By OC_Web@usgs.gov (Office of Communications and Publishing) from USGS Newsroom. Published on Jun 19, 2013.

Note to Editors: It is critical to the success of this scientific experiment that news media outlets do not deploy helicopters in the area during the planned implosion. The roar and "thump-thump-thump" of helicopter blades will drown out the small signal created by the implosion that we are trying to record. With planning, there are many vantages where news crews will be able to film the building demolition without using a helicopter.

MENLO PARK, Calif. — When California State University, East Bay demolishes its seismically unsafe Warren Hall this summer on its Hayward campus, the landmark building's implosion will produce energy similar to a small earthquake that can be used to study and map the nearby Hayward Fault. In cooperation with the university, the U.S. Geological Survey will observe and record the mid-August implosion on hundreds of seismographs temporarily set out in a roughly one-mile radius from Warren Hall. The data gathered will help characterize the underground geology around the Hayward Fault in three dimensions. Warren Hall's demolition can yield information to characterize very localized effects of shaking during an earthquake, and so will help prepare the community for future earthquakes. The section of the Hayward Fault that runs near the university has the highest probability of generating the next significant earthquake in the San Francisco Bay Area. 

The East Bay Seismic Experiment, a joint enterprise of USGS, CSUEB and other researchers, takes advantage of this unprecedented opportunity to monitor the ground response (identifying which areas will shake more than others) to a small, simulated earthquake in the Hayward Fault zone. Planned studies include a combined seismic reflection and refraction survey: by measuring the differences in seismic wave amplitudes and velocities of the energy generated by Warren Hall's collapse as it travels through the geological layers of the East Bay, researchers can infer information about these layers that can’t easily be learned any other way. They hope to learn the depth of the Hayward Fault near CSUEB, whether it joins with any other faults, and, if so, how this affects the seismic hazard of the area.

A small, known source of energy (as from the building collapse) will also be a rare opportunity for the USGS to calibrate its permanent seismic network in the Bay Area.

In addition to deploying seismometers before the demolition, USGS scientists hope to place tilt sensors in Warren Hall's debris immediately after the implosion in search of clues to how similar structures settle after natural or human-caused disasters. This work has applications for search-and-rescue agencies, which can benefit from any possible warning of a structure’s imminent collapse.

Throughout July, USGS scientists and volunteers will be in Hayward-area neighborhoods, surveying locations to place the seismic instruments that will record the implosion. Actual deployment of the instruments will be during the week of Aug. 12, 2013. The USGS field crew will be wearing USGS identification and will be traveling in vehicles with clearly visible USGS logo placards.

The detailed understanding of the ground response can contribute to improved building codes and other mitigation options for a more resilient community. Hundreds of residents and property owners in selected locations in and around the City of Hayward are helping with this effort to minimize future loss of life and property that could result from an earthquake on the Hayward Fault. 

By OC_Web@usgs.gov (Office of Communications and Publishing) from USGS Newsroom. Published on Jun 19, 2013.

MOSCOW, Idaho – Researchers at the University of Idaho and the U.S. Geological Survey have developed a way to identify New Zealand mudsnail infestations in their earliest stages – using only the small bits of DNA the snails shed in the water.

When New Zealand mudsnails move into a stream, they can wreak havoc on their new habitat. The tiny, invasive mollusks – barely larger than a sesame seed – multiply rapidly, pushing out native species. Salmon that pass through and eat the snails receive less nutrition than from their usual diet, resulting in smaller fish.

The team’s work could help stream managers control mudsnail invasions before they cause significant damage to an ecosystem.

“For invasive species, we really want to catch them long, long before they get to the point of being obvious,” said Caren Goldberg, a research scientist in UI’s fish and wildlife department, who led the study.

The team used a recently developed method of testing for a species’ presence that analyzes environmental DNA, or eDNA, which is collected from skin and other cells an animal sheds into the environment. Their procedure compares DNA in the water to known mudsnail DNA sequences.

“eDNA monitoring for New Zealand mudsnails is a significant advance in aquatic invasive species management because eDNA is more sensitive, faster and often cheaper than traditional monitoring approaches,” said USGS scientist Adam Sepulveda, co-author of the study. “Another benefit is that citizen science groups can become easily involved because collecting water samples in the field requires simple equipment and minimal training.”

“We can just take a water sample, filter it to catch the DNA and test it to see what species are in the water,” Goldberg said.

Researchers in France proved in 2008 that eDNA could effectively show the presence of animals in wetland. In 2011, a UI-based team first demonstrated the same technique worked in moving water, even though much of the DNA is diluted or washed downstream.

The New Zealand mudsnails added another layer of challenge because their hard shell may keep them from leaving behind large amounts of DNA, unlike fish or amphibians, which frequently shed scales or skin.

The team developed and tested their technique in UI’s Laboratory for Ecological, Evolutionary and Conservation Genetics. They also tested it in southern Idaho’s Portneuf River, in areas the mudsnail is known to live.

“It’s a challenge to catch that fragment of DNA,” Goldberg said. “We show we can do it, and reliably, too.”

The researchers are now hoping to attract interest from stream and fish hatchery managers who could use the technique to track and prevent mudsnails, which are considered invasive species around the world and have been spreading across the West since the late 1980s.

The snails can be spread by watercraft or by tagging along with other species. Just one snail can start an infestation, because the species is parthenogenetic – the snails have the ability to reproduce asexually, giving birth to clones of themselves.

“We hope this test will help agencies to detect mudsnails early enough to protect systems from invasion,” Goldberg said. 

The study, “Environmental DNA as a new method for early detection of New Zealand mudsnails (Potamopyrgus antipodarum),” is available online in the journal Freshwater Science.

By OC_Web@usgs.gov (Office of Communications and Publishing) from USGS Newsroom. Published on Jun 19, 2013.

The USGS is expanding its crowd-sourcing of geographic data and is seeking more volunteers to contribute structures information to 16 more states.

The mapping crowd-sourcing program, known as The National Map Corps (TNMCorps), encourages citizens to collect structures data by adding new features and/or correcting existing data within The National Map database. Structures being mapped in the project include schools, hospitals, post offices, police stations and other important public buildings.

The 16 recently added states needing help with structures are: Alabama, Arizona, California, Connecticut, Florida, Illinois, Louisiana, Massachusetts, Mississippi, Nebraska, Nevada, New Hampshire, Rhode Island, South Dakota, Vermont, and Wyoming, bringing the total number of states available for updating to 35.  The final release of states by the end of the year will open up the entire country for volunteer structures enhancement.

Preliminary results of the effort have been very promising. As part of the project pilot, The National Map Corps had 143 volunteers who improved data for more than 6,400 structures in Colorado. The quality of the volunteer data collected met the USGS standards for position, attribution, and completeness.

The release of 19 states last April resulted in an increase of 154 new citizen geographers who have contributed their skills and local knowledge to The National Map.

