Ethan Alpern ( Phone: 703-648-4406 ); Julio Betancourt ( Phone: 703-648-5840 );
In a finding authors are coining an "unintentional rewilding," scientists identified a cave dung deposit as belonging to bighorn sheep that became extinct on a desert island sometime between the 6th and the 20th century.
The unintentional rewilding occurred when in 1975 wildlife biologists introduced 16 female and 4 male bighorn sheep to Tiburón Island, the largest island in the Gulf of California. Today, the population numbers more than 500 individuals.
A team from the University of California-Riverside, the U.S. Geological Survey, Oregon State University, and East Tennessee State University discuss this non-native rewilding on Tiburón Island, located in the Gulf of California, in this week's PLOS ONE. Ben Wilder, Ph.D. Candidate of UC-Riverside and the lead author of the study, accidentally discovered the 1500-1600 year-old, urine-cemented dung mat on the floor of a small cave in the Sierra Kunkaak, a rugged mountain range of the eastern side of the island.
After comparing the pellets with an extensive collection of dung for both living and extinct herbivores, researchers determined that bighorn sheep formed the dung mat. The ancient sequences exactly matched DNA sequences from modern desert bighorn sheep, and differed substantially from other large herbivores that might have been present.
Until this discovery, there was no knowledge on whether or not bighorn sheep had previously occurred on the island.
"It's a very clear result," said Clinton Epps, a co-author and a conservation geneticist at Oregon State University. "Furthermore, the sequences are not identical to the modern bighorn populations on Tiburón Island - so we are confident that the sequences do not derive from modern use of the cave by introduced bighorn sheep."
Julio Betancourt, a USGS paleoecologist and co-author of the study, has previously collaborated with geneticists to extract and sequence ancient DNA from cave deposits. Betancourt thinks that, in the future, "molecular caving will become more than an afterthought in arid lands paleoecology."
Michael Hofreiter of the University of Potsdam, a leading authority in ancient DNA research and editor of the paper, notes that, "Given the ongoing progress in paleogenomics and DNA sequencing, it will soon be possible to sequence full genomes from samples like the one recovered from Tiburón island, compare those to genomes from various extant populations and thereby identify the population that is most suitable for reintroduction in a certain area."
The goal of the 1975 re-introduction was use a safe site to foster a large, breeding population that could be used in restocking the mainland, where historic land use decimated native bighorn sheep populations. A controversial aspect of the Tiburón experiment is that it introduced what was then presumed to be a non-native herbivore into a fragile island ecosystem with a unique desert flora.
Wilder said he hopes that these findings will trigger more systematic studies of recent colonization and extinction events throughout these islands and elsewhere to help guide conservation efforts.
The study, "Local extinction and unintentional rewilding of bighorn sheep (Ovis canadensis) on a desert island," was authored by Benjamin T. Wilder, Julio L. Betancourt, Clinton W. Epps; others, and was published this week in PLOS One.
Heidi Koontz ( Phone: 303-202-4763 );
A new method of viewing how humans and the natural environment impact each other is now available. ARIES (Artificial Intelligence for Ecosystem Services), one of the first methods to seamlessly integrate spatial data, modeling, and mapping, adopts a convention for evaluating ecosystem services that places society’s needs and natural processes on equal footing.
A new U.S. Geological Survey article published recently in PLOS ONE outlines the ARIES framework and how it can aid in better understanding nature’s value to society — today and under future scenarios for climate and land use change, energy and minerals extraction, water resources management, natural hazard impacts, and natural resource conservation.
"This methodological advance is designed to integrate diverse data and models more quickly and accurately, using principles from semantic meta-modeling and big data," said Ken Bagstad, USGS researcher and contributing author of the paper. "This is not just another tool for environmental assessment, but rather a new and different way to look at the linkages between people, nature, and the economy."
The ARIES methodology has been in development since 2007 and used in case studies since 2010. A variety of government and academic partners have contributed to its development, including the USGS, Basque Centre for Climate Change, University of Vermont, Conservation International and Earth Economics.
Everglades National Park, Fla.— Invasive Burmese pythons in South Florida are able to find their way home even when moved far away from their capture locations, a finding that has implications for the spread of the species.
A multi-organizational team of scientists found that when six Burmese pythons were relocated 13-22 miles from their capture locations, the snakes headed straight back home, navigating to within 3 miles of their original capture locations in Everglades National Park.
"Previous studies have shown that many snakes lack the ability to home, yet this study provides evidence that Burmese pythons are capable of homing after they have been displaced --- and they are able to do so at a scale previously undocumented for any snake species," said Shannon Pittman, lead author of the study and a postdoctoral fellow at Davidson College in North Carolina. "Understanding this large-scale navigational ability is critical to understanding the ability of Burmese pythons to expand their geographic range," Pittman added.
To find your way home requires a map sense on the part of the animal, which allows the animal to determine its position in relation to a goal; and a compass sense, which requires access to a reliable compass to maintain orientation toward the goal. The relocated snakes moved faster and straighter than snakes that were not relocated, demonstrating that Burmese pythons have navigational map and compass senses.
The relocated snakes also appeared to use local cues from their release site to determine their position relative to home. Potential cues underlying the map sense in pythons may be olfactory or magnetic that change predictably through space. The compass aspect of their navigational ability could be accomplished through the use of magnetic, celestial, olfactory or polarized light cues, all of which generate a reliable compass sense.
"The snakes maintained their oriented movement over the course of a relatively long time, between 94 and 296 days," said Kristen Hart, a USGS researcher and study coauthor. "This indicates that not only do pythons keep their long-term movement goal in mind, but also that they were highly motivated to get back home."
These findings have implications for management and conservation of the species, the study authors emphasized. Animals that are adept at navigating and homing are better able to exploit resources that are relatively far away, widely spaced or seasonally variable. These abilities also reduce risks associated with searching potentially hostile or unfamiliar areas because the dispersing snakes can always return to a safe location.
"Understanding navigation in invasive species improves the ability to control populations and limit dispersion," said Hart. "For example, the fine-tuned navigational capacity that the pythons exhibited may lower their risk when they move to and explore new areas."
This research is useful for resource managers because it has implications for python movement behavior at the edges of the invasion front where there is a need for containment, Pittman said.
"Invasive exotic reptiles continue to challenge agencies charged with protecting the health of south Florida ecosystems," said Everglades National Park Superintendent Dan Kimball. "Continued research like this on the invasive exotic Burmese python is critical so that we can make better informed management decisions and move closer to containment of this species that has adapted to this environment."
