Three major physiographic provinces in the Ozark Plateaus in Arkansas and Missouri include diverse topography and geomorphology, which greatly affects the hydrology of the area. Numerous studies within the Ozarks, combined with studies performed in karst environments worldwide, have documented the diverse hydrologic characteristics of karst aquifers and related susceptibility to surface-derived contamination. Pictured is a photograph of an Ozark Spring.

A recent USGS study found that groundwater in aquifers on the East Coast and in the Central United States has the highest risk of contamination from radium, a naturally occurring radioactive element and known carcinogen.

Why do these areas have more radium in the groundwater? Radium is naturally occurring, so human activity is not the sole source of the problem. The USGS study found that radium levels are determined by the chemical attributes of the water in a particular area. For example, if the groundwater has low oxygen or low pH, radium is more likely to become present in the groundwater.

This is the first nationwide study to identify factors that make an aquifer susceptible to radium contamination. Radium cannot be readily detected by taste or smell, and analytical methods for measuring this contaminant require professional testing. But simple geochemistry measurements, like pH and oxygen, are good indicators of where radium is likely to exceed a standard and can help managers and regulators anticipate areas where radium may be elevated.

Most rocks and sediments contain naturally occurring radioactive elements, such as uranium and thorium, that decay and form radium. Under the right geochemical conditions, as groundwater slowly flows through underground pores, it can pick up and dissolve these radioactive elements, producing radium.

Low oxygen conditions were found to be prevalent in the Mid-Continent and Ozark Plateau Cambro-Ordovician aquifer systems in the Central United States, and low pH conditions were prevalent in the North Atlantic Coastal Plain aquifer system on the East Coast, making these areas more susceptible to radium contamination. In most aquifers used for drinking water supply, however, radium concentrations were below U.S. Environmental Protection Agency standards, especially in the western United States.

In this study, USGS scientists found that three geochemical conditions were primarily associated with elevated concentrations of radium in groundwater, including low levels of dissolved oxygen (less than one milligram per liter), acidity (pH less than 6), or high concentrations of dissolved solids, such as calcium, barium, magnesium, strontium, potassium, sulfate, or bicarbonate. These conditions prevent radium from sticking to aquifer sediments and increase its solubility in groundwater.

Five other aquifer systems also had elevated radium concentrations, including the Floridan aquifer system, the granitic and metamorphic crystalline-rocks of the New England province, the Mesozoic sedimentary basins in or adjoining the Appalachian Piedmont, the Gulf Coast Coastal Plain aquifer systems in the Southeast, and the glacial deposits in the northern part of the country.  Low oxygen conditions were prevalent in each of these aquifers where high concentrations of radium occurred. The glacial aquifer systems have both low oxygen and low pH conditions, which were also associated with high concentrations of radium.

In this study, radium was measured in untreated source water in wells from aquifers that are used for public and domestic water supply. Concentrations measured in source water do not necessarily reflect the quality of finished water from public water systems after the water has been treated. However, these samples were compared to EPA standards to provide an initial perspective on the prevalence of radium in the United States and the potential significance of radium to human health.

Radium is more of a concern for homeowners who have their own private groundwater supply well. Unlike public supply wells, these domestic wells are not subject to required testing, and often do not have treatment systems. Therefore, radium may be of concern for homeowners with their own private wells in certain regions of the country.

Tests for radium, and other indicators of radioactivity, can only be made by qualified professionals, and these tests require specialized equipment.  Local, state, or county environmental agencies or health departments can be a good source for information on the potential for radium contamination and recommendations about companies qualified to do radium testing. Most states have homeowner guidance websites related to this topic.

However, litmus paper, a simple test for pH, can provide an indication that pH in a well is low.  Measuring dissolved oxygen requires special instruments or chemicals, but there are some crude indicators that low oxygen may be present, including high concentrations of metals such as iron or manganese, high concentrations of dissolved solids, or water with a rotten egg smell.

Fortunately, simple, commonly used, and relatively inexpensive treatment systems (such as water softeners) can be very effective at removing radium.  Private homeowners can contact the National Sanitation Foundation (NSF) and the Water Quality Association (WQA) for assistance in determining the best treatment options for radium. In addition, the National Ground Water Association (NGWA) is dedicated to education efforts aimed at reducing contaminant risks to water supplies and provides a summary of treatment considerations and an overview of strategies for well owners.  A similar organization with educational resources is the Water Systems Council.

The President’s 2013 budget request for the U.S. Geological Survey is $1.1 billion, $34.5 million above the 2012 enacted level. The 2013 proposal reflects administrative efficiencies and research priorities to respond to nationally relevant issues, including water quantity and quality, ecosystem restoration, hydraulic fracturing, natural disasters such as floods and earthquakes, and support for the National Ocean Policy.

Recognizing constrained fiscal resources, the 2013 USGS budget reflects careful investments in priority science to support a robust and growing economy and a strong and resilient nation. The proposal addresses key science issues while maintaining a strong commitment to the USGS mission and its core science functions to provide geologic, hydrologic, and topographic information that contributes to the wise management of the nation’s natural resources and promotes the health, safety, and well-being of the people.

“Our science is increasingly in demand as new energy supplies are developed, competition for water grows, and the cost of natural disasters mounts,” said USGS director Marcia McNutt. “Fundamental, multidisciplinary USGS science capabilities are necessary to address the nation’s increasingly connected societal and economic challenges. We are pleased that the President’s budget provides strong support for our mission, underscoring the Administration’s commitment to science as a foundation for decision making.”

Investments in research and development (R& D) promote economic growth and innovation and ensure American competitiveness in a global market. The 2013 USGS budget request reflects an eight percent increase in funding for R&D activities. The increased funding for R&D will advance USGS’ capacity to address the nation’s most important challenges, and provide the scientific basis for resource management and natural disaster mitigation.

Proposed USGS key increases are summarized below. For more detailed information on the President’s proposed 2013 budget for these and other priorities,visit http://www.usgs.gov/budget/2013/2013index.asp.

WaterSMART:

As competition for water resources grows, so does the need for better information about water quality and quantity. WaterSMART, through the combined efforts of the USGS and the Bureau of Reclamation, provides information to address the nation’s water challenges. The USGS is proposing a total of $21.0 million for WaterSMART priorities, in support of the Department of the Interior’s Water Challenges initiative, and includes establishing a national groundwater monitoring network, assessing how water quality influences water availability, and continuing water availability assessments in the Colorado River Basin, the Delaware River Basin, and the Apalachicola-Chattahoochee-Flint Basin.