"We are excited to open the next series states of our volunteer data project" said Elizabeth McCartney, the Volunteer Geographic Information Project Leader. "The response from the original set of states has been encouraging and we hope to have volunteer participation across the entire nation by the end of the year".

The tools on TNMCorps website explain how a volunteer can edit any area, regardless of their familiarity with the selected structures.

The citizen geographers/cartographers who participate in this program will make a significant addition to the USGS's ability to provide accurate information to the public. Data collected by volunteers become part of The National Map structures dataset which is available to users free of charge.

To show appreciation of our volunteer's efforts, The National Map Corps has instituted a recognition program that awards "virtual" badges" to volunteers. The badges consists of a series of antique surveying instruments ranging from a surveyor's chain (25 – 50 points) to the yet to be achieved theodolite (2000+ points). Additionally, volunteers are publically acclaimed.

In a recent development, the 4-H National Headquarters has announced that this year's 4-H National Youth Science Day planned for October 9, 2013 will feature geographic technology projects that are part of The National Map Corps data collection efforts.

Becoming a volunteer for TNMCorps is easy; go to The National Map Corps website to learn more and to sign up as a volunteer. If you have access to the Internet and are willing to dedicate some time to editing map data, we hope you will consider participating!

Newly added states in purple: Alabama, Arizona, California, Connecticut, Florida, Illinois, Louisiana, Massachusetts, Mississippi, Nebraska, Nevada, New Hampshire, Rhode Island, South Dakota, Vermont, and Wyoming. Currently participating states in green: Arkansas, Alaska, Colorado, Delaware, Georgia, Idaho, Maryland, Michigan, Montana, North Dakota, New Jersey, New Mexico, Ohio, Oregon, Pennsylvania, South Carolina, Utah, Washington, West Virginia - bringing the total number of states available for updating to 35.  (High resolution image)

By OC_Web@usgs.gov (Office of Communications and Publishing) from USGS Newsroom. Published on Jun 18, 2013.

Also anticipating smaller hypoxia levels than in past in Chesapeake Bay

Scientists are expecting a very large "dead zone" in the Gulf of Mexico and a smaller than average hypoxic level in the Chesapeake Bay this year, based on several NOAA-supported forecast models. 

NOAA-supported modelers at the University of Michigan, Louisiana State University, and the  Louisiana Universities Marine Consortium are forecasting that this year's Gulf of Mexico hypoxic "dead" zone will be between 7,286 and 8,561 square miles which could place it among the ten largest recorded. That would range from an area the size of Connecticut, Rhode Island and the District of Columbia combined on the low end to the New Jersey on the upper end. The high estimate would exceed the largest ever reported, 8,481 square miles in 2002. 

Hypoxic (very low oxygen) and anoxic (no oxygen) zones are caused by excessive nutrient pollution, often from human activities such as agriculture, which results in insufficient oxygen to support most marine life in near-bottom waters. Aspects of weather, including wind speed, wind direction, precipitation and temperature, also impact the size of dead zones. 

The Gulf estimate is based on the assumption of no significant tropical storms in the two weeks preceding or during the official measurement survey cruise scheduled from July 25-August 3 2013.  If a storm does occur the size estimate could drop to a low of 5344 square miles, slightly smaller than the size of Connecticut. 

This year's prediction for the Gulf reflects flood conditions in the Midwest that caused large amounts of nutrients to be transported from the Mississippi watershed to the Gulf. Last year's dead zone in the Gulf of Mexico was the fourth smallest on record due to drought conditions, covering an area of approximately 2,889 square miles, an area slightly larger than the state of Delaware. The overall average between 1995-2012 is 5,960 square miles, an area about the size of Connecticut. 

A second NOAA-funded forecast, for the Chesapeake Bay, calls for a smaller than average dead zone in the nation's largest estuary. The forecasts from researchers at the University of Maryland Center for Environmental Science  and the University of Michigan has three parts: a prediction for the mid-summer volume of the low-oxygen hypoxic zone, one for the mid-summer oxygen-free anoxic zone, and a third that is an average value for the entire summer season. 

The forecasts call for a mid-summer hypoxic zone of 1.46 cubic miles, a mid-summer anoxic zone of 0.26 to 0.38 cubic miles, and a summer average hypoxia of 1.108 cubic miles, all at the low end of previously recorded zones.  Last year the final mid-summer hypoxic zone was 1.45 cubic miles. 

This is the seventh year for the Bay outlook which, because of the shallow nature of large areas of the estuary, focuses on water volume or cubic miles, instead of square mileage as used in the Gulf. The history of hypoxia in the Chesapeake Bay since 1985 can be found at the EcoCheck website.

Both forecasts are based on nutrient run-off and river stream data from the U.S. Geological Survey (USGS), with the Chesapeake data funded with a cooperative agreement between USGS and the Maryland Department of Natural Resources.  Those numbers are then inserted into models developed by funding from the National Ocean Service's National Centers for Coastal Ocean Science (NCCOS). 

"Monitoring the health and vitality of our nation's oceans, waterways, and watersheds is critical as we work to preserve and protect coastal ecosystems," said Kathryn D. Sullivan, Ph.D., acting under secretary of commerce for oceans and atmosphere and acting NOAA administrator.  "These ecological forecasts are good examples of the critical environmental intelligence products and tools that help shape a healthier coast, one that is so inextricably linked to the vitality of our communities and our livelihoods." 

The dead zone in the Gulf of Mexico affects nationally important commercial and recreational fisheries, and threatens the region's economy. The Chesapeake dead zones, which have been highly variable in recent years, threaten a multi-year effort to restore the Bay's water quality and enhance its production of crabs, oysters, and other important fisheries. 

During May 2013, stream flows in the Mississippi and Atchafalaya rivers were above normal resulting in more nutrients flowing into the Gulf. According to USGS estimates, 153,000 metric tons of nutrients flowed down the rivers to the northern Gulf of Mexico in May, an increase of 94,900 metric tons over last year's 58,100 metric tons, when the region was suffering through drought. The 2013 input is an increase of 16 percent above the average nutrient load estimated over the past 34 years.

For the Chesapeake Bay, USGS estimates 36,600 metric tons of nutrients entered the estuary from the Susquehanna and Potomac rivers between January and May, which is 30 percent below the average loads estimated from 1990 to 2013. 

"Long-term nutrient monitoring and modeling is key to tracking how nutrient conditions are changing in response to floods and droughts and nutrient management actions," said Lori Caramanian, deputy assistant secretary of the interior for water and science. "Understanding the sources and transport of nutrients is key to developing effective nutrient management strategies needed to reduce the size of hypoxia zones in the Gulf, Bay and other U.S. waters where hypoxia is an ongoing problem." 

"Coastal hypoxia is proliferating around the world," said Donald Boesch, Ph.D., president of the University of Maryland Center for Environmental Science. "It is important that we have excellent abilities to predict and control the largest dead zones in the United States. The whole world is watching." 