The invasive Burmese python is an apex predator in the Everglades that became established in Florida several decades ago. The largest snakes removed from the Everglades have exceeded 18 feet and 150 pounds. Snakes of this size are capable of ingesting large prey like adult deer and alligators.
"Homing of invasive Burmese pythons is South Florida: evidence for map and compass senses in snakes" by S.E. Pittman, K.M. Hart, M.S. Cherkiss, R.W. Snow, I. Fujisaki, B.J. Smith, F.J. Mazzotti, and M.E. Dorcas, is published in the journal Biology Letters. The study can be accessed online.
Last year, the estimated value of mineral production in the U.S. was $74.3 billion, a slight decrease from $75.8 billion in 2012. According to the U.S. Geological Survey’s annual Mineral Commodity Summaries 2014 report, the 2013 decrease follows three consecutive years of increases. Net U.S. exports of mineral raw materials and old scrap contributed an additional $15.8 billion to the U.S. economy.
"To put this in context, the $90.1 billion value of combined mined, exported, and recycled raw materials is more than five times greater than the 2013 combined net revenues of Internet titans: Amazon, Facebook, Google, and Yahoo. This illustrates the fundamental importance of mineral resources to the nation’s economy, technology, and national security," said Larry Meinert, USGS Mineral Resources Program Coordinator.
Minerals remain fundamental to the U.S. economy, contributing to the real gross domestic product at several levels, including mining, processing, and manufacturing finished products. The U.S. continues to rely on foreign sources for raw and processed mineral materials.
This annual USGS report is the original source of mineral production data for the world. It includes statistics on about 90 mineral commodities essential to the U.S. economy and national security, and addresses events, trends, and issues in the domestic and international minerals industries.
"Decision makers and policy makers in the private and public sectors rely on the Mineral Commodity Summaries and other USGS minerals information publications as unbiased sources of information to make business decisions and national policy," said Michael J. Magyar, Acting Director of the USGS National Minerals Information Center.
Production increased for most industrial mineral commodities mined in the U.S., and prices remained stable. Industrial mineral commodities include cement, clays, crushed stone, phosphate rock, salt, sand and gravel, and soda ash, which are used in industrial applications such as building and road construction and chemical manufacturing.
Production of most metals was relatively unchanged compared with that of 2012, but reduced prices resulted in an overall reduction in the value of metals produced. Domestically produced metals include copper, gold, iron, molybdenum, and zinc, which are used in a wide variety of products including consumer goods, electronic devices, industrial equipment, and transportation systems.
Domestic raw materials and domestically recycled materials were used to process mineral materials worth $665 billion. These mineral materials, including aluminum, brick, copper, fertilizers, and steel, and net imports of processed materials (worth about $24 billion) were, in turn, consumed by downstream industries with a value added of an estimated $2.4 trillion in 2013.
The construction industry began to show signs of improvement in 2012, and those trends continued in 2013, with increased production and consumption of cement, construction sand and gravel, crushed stone, and gypsum, mineral commodities that are used almost exclusively in construction.
Mine production of 14 mineral commodities was worth more than $1 billion each in the U.S. in 2013. These were, in decreasing order of value, crushed stone, gold, copper, cement, construction sand and gravel, iron ore (shipped), molybdenum concentrates, phosphate rock, industrial sand and gravel, lime, soda ash, salt, zinc, and clays (all types).
In 2013, 12 states each produced more than $2 billion worth of nonfuel mineral commodities. These states were, in descending order of value—Nevada, Arizona, Minnesota, Florida, Texas, Alaska, Utah, California, Wyoming, Missouri, Michigan, and Colorado. The mineral production of these states accounted for 64% of the U.S. total output value.
Government agencies and the industrial and financial sectors use data from this and other USGS minerals reports to prepare legislation and key economic reports and to evaluate national defense mineral requirements. USGS produces more detailed and updated data throughout the year in the USGS Minerals Yearbook and Mineral Industry Surveys.
The USGS Mineral Resources Program delivers unbiased science and information to understand mineral resource potential, production, consumption, and their interaction with the environment. The USGS National Minerals Information Center collects, analyzes, and disseminates current information on the supply of and the demand for minerals and materials in the U.S. and about 180 other countries.
The USGS report "Mineral Commodity Summaries 2014" is available online. Hardcopies will be available later in the year from the Government Printing Office, Superintendent of Documents. For ordering information, please call (202) 512-1800 or (866) 512-1800 or go online.
For more information on this report and individual mineral commodities, please visit the USGS National Minerals Information Center.
Raw or undercooked Asian swamp eels could transmit a parasitic infection called gnathostomiasis to consumers.
U.S. Geological Survey scientists found parasitic worms known as gnathostomes in Asian swamp eels collected between 2010 and 2012 from ethnic food markets and in Florida waters where the eel species is invasive. If eaten raw or undercooked, these eels could transmit their parasites to people, causing mild to serious disease. Severe cases of the infection can lead to blindness, paralysis or death. The USGS study was published today in the journal Emerging Infectious Diseases.
"Because live Asian swamp eels are commonly imported to the U.S., a person's dietary history and not just travel history should be considered when diagnosing gnathostomiasis," said Rebecca Cole, USGS scientist and lead author of the study.
Swamp eels transported live from Southeast Asia are sold in many urban ethnic food markets in the United States, and have been released into waters in Florida, Georgia and New Jersey. During the USGS study, scientists found gnathostome worms in eels collected from markets in Manhattan, N.Y., Atlanta, Ga., and Orlando, Fla., and in wild eels caught in peninsular Florida. All of the infected eels obtained from markets were imported from Bangladesh.
"Consumers should be aware of the risk of contracting gnathostomiasis from Asian swamp eels if they are eating raw or undercooked eels," Cole said.
Co-author and USGS scientist Leo Nico said it is notable that North American species of gnathostome parasites have infected wild, invasive Asian swamp eels in Florida. Although the North American species found in the wild Florida eels has not been reported as infecting humans, some scientists suggest that all Gnathostoma species can most likely infect people. According to the authors, it is also concerning that this parasite could be transmitted into native fish and wildlife populations and domestic cats or dogs.
Swamp eels are native to Southeast Asia, and wild-caught and domestically-reared eels are widely consumed as food by humans. The eels are a common source of human gnathostomiasis in many parts of Asia. Wild populations of these invasive eels were first found in Florida in 1997, likely the result of the live food trade or aquarium releases. There are five established populations in the continental U.S. — three in Florida, and one each in Georgia and New Jersey. Introduced swamp eels have also been present in Hawaii for many decades.