Ecosystem Priorities:

Whether restoring clean water, conserving treasured places, restoring habitat for fish and wildlife, or better understanding ecosystem services, today’s environmental challenges call for an ecosystem-wide approach. Complementing Interior’s America’s Great Outdoors initiative, the USGS is requesting an increase of $16.2 million for ecosystem restoration activities that will focus on restoration science and research in priority ecosystems such as the Chesapeake Bay, California Bay Delta, Puget Sound, and Columbia River. Proposed funding also supports fish health and water quality studies for the Klamath Basin Restoration Agreement, research to control and manage invasive species in the Everglades, such as the Burmese python, and research on new methods to eradicate, control, and manage Asian carp in the Upper Mississippi River Basin and prevent their entering the Great Lakes. Additional funding of $2.0 million will address invasive brown tree snakes, coral reef health, and white-nose syndrome in bats.

Hydraulic Fracturing:

With appropriate safeguards, unconventional natural gas development through hydraulic fracturing has an important role to play in America’s energy economy. The USGS budget provides $18.6 million, a $13.0 million increase from 2012, to support a collaborative interagency research and development effort with the Department of Energy and the U.S. Environmental Protection Agency to better understand and minimize potential adverse environmental, health, and safety impacts of hydraulic fracturing on air, water, ecosystems, and seismicity (earthquakes). In support of Interior’s New Energy Frontier initiative, the 2013 proposed budget increase includes funding for natural gas assessments, as well as for science that addresses water quality and quantity, induced earthquakes, and habitat impacts.

Rapid Disaster Response:

In 2011, the USGS responded to earthquakes, hurricanes, and historic floods.  Proposed funding of $10.9 million, an $8.6 million increase from 2012, for rapid disaster response will improve the USGS’s capacity to provide timely and effective science to minimize hazard risks to populations and infrastructure. The funding will upgrade USGS monitoring and warning capabilities for earthquakes, floods, landslides, and volcanoes. It will also aid in the development of a strategic science capability to rapidly deliver scientifically based information on the likely range of impacts from a given natural hazard or other environmental crisis, and expand development and delivery of disaster scenario products, such as the California Shakeout and ARkSTORM scenarios.  These initiatives allow communities to understand hazard impacts and prepare before disaster strikes. In addition to efforts to improve rapid disaster response, the Earthquake Hazards Program will focus $1.6 million on research on East Coast earthquakes, in the wake of the magnitude 5.8 Virginia earthquake in August 2011.

Science for Coastal and Ocean Stewardship:

Increased population growth, energy development, and resource use in coastal areas pose challenges requiring the latest science for communities to make wise decisions about future resource use and protection. Balancing protections for human and environmental health and safety with prudent and sustainable management of offshore energy resources is one such challenge. An increase of $6.8 million will allow the USGS to provide the science and information necessary to assess resource potential, ecosystem and community vulnerability, and develop management tools for coastal, oceanic and Great Lakes resources, in support of the National Ocean Policy. This information will support the safe and sustainable use and protection of coastal areas and oceans – now and for future generations.

For more detailed information on the President’s proposed 2013 budget for these and other priorities, visit http://www.usgs.gov/budget/2013/2013index.asp.

USGS scientist Peter Van Metre examines a parking lot where coal-tar sealcoat has been applied.A USGS scientist adjusts an air pump used to measure emission of polycyclic aromatic carbons (PAHs) into the air.

What is sealcoat?

Coal-tar-based sealant is the black liquid sprayed or painted on many parking lots, driveways, and playgrounds.

Several PAHs are probable human carcinogens, and many are toxic to fish and other aquatic life. Coal tar, which can cause cancer in humans, is made up of more than 50 percent PAHs. An estimated 85 million gallons of coal-tar-based sealant are used on parking lots and driveways each year, primarily in the central and eastern United States.

What are the rates of PAH emissions to the air from coal-tar-based sealcoat?

Coal-tar-based sealants are emitting PAHs into the air at rates that could be greater than annual emissions from vehicles in the United States based on a study in which USGS scientists tracked PAH levels in air and in dried sealcoat following sealcoat application to a parking lot. Two hours after sealcoat application, PAH emissions were 30,000 times higher than those from unsealed pavement. In a second study, USGS scientists measured PAHs in air above parking lots with and without sealcoat, in suburban Austin, Texas. Parking lots with three- to eight-year-old sealant still released 60 times more PAHs to the air than parking lots without sealant.

A USGS scientist adjusts an air pump used to measure emission of polycyclic aromatic carbons (PAHs) into the air.

Children living near sealed parking lots are exposed to PAHs

Children living near coal-tar-sealed pavement are exposed to twice as many PAHs from ingestion of contaminated house dust than from food, according to a separate new study by Baylor University and the USGS. Baylor University scientist Spencer Williams used USGS measurements of PAHs in house dust to estimate the potential ingestion of PAHs by young children living near coal-tar-sealed parking lots. Ingestion of PAHs from food has long been thought to be the primary route by which children are exposed to PAHs. PAH ingestion by children living near coal-tar-sealed parking lots  is estimated to be 14 times higher than by children in apartments adjacent to unsealed parking lots.

Sealcoat is a major source of PAHs to the environment

Past and current  research on environmental contamination and coal-tar-based pavement sealants and implications for human health and stormwater management are summarized in a new Feature Article in the journal Environmental Science and Technology. The article is jointly authored by researchers with the USGS, Minnesota Pollution Control Agency, University of New Hampshire, City of Austin, Texas, and Baylor University.

Bans on coal-tar sealcoat

Some governments have taken action on the use of coal-tar-based sealcoat.  Fifteen municipalities and two counties in four states (Minnesota, New York, Texas and Wisconsin), the District of Columbia and the state of Washington all have enacted some type of ban, affecting almost 10.4 million people. Several national and regional hardware and home-improvement retailers have voluntarily ceased selling coal-tar-based driveway-sealer products.

Coal-tar sealcoat compared to asphalt-based sealcoat

USGS scientists prepare a sampler used to measure emission of polycyclic aromatic carbons (PAHs) into the air.

Two kinds of sealcoat products are widely used: coal-tar-based and asphalt-based.  The coal-tar products have PAH levels about 1,000 times higher than the asphalt products. Coal-tar-based sealcoat is more commonly used in the Midwest, southern, and eastern United States. Asphalt-based sealcoat is more commonly used in the western United States.  Consumers can determine whether a product contains coal tar by reading the product label or the associated Materials Safety Data Sheet (MSDS), available from the applicator, retailer or on the Internet.

For more information, please visit the USGS website on PAHs and sealcoat, or contact Jennifer LaVista.