The confirmed size of the 2013 Gulf hypoxic zone will be released in August, following a monitoring survey led by the Louisiana Universities Marine Consortium beginning in late July, and the result will be used to improve future forecasts. The final measurement in the Chesapeake will come in October following surveys by the Chesapeake Bay Program's partners from the Maryland Department of Natural Resources and the Virginia Department of Environmental Quality. 

Despite the Mississippi River/Gulf of Mexico Nutrient Task Force's goal to reduce the dead zone to less than 2,000 square miles, it has averaged 5,600 square miles over the last five years. Demonstrating the link between the dead zone and nutrients from the Mississippi River, this annual forecast continues to provide guidance to federal and state agencies as they work on the 11 implementation actions outlined by the Task Force in 2008 for mitigating nutrient pollution. 

NOAA's National Ocean Service has been funding investigations and forecast development for the dead zone in the Gulf of Mexico since 1990, and oversees national hypoxia research programs which include the Chesapeake Bay and other affected bodies of water. 

USGS operates more than 3,000 real-time stream gages and collects water quality data at numerous long-term stations throughout the Mississippi River basin  and the Chesapeake Bay to track how nutrient loads are changing over time. 

The National Centers for Coastal Ocean Science is the coastal science office for NOAA's National Ocean Service. Visit our website or follow our blog to read more about NCCOS research.  

NOAA's mission is to understand and predict changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources. Join us on Facebook, Twitter and our other social media channels at http://www.noaa.gov/socialmedia/ .

By OC_Web@usgs.gov (Office of Communications and Publishing) from USGS Newsroom. Published on Jun 18, 2013.

Great Lakes resource managers can now determine rivers that may be vulnerable to Asian carp spawning if they were to spread into the Great Lakes Basin, according to a new U.S. Geological Survey report.

Findings indicate that two species of Asian carp—silver and bighead carp—may be able to spawn in more Great Lakes tributaries than previously estimated. This information could help resource managers implement control measures and potentially prevent Asian carp from becoming established in the Great Lakes.

This forward-looking study characterized the minimum habitat requirements for successful Asian carp spawning. Results indicate that Asian carp can successfully spawn in river stretches as short as 16 miles, which is considerably shorter than the 62 miles previously thought to be required. Scientists analyzed water temperature, streamflow and water quality in two Lake Michigan tributaries (the Milwaukee and St. Joseph rivers) and two Lake Erie tributaries (the Maumee and Sandusky rivers). Findings and techniques from this report can be used to identify other rivers vulnerable to Asian carp spawning in the future.  

"If Asian carp spread into the Great Lakes, knowing where to expect them to spawn is a critical step in controlling these invasive species," said USGS scientist Elizabeth Murphy. "Our study combines the biology of Asian carp early life stages with the physics of rivers to identify potential spawning tributaries, thus giving managers an opportunity to develop targeted control strategies."

Although Asian carps primarily live in slow-moving water, they require streams with a fast current, sufficient length and turbulence to spawn. After eggs are released, they drift in the current while developing. The eggs are slightly heavier than water and require turbulent flowing water to remain adrift. A long stretch of uninterrupted river provides a better chance for the eggs to survive and hatch. If the eggs sink to the bottom and gather in areas with slower flows, known as "settling zones," they generally die. Dams, for example, could help prevent eggs from drifting and developing by slowing water current and creating settling zones.

All four Great Lakes tributaries studied exhibited sufficient temperatures, water-quality characteristics, turbulence and transport times outside of settling zones for Asian carp eggs to mature and hatch. Even though all four rivers had settling zones, findings indicate that under the right temperature and flow conditions, river reaches as short as 16 miles may allow Asian carp eggs sufficient time to develop to the hatching stage.

Two species of Asian carps (bighead carp and silver carp) are threatening to spread into the Great Lakes from the Mississippi River Basin. Asian carp are invasive species that could pose substantial environmental risks and economic impacts to the Great Lakes if they become established.

This USGS report was funded by the Great Lakes Restoration Initiative as administered by the U.S. Environmental Protection Agency.

Preventing establishment remains the main objective of ongoing efforts of the Asian Carp Regional Coordinating Committee (ACRCC), a partnership of federal and state agencies, municipalities and other groups, led by the White House Council on Environmental Quality. Actions of the ACRCC are diverse; they include aggressive tracking and monitoring of Asian carp, evaluating electric dispersal barriers in the Chicago Area Waterways System preventing movement toward Lake Michigan, and developing new technologies to control the abundance and distribution of Asian carp.

By OC_Web@usgs.gov (Office of Communications and Publishing) from USGS Newsroom. Published on Jun 12, 2013.

Standard atomic weights for chemical elements have commonly been considered as constants of nature, along with the speed of light and the attraction of gravity. Hold on to your Newtonian hat and prepare for the possibility of elementary nuances.   

The International Union of Pure and Applied Chemistry (IUPAC) Commission on Isotopic Abundances and Atomic Weights has published a new table that expresses the standard atomic weights of magnesium and bromine as intervals, rather than as single standard values. In addition, improved standard atomic weights have been determined for germanium, indium, and mercury. This new table is the result of cooperative research supported by the U.S. Geological Survey, IUPAC, and other contributing Commission members and institutions. 

Modern analytical techniques can measure the atomic weight of many elements with such precision that small variations in an element’s atomic weight serve as markers for certain physical, chemical, and biological processes. 

"The USGS has a long history of research in this field," said acting USGS Director Suzette Kimball. "Through isotopic analysis, USGS scientists detect slight variations in atomic weights of various elements, which can be applied to a wide variety of mission-critical investigations, such as the identification of the geographic origin of materials, quantification of surface-water groundwater interaction, and understanding paleoclimatic conditions." 

"We are pleased to partner with the International Union [IUPAC] in this vital work," Kimball added. 

Atoms of the same element that have different masses are called "isotopes." The atomic weight of an element depends upon how many stable isotopes it has and the relative amounts of each stable isotope present in a sample containing the element. 

Elements with only one stable isotope do not exhibit variations in their atomic weights. For example, the standard atomic weights for fluorine, aluminum, sodium, and gold are constant. Their values are known to better than six decimal places. Variations in atomic weight occur when an element has two or more naturally occurring stable isotopes that vary in abundance, depending on the sample. 

The standard atomic weights of magnesium and bromine will now be expressed as intervals to more accurately convey this variation in atomic weight. For example, bromine commonly is considered to have a standard atomic weight of 79.904. However, its actual atomic weight can be anywhere between 79.901 and 79.907, depending on where the element is found. 

IUPAC previously adjusted the standard atomic weights of the elements hydrogen, lithium, boron, carbon, nitrogen, oxygen, silicon, sulfur, chlorine and thallium as intervals to reflect variations in their atomic weights. 