The eels, which can reach lengths of about three feet, have the potential to become widespread in the U.S., impacting native aquatic and wetland species. The species has few known predators in the U.S., breathes air and can move across land, and can survive in both hot and cold climates.
Asian carp eggs, including late-stage embryos nearly ready to hatch from the egg, were recently identified in samples collected by U.S. Geological Survey scientists in 2013 from the Upper Mississippi River as far north as Lynxville, Wisc.
"This discovery means that Asian carp spawned much farther north in the Mississippi than previously recorded," said Leon Carl, USGS Midwest Regional Director. "The presence of eggs in the samples indicates that spawning occurred, but we do not know if eggs hatched and survived or whether future spawning events would result in live fish."
The Asian carp eggs and late-stage embryos were discovered two weeks ago while processing samples that were collected in mid-May and mid-June, 2013. The samples were taken as part of a larger research project designed to identify Asian carp spawning habitats. The eggs and late-stage embryos were 250 river miles upstream of previously known reproductive populations in the river. Spawning would have occurred upstream from this site.
Once the scientists visually identified the eggs, they examined other samples taken from the Mississippi River and found Asian carp eggs at seven locations between Pool 19 near Keokuk, Iowa, and Pool 9 of the main channel of the Upper Mississippi River near Lynxville. Iowa, Missouri, Illinois, Minnesota and Wisconsin border the navigation pools where these samples were collected.
The eggs and late-stage embryos were identified as bigheaded carps — either bighead carp or silver carp — through visual analyses of specific features of the eggs and embryos. It is also possible that some eggs could be from grass carp, although no eggs were visually identified as such. The USGS attempted genetic analyses to definitively determine which species of Asian carp the eggs belong to, but the results were inconclusive. Additional steps are being completed to attempt genetic confirmation, and those results are expected in one to two weeks.
The research project that collected these eggs is being coordinated by the USGS in collaboration with Western Illinois University. Scientists plan to collect additional samples from the Mississippi River in 2014 as part of their on-going research project.
"Invasive Asian carp could pose substantial environmental risks and economic impacts to the Upper Mississippi River if they become established," Carl said. "Further research will help us to better understand their habitat requirements and inform integrated control efforts."
For more information on Asian carp research, please visit the Asian Carp Regional Coordinating Committee (ACRCC) website. The ACRCC is a partnership of federal and state agencies, municipalities and other groups, led by the White House Council on Environmental Quality.
Leslie Gordon ( Phone: 650-329-4006 );
FLAGSTAFF, Ariz. — Researchers at the U.S. Geological Survey, the University of Michigan, the University of Arizona, and the University of Technology, Sydney (Australia) are collaborating with scientists in Brazil on a three-year research project that investigates a basic yet unanswered question in Earth-system and global carbon-cycle science: What controls the response of photosynthesis in Amazon tropical forests to seasonal variations in climate?
Results of the study will help improve the reliability of global climate forecasts by guiding improvements in the treatment of tropical forest photosynthesis and related water-cycle processes in Earth-system models.
This question of photosynthesis' response to climate variations, despite its seeming simplicity, is the subject of an ongoing scientific puzzle that has so far been remarkably difficult to answer with confidence. For example, seasonal patterns of photosynthesis simulated by several state-of-the-art, numerical models of the Earth system, and seasonal patterns of vegetation "greenness" as inferred from observations by Earth-observing satellites, disagree with patterns seen in measurements of ecosystem-atmosphere carbon dioxide exchange at monitoring sites in the central Amazon.
"Improving our understanding of how a changing climate affects the fundamental processes that control absorption of atmospheric carbon dioxide by tropical forests, can help us improve Earth system models, and help improve the reliability of global climate forecasts," said USGS geographer and project leader, Dennis Dye.
The project is designed to resolve disagreements between the computer models, and actual forest measurements by developing new knowledge and deeper understanding of seasonal climate, photosynthesis, and water relationships in Amazon tropical forests, through the use of advanced remote-sensing techniques and field observations. The project focuses on existing tropical forest study sites near Manaus and Santarem, Brazil. Scientists will measure physiological properties of leaves and trees, and water flow, and use innovative remote-sensing instruments to monitor the light-reflecting properties of the forest and the effects of clouds and smoke on solar radiation. Scientists will also model the three-dimensional variation in photosynthesis in various forest structures and light levels.
"The ability to monitor the ecohydrologic function of the rainforest at a range of scales – from leaf, to tree, to stand levels – will offer an unprecedented observational support for testing hypotheses and developing new types of forest representation in land-surface models," said University of Michigan Hydrologist Valeriy Ivanov.
The project is supported in part by the U.S. Department of Energy, Office of Biological and Environmental Research, Climate and Environmental Sciences Division, GOAmazon campaign.
ANCHORAGE, Alaska —A recent U.S. Geological Survey-led study of the bar-tailed godwit, a shorebird known famously as the ultimate marathon champion of bird flight, suggests that these birds can sense broad weather patterns and optimally time their long, nonstop, transoceanic migrations to destinations thousands of miles away.
Like airplane pilots examining weather charts for the course ahead, godwits awaiting to take flight ultimately selected dates of departure that corresponded to the best atmospheric wind conditions possible within a two-week window. Remarkably, not only were the conditions optimal for take-off, but they almost always provided the best possible conditions for the birds' entire transoceanic flights.
"We think that these behaviors represent a previously unknown cognitive ability that allows bar-tailed godwits to assess changes in weather conditions across widely separated atmospheric regions in different parts of the Pacific Ocean and to time their migration patterns accordingly," said Robert Gill, Jr., an Emeritus Scientist with the USGS and lead author of the study.
These findings are part of a new scientific publication by collaborators from the USGS, the National Oceanic and Atmospheric Administration, and the University of Groningen and the NIOZ Royal Netherlands Institute for Sea Research. The researchers used detailed information on individuals tracked by satellite transmitters, along with data on wind conditions across the Pacific Ocean, to investigate migration patterns along the 18,000 mile annual route of the bar-tailed godwit. Their study determined that bar-tailed godwits are able to make efficient decisions about when and where to fly during nonstop flights of up to 10 days long between wintering areas in New Zealand and breeding areas in Alaska.
"There are a number of broad-scale prevailing wind patterns through the Pacific Ocean, and the godwits take advantage of these winds to facilitate successful migration between their wintering and breeding areas. These wind patterns appear to be teleconnected, or linked, across broad expanses of the Pacific Ocean," said Gill. "Just like airline pilots, birds occasionally have to abort flights or change course drastically when they encounter severe, unexpected weather," noted David Douglas, Research Wildlife Biologist, who like Gill, works out of the USGS Alaska Science Center and is co-author of the study.
