Share

First State Geology Newsletter Signup

First State Geology has been the newsletter of DGS for over 25 years.

Click here to signup!

USGS Latest News

Reservoirs Affect the Movement of Carbon in Large Rivers of the Central and Western United States

USGS Newsroom - Mon, 06/16/2014 - 12:47
Summary: A recent study conducted by scientists from the U.S. Geological Survey and published in the Journal of Geophysical Research – Biogeosciences found that a combination of climate and human activities (diversion and reservoirs) controls the movement of carbon in two large western river basins, the Colorado and the Missouri Rivers

Contact Information:

Heidi  Koontz ( Phone: 303-202-4763 );



A recent study conducted by scientists from the U.S. Geological Survey and published in the Journal of Geophysical Research – Biogeosciences found that a combination of climate and human activities (diversion and reservoirs) controls the movement of carbon in two large western river basins, the Colorado and the Missouri Rivers. 

Rivers move large amounts of carbon downstream to the oceans. Developing a better understanding of the factors that control the transport of carbon in rivers is an important component of global carbon cycling research. 

The study is a product of the USGS John Wesley Powell Center for Analysis and Synthesis and the USGS Land Carbon program. 

Different downstream patterns were found between the two river systems. The amount of carbon steadily increased down the Missouri River from headwaters to its confluence with the Mississippi River, but decreased in the lower Colorado River. The differences were attributed to less precipitation, greater evaporation, and the diversion of water for human activities on the Colorado River.

For upstream/headwater sites on both rivers, carbon fluxes varied along with seasonal precipitation and temperature changes. There was also greater variability in the amount of carbon at upstream sites, likely because of seasonal inputs of organic material to the rivers. Reservoirs disrupted the connection between the watershed and the river, causing carbon amounts downstream of dams to be less variable in time and less responsive to seasonal temperature and precipitation changes. 

The study presents estimates of changes in the amount of carbon moving down the Colorado and Missouri Rivers and provides new insights into aquatic carbon cycling in arid and semi-arid regions of the central and western U.S, where freshwater carbon cycling studies have been less common. This work is part of an ongoing effort to directly address the importance of freshwater ecosystems in the context of the broader carbon cycle. In the future, changing hydrology and warming temperatures will increase the importance of reservoirs in carbon cycling, and may lead to an increase in Greenhouse Gas Emissions that contribute to global warming, but may also increase the amount of carbon buried in sediments.  

Austin Coal-Tar Sealant Ban Leads to Decline in PAHs

USGS Newsroom - Mon, 06/16/2014 - 11:00
Summary: The 2006 prohibition on the use of coal-tar-based pavement sealants in Austin, Texas, has resulted in a substantial reduction in polycyclic aromatic hydrocarbons (PAHs), according to a new study by the U.S. Geological Survey

Contact Information:

Peter Van Metre ( Phone: 512-927-3506 ); Jennifer LaVista ( Phone: 303-202-4764 );



The 2006 prohibition on the use of coal-tar-based pavement sealants in Austin, Texas, has resulted in a substantial reduction in polycyclic aromatic hydrocarbons (PAHs), according to a new study by the U.S. Geological Survey.

Pavement sealant is a black, shiny substance sprayed or painted on the asphalt pavement of parking lots, driveways and playgrounds to increase the longevity of the underlying asphalt pavement and enhance its appearance. Pavement sealants that contain coal tar have extremely high levels of PAHs compared to asphalt-based pavement sealants and other urban PAH sources such as vehicle emissions, used motor oil and tire particles. PAHs are an environmental health concern because several are probable human carcinogens and they are toxic to fish and other aquatic life.

In 2006, Austin became the first jurisdiction in the United States to ban the use of coal-tar sealants. USGS scientists evaluated the effect of the ban on PAH concentrations in lake sediments by analyzing trends in PAHs in sediment cores and surficial bottom sediments collected in 1998, 2000, 2001, 2012 and 2014 from Lady Bird Lake, a reservoir on the Colorado River in central Austin. Average PAH concentrations in the lower part of the lake have declined 58 percent since the ban, reversing a 40-year upward trend. The full study, reported in the scientific journal Environmental Science and Technology, is available online.

