feet (3 meters), crashed into parts of the shoreline. A few weeks later, a team of scientists from the U.S. and Haiti conducted geological field surveys of sites on and offshore near the quake’s epicenter.

The scientists determined the tsunamis were generated primarily by weak sediment at the shore that collapsed and slid along the seafloor, displacing the overlying water. Combined with newly discovered evidence of historic tsunamis, the survey revealed a third of all tsunamis in the area are generated in this way. Geologists had previously estimated only about 3 percent of tsunamis globally are generated through submarine landslides.

“We found that tsunamis around Haiti are about 10 times more likely to be generated in this way than we would have expected,” said Hornbach.

In addition to Hornbach, team members from The University of Texas at Austin include: Paul Mann, Fred Taylor, Cliff Frohlich, Sean Gulick and Marcy Davis. The team also includes researchers from Queens College, City University of New York; U.S. Geological Survey, University of Missouri; Lamont-Doherty Earth Observatory of Columbia University; University of California, Santa Barbara; Bureau of Mines and Energy (Haiti); and Universite d’Etat de Haiti.

The researchers gathered data on faults beneath the seafloor and land, vertical movement of the land, bathymetry (underwater topography) of the seafloor and evidence of tsunami waves. They worked on foot, on a small inflatable boat and on the 165-foot research vessel Endeavor.

This research was funded by a Rapid Response grant from the National Science Foundation and The University of Texas at Austin’s Jackson School of Geosciences.

With additional funding from The Society for Geophysics’ Geoscientists Without Borders program, Hornbach and others are now conducting a new research project in nearby Jamaica to assess the tsunami threat there.

“The geology of Kingston, Jamaica is nearly identical to Port Au Prince, Haiti,” said Hornbach. “It’s primed and ready to go and they need to prepare for it. The good news is, they have a leg up because they’re aware of the problem.”

Mount Etna’s mystery explained?

Dr. Wouter Schellart, Monash University, has developed a new theory of Earth dynamics. -  Monash University
Dr. Wouter Schellart, Monash University, has developed a new theory of Earth dynamics. – Monash University

Internationally renowned geophysicist Dr Wouter Schellart has developed the first dynamic model to explain the mystery of the largest and most fascinating volcano in Europe, Mount Etna.

Dr Schellart’s results from fluid dynamic models provide an alternative explanation for the existence of Mount Etna, its geological environment and evolution, as well as volcanism in the surrounding region.

His theory suggests that Mount Etna is not directly the result of tectonic plate boundary activity, but that it resulted from decompression melting of upper mantle material flowing around the nearby edge of the Ionian slab that is slowly sinking into the Earth’s mantle.

“Most volcanism on Earth occurs at plate boundaries in places where tectonic plates move apart (e.g. Iceland) and in places where tectonic plates come together with one plate diving (subducting) below the other plate into the mantle (e.g. Pacific ring of fire),” Dr Schellart said. “For the latter scenario, the volcanoes form directly above the subducted plate.”

However, Dr Schellart said some volcanism, appropriately named intraplate volcanism, occurs far from plate boundaries and its origin is more controversial.

“The chemistry of the volcanic rocks from Mount Etna and the nearby Iblean volcanics in Sicily and in the surrounding seas indicate that they are intraplate volcanics. Interestingly, the volcanics are located within a few hundred kilometres of, but are laterally offset from, the Calabrian subduction zone plate boundary, where the African plate sinks below the Eurasian plate,” Dr Schellart said.

“This suggests that the volcanics are somehow related to the Calabrian subduction zone.”

“New modeling of subduction and mantle flow confirms this, showing that backward sinking of the African plate at the Calabrian subduction zone induced flow around the southern edge of the subducted plate and upward below Sicily,” he said.

“The upward flow induced decompression melting of upper mantle material and these melts extruded at the surface in Sicily, forming Mount Etna and the Iblean volcanics,” Dr Schellart said.

Until now there had been many explanations for Mount Etna and that of the surrounding volcanics, but none had been able to explain the timing, origin and dynamics of the activity.

“That’s why Mount Etna has remained a mystery for so long,” Dr Schellart said.