The researchers observed two birds that made abrupt course changes when they encountered rapidly developing cyclones along their flight paths. In one case, the prolonged flight change resulted in the bird not breeding that season, likely due to energy spent fighting the headwinds of the storm.
The report on this study, entitled "Hemispheric-scale wind selection facilitates bar-tailed godwit circum-migration of the Pacific," was recently published in the journal Animal Behaviour.
Photos of bar-tailed godwits, their migration and habitats, are available from the USGS online.
ST. PETERSBURG, Fla.-- A first of its kind study has the potential to impact future regulatory decisions on disinfection practices for water prior to its recharge or following its storage in the Floridan Aquifer.
The U.S Geological Survey report found that coliform bacteria die off faster in a regional aquifer system than was previously known, though a small percentage survives. One of the state's regulatory criteria for ensuring the quality of recharged water is whether it contains coliform bacteria.
Aquifer storage and recovery facilities have been used in Florida for about 30 years to store large volumes of water over long periods of time, increasing water supply during seasonal and multi-year droughts. Potable water, treated and untreated groundwater, partially treated surface water and reclaimed water is recharged into zones of the Floridan Aquifer and later recovered when needed.
"Although it is commonly believed that bacteria are few in number and mostly inactive in the lower zones of the Floridan aquifer system, we found relatively high numbers of bacteria that are alive and active," said USGS microbiologist, John Lisle. "However, when we looked specifically at coliform bacteria, we found that they died off at higher rates in the aquifer than was previously known." Understanding that coliform bacteria die off faster than previously known has the potential to shape the standards or monitoring requirements that are set.
In addition to the coliform die off data, this study is the first to characterize both the geochemistry and natural microbial ecology of the Floridan Aquifer and how they influence groundwater quality. It provides a baseline that can be used to enhance geochemical models that predict changes in groundwater quality following any type of recharge event.
"Characterization of native bacterial communities in aquifers is important because of the direct connection between some groundwater quality variables and bacterial activities. Groundwater bacteria catalyze geochemical reactions under conditions that can be significantly different within the same aquifer," said June Mirecki, a hydrogeologist with the U.S. Army Corps of Engineers. "Fundamental studies, like this study, have significant implications for truly understanding the fate of contaminants in aquifers targeted for aquifer storage, carbon sequestration and deep well injection."
The Floridan Aquifer flows southward at between 800-3,000 feet below the ground. It is among the most productive groundwater sources in the U.S. The upper zones of the Floridan aquifer are used as a drinking water source, while the lower zones, like those in this study, have been targeted for the recharge of treated surface water and reclaimed water and carbon sequestration repositories.
The fate of coliform bacteria injected into the lower zones of the Floridan Aquifer was studied as part of the Comprehensive Everglades Restoration Plan. The study was done in cooperation with the South Florida Water Management District and the U.S. Army Corps of Engineers.
The full report "Survival of Bacterial Indicators and the Functional Diversity of Native and Microbial Communities in the Floridan Aquifer, South Florida" by John T. Lisle is available online.
A coalition of scientists from the United States and Afghanistan today released 60 high-tech maps that will help Afghanistan chart a course for future economic development. These maps represent a milestone as Afghanistan is the first country to be almost completely mapped using hyperspectral imaging data.
The coalition of the U.S. Geological Survey, the Afghanistan Ministry of Mines and Petroleum, and the Task Force for Business and Stability Operations (TFBSO), was created by the U.S. Department of Defense, to share American international science and technology as a strategic tool for promoting economic development.
"Hyperspectral data from this research provides a fingerprint that identifies Afghanistan’s natural resources," said Dr. Suzette Kimball, acting USGS director. "This detailed data serves as the backbone of crucial scientific information needed for economic development of natural resources as well as the potential to identify water, biological and natural hazard information."
Hyperspectral imaging is an advanced imaging technique that measures visible and near-infrared light reflecting off the Earth's surface. Researchers use hyperspectral imaging spectrometer data to identify and characterize mineral deposits, vegetation, and other land surface features.
Data were collected in 28 flights that commenced from Kandahar Air Field in 2007. Because of great advances in technology, this information was gathered in just two months where in the past, it would have likely taken up to 25 years to acquire.
The project utilized NASA's WB-57 high altitude research jet outfitted with an imaging spectrometer. Flying at an altitude of 50,000 feet, the spectrometer captured hyperspectral images over 400,000 square kilometers. Scientists using data from the flights have mapped an area that covers more than 70 percent of Afghanistan.
The maps are the newest and most detailed addition to a series of hyperspectral data from the USGS and the TFBSO. In July 2012, the hyperspectral data team released two surface materials maps of Afghanistan produced in partnership with the Afghan Geological Survey and TFBSO.
Learn more about USGS projects in Afghanistan.
Ethan Alpern ( Phone: 703-648-4406 );
A recent USGS-led study shows new, recently-formed patches of permafrost in one of Alaska's retreating lakes, a finding that, at first glance, would seem at odds with prevailing theories about arctic climate.
Widespread lake shrinkage in discontinuous regions of permafrost has been linked to climate warming and shallow permafrost thaw. Counter-intuitively, USGS scientists have observed newly forming permafrost around Twelvemile Lake in interior Alaska, where lake water level has dropped by several meters over the past three decades.
"Central Alaskan lake shrinkage may be caused by shallow permafrost changes and not by increasing deep aquifer connections," said Martin A. Briggs, USGS, lead author of the study. "Newly formed permafrost along the shores of shrinking lakes may reduce groundwater outflow and allow them to refill."
Permafrost, or frozen ground lasting at least two consecutive years, typically forms in colder climates when average annual temperatures remain close to or below freezing. Permafrost soils accumulate ice and plant material and can impede groundwater flow. While the upper 1-2 meters may thaw seasonally, frozen soil and dead plant material continues to accumulate at depth over thousands of years, depending on the strength and duration of the colder climate.
During periods of thaw, water and gases are released from their frozen pockets of ice. By understanding permafrost thaw, its degradation in a warming climate, and its impacts on ecosystems and society, managers will be able to plan for rising global temperatures, and climate change. New permafrost formation should also be considered as a possibility in some systems.
This study considered ecological succession, the pattern of vegetation regrowth, within the receded lake margin as the driver of new permafrost through alterations in ground shading and water infiltration. This hypothesis was tested by modeling variably saturated groundwater flow and heat transport under freeze-thaw conditions.
