A new online, interactive tool for estimating atrazine concentrations in streams and rivers is now available.
The online mapping tool can assist water managers, policy makers, and scientists in several ways, including:
- Understanding where and why pesticides occur in streams.
- Assessing geographic patterns in pesticide stream concentrations at many scales, ranging from the watershed to regional and national;
- Designing efficient and cost-effective monitoring programs and studies; and
- Identifying streams with the greatest likelihood to have concentrations that exceed a water-quality benchmark of potential concern.
“Assessment and management of pesticides require far more information on concentrations in streams and rivers than we can afford to directly measure for all the places and times of interest,” said Wes Stone, the USGS hydrologist who developed the model. “For these situations, statistical models can be used to estimate water-quality conditions at unmonitored locations under a range of possible circumstances.”
The estimates are based on a USGS statistical model — referred to as Watershed Regression for Pesticides (or “WARP”) — which also provides key statistics for each selected stream, including the probability that a pesticide may exceed a water-quality benchmark of potential concern, and a level of confidence and uncertainty associated with each estimate.
The release for atrazine is the first in a series of statistical models for other pesticides, each of which is based on USGS National Water-Quality Assessment (NAWQA) monitoring in streams from 1992-2011, agricultural pesticide use, and environmental characteristics, such as soil characteristics, hydrology, and climate.
Future updates will provide similar mapping and modeling for additional pesticides. Estimates and interactive mapping of pesticides for streams in the U.S. are available at this USGS website. The new website replaces an earlier version of the model for atrazine.
The U.S. Geological Survey expects to award up to $7 million in grants for earthquake hazards research in 2016.
“The USGS Earthquake Hazards Program annually provides grants to support research targeted toward improving our understanding of earthquake processes, hazards and risks,” said Bill Leith, USGS Senior Science Advisor for Earthquake and Geologic Hazards. “We seek cutting-edge proposals that will further our efforts to reduce losses from earthquakes, provide more accurate and timely earthquake information and forecasts and better inform the public about earthquake safety.”
Interested researchers can apply online at GRANTS.GOV under funding opportunity number G15AS00037. Applications are due May 19, 2015.
Every year the USGS awards earthquake research grants to universities, state geological surveys and private institutions. Past projects included:
- trench investigations to better understand the size and age of large earthquakes between Salt Lake City and Provo, Utah;
- the application of innovative techniques to map seismic hazards near the nation’s capital;
- exploring the use of rapid and precise GPS recordings to improve earthquake early warning;
- analysis of the potential for large earthquakes in the Gorgonio Pass, an area of complex faulting east of San Bernardino, California;
- investigation of recent earthquake activity along major fault lines crossing southeast Alaska; and
- studies to characterize and understand the causes of potentially induced earthquakes in California, Kansas, Wyoming, Texas, and Ohio.
A complete list of funded projects and reports can be found on the USGS Earthquake Hazards Program external research support website.
SPOKANE, Wash. — A new U.S. Geological Survey report covering major parts of the world’s largest mountain belt in central Asia estimates the existence of about five times as much copper in undiscovered deposits as has been identified to date. These areas host 20 known porphyry copper deposits, including the world class Oyu Tolgoi deposit in Mongolia that was discovered in the late 1990s.
The results of this new assessment estimate the probability that there may be as many as 97 undiscovered porphyry copper deposits within the assessed permissive tracts, which would represent nearly five times the 20 known deposits. Grade and tonnage models predict estimated resources associated with undiscovered deposits as mean values of 370,000,000 metric tons of copper, 10,000 t of gold, 7,700,000 t of molybdenum, and 120,000 t of silver. These estimated mean tonnages are predictions based on comparisons to known deposits of similar type.
Copper was one of the first metals ever extracted and used by humans, and it has been one of the important materials in the development of civilization. Because of its properties, of high ductility, malleability, and thermal and electrical conductivity, and its resistance to corrosion, copper has become a major industrial metal, ranking third after iron and aluminum in terms of quantities consumed.