"For more than a century and a half, many students have been taught to use standard atomic weights — a single value — found on the inside cover of chemistry textbooks and on the periodic table of the elements," said Ty Coplen, director of the USGS Stable Isotope Laboratory in Reston, Va. "Though this change offers significant benefits in the understanding of chemistry, one can imagine the challenge now to educators and students who will have to select a single value out of an interval when doing chemistry calculations." 

Practical applications of this research can be easily found in daily life. For example, precise measurements of the abundances of isotopes of carbon can be used to determine the purity and source of food products, such as vanilla and honey. Isotopic measurements of nitrogen, chlorine and other elements are used for tracing pollutants in streams and groundwater. In investigations of sports doping, performance enhancing testosterone can be identified in the human body because the atomic weight of carbon in natural human testosterone is different from that in pharmaceutical testosterone. 

The importance of determining precise atomic weights has long been recognized. As far back as 1882, Frank W. Clarke, then a professor at the University of Cincinnati, prepared a table of atomic weights for use in science, industry, and trade. He carried on this work as Chief Chemist of the USGS (1883-1924). Clarke was a founder of the American Chemical Society and a member of the National Academy of Sciences. Recently, IUPAC has overseen the periodic evaluation and dissemination of atomic-weight values. 

The report, published in Pure and Applied Chemistry, also includes educational material and a Periodic Table of the Isotopes illustrating the relationship between isotopes and atomic weights.

By OC_Web@usgs.gov (Office of Communications and Publishing) from USGS Newsroom. Published on Jun 11, 2013.

LARAMIE, Wyo. — The mere presence of wolves, previously shown to affect the behavior of elk in the greater Yellowstone ecosystem, is not potent enough to reduce the body condition and reproductive rates of female elk, according to new research published today.

The research, led by recent University of Wyoming Ph.D. graduate Arthur Middleton, provides the most comprehensive evidence to date refuting the idea that wolves are capable of reducing elk calf recruitment indirectly through predation risk. The findings were published in the scientific journal Ecology Letters.

"Elk respond to wolves, but less strongly and less frequently than we thought," says Middleton, who for three years closely followed the Clarks Fork elk herd west of Cody, along with the wolf packs that prey on it. "We found that wolves influence elk behavior, but the responses were subtle and -- over the course of winter -- did not reduce body fat or pregnancy. Our work indicates that the effect of wolves on elk populations is limited to direct predation and doesn't include so-called harassment, stress and fear, which have been proposed as additional indirect effects on prey populations."

Working as part of the Wyoming Cooperative Fish and Wildlife Research Unit -- a U.S. Geological Survey program housed at UW in cooperation with the Wyoming Game and Fish Department -- Middleton and colleagues used state-of-the-art GPS collars and firsthand observation to track the interactions of the Clarks Fork herd with wolves from the Sunlight, Hoodoo, Beartooth and Absaroka wolf packs in 2008, 2009 and 2010. The detailed movement data on both wolves and elk allowed the researchers to identify each time one of the collared elk encountered a collared wolf. The elk herd, one of several migratory herds in the greater Yellowstone area, spends summers in Yellowstone National Park and moves into the Sunlight Basin during winter. The researchers also recaptured GPS-collared elk at the end of winter and the end of summer each year to assess their annual fat dynamics and pregnancy rates using ultrasonography.

The research found that when wolves approached within 1 kilometer (a little over a half mile), elk increased their rates of movement, displacement and vigilance. However, the behaviors only lasted about 24 hours and didn't significantly reduce elk foraging or force elk into poor habitats. And such encounters with wolves took place at a rate of only one in nine days on average for the migratory elk in the Clarks Fork herd -- the maximum was once every four days.

The key finding of the study is that even though elk varied widely in their encounters with wolves, those that encountered wolves frequently were not less fat -- or any less likely to be pregnant -- than those that rarely bumped into the predators. This finding differs from some previous studies that indicated wolves influence elk behavior strongly enough to contribute to regionwide declines in calf production.

"Our research was unique in that we tracked wolves while also monitoring the movements, foraging behavior, body fat and pregnancy of the elk they hunted," says Middleton, who worked under Matt Kauffman, head of the Wyoming Cooperative Fish and Wildlife Research Unit working under a dual appointment with the USGS and the UW's Department of Zoology and Physiology where he is an assistant professor. "This approach, essentially connecting the dots from wolf movements all the way to elk behavior and nutrition, revealed that elk respond to wolves too weakly and too infrequently for those behaviors to carry nutritional costs." 

The study casts additional doubt on the idea that wolf reintroduction has caused what scientists call a "behaviorally mediated trophic cascade" in the greater Yellowstone ecosystem -- prompting elk to alter their foraging behavior or avoid risky areas, thereby allowing aspen and willows to recover from overbrowsing. These new findings are consistent with studies by Kauffman and others showing little or no evidence for cascading effects caused by purported broad-scale shifts in elk habitat use or foraging behavior in response to wolves.

Both Middleton and Kauffman have pointed out in their studies that the wide-ranging hunting strategy of wolves, which differs from the tactics of a stalking predator, might be the reason that elk responses are too weak and inconsistent to alter their foraging patterns or nutritional gain.

"A key factor in the ability of predators to cause these sorts of cascading effects is the ways in which they hunt and kill their prey," says Kauffman, who initiated the study in 2006 along with Game and Fish Department wildlife biologist Doug McWhirter and U.S. Fish and Wildlife Service wolf manager Mike Jimenez. "Wolves are coursing predators that chase down their prey, as opposed to stalking predators that lurk in concealed areas. We are learning that coursing predators are less likely to induce strong behavioral responses in their prey, and this new work suggests that the coursing hunting mode of wolves may constrain both their ability to influence prey condition and cause cascading ecological effects on plants." 

Kauffman adds that the concept of non-consumptive effects of predators on prey has been well tested in small, well-controlled environments -- often involving insect predators and prey -- but that researchers are still sorting out how it all works in the large landscapes occupied by species such as wolves and elk.

Calf production has been declining among migratory elk herds in the greater Yellowstone area, but wolves may not be the primary culprit, Middleton says. For the Clarks Fork herd at least, other recent research findings point to high rates of bear predation and reduced habitat quality due to drought -- both on summer ranges largely inside Yellowstone -- as being the more likely cause of declines in elk calf numbers.

"The recovery of large carnivores, particularly grizzly bears, has brought major increases in predation on newborn elk during early summer," wrote Middleton, who added that the region has experienced severe drought and warmer temperatures in recent years. "These effects of drought and predation could largely explain both low pregnancy and declining calf production among elk of the Yellowstone region."

Kauffman, a USGS scientist, is one of the co-authors of the report published today -- along with a collaborative team of researchers from the Game and Fish Department, the Fish and Wildlife Service, the National Council for Air and Stream Improvement, Yellowstone National Park and UW.

The article summarizing the research in Ecology Letters is available online.