Small hills NNE of Mt. Shasta are hummockslide 380,000 and 300,000 years ago. This view is from the top of Gregory Mountain, located about 40 km from the summit of the volcano. The prominent cone on the right skyline is Black Butte, a collection of four overlapping lava domes that were erupted about 9,500 years ago.

“More than 500 volcanic vents have been identified in the State of California. At least 76 of these vents have erupted, some repeatedly, during the last 10,000 years. …  Sooner or later, volcanoes in California will erupt again, and they could have serious impacts on the health and safety of the State’s citizens as well as on its economy.”   Miller, C. Dan, 1989, Potential Hazards from Future Volcanic Eruptions in California: U.S. Geological Survey Bulletin 1847, 17p.

The U.S. Geological Survey announces the establishment of the USGS California Volcano Observatory, or CalVO, headquartered within existing USGS facilities in Menlo Park, Calif. Establishing CalVO will increase awareness of and resiliency to the volcano threats in California, many of which pose significant threats to the economy and well being of the state and its inhabitants.

“By uniting the research, monitoring, and hazard assessment for all of the volcanoes that pose a threat to the residents of California, CalVO will provide improved hazard information products to the public and decision makers alike,” explained USGS director Marcia McNutt. “This realignment is part of the USGS’s efforts to build the National Volcano Early Warning System, a prioritized modernization of USGS volcano monitoring enabled through the American Reinvestment and Recovery Act.”

CalVO takes on responsibility for research, monitoring, and assessing hazards for all of the potentially active volcanoes in California and coordinating with local and State emergency managers to prepare for responding to renewed volcanic activity. Previously, the USGS Cascades Volcano Observatory in Vancouver, Wash was responsible for responding to volcanic unrest at some northern California volcanoes.

CalVO replaces the former Long Valley Observatory, established in 1982 to monitor the restless Long Valley Caldera and Mono-Inyo Craters region of California. The creation of CalVO will improve coordination with federal, state, and local emergency managers during volcanic crises, and create new opportunities for volcanic hazard awareness and preparedness. The realignment of USGS Volcano Observatories will further facilitate collaboration with federal and state partner agencies including the California Emergency Management Agency and the California Geological Survey.

Obsidian Flow, a large circular-shaped lava flow, is part of the Mono-Inyo Chain.

“California has always led the nation in comprehensive planning for potential disasters. Having the USGS take the initiative to enhance their volcanic threat capabilities and, most importantly, improve planning and coordination with California’s emergency managers is welcomed news.  At the end of the day, the public expects us to plan for all hazards, and this is another great example,” said Mike Dayton, Undersecretary of the California Emergency Management Agency.

“California is the most geologically diverse state in the nation. We are known for our earthquakes, landslides and flood hazards. But our nearly forgotten hazard is our volcanoes,” said Dr. John Parrish, the State Geologist of California. “The California Geological Survey welcomes the new CalVO with its expanded scope and organization, and we look forward to its successful operations. The new CalVO will streamline our emergency response operations since CGS has offices at the USGS Menlo Park complex, and CalVO’s authority now encompasses all of California’s volcanic provinces in one center.”

In 2005, the USGS issued an assessment entitled “Volcanic Threat and Monitoring Capabilities in the United States” (USGS OFR 2005-1164). Volcanic threat rankings for U.S. volcanoes were derived from a combination of factors including age of the volcano, potential hazards (the destructive natural phenomena produced by a volcano), exposure (people and property at risk from the hazards), and current level of monitoring (real-time sensors in place to detect volcanic unrest).

The list of potentially threatening volcanoes on CalVO’s watch list includes Mount Shasta, Medicine Lake Volcano, Clear Lake Volcanic Field, and Lassen Volcanic Center in northern California; Long Valley Caldera and Mono-Inyo Craters in east-central California; Salton Buttes, Coso Volcanic Field, and Ubehebe Craters in southern California; and Soda Lakes in central Nevada. CalVO’s watch list is subject to change as new data on past eruptive activity becomes known, as volcanic unrest develops, as monitoring networks are upgraded, and/or as exposure factors change.

Under the Stafford Act, the USGS has the federal responsibility to issue timely and effective warnings of potential volcanic disasters.  In addition to CalVO, the USGS operates four other volcano observatories. The Cascade Volcano Observatory oversees efforts at all potentially active volcanoes in Oregon, Washington, and Idaho. The Yellowstone Volcano Observatory is responsible for volcanoes in Montana, Wyoming, Colorado, Utah, New Mexico, and Arizona. The Alaska Volcano Observatory oversees Alaskan volcanoes and those within the Commonwealth of the Northern Mariana Islands. The oldest USGS volcano observatory, the Hawaiian Volcano Observatory, is responsible for the state of Hawaii and is celebrating its 100^th anniversary this year. All USGS volcano observatories share scientific expertise, administrative staff, and equipment.

For more information on the USGS Volcano Hazard Program visit http://volcanoes.usgs.gov/.  See also USGS fact sheets: “The National Volcano Early Warning System (NVEWS)” FS-2006-3142 and “U.S. Geological Survey’s Alert Notification System for Volcanic Activity,” FS-2006-3139.

Visit the new CalVO website.

Check out the news release!

Contact: Wendy K. Stovall

In 1986, Lake Nyos, in the volcanic region of Cameroon, released a cloud of CO2 into the atmosphere, killing 1,700 people and 3,500 livestock in nearby towns and villages. Since then, engineers have been artificially removing the gas from the lake through piping. The gas burst in 1986 from the 200-meter deep Lake Nyos was so violent that water washed over the 80-meter high promontory in the foreground.

In 1986 Lake Nyos, in the volcanic region of Cameroon, suddenly released a cloud of carbon dioxide into the atmosphere, killing 1,700 people and 3,500 livestock in nearby towns and villages.

The cause was a phenomenon later named “exploding lakes,” a hazard scientists hadn’t even known existed before the 1986 tragedy. But since then, to prevent Lake Nyos from exploding again, an international team of scientists and engineers has developed and implemented a program to artificially remove gas from the lake through piping.

USGS scientists initially advised on the project and have long monitored gas levels in the lake to determine whether this removal has been successful. This winter, USGS again joins a team traveling back to Cameroon to upgrade and re-install the monitoring devices. They’ll also update devices monitoring gas levels in nearby Lake Monoun, another exploding lake, where CO₂ has now been completely removed as part of the same project.