USGS scientists worked in collaboration with colleagues in the China Geological Survey, the Centre for Russian and Central Eurasian Mineral Studies, and the Russian Academy of Sciences to complete the assessment. Participants evaluated applicable grade and tonnage models and estimated numbers of undiscovered deposits at different confidence levels for each permissive tract. The estimates were then combined with the selected grade and tonnage models using Monte Carlo simulations to generate probabilistic estimates of undiscovered resources. Additional resources in extensions of deposits with identified resources were not specifically evaluated.
The full report, USGS SIR 2010-5090-X, “Porphyry Copper Assessment of the Central Asian Orogenic Belt and eastern Tethysides— China, Mongolia, Russia, Pakistan, Kazakhstan, Tajikistan, and India,” is available online and includes a summary of the data used in the assessment, a brief overview of the geologic framework of the area, descriptions of permissive tracts and known deposits, maps, and tables. A geographic information system database that accompanies this report includes the tract boundaries and known porphyry copper deposits, significant prospects, and prospects. Assessments of overlapping younger rocks and adjacent areas are included in separate reports, which are also available online.
Appalachian coal and petroleum resources are still available in sufficient quantities to contribute significantly to fulfilling the nation’s energy needs, according to a recent study by the U.S. Geological Survey.
The Appalachian basin, which includes the Appalachian coalfields and the Marcellus Shale, covers parts of Alabama, Georgia, Kentucky, Maryland, New York, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia and West Virginia.
“The study we conducted is a modern, in-depth collection of reports, cross sections and maps that describe the geology of the Appalachian basin and its fossil fuel resources,” said USGS scientist Leslie Ruppert, the study’s lead editor.
Petroleum resources, including oil and natural gas, remain significant in the Appalachian basin. Although both conventional oil and gas continue to be produced in the Appalachian basin, most new wells in the region are drilled in shale reservoirs, such as the famous Marcellus and Utica Shale, to produce natural gas.
The Appalachian basin contains significant coalbed methane and high-quality, thick, bituminous coal resources although the resource is deeper and thinner than the coal that has already been mined.
Although this volume is not a quantitative assessment of all notable geologic and fossil fuel localities in the Appalachian basin, the selected study areas and topics presented in the chapters pertain to large segments of the basin and a wide range of stratigraphic intervals. This updated geologic framework is especially important given the significance of shale gas in the basin.
This volume discusses the locations of coal and petroleum accumulations, the stratigraphic and structural framework, and the geochemical characteristics of the coal beds and petroleum in the basin, as well as the results of recent USGS assessments of coal, oil and gas resources in the basin.
Many of the maps and accompanying data supporting the reports in this volume are available from chapter I.1 as downloadable geographic information system (GIS) data files about the characteristics of selected coal beds and oil and gas fields, locations of oil and gas wells, coal production, coal chemistry, total petroleum system (TPS) boundaries and bedrock geology. Log ASCII Standard (LAS) files for geophysical (gamma ray) wireline well logs are included in other chapters.
USGS is the only provider of publicly available estimates of undiscovered technically recoverable oil and gas and coal resources of onshore lands and offshore state waters. This study of the Appalachian basin will underpin energy resource assessments and may be found online. To find out more about USGS energy assessments and other energy research, please visit the USGS Energy Resources Program website, sign up for our Newsletter, and follow us on Twitter.
The U.S. Geological Survey National Geospatial Program is pleased to announce the first round of awards resulting from the USGS Broad Agency Announcement (BAA) for the 3D Elevation Program (3DEP), initially issued on July 18, 2014. (Solicitation Number: G14PS00574).
The BAA is a publicly accessible process to develop partnerships for the collection of lidar and derived elevation data for 3DEP. The primary goal of 3DEP is to systematically collect nationwide lidar coverage (ifsar in Alaska) over an 8-year period to provide more than $690 million annually in new benefits to government entities, the private sector and citizens.