The simulations supported new permafrost development under current climatic conditions, when the net changes effects of woody vegetation are considered, thus pointing to the role of ecological succession.
"Large lake level swings due to shallow permafrost thaw and subsequent refreezing due to ecological succession may be an important natural cycle," said Briggs. "However, in the long term, model simulations projected into the future to reflect even moderate climate warming indicate new permafrost around similar lake sites will stop forming and recede within seven decades, possibly ending the current natural cycle of lake level waning and waxing."
In summary, the findings in this study highlight the importance of vegetation succession in promoting permafrost regeneration in a lake system near the Arctic Circle, which is highly sensitive to subtle soil temperature changes.
This study was conducted by team of scientists from the U.S. Geological Survey and McGill University in Montreal, Canada, and was published in the journal of Geophysical Research Letters.
Susan Garcia ( Phone: 650-346-0998 );
PASADENA, Calif. — In a new study involving researchers at the U.S. Geological Survey, scientists observed that a human-induced magnitude 5.0 earthquake near Prague, Oklahoma in November 2011 may have triggered the larger M5.7 earthquake less than a day later. This research suggests that the M5.7 quake was the largest human-caused earthquake associated with wastewater injection.
"The observation that a human-induced earthquake can trigger a cascade of earthquakes, including a larger one, has important implications for reducing the seismic risk from wastewater injection," said USGS seismologist and coauthor of the study Elizabeth Cochran.
Historically, earthquakes in the central United States have been uncommon. Yet in the year 2011 alone, numerous moderate-size earthquakes occurred in Colorado, Texas, Oklahoma, Ohio and Arkansas. Many of these earthquakes occurred near waste-water injection wells, and some have been shown to be caused by human activities.
The 2011 Oklahoma earthquake sequence included the November 6, 2011, M5.7 earthquake that ruptured a part of the Wilzetta fault system, a complex fault zone about 200 km (124 mi) in length near Prague, Oklahoma. Less than 24 hours prior to the M5.7 earthquake, a M5.0 foreshock occurred on November 5, 2011. That foreshock occurred near active waste-water disposal wells, and was linked in a previously published study to fluid injection in those wells. The earthquakes have not been directly linked to hydrofracturing.
The research published this week suggests that the foreshock, by increasing stresses where M5.7 mainshock ruptured, may have triggered the mainshock, which in turn, triggered thousands of aftershocks along the Wilzetta fault system, including a M5.0 aftershock on November 8, 2011. If this hypothesis is correct, the M5.7 earthquake would be the largest and most powerful earthquake ever associated with wastewater injection. All three earthquakes of magnitude 5.0 and greater along the Wilzetta fault exhibited strike-slip motion at three independent locations along the fault, suggesting that three separate portions of the Wilzetta fault system were activated.
The paper, "Observations of Static Coulomb Stress Triggering of the November 2011 M5.7 Oklahoma Earthquake Sequence," by D.F. Sumy, E.S. Cochran, K.M. Keranen, M. Wei, G.A. Abers, from the University of Southern California, USGS, Cornell University, Brown University, and the Lamont Doherty Earth Observatory at Columbia University, was published in the "Journal of Geophysical Research" this week.
The first-ever, geologically-based global assessment of undiscovered copper resources estimates that 3.5 billion metric tons of copper may exist worldwide. The U.S. Geological Survey outlined 225 areas for undiscovered copper in 11 regions of the world. The amount of undiscovered global copper estimated by the USGS would be enough to satisfy current world demand for more than 150 years.
According to the assessment, South America is the dominant source for both identified and undiscovered copper resources. Particularly important, several regions of Asia including China have a large potential for undiscovered copper resources.
"This ground-breaking USGS assessment of future copper resources identifies a huge potential supply that is roughly six times greater than all the copper mined throughout human history," said Interior Assistant Secretary for Water and Science, Anne Castle. "If enough of this copper can be developed in an environmentally responsible and economical way, it will be a boon to new manufacturing and other initiatives that rely on the availability of copper such as the Administration's energy efficiency initiative."
Copper is one of the first metals ever extracted and its first use in coins dates back to about 8000 B.C. It continues to be the material of choice for a variety of industrial needs.
"Copper is one of the building blocks of civilization and is used in almost every aspect of modern life such as plumbing, electrical wiring, cars, cell phones, and energy systems such as wind turbines. In fact, copper has become so valuable that it is even being stolen from construction sites and out of backyards," said Larry Meinert, USGS Mineral Resources Program Coordinator.
U.S. consumption is 2 million metric tons of copper per year whereas world consumption is about 20 million metric tons per year.
The USGS Global Copper Assessment was completed in cooperation with numerous international collaborators from national geological surveys, industry, and academia. The USGS is the principal Federal provider of research and information on nonfuel mineral resources.
Supporting studies, including documentation of the assessment methodology, descriptions of individual tracts, and spatial data for use in geographic information systems (GIS) are available from the USGS Mineral Resources Program. Information on production and consumption of copper as well as general information about copper is available from the USGS.Global copper consumption. (High resolution image)
The President's fiscal year (FY) 2015 budget request for the U.S. Geological Survey is $1.1 billion, an increase of $41.3 million above the FY 2014 enacted level. The FY 2015 Budget reflects the President's ongoing commitment to scientific discovery and innovation to support decision making in addressing critical societal needs and to support a robust economy, while protecting the health and environment of the Nation.
The Budget includes increases totaling $76.4 million to advance key research and development priorities in the sustainable stewardship of natural resources, as identified in the USGS Science Strategy and Department of the Interior and Administration initiatives. This includes robust funding for science to support the sustainable development of energy and mineral resources, water resources management; ecosystem restoration and management; wildlife and environmental health; and climate resilience.
"The USGS has a strong 135-year legacy of providing reliable and relevant scientific information to decision-makers," said Suzette Kimball, Acting USGS Director. "The President's proposed budget recognizes the USGS is uniquely positioned to support our Nation's needs through multi-disciplinary earth science research. This is key for understanding our land, its resources, and our changing climate."
Key increases in the FY 2015 Budget are summarized below. For more detailed information on the President’s 2015 budget, visit the USGS Budget, Planning, and Integration website.