Although most of us may not realize it, volcanoes release more than 100 million tons of CO₂ into the atmosphere each year. (For most of the Earth’s history, volcano emissions were the primary source of CO₂ to the atmosphere; now emissions are estimated to be about 30 billion tons per year, with 100 million tons from volcanoes.) Usually the gas released during an eruption is harmless because it is rapidly diluted to low concentrations. However, sometimes the gas can get trapped underground, where it cools and becomes pressurized. If an earthquake or other disturbance later breaks the seal on this trapped gas, a dangerous, large cloud of cold, dense CO₂gas can be released in a very short period.

In 1986, Lake Nyos, in the volcanic region of Cameroon, released a cloud of CO2 into the atmosphere, killing 1,700 people and 3,500 livestock in nearby towns and villages. Since then, engineers have been artificially removing the gas from the lake through piping. A small CO2 cloud from Lake Monoun killed 37 people in 1984.

Cameroon’s exploding lakes are a unique example of this phenomenon, where CO₂ is trapped in the bottom water of deep volcanic craters. The gas stays at the bottom of the lake, held down by the pressure of the overlying water. But eventually, CO₂ gas can start to bubble up to the top of the lake, which reduces the water pressure that usually holds the gas down. When this happens, the gas from the bottom of the lake can vent with exploding force, creating a suffocating cloud that can kill people and animals in low-lying areas.

In 1986 scientists from all over the world, including USGS scientists, traveled to Cameroon to study the disasters. Over the following years, they helped establish a plan to prevent CO₂ from ever again harming the people and livestock in the surrounding villages. Beginning in 2001, a French engineering firm installed pipes that reached the very bottom of the lakes. Pumps initially push some of the lower water upward, releasing water pressure and allowing CO₂ gas bubbles to form. Once bubbles form, the gas naturally flows up and out of the pipe at a controlled rate.

This technique has successfully resulted in the complete degassing of Cameroon’s Lake Monoun, which now poses no risk of gas release. Much of the gas in Lake Nyos has been removed as well, but degassing will continue for several more years before the CO₂ is completely gone.

The USGS continues to monitor water conditions at these two lakes. The probes that measure the dissolved gas pressure are built at USGS, and are permanently installed in the lakes. After a decade of use, the most recent probes now need to be replaced.

In 1986, Lake Nyos, in the volcanic region of Cameroon, released a cloud of CO2 into the atmosphere, killing 1,700 people and 3,500 livestock in nearby towns and villages. Since then, engineers have been artificially removing the gas from the lake through piping. This photo shows a pipe top and raft at Lake Nyos. The self-driven fountain (inset) can reach a height of 150 feet above the lake surface while dissipating carbon dioxide.

These probes allow the USGS and other scientists to understand the natural recharge rate of gas to Lake Monoun, which will reveal the number of years required for gas to build back up to dangerous levels. Also, the probes help scientists track the build-up of methane, another potentially dangerous gas and a byproduct of the degassing. (When the water is piped up, nutrient-rich bottom waters settle on the surface and boost algal growth, resulting in a larger supply of organic material that eventually settles back to the bottom of the lake and produces methane.)

While exploding lakes in Cameroon are unique, volcanic CO₂ poses problems in some areas of the U.S., as well. In fact, in 1994, USGS researchers discovered that large volumes of CO₂ were seeping from beneath Mammoth Mountain, a young volcano in the Long Valley area of California. The seepage was triggered by a persistent swarm of earthquakes, and killed more than 100 acres of trees. The CO₂also forced the U.S. Forest Service to close the area to camping. The USGS continues to monitor this area, where earthquakes and gas seepage remain a concern.

In 1986, Lake Nyos, in the volcanic region of Cameroon, released a cloud of CO2 into the atmosphere, killing 1,700 people and 3,500 livestock in nearby towns and villages. Since then, engineers have been artificially removing the gas from the lake through piping. This photo shows the Lake Nyos pipe in operation. The 200-meter-long pipe is suspended from the raft and allows gas-rich water from the lake bottom to vent to the surface, where the CO2 dissipates into the atmosphere at a controlled rate. The shed on the control raft is about 6 feet high and the fountain is about 120 feet high. There are no pumps involved because the CO2 drives the fountain, just like a shaken bottle of champagne.

Every year in the U.S. and around the world, natural hazards cost lives and billions of dollars in damage. The USGS provides policymakers and the public with a clear understanding of natural hazards and their potential threats to society, and assists with developing smart, cost-effective strategies for achieving preparedness and resilience. The CO₂ removal in Cameroon and monitoring near Mammoth Mountain both save lives and underscore the value of sound science in mitigating natural disasters.

Bill Evans is the USGS scientist traveling to Cameroon for this work, which is part of the USGS National Research Program. NRP researchers study the flow and chemistry of water in the environment, and the techniques they develop can be applied in many fields, including in this case, the mitigation of natural hazards.

For more information, contact Kara Capelli.

An American alligator and a Burmese python locked in a struggle to prevail in Everglades National Park. This python appears to be losing, but snakes in similar situations have apparently escaped unharmed, and in other situations pythons have eaten alligators. Photo by Lori Oberhofer, National Park Service.

Mid-sized mammals in Everglades National Park are getting a big squeeze from invasive Burmese pythons, according to a USGS co-authored study published in the Proceedings of the National Academy of Sciences. These pythons, large constricting snakes native to Asia that can reach more than 20 feet in length and upwards of 200 pounds, are now found throughout much of southern Florida, including all of Everglades National Park. Since the recognition 11 years ago that these invasive, exotic snakes were breeding in the park, formerly common mammals there have declined dramatically.

The status of species that are rare, patchily distributed, active during the day, or that don’t cross roads was not assessed in this new study.

The university and federal scientists who conducted the study found that the most severe declines in mammals appear to have occurred in the remote southernmost regions of the park, where pythons have been established the longest.  In this area, observations of raccoons dropped 99.3 percent, opossums 98.9 percent and bobcats 87.5 percent.  Marsh and cottontail rabbits, as well as foxes, were not seen at all in recent years, despite having been present in the 1990s.

The authors suggested that one reason for such dramatic declines in such a short time is that these prey species may be “naïve” to large constrictor snakes — that is, they are not used to being preyed upon by pythons since such large snakes have not existed in the eastern United States for millions of years. In addition, some of the declining species could be both victims of being eaten by pythons and of having to compete with pythons for food.

Florida Everglades. Photo by: USGS Florida Cooperative Fish and Wildlife Research Unit, U.S. Geological Survey

Pythons have increased dramatically in both abundance and geographic range in South Florida since 2000. Based on the geographic extent of the Burmese python population in Florida and knowledge of detection rates for other snakes, experts estimate that a population of at least tens of thousands now live in the wild in Florida, but stress that this estimate is extremely rough.  Population size may have dropped somewhat as a result of the severe cold snap of early 2010, but the population is expected to quickly recover from this unusual event.