3DEP presents a unique opportunity for collaboration between all levels of government to leverage the services and expertise of private sector mapping firms that acquire the data, and to create jobs now and in the future. The USGS, along with other federal, state, local and private agencies, is establishing the collection program to respond to the growing needs for high-quality, three-dimensional mapping data of the United States.
“We are very excited about the high level interest in the BAA as demonstrated by the number and dollar value of the proposals we received,” said Kevin Gallagher, USGS Associate Director for Core Science Systems.
Current and accurate 3D elevation data are essential to help communities cope with natural hazards and disasters such as floods and landslides, support infrastructure, ensure agricultural success, strengthen environmental decision-making and bolster national security. Lidar, short for light detection and ranging, is a remote sensing detection system that works on the principle of radar, but uses light from a laser. Similarly, interferometric synthetic aperture radar (ifsar) is used to collect data over Alaska.
Federal funds to support this opportunity were provided by the USGS, the Federal Emergency Management Agency and the Natural Resources Conservation Service. The USGS is acting in a management role to facilitate planning and acquisition for the broader community, through the use of government contracts and partnership agreements.
The Fiscal Year 2015 Awards offered partnership funding to 29 proposals in 25 States and Territories. The FY15 body of work is expected to result in the influx of more than 95,000 square miles of public domain lidar point cloud data and derived elevation products into the 3DEP program.
More information about 3DEP including updates on current and future 3DEP partnership opportunities is available online.Map depicts the proposed body of work for 3DEP in Fiscal Year 2015. The BAA awards will add more than 95,000 square miles of 3DEP quality lidar data to the national database. (high resolution image 98 MB)
Thousands of photos and videos of the seafloor and coastline—most areas never seen before—are now available and easily accessible online. This is critical for coastal managers to make important decisions, ranging from protecting habitats to understanding hazards and managing land use.
Imagery is available through the U.S. Geological Survey (USGS) Coastal and Marine Geology Video and Photograph Portal.
This USGS portal is unique, due to the sheer quantity and quality of data presented. It is the largest database of its kind, providing detailed and fine-scale representations of the coast. The "geospatial context" is also unique, with maps displaying imagery in the exact location where it was recorded.
Prior to development of the data portal, retrieving this imagery required internal USGS access with specific hardware and software. It was difficult to manage and challenging to share such a large amount of information.
"The USGS has been dedicated to developing a system that allows for convenient communication internally as well as to outside collaborators and the public to access our abundance of coastal and seafloor imagery," said USGS geographer Nadine Golden, who is the Lead Principal Investigator for the USGS portal. "The portal makes it easy for users to discover, obtain and disseminate information."
This portal contains coverage of the seafloor off California and Massachusetts, and aerial imagery of the coastline along the Gulf of Mexico and mid-Atlantic coasts. Additional video and photographs will be added as they are collected, and archived imagery will also be incorporated soon. Areas of future focus include data sets for Washington State’s Puget Sound, Hawaii and the Arctic.
"As part of an ongoing seafloor mapping partnership, Massachusetts has worked with the USGS Woods Hole Science Center to map more than 850 square miles of marine waters and collect extensive video footage and photographs of the seafloor," said Massachusetts Office of Coastal Zone Management Director Bruce Carlisle. "The Coastal and Marine Geology Video and Photograph Portal is a great resource, providing direct and easy access to this imagery. It will support several key elements of the recently updated Massachusetts Ocean Management Plan, including habitat characterization and the review of ocean development projects under the plan."
Information in this portal helps create coastal maps and representations of seafloor composition and habitats. It provides references for short- and long-term monitoring of changes to the coast, whether from anthropogenic modifications or natural occurrences. Hurricanes and extreme storms are of particular concern, and USGS imagery helps managers, emergency responders and researchers understand circumstances before, during and after such events. Other critical hazards include coastal flooding and sea-level rise, as well as assessments for earthquake and tsunami awareness.