Science Research, Monitoring, and Tools to Support Climate Preparedness and Resilience
The FY 2015 Budget includes $67.6 million for Climate Change Science for a Changing world, a program increase of $18.2 million above the FY 2014 enacted level. The budget provides funding to the USGS National Climate Change and Wildlife Science Center/DOI Climate Science Centers Program, the Climate Research and Development Program, and the Biologic Carbon Sequestration Project for research and the development of information and tools to help communities, States, Tribes, and the Federal government understand, plan for, and respond to the impacts of global change. Resilience in the face of a changing climate requires that the Nation prepare for an increasingly wide range in temperature and precipitation patterns, which could impact all sectors of society, infrastructure, and natural systems. Natural resource managers and infrastructure planners face complex challenges under changing conditions such as drought, wildfire, flooding, and sea level rise. The USGS provides science necessary to inform planning and resource management strategies to help mitigate and adapt to changing conditions.
Restoring, Protecting, and Sustainably Managing Ecosystems
The FY 2015 Budget request includes a total of $51.1 million for Ecosystem Priorities, an increase of $12.4 million above the FY 2014 enacted level. Increases in FY 2015 provide support for research and development to advance ecosystem restoration in key landscapes, such as the California Bay-Delta and the Chesapeake Bay ($1.5 million each), the Puget Sound ($1.1 million), the Columbia River ($850,000) and the Upper Mississippi River ($200,000). These multi-disciplinary projects are designed to serve local ecosystem management needs and develop knowledge and approaches that are transferable to similar ecosystems across the nation.
Invasive plants and animals cause significant costs to society and impacts to the health of human and natural systems, including transmitting diseases, threatening fisheries, clogging waterways, increasing fire vulnerability, and adversely effecting ranchers and farmers. Increases of $4.5 million for invasive species research focus on brown tree snakes in Guam, invasive species in the Everglades, Asian carp in the Great Lakes and Upper Mississippi, and new and emerging invasive species of national concern.
The Budget provides a number of other increases to understand and manage ecological resources in priority areas, including $500,000 for managing and restoring landscapes after wildfires and $300,000 for research on pollinators critical to ecosystem health. The Budget provides $2.8 million for the development of critical ecosystem services tools to enable agencies to manage multiple sources of information into assessment products for land and resource management. Efforts to engage the next generation are illustrated with a requested increase of $2.7 million for the USGS’ Earth Scientists for Tomorrow initiative, which will be carried out in partnership with the Cooperative Research Units.
Sustainable Development of Energy Resources
The 2015 Budget provides $40.7 million for USGS research on conventional and renewable energy. The Budget supports the responsible development of renewable and conventional energy resources, with increases of $1.3 million for geothermal energy resource assessments on Federal lands, $8.3 million for studies on hydraulic fracturing, and $500,000 on research on energy development in the Outer Continental Shelf. The Budget supports the safe and responsible production of natural gas and cleaner energy from fossil fuels, including research and development to enable safe and responsible natural gas production. A total of $18.6 million is provided for the USGS as part of a $48 million interagency R&D initiative aimed at understanding and minimizing potential environmental, health, and safety impacts of unconventional gas resource development and production through hydraulic fracturing. This research is being coordinated between the USGS, the Department of Energy, and the Environmental Protection Agency and focuses on timely, policy-relevant science to enable prudent development while protecting human health and the environment. The development of unconventional oil and gas resources through hydraulic fracturing plays an important and rapidly growing role in the domestic energy portfolio of the Nation, and the USGS has unique capability to provide critically needed science to inform decisions.
The FY 2015 Budget provides $210.4 million for the USGS Water Mission Area, $3.1million above 2014 enacted. The request includes $14.5 million for the WaterSMART program, which is an increase of $6.4 million above the 2014 enacted level. As competition for water resources grows for activities like farming and energy production, so does the need for information and tools to aid water and natural resource managers. The 2015 Budget includes an increase of $2.4 million for the groundwater-monitoring network and $2.0 million for grants to State water resource agencies to improve the availability and quality of water-use data they collect and to integrate those data with the USGS Water Census. The Budget also proposes increases of $1.2 million to fund more than 50 streamgages in the National Streamflow Information Program, $1.0 million to expand work related to water availability issues on tribal lands, $750,000 for national hydrologic modeling for groundwater sustainability, and $700,000 to develop and improve the next generation of streamflow measurement techniques.
Earth Observations and Data to Support Global and Landscape Scale Understanding
The 2015 Budget invests in Earth observation systems, data, and tools to support understanding and management of lands and resources on a global and landscape scale. This includes continued funding for the operation of the Landsat satellite program, which is celebrating the anniversary of the successful launch of Landsat 8, continuing the program’s 41 year history of imaging the Earth’s surface. In 2015, the USGS will continue to work with NASA to analyze user requirements and implement a 20-year sustained land imaging program to provide for Landsat data continuity. Funding for the land imaging program is provided in the 2015 budget for NASA, which will be responsible for development of a sustained, space-based, global land imaging capability. Increases in FY 2015 for the USGS will support improving the accessibility and usability of Landsat data and products, particularly in resource decision making.
The Budget invests in numerous landscape scale earth observation and data efforts including the Federal Geospatial Platform, which provides the Nation with access to science, information, and geospatial frameworks for use in planning, natural resource management, and a myriad of other societal uses. Reflecting the multitude of societal benefits derived from Lidar elevation data, the Budget requests a $5.2 million increase for the 3D Elevation Program (3DEP) initiative as well as increased funding for collecting data and updating elevation maps in Alaska. A $2.0 million increase will support the Big Earth Data Initiative, which is working to make scientific data collected by the Federal government easier to find and use.
The 2015 budget request proposes funding for research on the impacts of human activities that introduce chemical and pathogenic contaminants into the environment and threaten human, animal, and ecological health. Increases proposed include $3.2 million to study the environmental impacts of uranium mining on public lands in the area of the Grand Canyon and $1.5 million to support a national assessment of 800 common and emerging contaminants in stream systems.
During this year, National Atlas of the United States and The National Map will transition into a combined single source for geospatial and cartographic information. This transformation is projected to streamline access to maps, data and information from the USGS National Geospatial Program (NGP). This action will prioritize our civilian mapping role and consolidate core investments while maintaining top-quality customer service.
The USGS will continue its long history of providing topographic maps, geospatial data and other geographic information by offering a range of scales and layers of geospatial information on The National Map Viewer and through US Topo maps. As a result of the conversion to an integrated single source for geospatial and cartographic information, nationalatlas.gov will be removed from service on September 30, 2014.
"We recognize how important it is for citizens to have access to the cartographic and geographic information of our nation. We are committed to providing that access through nationalmap.gov", said Mark DeMulder, NGP Director.