Burmese pythons have traits that increased their risk of establishment and that make their eradication difficult. Specifically, Burmese pythons:

• grow rapidly to a large size (one over 16-feet long was captured in the Everglades in January 2012);
• are habitat generalists (they can live in many kinds of habitats);
• are dietary generalists (can eat a variety of mammals, birds and reptiles);
• may be arboreal (tree-living) when young, which puts birds and arboreal mammals such as squirrels and bats at risk and provides another avenue for quick dispersal of the snakes;
• are tolerant of urbanization (can live in urban/suburban areas);
• are well-concealed “sit-and-wait” predators (difficult to detect and difficult to trap due to their infrequent movements between hiding places);
• mature rapidly  and produce many offspring (females can store sperm and fertilize their eggs —which can number more than 100 — when conditions are favorable for bearing young);
• achieve high population densities (resulting in a greater impact on native wildlife); and
• serve as potential hosts for parasites and diseases of economic and human health significance.

As a result, Burmese pythons pose considerable challenges for the ecosystems of South Florida and many of the animals that live there, including threated and endangered species. Federal and state agencies or institutions are working hard to deal with the serious threats caused by this invasive species.  USGS research aims to help managers preserve and restore the Everglades’ ecosystems.

A female Burmese python (Python molurus) on her nest with eggs. Photo by Jemeema Carrigan, University of Florida. Courtesy of Skip Snow, National Park Service. Used with permission.

Everglades Restoration Includes the Management of Invasive Species

Invasive species are plants or animals that are non-native to a given ecosystem and which pose economic or ecological threats to native plants, animals, ecosystems, and sometimes people. In the case of the Burmese python, the new study shows that pythons appear to have begun to markedly alter the Everglades ecosystem by changing food webs through depleting or eliminating vulnerable native species. If enough animals are lost, entire ecosystem processes could be disrupted.

Scientists found little support for alternative explanations for the mammals’ decline, such as disease or changes in habitat. Scientists also ruled out predation by black bears and Florida panthers as the cause, since these populations have not grown in size during the past 15 years. Additionally, researchers ruled out mid-sized predators, such as foxes and bobcats, as the cause of these mammal declines since these two species have also experienced significant declines.

Can the Everglades be Rid of These Pythons?

The odds of eradicating an introduced population of reptiles once it has spread across a large area are very low, pointing to the importance of prevention, early detection and rapid response.  And with the Burmese python now distributed across more than a thousand square miles of southern Florida, including all of Everglades National Park and areas to the north such as Big Cypress National Preserve, the chances of eliminating the snake completely from the region is low. However, controlling their numbers and preventing their spread are critical goals for South Florida land managers. For example, a number of Burmese pythons have been found in the Florida Keys, but there is no confirmation yet that a breeding population exists in the Keys.  Given a recent USGS study that showed the python’s apparent ability to disperse via salt water, island residents and resource managers need to stay vigilant so as to be able to detect and eliminate arriving pythons before they become established.

On Jan. 23, 2012, the U.S. Fish and Wildlife Service published a rule in the Federal Register that will restrict the importation and interstate transportation of four non-native constrictor snakes (Burmese python, northern and southern African pythons, and the yellow anaconda) that threaten the Everglades and other sensitive ecosystems. These snakes are being listed as injurious species under the Lacey Act. In addition, the FWS will continue to consider listing as injurious five other species of nonnative snakes: the reticulated python, boa constrictor, DeSchauensee’s anaconda, green anaconda and Beni anaconda. For more information about the Lacey Act and the listing of these four constrictors as injurious, please visit this FWS News and Resources site.

How does USGS Research Help Managers Deal with Invasive Species?

Fishing guide Camp Walker, Catalyst Charters, of Islamorada, Fla., took this photo of a Burmese python swimming in Florida Bay from the end of Twisty Channel toward End Key on Nov. 16, 2011.

According to the USGS Invasive Species Program, the U.S. is under an economic and ecological siege by having to deal with more than 6,500 harmful non-native species estimated to cause more than a hundred billion dollars in damage each year to the U.S. economy. These costs are borne by farmers, ranchers, businesses, and local, state, tribal and federal governments battling to control the economic, health and environmental threats these invaders pose.  Invasive species adversely affect every state in the country,  in both urban centers and wilderness areas. Increased global travel and trade provides pathways for both intentional and unintentional introductions of invasive species.

Experts note that Florida has the largest number of established non-indigenous reptile and amphibian species in the entire world. Fifty-six are established including three frogs, four turtles, one crocodilian, 43 lizards and five snakes.

Researchers with the USGS Invasive Species Program work collaboratively on all significant groups of invasive organisms in terrestrial and aquatic ecosystems in all regions of the United States.  USGS plays an important role in Federal efforts to combat invasive species by providing tools, technology and information to assess, prevent, contain, control, and manage invasive species nationwide. Key components of invasive species activities include prevention, monitoring and forecasting threats, and control and management of established invaders.

For more information, see the USGS Invasive Species Program Web site.

Multi-Media:

News Releases & Other Info:

USGS News Release: Severe Declines in Everglades Mammals Linked to Pythons

USGS News Release: Salt Water Alone Unlikely to Halt Burmese Python Invasion

Everglades and Python Prey Study FAQs

Video:

Title: Constrictor Snakes
Description: Video footage (B-roll) of Everglades National Park biologists hunting and capturing a Burmese Python in Florida.

URL: http://gallery.usgs.gov/videos/169

USGS Scientist Paul Hsieh, 2011 Federal Employee of the Year

The USGS scientist Dr. Paul Hsieh was named Federal Employee of the Year, highlighting the value of our science to the Nation. Hsieh was recognized by the Partnership for Public Servicefor his timely scientific analysis that convinced Federal leaders responding to the 2010 Deepwater Horizon oil spill that the cap placed over the Macondo well was working, allowing for a safe shutdown.

DOI Assistant Secretary Anne Castle Christens the USGS R/V Kaho. The Kaho is one of two sister ships that will begin research work in the Great Lakes.

USGS scientists worked on several regional and national issues. We contributed to the Great Lakes Restoration Initiative, including new treatment tools to help control Asian carp, an invasive species, and launch of new research vessels being deployed to understand the deep-water ecosystems and fishes of Lake Erie and Lake Ontario. USGS water quality monitoring and analysis, and water availability monitoring is taking place in waterways across the Nation at seven pilot locations that are part of the Urban Waters Federal Partnership: the Anacostia, Patapsco, Harlem, Bronx, and Los Angeles watersheds; the South Platte River, and the Lake Pontchartrain area. In the Grand Canyon, USGS science on uranium resources, hydrology, and the past impacts of mining informed the decision to withdraw Federal lands around the Grand Canyon from new mining claims. USGS science also played a significant role in Department of the Interior Natural Resource Damage Assessmentsettlements including the Deepwater Horizon oil spill and the Tyrone Mine area in New Mexico.