By OC_Web@usgs.gov (Office of Communications and Publishing) from USGS Newsroom. Published on Jun 05, 2013.

LARAMIE, Wyo. — Migratory elk are coming back from Yellowstone National Park with fewer calves due to drought and increased numbers of big predators – two landscape-level changes that are reducing the benefits of migration with broader implications for conservation of migratory animals, according to a new study published in the journal Ecology.

The new study by the Wyoming Cooperative Fish and Wildlife Research Unit – a joint program involving U.S. Geological Survey, the University of Wyoming, and the Wyoming Game and Fish Department, describes a long-term decline in the number of calves produced annually by the Clarks Fork herd, a population of about 4000 elk whose migrants travel annually between winter ranges near Cody, Wyoming and summer ranges within Yellowstone National Park.  Migratory elk experienced a 19 percent depression in rates of pregnancy over the four years of the study and a 70 percent decline in calf production over 21 years of monitoring by the WGFD, while the elk that did not migrate, known as resident elk, in the same herd experienced high pregnancy and calf production and are expanding their numbers and range into private lands outside of the park.

"This is one of North America's wildest and best-protected landscapes, where elk and other ungulates still retain their long-distance seasonal migrations – and yet it is the migratory elk that are struggling while their resident counterparts thrive in the foothills," said Arthur Middleton, who led this work as a University of Wyoming doctoral student and is now a postdoctoral fellow at the Yale School of Forestry and Environmental Studies.

A key finding of the study was that only 70 percent of migratory elk were pregnant, compared to 90 percent of residents – a rate more typical of Rocky Mountain elk. The study shows that the hotter and dryer summer conditions of the last two decades, coincident with the long-term drought widely affecting the West, has reduced the duration of the spring period when tender new grasses are available to elk. This makes it harder for female migratory elk to find the forage they need to both nurse a calf and breed. Though elk typically bear a calf every year, migratory elk that nursed a calf had only a 23 percent chance of becoming pregnant again in the following year.

Another likely cause of the declining calf numbers among migrants was predation. Migrants share their range with four times as many grizzly bears and wolves than resident elk, and both predators are well known to prey on young elk calves. Resident elk get a break from high levels of predation in part because when predators kill livestock on the resident range, they are often lethally removed by wildlife managers and ranchers.

"A lower pregnancy rate reduces the number of calves that are born in the first place, then predation seems to reduce the number of migratory calves that survive the first few months of life," said Matthew Kauffman a research wildlife biologist with the USGS and Assistant Professor at the University of Wyoming. Kauffman goes on to explain that resident elk numbers are growing in the foothills not because migrants are choosing to stay behind, but rather because irrigated fields and lower predator numbers are allowing residents to raise more calves to adulthood.

Globally, wildlife migration is a dwindling phenomenon. Research and management often focus on conspicuous barriers like fences, roads, and other kinds of development that can physically impede migration corridors. While those are important, this study suggests that even in a landscape as well-protected as the Greater Yellowstone Ecosystem, subtler changes in predator management and forage quality on the seasonal ranges of migratory animals will also play an important role. Migration is conventionally understood as a strategy to gain better forage quality while also reducing exposure to denning predators, but in this case, it seems those benefits are instead being realized by the residents.

The study's authors note that their work does not predict that migratory elk will disappear, but rather that there could be a long-term shift underway in the relative abundance of migratory versus resident elk in the system. The study also highlights the perils of characterizing Yellowstone wolf re-introduction as a "natural experiment." Other key factors have changed since wolves were re-introduced, including growth in grizzly bears numbers and recurrent long-term drought associated with reduced snowpack and hotter summers. The authors caution that such factors should be taken into account in the effort to understand ongoing ecological changes in Yellowstone.

Middleton also points out that this work highlights the complex challenges facing regional wildlife managers and other stakeholders as they continue to adapt to the reintroduction and recovery of large carnivores, and severe drought that some studies suggest is linked to longer-term climate change. "Most immediately, these trends have meant lost hunting opportunity in the backcountry areas frequented by migratory elk, and increasing crop damage and forage competition with domestic livestock in the frontcountry areas where resident elk are expanding," said Middleton.

This work was a collaboration among the USGS’s Wyoming Cooperative Fish and Wildlife Research Unit, the WGFD, and the U.S. Fish and Wildlife Service, with cooperation from YNP and other agencies.  Primary funders include the WGFD, the Rocky Mountain Elk Foundation, the Wyoming Animal Damage Management Board, the Wyoming Governor’s Big Game License Coalition, and USGS, among others. 

The study is featured in a Forum section of Ecology, with a series of commentaries from other ecologists who study wildlife migration and predator-prey interactions.

Funding from the USGS National Climate Change and Wildlife Science Center contributed to this study.

By OC_Web@usgs.gov (Office of Communications and Publishing) from USGS Newsroom. Published on Jun 04, 2013.

A unique deposit of heavy rare earth elements at Alaska's Bokan Mountain could help scientists understand how rare earth element deposits form, according to new research by geologists from Saint Mary's University in Halifax and the U.S. Geological Survey. Rare earth elements are important, but scarce, elements used in components in many cutting edge electronic and defense technologies.

Currently, very little is known about the geologic setting in which REE deposits form. Understanding these geologic settings and how they come to be is a crucial step to being able to determine where mineable concentrations of REE might be found.

REE are made up of 17 elements, including Yttrium, Scandium, and the 15 members of the Lanthanide series. They are divided into light and heavy REE, depending on their atomic weights. Light REE are more commonly dominant in REE deposits, which is why HREE-enriched deposits at Bokan Mountain are noteworthy.

HREE are very valuable for producing tiny high-grade magnets used in smart phones and tablets, and for increasing the ability of engines and transmissions to operate at higher temperatures. Bokan Mountain is one of the few known deposits where heavy rare earth elements are concentrated and can be more efficiently produced.

"Our work in southeastern Alaska has demonstrated the potential for a viable, world-class supply of heavy rare earths from a domestic source. The collaboration between the USGS, universities and Ucore Rare Metals is an excellent example of how public-private partnerships can directly succeed in assisting significant economic growth," said lead author Dr. Jaroslav Dostal, with Saint Mary's University in Halifax, Nova Scotia.

To determine how these deposits formed at Bokan Mountain, Dostal analyzed the granite using geochemistry and isotopic analysis, and then compared his results to other granites.

He found that the granite of Bokan Mountain is similar to granites that formed in what is known as a "rift setting," in which the Earth's crust splits apart and magma wells up from below. This magma then cools to form a distinctive type of granite.

USGS geologist Susan Karl mapped the structures in the Bokan Mountain granite and the rocks that the granite intruded. Her studies indicate the granite magma was emplaced on active structures associated with rifting.

"This research contributes to more efficient exploration for REE deposits," said Karl, who is located at the USGS Alaska Science Center in Anchorage. "By knowing more about how REE deposits form, scientists and mining companies can more accurately target rocks that might contain mineable concentrations of these critical minerals."