"We value the National Atlas customers and stakeholders and want to make this transition as easy as possible," explained Jay Donnelly, the National Atlas Program Manager. "We will post updates to The National Map and National Atlas Websites as this transition unfolds, including information on the future availability of the products and services currently delivered by nationalatlas.gov."
Further information is available at: http://nationalatlas.gov/transitionfaq.html
Yvette Gillies ( Phone: 907-786-7039 );
Sea otter in kelp. Photograph by Benjamin Weitzman, U.S. Geological Survey. (High resolution image)
ANCHORAGE Nearly 25 years after the Exxon Valdez oil spill injured wildlife off the coast of Alaska, a new report issued today by the U.S. Geological Survey indicates that sea otters have returned to pre-spill numbers within the most heavily oiled areas of Prince William Sound.
Sea otters in the path of the oil incurred heavy mortality when 42 million liters of Prudhoe Bay crude oil were spilled in Prince William Sound in March 1989, with an estimated loss of several thousand otters. Through long-term data collection and analysis, scientists found that sea otters were slow to recover, likely because of chronic exposure to lingering oil. Other studies documented persistence of oil in the sea otters intertidal feeding habitats.
"Although recovery timelines varied widely among species, our work shows that recovery of species vulnerable to long-term effects of oil spills can take decades," said lead author of the study, Brenda Ballachey, research biologist with the U.S. Geological Survey. "For sea otters, we began to see signs of recovery in the years leading up to 2009, two decades after the spill, and the most recent results from 2011 to 2013 are consistent with recovery as defined by the Exxon Valdez Oil Spill Trustee Council."
Scientists assessed recovery by estimating the number of living sea otters based on aerial surveys and comparing that to pre-spill numbers. They also collected carcasses of otters that had died in the spill area. Carcasses were evaluated to determine how old sea otters were when they died. Historically, and prior to the spill, most dead otters were either very old or very young, but following the spill, more middle-aged otters were dying as well. The ages of dead animals has now returned to the pre-spill pattern.
Recovery also was assessed using studies to detect oil exposure using gene expression as a biochemical indicator. The most recent genetic evidence suggested a reduction in oil exposure since 2008.
Scientists concluded that the status of sea otters in western Prince William Sound is now consistent with the criteria established for population recovery set by the Exxon Valdez Oil Spill Trustee Council.
The sea otter was one of more than 20 nearshore species considered to have been injured by the spill.
The publication "2013 update on sea otter studies to assess chronic injury from the 1989 Exxon Valdez oil spill, Prince William Sound, Alaska" is available online.
EVERGLADES NATIONAL PARK, Fla. -- The estimated tens of thousands of Burmese pythons now populating the Everglades present a low risk to people in the park, according to a new assessment by U.S. Geological Survey and National Park Service scientists.
The human risk assessment looked at five incidents that involved humans and Burmese pythons over a 10-year period in Everglades National Park. All five incidents involved pythons striking at biologists who were conducting research in flooded wetlands.
"Visitor and staff safety is always our highest priority at Everglades National Park," said Superintendent Dan Kimball. "Everglades, as many other national parks, draws many thousands of visitors for the opportunity to view the wildlife that live here in a natural setting. Our guidance to visitors with respect to Burmese pythons is the same as for our native wildlife -- please maintain a safe distance and don't harass the wildlife. With respect to controlling Burmese pythons, we are working diligently with our state, federal, tribal, and local partners to manage this invasive species and educate the public on the importance of not letting invasive species loose in the wild."
Although there have been numerous bites to people provoking Burmese pythons by attempting to capture or kill the snakes, this study examined only unprovoked strikes directed at people.
"The strikes did not appear to be defensive, but were more likely were associated with aborted feeding behavior," said USGS wildlife biologist and herpetologist Bob Reed, the lead author of the study. "Pythons usually direct defensive strikes at the front of a person, not from the side or rear, as all of these strikes were. Additionally, Burmese pythons rely on being secretive and evading detection as their primary means of avoiding interactions with people, and typically don’t strike until provoked."
The biologists did not detect any of the snakes before the strikes occurred, making it even more likely that the attacks were related to feeding and not defense, Reed noted. Two of the attacks resulted in very minor injuries from the pythons’ teeth and none involved constriction.
Reed and his co-author, retired Everglades National Park scientist Skip Snow, consider the attacks as cases of mistaken identity. In four of five cases the python was small compared to the size of the person, which resulted in the snake likely aborting the attack upon realizing the large size of its prey. Aborting strikes before actual bites with the possible prey indicates that pythons may be able to assess the size of the prey mid-strike and adjust accordingly, the study said.
Although the pythons’ threat to people is low, previous studies have shown that this invasive snake species is having a negative effect on many of the native mammals in the South Florida Everglades. One study suggests the population of raccoons, opossums, and bobcats have declined significantly in the regions of Everglades National Park where pythons have been established the longest.
More than one million people visit Everglades National Park every year, often traveling along hiking and canoeing trails where Burmese pythons have been spotted or captured. Despite this close interaction, the study noted that none of the reported incidents involved a park visitor. All of the incidents were directed at biologists moving through remote and flooded areas of the park
"As people wade through shallow water, they produce ripples that move ahead of them, and these pressure waves may be detectable to a motionless snake in ambush posture," said Reed. "We speculate that detecting these changes in water pressure may alert a python that an animal is approaching, perhaps priming it to strike immediately when a potential prey item is detected."
Burmese pythons became established in Florida several decades ago as a result of the international pet trade. The largest snakes removed from the Everglades have exceeded 18 feet and 150 pounds. Snakes of this size are capable of ingesting large prey like deer and alligators.
This human risk assessment concluded that although the risk of an unprovoked attack by a Burmese python in Everglades National Park is low, it is not non-existent. Available evidence from captive snakes suggests that even those strikes that result from cases of mistaken identity or defensive behavior may still result in constriction, which can prove fatal to people when a large python or a small human is involved.
The study focused only on the risk associated with Burmese pythons, but did not address other invasive constrictor species, such as the Northern African python, which is also known as the African Rock python, which are also known to be established and breeding in South Florida outside of Everglades National Park. USGS scientists continue to work with partners to better understand the impacts on invasive reptiles in the Everglades, help reduce their spread into new areas and help prevent new species from becoming established.
"Assessing risks to humans from invasive Burmese pythons in Everglades National Park, Florida, USA" by Robert Reed and Skip Snow is published online in the Wildlife Society Bulletin.
LAFAYETTE, La. – Portions of the Mekong River Basin contain hotspots of persistent organic pollutants that pose a significant threat to the residents and wildlife of the Mekong Basin, according to a new U.S. Geological Survey study.