Wind turbines at certain sites in North America each cause dozens of bat fatalities per year.

On the new energy frontier the USGS continues to lead the way in the Department of the Interior with the release of “Wind Energy in the United States and Materials Required for the Land Based Wind Turbine Industry from 2010 Through 2030.” The data suggest that, with the exception of rare earth elements, there should not be a shortage of the principal materials required for electricity generation from wind energy. In the area of wind and wildlife, our scientists are using near-infrared videography to monitor and research bat activity at wind turbines, as a side effect of the expansion of wind energy is increased bird and bat mortality at turbines. We also continue to focus on conventional sources of energy development, evidenced in our summary report of the science needs for conventional energy development for the Chukchi and Beaufort seas. In the area of unconventional gas, the USGS worked with the Department of Energy and provided information for their report on the needed reforms for unconventional gas production, and the USGS is working with the Environmental Protection Agency and DOE on a strategy to fill those research gaps.

A submarine berg emerges from the advancing terminus of Yahtse Glacier. Iceberg calving is a key process in the global sea level budget.

In the area of climate change, the USGS completed the establishment of the eight climate science centers across the country with universities and consortia in Alaska, Colorado, Massachusetts, Oregon, Hawaii, Oklahoma, North Carolina, and Arizona. We also completed a study measuring the amount of stored carbon in the ecosystems of the Great Plains. This study was the first regional report that applied a comprehensive methodology designed by the USGS in 2010.

Scientists hike up the Little Colorado River to assist in installing remote PIT tag readers to more efficiently keep track of native, endangered fish populations.

Water continues to be a contentious issue in various parts of the country. In 2011, the USGS launched a geographic focus study on the Colorado River basin, part of the WaterSMART availability and land use assessment, a three-year study that will provide an inventory of water supply and demand. The effort includes assessing water needed to support ecosystems and will report significant competition over water resources and the factors causing the competition. Water information can also be sent to your email inbox or your phone, thanks to WaterAlert. This tool allows users to be notified daily of water levels at any of our 7,600 real-time streamgages across the country. Addressing the Nation’s water resource challenges is a priority for the USGS, and in 2011 we formed an innovative partnership to do just that with the U.S. Army Corps of Engineers and the National Oceanic and Atmospheric Administration. This partnership will provide a one-stop portal to integrated water information for stakeholders with forecasts showing where water for drinking, industry, and ecosystems will be available.

Josh Latimore stands in front of Burney Falls. Latimore started at the USGS as a summer intern and now serves as a USGS hydrologic technician while pursuing his bachelor of science.

The USGS engaged in a wide array of youth activities nationwide in 2011. From the collaboration with GeoFORCE at the University of Texas-Austin, to the National Cooperative Geologic Mapping Program’s EDMAP training component, to the Rocky Mountain Science and Sustainability Summer Academy (RMSSN). GeoFORCE engages minority high school students in the earth sciences, the EDMAP encourages high school graduates of this program to continue to work with the USGS throughout their college careers, and RMSSN provides training in field observation, data entry, and scientific communication to diverse students.

This map shows the various reported levels of shaking around Oklahoma City after the November 5 M5.6 earthquake

The Great Central U.S. ShakeOut drill, held in April of 2011, is just one example of the USGS’s role in preparing for and responding to natural hazards. Another example is the National Earthquake Information Center’s provision of real-time data to on the magnitude and potential damage of the August earthquake in Virginia, and the November earthquake and aftershocks in Oklahoma. To better monitor aftershocks, mobile seismic monitors were deployed, bringing the total of earthquake sensors in the Advanced National Seismic System to over 2,200. Flooding was also a concern last year, with more than 30 states affected. To educate Congress about the 2011 floods, we conducted a congressional briefing titled “2011 — The Year of the Flood?” For more than 100 years the USGS has played a critical role in reducing flood losses by operating a nationwide streamgage network that monitors the water level and flow of the Nation’s rivers and streams. This information was critical to the Army Corps of Engineers’ decision to simultaneously open the Mississippi River floodgates for the first time.

The 2006 image (left) show the river in a more normal state, while the 2011 image (right) shows the massive flooding. The dark blue tones represent water or flooded areas, the light green is cleared fields, and light tones are clouds.

During the heavy flooding that occurred on the Mississippi River, Missouri River, and other major waterways, the USGS’s Landsat satellites produced images of the affected areas to provide an overview of the situation. Landsat has often helped provide a big-picture perspective on natural hazards both domestic and foreign and ranging from tornados to tsunamis to wildfires. Landsat is a joint effort of both USGS and NASA. In addition to imagery of natural hazard events, Landsat provides valuable data for land use research and advances the Department of the Interior’s important role in land remote sensing under the President’s National Space Policy. Landsat images provide complete global coverage, they are available for free, and they span nearly 40 years of continuous earth observation. No other satellite imagery has that combination of attributes. To date, over 6 million scenes have been downloaded; over 2.6 million were downloaded in 2011.

These highlights are but a few of the USGS’s significant accomplishments and activities in 2011. Keep up with what we do in 2012 by visiting www.usgs.gov and following us on Twitter @usgs or on Facebook.

Gagehouse at 06225500 Wind River near Crowheart WY right before it washed away.

Hi, I’m Kristina Yamamoto. At the USGS, I work as a geographer for the Center of Excellence for Geospatial Information Science, part of the National Geospatial Program. I am also in the Student Career Experience Program (SCEP). As a SCEP, I mainly work on remote sensing and GIS projects to support the research goals of the Geospatial Information Science program. Some of my past work has been using satellite imagery for soil moisture and vegetation comparisons and evaluating different map projections. I’ve been working at the USGS for two years, and I’m also finishing my Ph.D. dissertation in geography from the University of Denver. I hope to graduate in June 2012.

How has your USGS experience helped you succeed?

I recently had my first peer-reviewed paper (PDF) published on a project I worked on at USGS — I am a co-author. I had been waiting for a publication for a long time, and I was so excited to see the paper in print. This was followed by two more publications in just a few weeks, including my first as the lead author. Learning even more about the publishing process, including how to address reviewers’ comments and formatting images, has been very helpful for me, not just as a researcher with USGS, but also in my own Ph.D. work.

What’s your most memorable moment with USGS?