In 2010, USGS completed a report characterizing the principal REE deposits in the United States, including Bokan Mountain, AK and Mountain Pass, CA, which is the largest known deposit of REE in the United States. At the present time, the United States obtains its REE raw materials from foreign sources, almost exclusively from China. Import dependence upon a single country raises serious issues of supply security. This study will help to define domestic supply in the United States.

The USGS Mineral Resources External Research Program funded this research in 2009 with a grant to Saint Mary's University where Dostal is a professor emeritus. The USGS MRERP grant program is designed to support academic studies of topics such as the genesis of certain types of mineral deposits and make the information available to the general public, including the resource community and land stewards.

The USGS Mineral Resources Program delivers unbiased science and information to understand mineral resource potential, production, consumption, and how minerals interact with the environment.

In addition to his long career on the faculty at Saint Mary's University, Dostal also sits on the board of UCORE, the company that is currently developing the property at Bokan Mountain.

The report "Bokan Mountain peralkaline granitic complex, Alexander terrane (southeastern Alaska): Evidence for Early Jurassic rifting prior to accretion with North America" has been published in the Canadian Journal of Earth Sciences.

For more on this report and other USGS research on rare earth elements, please visit the USGS Rare Earths page. For more information on USGS mineral research, please visit the USGS Mineral Resources Program.

By OC_Web@usgs.gov (Office of Communications and Publishing) from USGS Newsroom. Published on Jun 03, 2013.

A Baseline Environmental Report (BER) newly released by the U.S. Geological Survey will provide a consistent set of information about the Greater Sage-Grouse. The report is one of a suite of documents that will help guide the Bureau of Land Management (BLM) and the U.S. Forest Service (USFS) in their joint efforts to conserve Greater Sage-Grouse. 

"This report summarizes several decades of work on sage-grouse populations and sagebrush habitat. It will serve as a useful tool for land and wildlife managers and provides a needed range-wide perspective," said Suzette Kimball, Acting Director of the USGS.

The BLM and the USFS are preparing Environmental Impact Statements to address the effects of implementing proposed Greater Sage-Grouse conservation measures on the lands they manage. The agencies will use the BER in summarizing the effect of their joint planning efforts intended to help conserve the bird and its sagebrush habitat across its range in the western United States.   

The report, assembled, peer reviewed and published by the USGS, is intended to provide a framework for considering potential implications and management options, and demonstrate a regional context and perspective needed for local planning and decision-making.

The BER looks at each of the threats to Greater Sage-Grouse identified in the U.S. Fish and Wildlife Service’s (FWS) "warranted but precluded" finding for listing the species under the Endangered Species Act. For these threats, the report summarizes the current scientific understanding of various impacts to Greater Sage-Grouse populations and habitats.  The report also covers the location, magnitude, and extent of each threat. The BER does not provide management options.

The data for this report were gathered from BLM, USFS, and other sources. All data, both internal and external, were the "best available" at the range-wide scale at the time collected.  At the conclusion of the 2012 fire season, the BER’s wildland-fire statistics were updated. 

The BER report joins two other key documents being used by the agencies to prepare and evaluate their conservation plans, the BLM’s National Technical Team Report (NTT report) and the FWS's Conservation Objectives Team (COT) report. The NTT report provides habitat management recommendations for species across its entire range with detailed input by management zone, from State and local experts. The COT Report identifies conservation objectives and measures for each of the habitat threats assessed. For some threats, the team identified examples of actions that could be used to help attain the conservation objectives.   

By OC_Web@usgs.gov (Office of Communications and Publishing) from USGS Newsroom. Published on May 30, 2013.

WASHINGTON -- NASA transferred operational control Thursday of the Landsat 8 satellite to the U.S. Geological Survey (USGS) in a ceremony in Sioux Falls, S.D.

The event marks the beginning of the satellite's mission to extend an unparalleled four-decade record of monitoring Earth's landscape from space. Landsat 8 is the latest in the Landsat series of remote-sensing satellites, which have been providing global coverage of landscape changes on Earth since 1972. The Landsat program is a joint effort between NASA and USGS.

NASA launched the satellite Feb. 11 as the Landsat Data Continuity Mission (LDCM). Since then, NASA mission engineers and scientists, with USGS collaboration, have been putting the satellite through its paces -- steering it into its orbit, calibrating the detectors, and collecting test images. Now fully mission-certified, the satellite is under USGS operational control.

"Landsat is a centerpiece of NASA's Earth Science program," said NASA Administrator Charles Bolden in Washington. "Landsat 8 carries on a long tradition of Landsat satellites that for more than 40 years have helped us to learn how Earth works, to understand how humans are affecting it and to make wiser decisions as stewards of this planet."

Beginning Thursday, USGS specialists will collect at least 400 Landsat 8 scenes every day from around the world to be processed and archived at the USGS Earth Resources Observation and Science Center in Sioux Falls. The newest satellite joins Landsat 7, which launched in 1999 and continues to collect images. Since 2008, USGS has provided more than 11 million current and historical Landsat images free of charge to users over the Internet.

"We are very pleased to work with NASA for the good of science and the American people," said U.S. Interior Secretary Sally Jewell in Washington. "The Landsat program allows us all to have a common, easily accessible view of our planet. We are especially proud that Landsat images have not only been the starting points for some of the world’s best commercial innovations in earth imagery, but also are available free of charge."

Remote-sensing satellites such as the Landsat series help scientists observe the world beyond the power of human sight, monitor changes to the land that may have natural or human causes, and detect critical trends in the conditions of natural resources.

The 41-year Landsat record provides global coverage at a scale that impartially documents natural processes such as volcanic eruptions, glacial retreat and forest fires and shows large-scale human activities such as expanding cities, crop irrigation and forest clear-cuts. The Landsat Program is a sustained effort by the United States to provide direct societal benefits across a wide range of human endeavors including human and environmental health, energy and water management, urban planning, disaster recovery, and agriculture.

With Landsat 8 circling Earth 14 times a day, and in combination with Landsat 7, researchers will be able to use an improved frequency of data from both satellites. The two observation instruments aboard Landsat 8 feature improvements over their earlier counterparts while collecting information that is compatible with 41 years of land images from previous Landsat satellites. 

By OC_Web@usgs.gov (Office of Communications and Publishing) from USGS Newsroom. Published on May 28, 2013.

Turtles dine in waters affected by oil spills, fishing and oxygen depletion

CORPUS CHRISTI, Texas – The favored feeding grounds of the endangered Kemp’s ridley sea turtle coincide with some Gulf of Mexico waters that are subject to oil spills, extensive commercial fishing and oxygen depletion.

These first-of-their kind details on foraging locations and migration patterns of the Kemp’s ridley sea turtle are from a new National Park Service and U.S. Geological Survey study, providing resource managers new information on how best to manage the species.