Data also support coastal and marine spatial planning, including evaluation of sites for renewable ocean energy facilities as well as the development of communities and infrastructure. USGS science helps designate marine protected areas, define habitats, identify needs for ecosystem restoration, and inform regional sediment management decisions.
In total, approximately 100,000 photographs and have been collected as well as 1,000 hours of trackline video covering almost 2,000 miles of coastline. Imagery was taken by video and still cameras towed by boat or from aerial flights.
This effort supports the National Ocean Policy mandate to provide access to federal data resources.
How does it work? Start with the tutorial and then dive in!
In 2013, a successful video and photograph pilot interactive website was launched for the California Seafloor Mapping Program, and this helped build the newly released portal.
Also, check out a new crowdsourcing application called, "USGS iCoast – Did the Coast Change?" This application allows citizen scientists to identify changes to the coast by comparing aerial photographs taken before and after storms.
Learn more about USGS science by visiting the USGS Coastal and Marine Geology Program website.Screenshot from the USGS Coastal and Marine Geology Video and Photograph Portal. Zooming into an area of interest reveals lines where continuous video footage was acquired and dots where still photographs were taken. Clicking on a segment launches the video in a pop-up window. Photographs appear beside the video, changing as the video passes each point where a photograph was taken. (High resolution image)
While the earth contains enough potash to meet the increased global demand for crop production and U.S. supplies are likely secure, some regions lack potash deposits needed for optimal food crop yields. According to a recent USGS global assessment of potash resources, the costs of importing potash long distances can limit its use and imports are subject to supply disruptions.
“Global scarcity is not the issue with potash – transportation costs are,” said USGS scientist Greta Orris, who led the assessment. “We chose to assess potash because it is used primarily for fertilizer and with the increasing global population, the need for agricultural lands to be increasingly productive will continue,” said Orris.
The U.S. imports more than 80 percent of the potash it uses, mostly from the Elk Point Basin in Saskatchewan, Canada. The Elk Basin is the world’s largest source of potash, having provided at least 20 percent of the world’s potash supply for nearly 40 years.
The U.S. produces potash from deposits in Utah and New Mexico. While production from the Michigan basin recently ceased, a large potash resource exists there. Production and development of resources in Michigan have been hindered by low potash prices, dated production equipment, and poor transport infrastructure amongst other factors. A significant potash resource in Arizona has also been identified, but resources in other states tend to be relatively small.
This global assessment, which includes a summary report and accompanying database, is the most complete, up-to-date, GIS-based, global compilation of information on known and potential potash resources from evaporite sources. The database includes more than 900 known potash deposits with measured resources. It also outlines 84 tracts throughout the world where undiscovered future resources might be found.
“A significant finding of this assessment is that there appears to be little to no potential to develop potash mines in either China or India, where large populations create the need for highly productive agricultural land, which in turn requires large amounts of appropriate fertilizers,” said Orris. “High import costs have resulted in lower usage of potash fertilizers than commonly seen in the U.S., and the potential for the land to be less productive.”
Potash includes a variety of minerals, ores, or processed products that contain potassium, one of three primary plant nutrients essential for growing food crops and biofuels. Modern agriculture requires large quantities of potassium so crop production is adequate to feed a growing population as arable land acreage becomes more limited. While potassium can be derived from other sources, conventional potash deposits – those formed by evaporation -- are the only cost- effective source for large quantities of potassium needed for high-yield agriculture.
The known deposits include location, geology, resource, production and other descriptive information. Potash-bearing basins may host tens of millions to more than 100 billion metric tons of potassium. Examples include Elk Point Basin in Canada, the Pripyat Basin in Belarus, the Solikamsk Basin in western Russia, and the Zechstein Basin in Germany.
The biggest potash producers are Canada, Russia, Belarus, and Israel. In addition to China and India, other areas lacking conventional deposits include much of Africa, Australia, and South America.