“The new research provides a dynamic explanation and completes the puzzle,” he said
Mount Etna is one of the most active volcanoes in the world and is in an almost constant state of activity. The most recent ash explosion occurred in August of this year, producing an ash plume that rose 800 meters above the crater edge.

The research was recently published in the journal Geology.

Bacteria keep tabs on state of oil field

The ups and downs of the bacteria in an oil field provide a useful source of information for keeping tabs on the state of the oil field itself. In theory, this process known as ‘biomonitoring’ can increase the yield from an oil field. This is the conclusion reached by Geert van der Kraan, who obtained his doctorate on this topic at TU Delft on Tuesday, 5 October.

Seawater

Oil fields are highly specific ecosystems. For instance, they contain no oxygen and the temperature, pressure and salinity are often high. This means that oil fields are home to a very particular community of bacteria. The exploitation of oil fields gives rise to a great many changes. In order to obtain more oil from a field, methods such as pumping seawater into the field are used in order to flush through the oil. Seawater injection has a number of effects, such as the introduction of sulphate. This changes the composition of the bacteria populations in the oil field. Bacteria that reduce sulphate thrive, prompting the release of hydrogen sulphide, which is not only toxic but also has an adverse effect on the quality of the oil and damages the pipelines.

Information source

For this reason, these bacteria have always been closely monitored by the oil industry. For his doctorate research, Geert van der Kraan investigated whether a brand new step could be taken. He wanted to know whether the microbial changes (i.e. the types and quantity of bacteria present) could be used as an information source to track what is taking place in the oil field. This concept is known as biomonitoring. It is an approach that has the potential to boost oil exploitation or to prevent the production of harmful hydrogen sulphide at an early stage. This can be achieved by smart management of oil wells.

Positive indications

Geert van der Kraan has studied various Dutch oil fields, focusing on the microbial communities living there. “There are very positive indications that biomonitoring is a realistic option. The changes in the microbial diversity of the pore water from the oil well can provide a good understanding of the changing geochemical conditions in the oil field itself. This may well enable the oil field to be exploited more efficiently.”

Biofilms

In addition to monitoring, bacteria can also be used to improve oil extraction. Geert van der Kraan explains: “Encouraging the growth of certain groups of bacteria at specific locations in the oil field is an interesting proposition. This growth partially blocks the porous structure of the rock that contains the oil, forcing the water to take another route. It can then move oil that is more difficult to reach, increasing the effectiveness of oil extraction.”

Geert van der Kraan is the first researcher to obtain his doctorate as part of the ISAPP programme (Integrated System Approach Petroleum Production). ISAPP is a collaboration between TU Delft, Shell International Exploration & Production and TNO.

New deep-sea hot springs discovered in the Atlantic

<IMG SRC="/Images/82986772.jpg" WIDTH="350" HEIGHT="262" BORDER="0" ALT="The hydrothermal vent crab Segonzacia is on a mound that is covered with white bacteria and mineral precipitates. – MARUM”>
The hydrothermal vent crab Segonzacia is on a mound that is covered with white bacteria and mineral precipitates. – MARUM

Scientists from the MARUM Center for Marine Environmental Sciences and the Max Planck Institute for Marine Microbiology in Bremen on board the German research vessel Meteor have discovered a new hydrothermal vent 500 kilometers south-west of the Azores. The vent with chimneys as high as one meter and fluids with temperatures up to 300 degrees Celsius was found at one thousand meters water depth in the middle of the Atlantic Ocean. The discovery of the new deep-sea vent is remarkable because the area in which it was found has been intensively studied during previous research cruises. The MARUM and Max Planck researchers describe their discovery in their video blog.

The Bremen scientists were able to find the hydrothermal vent by using the new, latest-generation multibeam echosounder on board the research vessel Meteor that allows the imaging of the water column above the ocean floor with previously unattained precision. The scientists saw a plume of gas bubbles in the water column at a site about 5 kilometers away from the known large vent field Menez Gwen that they were working on. A dive with the remote-controlled submarine MARUM-QUEST revealed the new hydrothermal site with smokers and animals typically found at vents on the Mid-Atlantic Ridge.