Scientists do not know why the turtles feed where they do, how human influences may affect turtle health or behavior, or whether human impacts on their chosen feeding areas might change their future foraging behavior. 

The researchers identified the feeding grounds of the Kemp’s ridley, considered the most endangered and smallest hard-shelled sea turtle in the world, by analyzing 13 years of satellite-tracking data.  The researchers tagged turtles at nesting sites between 1998 and 2011 and tracked them as they went on to foraging locations throughout the Gulf. Turtles from two major nesting sites in the study fed at specific locations off the coasts of Louisiana and Mississippi and at other locations in the Gulf.  

Donna Shaver, chief of the National Park Service’s Sea Turtle Science and Recovery Division at Padre Island National Seashore, said,  “Protecting feeding grounds for adult female sea turtles is important for the recovery of the species and this new information is important for future planning and restoration decisions.”

Cooperative efforts between Mexico and several U.S. agencies have helped increase the population of this species of sea turtle. Species support includes protection of nesting turtles and their eggs on nesting beaches and reducing threats from fishing. The number of Kemp’s ridleys nesting in the region has increased from 702 nests in 1985 to about 22,000 in 2012.

The research, in which dozens of adult female sea turtles were tagged after they nested on the beach at Padre Island National Seashore offers a “first glimpse” of how and when the turtles feed, said Kristen Hart, a research ecologist for the USGS Southeast Ecological Science Center. “We were able to decipher Kemp’s ridleys foraging behavior in space and time using a combination of satellite telemetry and new statistical techniques.”

Previous tracking studies generally showed Kemp’s ridley migration from nesting beaches along the Gulf of Mexico coastline to northern Texas and Louisiana with some turtles migrating as far as peninsular Florida. Until the current study, it was not known whether turtles displayed movement behavior indicative of foraging or migration at a particular location. The modeling done as part of the study has allowed scientists to pinpoint where these turtles may be feeding, a key finding in terms of identifying important at-sea habitats for these imperiled turtles.  

In addition to tagging turtles at Padre Island, Shaver said the researchers tagged turtles at nesting sites in Rancho Nuevo, Mexico, about 200 miles south of Padre Island. Shaver added, “This is the first time we’ve tracked the Mexican turtles to habitats in the Northern Gulf of Mexico.”

The feeding habitat discovery came when scientists differentiated time the sea turtles spent in feeding or breeding mode from the time spent migrating. Once scientists located when and where the turtles were feeding, they were also able to coarsely profile what type of habitat offered the best feeding grounds for Kemp’s ridleys.

“We have a lot more to learn about how and why Kemp’s ridleys use their foraging sites,” Hart said.  “We don’t know enough about individual turtles yet to draw conclusions about their behavioral responses to conditions at foraging grounds, and we are just beginning to understand differences among different sea turtles species. For example, Kemp’s ridleys appear to migrate, then feed, and then migrate to a final feeding destination. Loggerheads, in contrast, seem to head straight for feeding hotpots.”

Hart added, “We plan to continue fleshing out the major scientific gaps that managers need addressed in order to develop long-term survival and recovery plans for Kemp’s ridleys.”

Read the study, “Foraging area fidelity for Kemp’s ridleys in the Gulf of Mexico,” in the journal Ecology and Evolution.

About Kemp’s Ridley sea turtles

The Kemp''s ridley turtles are considered the smallest sea turtle in the world, with adults reaching about 2 feet long and weighing up to 100 pounds. They are found in the Gulf of Mexico and the Atlantic seaboard and feed primarily on crab species living on the sea floor (or benthos) of shallow waters. Their name comes from a fisherman named Richard Kemp of Key West, Florida, who provided the specimen used to describe the species in 1880. They are related to olive ridleys, another small sea turtle found around the world.

Kemp’s ridley sea turtles are listed in the U.S. and internationally as endangered throughout their range due to dramatic population declines in the 20^th century. The vast majority of Kemp’s ridleys converge on three major sites in the state of Tamaulipas, Mexico every year to nest. In the early 1960s, a film was discovered that showed an estimated 40,000 females nesting at one particular site – Rancho Nuevo – on one day.

Threats to Kemp’s ridleys once included egg collection, overhunting, and unintentional capture during fisheries operations.  Today, most of their nesting occurs on protected lands. Nonetheless, nesting habitat is still sometimes disturbed by natural and human events such as hurricanes, oil spills, or erosion. Also, activities that affect the seafloor (what scientists call benthic habitat) can disturb their feeding habitat. This includes bottom trawling and dredging. Another known threat is incidental capture, or unintentional by-catch, in fishing gear.

Although conservation efforts began in the 1960s, the number of nesting females continued to decline. By 1978, the U.S. and Mexico started a multi-agency effort to safeguard Kemp’s ridleys from extinction by encouraging nesting at Padre Island National Seashore in Texas. Biologists have since been monitoring nesting activity, and there has been an increase in the number of nests since 1985.

END

About the National Park Service: More than 20,000 National Park Service employees care for America’s 401 national parks and work with communities across the nation to help preserve local history and create close-to-home recreational opportunities. Learn more at www.nps.gov.

By OC_Web@usgs.gov (Office of Communications and Publishing) from USGS Newsroom. Published on May 22, 2013.

CORVALLIS, Ore. — The first-ever estimate of how fast frogs, toads and salamanders in the United States are disappearing from their habitats reveals they are vanishing at an alarming and rapid rate.

According to the study released today in the scientific journal PLOS ONE, even the species of amphibians presumed to be relatively stable and widespread are declining. And these declines are occurring in amphibian populations everywhere, from the swamps in Louisiana and Florida to the high mountains of the Sierras and the Rockies.

The study by USGS scientists and collaborators concluded that U.S. amphibian declines may be more widespread and severe than previously realized, and that significant declines are notably occurring even in protected national parks and wildlife refuges.

"Amphibians have been a constant presence in our planet's ponds, streams, lakes and rivers for 350 million years or so, surviving countless changes that caused many other groups of animals to go extinct," said USGS Director Suzette Kimball. "This is why the findings of this study are so noteworthy; they demonstrate that the pressures amphibians now face exceed the ability of many of these survivors to cope."

On average, populations of all amphibians examined vanished from habitats at a rate of 3.7 percent each year. If the rate observed is representative and remains unchanged, these species would disappear from half of the habitats they currently occupy in about 20 years. The more threatened species, considered "Red-Listed" in an assessment by the global organization International Union for Conservation of Nature, disappeared from their studied habitats at a rate of 11.6 percent each year. If the rate observed is representative and remains unchanged, these Red-Listed species would disappear from half of the habitats they currently occupy in about six years.

"Even though these declines seem small on the surface, they are not," said USGS ecologist Michael Adams, the lead author of the study. "Small numbers build up to dramatic declines with time. We knew there was a big problem with amphibians, but these numbers are both surprising and of significant concern."