“Identifying contaminant trends in water and sediment is key to evaluating the effect of environmental regulations, and provides vital information for resource managers and the public,” said lead USGS scientist Dr. Peter Van Metre.

Results of the USGS study support the conclusions of previous studies that coal-tar sealants are a major source of PAHs to Lady Bird Lake and to other lakes in commercial and residential settings. A sediment core collected by the USGS from Lady Bird Lake in 1998 was part of a study of 40 lakes from across the United States that used chemical fingerprinting to determine that coal-tar sealants were, on average, the largest contributor of PAH to the lakes studied. Chemical fingerprinting of sediment collected for the new study indicates that coal-tar-based sealant continues to be the largest source of PAHs to Lady Bird Lake sediment, implying that PAH concentrations should continue to decrease as existing coal-tar-sealant stocks are depleted.

To learn more, visit the USGS website on PAHs and sealcoat.

Human Activities Increase Salt Content in Many of the Nation's Streams

USGS Newsroom - Mon, 06/16/2014 - 09:18
Summary: Concentrations of dissolved solids, a measure of the salt content in water, are elevated in many of the Nations streams as a result of human activities, according to a new USGS study

Contact Information:

Ethan Alpern ( Phone: 703-648-4406 ); David Anning ( Phone: 928-556-7139 );



Concentrations of dissolved solids, a measure of the salt content in water, are elevated in many of the Nations streams as a result of human activities, according to a new USGS study. Excessive dissolved-solids concentrations in water can have adverse effects on the environment and on agricultural, domestic, municipal, and industrial water users.

Results from this study provide a nation-wide picture of where dissolved-solids concentrations are likely to be of concern, as well as the sources leading to such conditions.

“This study provides the most comprehensive national-scale assessment to date of dissolved solids in our streams,” said William Werkheiser, USGS Associate Director for Water. “For years we have known that activities, such as road de-icing, irrigation, and other activities in urban and agricultural lands increase the dissolved solids concentrations above natural levels caused by rock weathering, and now we have improved science-based information on the primary sources of dissolved-solids in the nation’s streams.”

The highest concentrations are found in streams in an area that extends from west Texas to North Dakota. Widespread occurrences of moderate concentrations are found in streams extending in an arc from eastern Texas to northern Minnesota to eastern Ohio. Low concentrations are found in many states along the Atlantic coast and in the Pacific Northwest.

The total amount of dissolved solids delivered to all of the Nation’s streams is about 270 million metric tons annually, of which about 71% comes from weathering of rocks and soil, 14% comes from application of road deicers, 10% comes from activities on agricultural lands, and 5% comes from activities on urban lands.

All water naturally contains dissolved solids as a result of weathering processes in rocks and soils. Some amount of dissolved solids is necessary for agricultural, domestic, and industrial water uses and for plant and animal growth, and many of the major ions are essential to life and provide vital nutritional functions. Elevated concentrations, however, can cause environmental and economic damages. For instance, estimated damages related to excess salinity in the Colorado River Basin exceed $330 million annually.

“This study applied statistical modeling to understand the sources and transport processes leading to dissolved-solids concentrations observed in field measurements at over 2,500 water-quality monitoring sites across the Nation,” said David Anning, USGS lead scientist for the study. “This new information was then used to estimate contributions from different dissolved-solids sources and the resulting concentrations in unmonitored streams, thereby providing a complete assessment of the Nation’s streams.”

The study determined that in about 13 percent of the Nation’s streams, concentrations of dissolved solids likely exceed 500 mg/L, which is the U.S. Environmental Protection Agency’s secondary, non-enforceable drinking water standard. Many of these streams are found in a north-south oriented band stretching from west Texas to North Dakota.

While this standard provides a benchmark for evaluating predicted concentrations in the context of drinking-water supplies, it should be noted that it only applies to drinking water actually served to customers by water utilities.