For the 84 tracts, the quantities of undiscovered resources are not estimated in this report. Instead, the tracts are classified into six categories that rank their potential to provide potash resources in 25 to 50 years based on known resources in the tract, level of available information, and whether geologic or other deficiencies, such as lack of water, power, or other infrastructure, could prevent or delay development of deposits. Potash tracts that may have potash deposits in production within the next five years include those in Ethiopia and the Republic of Congo.
More information on global and domestic potash, including demand, production, and uses is available from the USGS.
After surveying and analyzing centuries of evidence in the floodplain of the lower Roanoke River, USGS researchers, along with colleagues from the universities of Wisconsin and North Carolina, have developed a highly accurate estimate of sediment deposition amounts along the course of the river over three timescales — annual, decadal, and centennial.
The investigators used a range of techniques, including evidence from clay pads, tree-rings, and pollen analyses, at numerous locations (58 transects, 378 stations) and employed GIS technology to model sediment deposition rates and characteristics to gain insight into the sediment dynamics of the Roanoke, one of the largest river flood plains on the mid-Atlantic coast.
The scientists found that sediment deposition rates from AD 1725 to 1850 were an order of magnitude higher than present deposition rates and still affect the sediment dynamics of today. These high rates have been attributed to land clearance and poor agricultural practices during and after the colonial period. This legacy sediment deposition formed high banks upstream and the large, wide levees found along the middle reaches of the river.
Furthermore, dam operations, most notably the Kerr Dam completed in 1953, have reduced deposition on natural levees but facilitated backswamp deposition. A GIS-model of current river dynamics indicates that little sediment presently reaches Albemarle Sound because it is trapped on the floodplain, generally benefitting lower floodplain ecosystems and mitigating the transport of excess nutrients to coastal marine systems.
The study findings highlight the important role played by landscape alteration, including post-Colonial forest clearance and dam emplacement, in controlling modern sediment dynamics. The use of multiple techniques to determine sediment deposition rates should improve capabilities of developing accurate sediment budgets along different reaches of the river. In turn, this will aid predictions of the response of the river and associated habitats to changing sea level.
The research was recently published in the journal Geomorphology.
Marisa Lubeck ( Phone: 303-202-4765 );
New and improved science tools can help managers and researchers evaluate current threats and develop management strategies to protect and restore the valuable Great Lakes ecosystem.
The recently released U.S. Geological Survey products provide free environmental data to the public as part of the Great Lakes Restoration Initiative (GLRI), a collaborative effort to conserve the Great Lakes. The new GLRI Science Explorer and redesigned GLRI website (most compatible with the Google Chrome browser*), launched in November 2014, offer critical information pertaining to USGS GLRI projects, and allow researchers to contribute their own material. The interactive Science in the Great Lakes (SiGL) mapper was released in December 2014 and provides information about current and past Great Lakes studies.
Researchers, managers and the public can use the GLRI Science Explorer to find information about USGS GLRI science projects, as well as publications and datasets resulting from those projects. It currently contains information about 74 projects that are completed and in progress, 66 publications and 11 datasets. Science Explorer information is stored in ScienceBase, a cataloging and content management platform developed by the USGS, which allows for contributions from USGS scientists and collaborators.
“We are eagerly seeking contributions of data or metadata to the Science Explorer,” said USGS scientist Jessica Lucido.
The interactive SiGL mapper is a centralized place where researchers and managers can identify relevant scientific activities and access fundamental information about these efforts. It was designed to help coordinate all of the scientific projects in the Great Lakes Basin. SiGL captures information about any type of scientific activity and provides details on how to access the data and results from those projects.
“SiGL can help researchers and managers strategically plan, implement and analyze their monitoring and restoration activities,” said Jennifer Bruce, a USGS scientist. “We hope to encourage coordination and collaboration among all organizations throughout the Great Lakes Basin with this tool.”