For nine years, researchers looked at the rate of change in the number of ponds, lakes and other habitat features that amphibians occupied. In lay terms, this means that scientists documented how fast clusters of amphibians are disappearing across the landscape.

In all, scientists analyzed nine years of data from 34 sites spanning 48 species. The analysis did not evaluate causes of declines.

The research was done under the auspices of the USGS Amphibian Research and Monitoring Initiative, which studies amphibian trends and causes of decline. This unique program, known as ARMI, conducts research to address local information needs in a way that can be compared across studies to provide analyses of regional and national trends.

Brian Gratwicke, amphibian conservation biologist with the Smithsonian Conservation Biology Institute, said, "This is the culmination of an incredible sampling effort and cutting-edge analysis pioneered by the USGS, but it is very bad news for amphibians. Now, more than ever, we need to confront amphibian declines in the U.S. and take actions to conserve our incredible frog and salamander biodiversity."

The study offered other surprising insights. For example, declines occurred even in lands managed for conservation of natural resources, such as national parks and national wildlife refuges.

"The declines of amphibians in these protected areas are particularly worrisome because they suggest that some stressors – such as diseases, contaminants and drought – transcend landscapes," Adams said. "The fact that amphibian declines are occurring in our most protected areas adds weight to the hypothesis that this is a global phenomenon with implications for managers of all kinds of landscapes, even protected ones."

Amphibians seem to be experiencing the worst declines documented among vertebrates, but all major groups of animals associated with freshwater are having problems, according to Adams. While habitat loss is a factor in some areas, other research suggests that things like disease, invasive species, contaminants and perhaps other unknown factors are related to declines in protected areas.

"This study," said Adams, "gives us a point of reference that will enable us to track what's happening in a way that wasn’t possible before."

Read FAQs about this research

The publication, Trends in amphibian occupancy in the United States, is authored by  Adams, M.J., Miller, D.A., Muths, E., Corn, P.S., Campbell Grant, E.H., Bailey, L., Fellers, G.M., Fisher, R.N., Sadinski, W.J., Waddle, H., and Walls, S.C., and is available to the public.

Read a USGS blog, Front-row seats to climate change, about 3 other recent USGS amphibian studies. For more information about USGS amphibian research, visit http://armi.usgs.gov/

By OC_Web@usgs.gov (Office of Communications and Publishing) from USGS Newsroom. Published on May 22, 2013.

Citizen volunteers are making significant additions to the U.S. Geological Survey's ability to provide accurate information to the public. Using crowd sourcing techniques, the USGS project known as The National Map Corps (TNMC) encourages citizen volunteers to collect manmade structure data in an effort to provide accurate and authoritative spatial map data for the National Geospatial Program’s web-based The National Map.

These structures can include schools, hospitals, post offices, police stations and other important public places along with data from other sources, the data currently being collected by volunteers become part of TNM Structures dataset which is made available to users free of charge.

In an effort to recognize the important work being done by volunteers, TNMC has created a recognition program based on the number of points a volunteer contributes. Levels of recognition are displayed in the form of icons or badges of antique catalog drawings of different and increasingly sophisticated pieces of surveying equipment. Each badge comes with a description of the item and encouragement to achieve the next level. As a volunteer attains each level, a congratulations email is sent, and the accomplishments are recognized via The National Map Twitter site (#TNMCorps) and the USGS Facebook page. 

Recognition Categories:

Order of the Surveyor’s Chain award. (Larger image)	Theodolite Assemblage award. (Larger image)

Becoming a volunteer for TNMC is easy; go to The National Map Corps project site to learn more and to sign up as a volunteer. If you have access to the Internet and are willing to dedicate some time editing map data, we hope you will consider participating.

While some familiarity with the area that a volunteer chooses is helpful, you do not have to live near a particular place to contribute. The tools on TNMC website, along with ancillary information available on the Internet, are generally sufficient to edit a distant area. There are presently nineteen states available for volunteers to choose to update structures in.

See for yourself how much fun participating can be. Go to The National Map Corps home page, give it a try and before you know it you’ll be hanging out with the Pedometer Posse!

By OC_Web@usgs.gov (Office of Communications and Publishing) from USGS Newsroom. Published on May 20, 2013.

A new U.S. Geological Survey study documents that the Nation's aquifers are being drawn down at an accelerating rate. 

Groundwater Depletion in the United States (1900-2008) comprehensively evaluates long-term cumulative depletion volumes in 40 separate aquifers (distinct underground water storage areas) in the United States, bringing together reliable information from previous references and from new analyses. 

"Groundwater is one of the Nation's most important natural resources. It provides drinking water in both rural and urban communities. It supports irrigation and industry, sustains the flow of streams and rivers, and maintains ecosystems," said Suzette Kimball, acting USGS Director. "Because groundwater systems typically respond slowly to human actions, a long-term perspective is vital to manage this valuable resource in sustainable ways." 

To outline the scale of groundwater depletion across the country, here are two startling facts drawn from the study's wealth of statistics. First, from 1900 to 2008, the Nation's aquifers, the natural stocks of water found under the land, decreased (were depleted) by more than twice the volume of water found in Lake Erie. Second, groundwater depletion in the U.S. in the years 2000-2008 can explain more than 2 percent of the observed global sea-level rise during that period.   

Since 1950, the use of groundwater resources for agricultural, industrial, and municipal purposes has greatly expanded in the United States. When groundwater is withdrawn from subsurface storage faster than it is recharged by precipitation or other water sources, the result is groundwater depletion. The depletion of groundwater has many negative consequences, including land subsidence, reduced well yields, and diminished spring and stream flows. 

While the rate of groundwater depletion across the country has increased markedly since about 1950, the maximum rates have occurred during the most recent period of the study (2000–2008), when the depletion rate averaged almost 25 cubic kilometers per year. For comparison, 9.2 cubic kilometers per year is the historical average calculated over the 1900–2008 timespan of the study. 

One of the best known and most investigated aquifers in the U.S. is the High Plains (or Ogallala) aquifer. It underlies more than 170,000 square miles of the Nation's midsection and represents the principal source of water for irrigation and drinking in this major agricultural area. Substantial pumping of the High Plains aquifer for irrigation since the 1940s has resulted in large water-table declines that exceed 160 feet in places. 

The study shows that, since 2000, depletion of the High Plains aquifer appears to be continuing at a high rate. The depletion during the last 8 years of record (2001–2008, inclusive) is about 32 percent of the cumulative depletion in this aquifer during the entire 20th century. The annual rate of depletion during this recent period averaged about 10.2 cubic kilometers, roughly 2 percent of the volume of water in Lake Erie. 

Learn more

• Groundwater Depletion in the United States (1900-2008)
• USGS Groundwater Information
• USGS High Plains Groundwater Availability Study
• Contribution of global groundwater depletion since 1900 to sea‐level rise (journal article)