I recently received an award from my project lead/supervisor for my research efforts on one of my latest USGS projects on vegetation and soil moisture. It was completely unexpected, and it was so nice to be recognized for the work I have done for the USGS so far.

What are your day-to-day responsibilities?

I work best with a lot of tasks to sort through at a time, and luckily for me, my USGS job has provided me with a variety of duties and responsibilities. On any given day, I could be working on original research projects, editing and reviewing documents that are getting ready for publication, managing data, emailing other researchers in our group or from other government agencies and universities, reading journal articles and reports, or all of the above. Multi-tasking keeps me happy.

My dissertation work involves using remote sensing to research sea turtle nesting habitat. My USGS work also has remote sensing and GIS focuses, but my projects here are usually more focused on non-wildlife issues, such as soil moisture or map projections. So, while I am strengthening my remote sensing and GIS skills here at USGS, each day I also have to push the limits of my knowledge, which I would have never had a chance to do otherwise.

Why it matters?

My research supports the development of geographic tools and methods to help in decision making involving the human and environmental consequences of land change. It also provides information about our nation’s natural resources, including the effects of climate on those resources, which can provide information needed to plan now for the future management and preservation of America’s lands.

Although field work is very important (and I, like most geographers, love nothing more than traveling and being outside), there are also many research questions that can be better investigated using remotely sensed data. For example, for one of our research projects, we needed to compare several large geographic areas across different years. Satellite imagery allowed us to make these comparisons more quickly, completely, and less expensively than having field crews measure variables every 30 meters for hundreds of miles.  The USGS provides “science for a changing world,” and one of the best ways to learn more about our planet is to conduct new research with the methods best suited for your research goals.

Kristina Yamamoto

What would you like people to know about the USGS?

I know a lot of people have only two things in mind when they think of the USGS: topo maps and tectonic activity. The Survey is actually much much more than that — the topics covered by the employees are far-reaching, from water issues and contaminants to energy and ecological and environmental challenges. I would bet many students could find a niche here, even if they don’t have a background in geology.

Where do you want to do from here?

My Ph.D. is slowly and painfully wrapping up — I am hoping to graduate in June. Like most geographers, I have a broad range of interests. For me, geospatial research is interesting and a key component to my dissertation, and I hope it will lead me to a rewarding career at the USGS. Of course, wildlife studies will always remain dear to my heart! No matter where I end up, though, I want to make sure I am contributing good work, both to my team and to the agency as a whole.

The arc of light heading towards the earth is a coronal mass ejection, which impacts the earth's magnetic field (shown in purple), causing magnetic storms.

Everyone is familiar with weather systems on Earth like rain, wind and snow. But space weather – variable conditions in the space surrounding Earth – has important consequences for our lives inside Earth’s atmosphere.

Solar activity occurring miles outside Earth’s atmosphere, for example, can trigger magnetic storms on Earth. These storms are visually stunning, but they can set our modern infrastructure spinning.

On Jan. 19, scientists saw a solar flare in an active region of the Sun, along with a concentrated blast of solar-wind plasma and magnetic field lines known as a coronal mass ejection that burst from the Sun’s surface and appeared to be headed for Earth.

When these solar winds met Earth’s magnetic field, the interaction created one of the largest magnetic storms on Earth recorded in the past few years. The storm peaked on Jan. 24, just as another storm began.

“These new storms, and the storm we witnessed on Sept 26, 2011, indicate the up-tick in activity coming with the Earth’s ascent into the next solar maximum,” said USGS geophysicist Jeffrey Love.” This solar maximum is the period of greatest activity in the solar cycle of the Sun, and it is predicted to occur sometime in 2013, which will increase the amount of magnetic storms on Earth.

Magnetic storms, said Love, are a space weather phenomenon responsible for the breathtaking lights of the aurora borealis, but also sometimes for the disruption of technology and infrastructure our modern society depends on. Large magnetic storms, for example, can interrupt radio communication, interfere with global-positioning systems, disrupt oil and gas well drilling, damage satellites and affect their operations, and even cause electrical blackouts by inducing voltage surges in electric power grids. Storms can also affects airline activity — as a result of last weekend’s  storm, both Air Canada and Delta Air Lines rerouted flights over the Arctic bound for Asia as a precautionary measure. Although the storm began on the 19th of January, it did not peak until January 24th.

While this particular storm had minor consequences on Earth, other large storms can be crippling, Love said. He noted that the largest storm of the 20^th century occurred in March, 1989, accompanied by auroras that could be seen as far south as Texas, and sent electric currents into Earth’s crust that made their way into the high-voltage Canadian Hydro-Quebec power grid. This caused the transformer to fail and left more than 6 million people without power for 9 hours. The same storm also damaged and disrupted the operation of satellites, GPS systems, and radio communication systems used by the United States military.

While large, the 1989 storm pales in comparison to one that occurred in September 1859 and is the largest storm in recorded history. Scientists estimate that the economic impact to the United States from a storm of the same size in today’s society could exceed $1 trillion as a result of the technological systems it could disrupt.

The USGS, a partner in the multi-agency National Space Weather Program, collects data that can help us understand how magnetic storms may impact the United States. Constant monitoring of Earth’s magnetic field allows us to better assess the impact of these phenomena on Earth’s surface. To do this, the USGS Geomagnetism Program maintains 14 observatories around the United States and its territories, which provide ground-based measurements of changes in the magnetic field. These measurements are being used by the NOAA Space Weather Prediction Center and the US Air Force Weather Agencyto track the intensity of the magnetic storm generated by this solar activity.

Absolutes, variations and proton buildings at Cayey magnetic observatory, Puerto Rico.

In addition to providing data to its customers, the USGS produces models of the Earth’s magnetic field that are used in a host of applications, including GPS receivers, military and civilian navigational systems, and in research for studies of the effects of geomagnetic storms on the ionosphere (a shell of electrons and electrically charged atoms and molecules surrounding Earth), atmosphere, and near-space environment.

• Visit the USGS Geomagnetism Program home page.
• Are solar storms related to climate change? Find out the answer by watching USGS Climate Connections.
• Learn more with the USGS Calendar.

Figure 1: Gas hydrates have been found in many locations worldwide. Scientists predict that they occur in many areas that have not yet been surveyed.

News stories and web postings have raised concerns that climate warming will release large volumes of methane from gas hydrates, kicking off a chain reaction of warming and methane releases.

Figure 2: Solid gas hydrate recovered from sediments about 20 feet below the seafloor near Canada’s Vancouver Island

But recent research indicates that most of the world’s gas hydrate deposits should remain stable for the next few thousand years. Of the hydrates likely to become unstable, few are likely to release methane that could reach the atmosphere and intensify global warming.