SiGL contains over 250 projects and 10,500 sites, including all the USGS GLRI projects in the Science Explorer. Over 65 organizations have contributed to SiGL, including federal, state and local governments and agencies, tribes, universities and non-profit organizations. It provides information about general project details, specific sampling efforts, publications, data availability and access and contact information.
For more information about these and other USGS GLRI tools, please visit the USGS GLRI website.
The GLRI accelerates efforts to protect and restore the Great Lakes, the largest system of fresh surface water in the world. It targets the most significant problems in the region, including invasive aquatic species, pollution and contaminated sediment.
SPOKANE, Wash. — In cooperation with the Polish Geological Institute — National Research Institute, U.S. Geological Survey scientists have published a new assessment of copper resources in Poland and Germany. This investigation is part of the U.S. Geological Survey’s Global Mineral Resource Assessment. The study synthesizes available information on known resources and estimates the location and quantity of undiscovered copper associated with the well-known late Permian (approximately 255 million years old), carbon-enriched shale, the Kupferschiefer, of the Southern Permian Basin in Europe.
The ore deposits associated with the Kupferschiefer in Germany and Poland have been mined for over 800 years and are world-famous among geologists because research on these deposits played a significant role in the scientific debates on ore genesis. The largest Kupferschiefer copper deposit occurs in the Lubin-Sieroszowice mining area, Poland. It is the largest copper deposit in Europe and one of the largest copper deposits on the Earth.
Most of the known copper resource and almost all of the estimated undiscovered copper resources occur in southwestern Poland and adjacent parts of eastern Germany. Since 1958, about 15 million metric tons of copper have been produced, and about 30 million metric tons of discovered copper remains to be developed. The USGS estimates a mean value of 110 million metric tons of copper may be undiscovered to a depth of 2.5 km below the surface in this area. Most of the undiscovered resource in southwestern Poland would be deeper than 1.5 km, where virgin rock temperatures exceed 50 degrees C (122 degrees F).
In 800 years of mining, about 2.6 million metric tons of copper were produced from Kupferschiefer deposits in east-central Germany. The areas near the deposits in east-central Germany have been well explored; less than one million metric tons of discovered copper remain in identified deposits. Mean undiscovered copper estimates for this area are about 20 million metric tons.
This USGS study supports previous findings by the Polish Geological Institute for the amount of undiscovered copper in Poland. Mean values from the USGS study are remarkably similar to the values estimated by Polish geologists. The USGS study differs from the Polish study in that two different methods are used to probabilistically estimate the amount of undiscovered copper and maps are included to show where undiscovered resources are likely to occur.
The full report, USGS Scientific Investigations Report 2010–5090–U, “Assessment of undiscovered copper resources associated with the Permian Kupferschiefer, Southern Permian Basin, Europe,” by Michael Zientek and others, is available online.
Additional USGS mineral resource assessment results and reports, including previous volumes of this publication series, and an estimate of undiscovered copper resource of the world in 2013, are online.
The U.S. Geological Survey (USGS) has released a convenient and informative new method for the analysis of groundwater and surface-water hydrologic data called the Groundwater (GW) Toolbox. The GIS-driven graphical and mapping interface is a significant advancement in USGS software for estimating base flow (the groundwater-discharge component of streamflow), surface runoff, and groundwater recharge from streamflow data.
The GW Toolbox brings together several analysis methods previously developed by the USGS and Bureau of Reclamation. Each of the methods included with the GW Toolbox use daily streamflow data automatically retrieved from the USGS National Water Information System (NWIS) for more than 26,000 streamgage sites across the United States. In addition to streamflow data, the GW Toolbox facilitates the retrieval of groundwater-level and precipitation time-series data from the NWIS database.
The GW Toolbox will be of use to engineers, academia, and government agencies at all levels for the analysis of many of the water-budget components of a typical watershed. The intensively visual interface will help shed light on water availability and hydrologic trends in response to climate and land-use changes and variability in these watersheds.