A research team comprised of members from the University Network for Wetland Research and Training in the Mekong Region, the International Crane Foundation and the USGS found that the total loading of persistent organic pollutants in wetland sediments of the Mekong Basin was generally low, but hotspot sites occurred where concentrations exceeded established ecological risk thresholds. Team members from the University Network are providing the results to officials within their own countries so they can determine how to address the issues.
"The overall results of this study provide crucial baseline data that will guide future development and conservation efforts in the Mekong Basin," said Scott Wilson of the USGS National Wetlands Research Center and co-author of the study. "Future work will focus on the classification and distribution of wetlands in the Mekong River Basin, an investigation into heavy metal contamination, and surface elevation monitoring in the coastal area of Southeast Asia."
Persistent organic pollutants are not readily biodegradable and are known to induce a variety of toxic effects in humans and other organisms. In humans, adverse health effects related to reproductive, developmental, behavioral, neurologic, endocrine, and immunologic processes have been linked to exposure. Since persistent organic pollutants do not degrade easily, they can persist in the environment for long periods of time. The pollutants come from agricultural pesticides, industrial pollutants, and other unintentional by-products. This study focused primarily on persistent organic pollutants used in agricultural practices.
The persistent organic pollutants accumulate in the fatty tissue of fish, amphibians, snakes and water birds that make up a large portion of the local population's diet. Animals tested in some hotspots, such as the Tonle Sap, are known to have high levels of bioaccumulation.
The international team looked at 531 samples from approximately 450 wetlands across five countries in Southeast Asia and analyzed them for 39 persistent organic pollutants -- in this case organochlorines and PCBs.
"Conducting quality science at this spatial scale requires intimate knowledge of local areas," said Wilson. "This effort could only be completed with the help of local universities, regional organizations like the International Crane Foundation, and the interdisciplinary science program of agencies like USGS."
Results showed that the use of DDT, a known persistent organic pollutant that has been banned in the study countries, has declined in the region, however, some wetland hotspots were found that contain levels of DDT above established risk thresholds and even suggest continued illegal use. The concentration and distribution of endosulfan, a chemical being phased out in the U.S. and other parts of the world, and its metabolites were also studied and represent a serious problem that requires further study and management action in the Mekong River Basin.
The USGS study, "Persistent Organic Pollutants in Wetlands of the Mekong Basin," was initiated by the U.S. Department of State and was prepared in cooperation with the University Network for Wetland Research and Training in the Mekong Region and the International Crane Foundation.
Scientists have successfully produced hybrid pups between a male western gray wolf and a female western coyote in captivity.
By artificially inseminating a female western coyote with western gray wolf sperm, U.S. Geological Survey scientists and partners from the St. Louis Zoo, University of California, Davis, and Wildlife Science Center recently demonstrated that coyotes are able to bear and nurture healthy hybrid offspring. The results contribute new information to an ongoing question about whether the eastern wolf of southeastern Canada (and formerly of the eastern U.S.) is a unique species that could be protected by the U. S. Endangered Species Act. The findings are published in the journal PLOS ONE.
"Our study adds one more piece to the ongoing controversy over whether the eastern wolf is a valid species," said David Mech, USGS scientist and the report's lead author.
During the 2012 and 2013 study, the scientists attempted to inseminate nine captive western coyotes with sperm from eight different gray wolves at the U.S. Department of Agriculture Wildlife Services National Wildlife Research Center Predator Research Facility in Logan, Utah. Three coyotes became pregnant, and one successfully birthed and nursed six live, healthy pups, currently housed at the Wildlife Science Center in Forest Lake, Minn., north of the Twin Cities.
Some geneticists have suggested recognizing the eastern wolf as a new species of wolf, and potentially adding it to the Endangered Species List. This proposal is based on mitochondrial DNA (mtDNA)—a type of DNA that can only be passed on to offspring by the mother—that has been found in wolves from Manitoba, Canada, through the Great Lakes into southeast Canada. Those wolves could have gotten their coyote-like mtDNA either from hybridization with coyotes or by hybridizing with the eastern wolf. The latter view is that of the geneticists who claim that the coyote-like mtDNA is from the eastern wolf, which is closely related to the coyote.
Scientists who propose that the coyote-like mtDNA came from female coyotes that bred with male, western wolves long ago believe that the eastern wolf is merely a smaller race of the wolf of the West.
The new USGS study shows that it is at least possible for western wolf sperm to fertilize western coyote eggs and that the mother coyote can bear and raise the hybrids.
"Our findings leave the eastern wolf debate open by adding further merit to the hybrid theory rather than disproving it," Mech said. "However, the findings are applicable to captive animals and are not necessarily true under natural conditions, so the counter-hybrid theory is not disproved either."
For more information on USGS wolf research, please visit the USGS Northern Prairie Wildlife Research Center website.
Nutrient enrichment of our nation's streams, lakes, and estuaries is widespread and can contribute to harmful algal blooms, increasing costs for drinking water and causing declines in ecosystem health.
Maps and tables describing the major sources and watershed inputs of nutrients to the Great Lakes and estuaries along the Atlantic coast, Gulf of Mexico, and the Pacific Northwest are now available online. These new maps and the data tables highlight the major sources of nutrients and the areas within a watershed that contribute the largest amounts of nutrients to 115 estuaries along the coastal areas and from 160 watersheds draining into the Great Lakes.
The data can serve further uses. For instance, water resource managers interested in a particular stream or estuary can use the online, interactive decision support tool to estimate how changes in nutrient inputs (source, type, and amount) affect nutrient loads at a downstream location.
A new reporting feature within the tool provides summary information on the amount and source of nutrients from upstream states or major hydrologic regions. For instance, output from the new tool shows the amount of nitrogen contributed from each of the 31 states that drain from the Mississippi River Basin into the Gulf of Mexico.
"This innovative combination of national maps and an online decision support tool provides unparalleled access to water-quality modeling information," said Jerad Bales, USGS acting associate director for Water. "It can be used to improve nutrient reduction strategies and inform nutrient policies across the nation."
These maps and data tables were produced using the USGS Spatially Referenced Regressions On Watershed attributes (SPARROW) nutrient models to explain spatial patterns in stream nutrient loads in relation to human nutrient inputs and natural processes and sources.
Successful management of our nation's waters requires an integrated approach that includes both monitoring and modeling to understand the affect, source type, input amounts, and performance of management activities on nutrients in local streams and ultimately in our Nation’s estuaries
Additional information on USGS nutrient monitoring and modeling activities by the National Water-Quality Assessment Program is available online.