Background: Gas hydrates are an ice-like combination of natural gas and water that can form in deep-water ocean sediments near the continents, or beneath extensive permafrost, particularly in the circum-Arctic. Specific temperatures and pressures and an ample supply of natural gas are required for gas hydrates to form and remain stable.

An estimated 99 percent of gas hydrates are in ocean sediments, with the remaining 1 percent in permafrost areas (fig.1). Methane hydrate or “methane ice” is the most common type of gas hydrate (fig. 2). It is a highly concentrated form of methane. One cubic foot of methane hydrate traps about 164 cubic feet of methane gas.

The amount of methane trapped in the earth’s hydrate deposits is uncertain, but even the most conservative estimates conclude that about 1000 times more methane is trapped in hydrates than is consumed annually worldwide. The most active area of gas hydrate research focuses on their potential as an alternate source of natural gas (fig. 3), and the USGS Gas Hydrates Projecthas several programs in this area.

Figure 3: Methane hydrate is sometimes called “the ice that burns” because the warming hydrates release enough methane to sustain a flame.

Gas Hydrates and Climate Change– A Theoretical View

Figure 4: Schematic of the theoretical scenario -- Arctic methane emissions from gas hydrates and increased climate warming.

Gas hydrate researchers are examining the link between climate change and the stability of methane hydrate deposits. A warming climate could cause gas hydrates to break down (dissociate), releasing the methane that they now trap.

Methane is a potent greenhouse gas. A given volume of methane causes 15 to 20 times more greenhouse gas warming than carbon dioxide, so the release of large quantities of methane to the atmosphere could exacerbate atmospheric warming and cause more gas hydrates to destabilize (fig. 4).

Some research suggests that this has happened in the past. Extreme warming during the Paleocene-Eocene Thermal Maximum about 55 million years ago may have been related to a large-scale release of global methane hydrates. Some scientists have also advanced the Clathrate Gun Hypothesis to explain observations that may be consistent with repeated, catastrophic dissociation of gas hydrates and triggering of submarine landslides during the Late Quaternary (400,000 to 10,000 years ago).

Methane in the Atmosphere: Current Observations

The atmospheric concentration of methane, like that of carbon dioxide, has increased since the onset of the Industrial Revolution (fig. 5). Methane in the atmosphere comes from many sources, including wetlands, rice cultivation, termites, cows and other ruminants, forest fires, and fossil fuel production (fig. 6). Some researchers have estimated that up to 2 percent of atmospheric methane may originate with dissociation of global gas hydrates. Currently, scientists do not have a tool to say with certainty how much, or if any, atmospheric methane comes from hydrates.

Although methane is a potent greenhouse gas, it does not remain in the atmosphere for long. Within about 10 years, it is transformed to carbon dioxide. Thus, methane that is released to the atmosphere ultimately adds to the amount of carbon dioxide, the main greenhouse gas.

Figure 5: Atmospheric concentrations of carbon dioxide in parts per million and methane in parts per billion. Source: NOAA

Figure 6: Possible sources of atmospheric methane. Currently, there is no proof that gas hydrates are contributing to total atmospheric methane budgets. Source: U.S. Department of Energy, Methane Hydrates R&D Program

Expected Impact of Warming Climate on Methane Hydrate Deposits For the most part, warming at rates documented by the Intergovernmental Panel on Climate Change for the 20th century should not lead to catastrophic breakdown of methane hydrates or major leakage of methane to the ocean-atmosphere system from gas hydrates that dissociate. While the vast majority of methane hydrates would require a sustained warming over thousands of years to trigger dissociation, gas hydrates in some locations are dissociating now in response to short-term and long-term climate processes.

The following discussion refers to the numbered type locales or sectors, shown in Figure 7.

Figure 7: Gas hydrate deposits by sector. Currently, gas hydrates are most likely dissociating in sectors 2 and 3. Only sector 2 is likely to release methane that could reach the atmosphere. Figure modified from Ruppel (2011).

Sector 1, Thick Onshore Permafrost: Gas hydrates that occur within or beneath thick terrestrial permafrost will remain largely stable even if climate warming lasts hundreds of years. Over thousands of years, warming could cause gas hydrates at the top of the stability zone, about 625 feet below the earth’s surface, to begin to dissociate.

Sector 2, Shallow Arctic Shelf: The shallow water continental shelves that circle parts of the Arctic Ocean were formed when sea level rise during the past 10,000 years inundated permafrost that was at the coastline. Subsea permafrost is thawing beneath these continental shelves and associated methane hydrates are likely dissociating now. If methane from these gas hydrates rises to the ocean floor, it will likely reach the atmosphere. Less than one percent of the world’s gas hydrates probably occur in this setting, but this estimate could be revised as scientists learn more.

Sector 3, Upper Edge of Stability: Gas hydrates on upper continental slopes, beneath 1000 to 1600 feet of water, lie at the shallowest water depth for which methane hydrates are stable. The upper continental slopes, which ring all of the world’s continents, could host gas hydrate in zones that are roughly 30 feet thick. Warming ocean waters could completely dissociate these gas hydrates in less than 100 years. Methane emitted at these water depths will probably oxidize in the water column or simply dissolve and is not likely to reach the atmosphere. About 3.5 percent of the earth’s gas hydrates occur in this climate sensitive setting.

Sector 4, Deepwater: Most of the earth’s gas hydrates, about 95 percent, occur in water depths greater than 3000 feet. They are likely to remain stable even with a sustained increase in bottom temperatures over thousands of years. Most of the gas hydrates in these settings occur deep within the sediments. If they do dissociate, the released methane should remain trapped in the sediments, migrate upward to form new gas hydrates, or be consumed by oxidation in near-seafloor sediments. Most methane released at the seafloor would likely dissolve or be oxidized in the water column. A recent article, Methane Hydrates and Contemporary Climate Change, provides more detail.

USGS Gas Hydrates Project

Figure 8: USGS researchers deploy a mini-sparker source to image seafloor sediments in the shallow Beaufort Sea near Prudhoe Bay, Alaska, August 2011. The USGS and the U.S. Department of Energy are cooperating in this work.

The USGS is studying various sources of methane and the impact of climate change. Since 2009, the USGS Gas Hydrates Project has been conducting field research to determine whether gas hydrates are currently dissociating due to climate warming and, if so, how much methane emitted from these gas hydrates might reach the atmosphere. Research locations include the U.S. Beaufort Sea and Alaska’s North Slope. The USGS has also organized workshops to identify priorities in climate-hydrates research and to plan ocean drilling projects related to these issues.

Contact: Diane Noserale