Since the discovery of the new vent, the scientists have been intensively searching the water column with the multibeam echosounder. To their astonishment, they have already found at least five other sites with gas plumes. Some even lie outside the volcanically active spreading zone in areas where hydrothermal activity was previously not assumed to occur.

“Our results indicate that many more of these small active sites exist along the Mid-Atlantic Ridge than previously assumed,” said Dr. Nicole Dubilier, the chief scientist of the expedition. “This could change our understanding of the contribution of hydrothermal activity to the thermal budget of the oceans. Our discovery is also exciting because it could provide the answer to a long standing mystery: We do not know how animals travel between the large hydrothermal vents, which are often separated by hundreds to thousands of kilometres from each other. They may be using these smaller sites as stepping stones for their dispersal.”

Research on deep-sea hydrothermal vents in the Atlantic is the objective of the 30 marine scientists from Hamburg, Bremen, Kiel, Portugal, and France who have been on board the German research vessel Meteor since September 6th. The expedition to the submarine volcano Menez Gwen near the Azores is financed by MARUM, the Center for Marine Environmental Sciences in Bremen. “One of the questions that the team would like to answer is why the hydrothermal sources in this area emit so much methane – a very potent greenhouse gas,” says chief scientist Nicole Dubilier, who is also a member of the Steering Committee of the Census of Marine Life Vents and Seeps project ChEss (Chemosynthetic Ecosystem Science). “Another important focus of the research is the deep-sea mussels that live at the hydrothermal vents and host symbiotic bacteria in their gills. The mussels obtain their nutrition from these bacteria.”

Animations show extent of marcellus shale development

Extent and Thickness of Marcellus Shale - The organic-rich, gas-producing layers of the Marcellus shale range from less than 5 feet thick to more than 250 feet thick.
Extent and Thickness of Marcellus Shale – The organic-rich, gas-producing layers of the Marcellus shale range from less than 5 feet thick to more than 250 feet thick.

The pace and extent of Marcellus Shale development across Pennsylvania can be “seen” in animated maps produced by the Penn State Marcellus Center for Outreach and Research.

Based on data from the Pennsylvania Department of Environmental Protection, the animations (http://www.marcellus.psu.edu/resources/maps.php) show both the number of drilling permits issued for the Marcellus Shale target and the number of wells drilled by year from 2007 through August 2010. Although permits were issued prior to 2007, information on those permits did not include latitude and longitude.

“These animations give people a chance to see how the pace of Marcellus development has accelerated,” said Tom Murphy, co-director of the Marcellus Center and extension educator with Penn State Cooperative Extension. “When you look at these animations, you are able to trace where development is occurring and get a sense of the rate at which it is occurring.”

The two animations also allow comparison between the number of permits issued and the actual number of wells drilled.

The animations show that interest in the Marcellus has skyrocketed with just 99 drilling permits issued in 2007 compared to 2,108 in the first eight months of 2010. A similar surge in the numbers of wells drilled is also evident. In 2010, through August 31, 950 wells had been drilled in the Marcellus Shale while in all of 2007, only 43 wells were drilled.

“We expect that the uptick in Marcellus well drilling activity will continue, given the high production rates being seen in the wells and the relatively low cost to develop this gas resource,” said Michael Arthur, co-director of Penn State’s Marcellus Center and professor of geosciences. “Even with the low natural gas commodity pricing, drilling in the Marcellus can still be profitable for efficient companies.”

The DEP updates its permit and well reports weekly at http://www.dep.state.pa.us/dep/deputate/minres/oilgas/RIG10.htm. A separate spreadsheet identifies Marcellus permits and whether they are for horizontal or vertical wells.

The Marcellus Shale occurs as deep as 9,000 feet below ground surface and covers about 95,000 square miles over six states including Pennsylvania. Its organic carbon-rich, gas-producing layers range from less than five feet thick to more than 250 feet thick. Estimates are that the Marcellus has enough recoverable natural gas to supply the entire U.S. for at least 20 years at the current rate of consumption.