An online, interactive decision support system provides easy access to the national-scale model describing how streams receive and transport dissolved solids from human sources and weathering of geologic materials. The decision support system can used to evaluate combinations of reduction scenarios that target one or multiple sources and see the change in the amount of dissolved solids transported downstream waters.

The dissolved-solids model was developed by the USGS National Water-Quality Assessment Program, which provides information about water-quality conditions and how natural features and human activities affect those conditions. Information on modeling applications, data, and documentation can be accessed online.

Through the Eyes of a Polar Bear

USGS Newsroom - Fri, 06/06/2014 - 10:38
Summary: ANCHORAGE— The first "point of view" video from a polar bear on Arctic sea ice has just become available courtesy of the U.S. Geological Survey. Scientists applied video camera collars to four female polar bears on the sea ice north of Prudhoe Bay, Alaska this past April and are releasing the first clips of footage that provide unique insight into the daily lives of the bears.

Contact Information:

Anthony Pagano ( Phone: 907-538-2399 ); Paul  Laustsen ( Phone: 650-329-4046 );



ANCHORAGE— The first "point of view" video from a polar bear on Arctic sea ice has just become available courtesy of the U.S. Geological Survey. Scientists applied video camera collars to four female polar bears on the sea ice north of Prudhoe Bay, Alaska this past April and are releasing the first clips of footage that provide unique insight into the daily lives of the bears.

"We deployed two video cameras in 2013, but did not get any footage because the batteries weren’t able to handle the Arctic temperatures,” said Dr. Todd Atwood, research leader for the USGS Polar Bear Research Program. “We used different cameras this year, and we are thrilled to see that the new cameras worked."

The video collars were deployed as part of a new study to understand how polar bears are responding to sea ice loss from climate warming. The study, led by USGS research biologist and University of California Santa Cruz PhD student Anthony Pagano, is taking a close look at polar bear behaviors and energetics. 

Scientists with the USGS have been studying polar bear movement and habitat use for decades using radio and satellite telemetry, mostly used to determine a polar bear’s location. New video collars allow scientists to link the location data from the collar with the actual behavior recorded by the cameras.

Although these collars were only on for about 8-10 days, scientists can start to understand the activity patterns of polar bears, for example how often they eat, hunt, rest, walk, and swim and how these behaviors may be affected by sea ice conditions and other variables. Ultimately, this information will help scientists examine the energetic rates and nutritional demands of these animals and the potential effects of declining sea ice conditions,” said Pagano. 

This ongoing research is part of the USGS Changing Arctic Ecosystems Initiative. This research is also relevant to the U.S. Fish and Wildlife Service Polar Bear Recovery Team of which the USGS is a member. The team is drafting the Polar Bear Conservation Management Plan, which will meet requirements of both the Endangered Species Act and Marine Mammal Protection Act. The required plan, when finalized, will guide activities for polar bear conservation in response to the 2008 determination that the polar bear is a threatened species due to the ongoing loss of sea ice habitat from global climate-change.

Discover the Northwest with Revised Montana Maps

USGS Newsroom - Wed, 06/04/2014 - 09:00
Summary: Just in time to explore the great outdoors this summer, newly designed US Topo maps covering Montana are now available online for free download

Contact Information:

Mark Newell, APR ( Phone: 573-308-3850 ); Lance Clampitt ( Phone: 406-994-6919 ); Bob  Davis ( Phone: 573-308-3554 );



Just in time to explore the great outdoors this summer, newly designed US Topo maps covering Montana are now available online for free download.

US Topo maps now have a crisper, cleaner design - enhancing readability of maps for online and printed use. Map symbols are easier to read over the digital aerial photograph layer whether the imagery is turned on or off. Improvements to symbol definitions (color, line thickness, line symbols, area fills), layer order, and annotation fonts are additional features of this latest release. The maps also have transparency for some features and layers to increase visibility of multiple competing layers.