The GW Toolbox runs in a Microsoft Windows environment and includes the Base Flow Index (BFI), HYSEP, and PART hydrograph-separation methods to estimate base flow and surface runoff and the RORA and RECESS methods to estimate groundwater recharge.
Groundwater chemists and hydrologists are keenly interested in expanding the knowledge of environmental tracers that can be used to determine groundwater age. The age of groundwater is a valuable parameter that serves to inform many types of groundwater availability studies.
Many environmental tracers — such as chlorofluorocarbons (CFCs), SF6, and tritium — are of atmospheric origin. However, there are several classes of atmospheric trace gases whose application as groundwater age tracers have not been fully explored. Hydrofluorocarbons and hydrochlorofluorocarbons (HFCs and HCFCs) are among them.
USGS scientists have recently developed a high-sensitivity technique to measure two of these compounds (HCFC-22 and HFC-134a) in groundwater and the unsaturated zone.
The investigators found that, contrary to many simpler laboratory studies, these compounds can be degraded by bacteria in the environment. Consequently, both classes of compound (HFCs and HCFCs) are not likely to be useful for dating groundwater. Since they are depleted in the unsaturated zone, this reduction implies a weak environmental sink (a few percent or less) that has not been previously discussed.
The study by USGS hydrologists Haase, Busenberg, Plummer, Casile, and Sanford has been published in the journal Chemical Geology.
GAINESVILLE, Fla.—The U.S. Geological Survey Southeast Ecological Science Center has acquired a state-of-the-art genetic analysis machine that will help advance environmental DNA research efforts. The use of environmental DNA, or eDNA, could assist resource managers nationwide conserve imperiled species and improve control efforts of invasive species.
The new technology, a droplet digital PCR machine, is the first of its kind to be acquired by a USGS facility. The machine can detect a single molecule of DNA from an environmental sample and enhances output compared to traditional methods. From water samples, it is possible to detect rare species or those that are difficult to observe due to secretive behavior, camouflaged coloration, or a resemblance to other species. Species identification via the detection of eDNA can make the physical capture or sighting of the target species unnecessary.
“This new platform allows us to process samples efficiently and with greater precision. With just a few copies of genetic material from the aquatic environment, we can detect the presence of an animal that may not otherwise be seen,” commented USGS research geneticist Margaret Hunter, who leads the SESC Conservation Genetics Laboratory.
Environmental DNA comes from organisms shedding biological material into the aquatic environment via feces, mucus, saliva, or skin cells. This material can be used to determine the presence of species, establish range limits, and estimate occupancy and detection probabilities to inform management actions. The environmental DNA exists for approximately 20 days before it degrades, allowing researchers to detect animals, such as pythons, manatees, or Grass Carp, as they move throughout the environment. As compared to traditional laboratory techniques, ddPCR reduces time and laboratory costs, and uses more rigorous statistical analyses to determine the number of DNA copies in a sample. While both techniques can detect and count molecules of DNA, ddPCR has been shown to enhance accuracy and precision.
To detect individual species, genetic researchers first design a species-specific genetic marker. Then filtered surface water samples are split into 20,000 PCR droplets, each containing the marker and, if present, a copy of the target species’ DNA. The droplets illuminate fluorescently if DNA of the targeted species is detected, with the number of illuminated droplets corresponding to the number of DNA molecules in the sample. Assessing the 20,000 droplets for positive detection of the species takes approximately two minutes.
“This technology can provide resource managers invaluable assistance in detecting and defining the habitat of imperiled and invasive species,” Hunter said. “For example, using eDNA and ddPCR can help to better delineate the spread of Burmese pythons in south Florida. Or, the habitat used by imperiled or rare species, such as elusive West Indian manatees, could be defined for research and conservation efforts.”
For more information:
http://fl.biology.usgs.gov/genetics/index.html (SESC Genetics Website)
http://pubs.usgs.gov/fs/2012/3017/ (Fact Sheet: Using Genetic Research to Inform Imperiled and Invasive Species Management)