This new design was launched earlier this year and is now part of the new US Topo quadrangles for Montana (2,913 maps) replacing the first edition US Topo maps for the state. 

 “Users in Montana will appreciate improvements in the US Topo product, including the availability of  Forest Service trails, and vegetation cover (green tint), as well as updated structures data through a partnership with the State,” said Lance Clampitt, USGS Geospatial Liaison for Montana. “It is very exciting to see the cooperative work between the State of Montana, Montana State Library (MSL) and the USGS in using the best available source data to make the US Topo maps.”

The MSL is using the USGS mapping and crowd-sourcing program, known as The National Map Corps to collect and update new structures data for US Topo map revisions.  “This new product will be beneficial to the citizens of Montana as well as numerous recreational users that visit the state each year,” Clampitt continued. “The added capability to use the US Topo maps on mobile devices is also very exciting for our outdoor enthusiast.  We look forward to seeing these improvements on the 2014 release for the Treasure State.”  

US Topo maps are updated every three years. The initial round of the 48 conterminous states coverage was completed in September of 2012.  Hawaii and Puerto Rico maps have recently been added. More than 700 new US Topo maps for Alaska have been added to the USGS Map Locator & Downloader, but will take several years to complete.

Re-design enhancements and new features:

  • Crisper, cleaner design improves online and printed readability while retaining the look and feel of traditional USGS topographic maps
  • New functional road classification schema has been applied
  • A slight screening (transparency) has been applied to some features to enhance visibility of multiple competing layers
  • Updated free fonts that support diacritics
  • New PDF Legend attachment
  • Metadata formatted to support multiple browsers
  • New shaded relief layer for enhanced view of the terrain
  • Military installation boundaries, post offices and cemeteries
  • The railroad dataset is much more complete from a new contractor 

The previous versions of US Topo maps for Montana, published in 2011, can still be downloaded from USGS web sites. Also, scanned images of the entire USGS map library of topographic maps from the period 1884-2006 can be downloaded from the USGS Historical Topographic Map Collection. These scanned images of legacy paper maps are available for free download from The National Map and the USGS Map Locator & Downloader website.

US Topo maps are created from geographic datasets in The National Map, and deliver visible content such as high-resolution aerial photography, which was not available on older paper-based topographic maps. The new US Topo maps provide modern technical advantages that support wider and faster public distribution and on-screen geographic analysis tools for users. The new digital electronic topographic maps are delivered in GeoPDF ® image software format and may be viewed using Adobe Reader, available as a no cost download. 

For more information, go to: http://nationalmap.gov/ustopo/

2014 US Topo map of the Dewey, Montana area with image layer turned on (1:24,000 scale). (high resolution image 1.1 MB) Scan of 1893 USGS topographic map of the Dewey, Montana area from the USGS Historical Topographic Map Collection (1:250,000 scale). (high resolution image 1.9 MB)

Ultra-violet Light Works as Screening Tool for Bats with White-nose Syndrome.

USGS Newsroom - Thu, 05/29/2014 - 10:00
Summary: Scientists working to understand the devastating bat disease known as white-nose syndrome (WNS) now have a new, non-lethal tool to identify bats with WNS lesions —ultraviolet, or UV, light. Scientists discover a non-destructive yet effective way to screen bats in hibernation for white-nose syndrome

Contact Information:

Alex Demas ( Phone: 703-648-4421 ); Carol Meteyer ( Phone: 703-648-4057 ); David Blehert ( Phone: 608-270-2466 );



Scientists working to understand the devastating bat disease known as white-nose syndrome (WNS) now have a new, non-lethal tool to identify bats with WNS lesions —ultraviolet, or UV, light.

If long-wave UV light is directed at the wings of bats with white-nose syndrome, it produces a distinctive orange-yellow fluorescence. This orange-yellow glow corresponds directly with microscopic skin lesions that are the current “gold standard” for diagnosing white-nose syndrome in bats.

“When we first saw this fluorescence of a bat wing in a cave, we knew we were on to something,” said Greg Turner from Pennsylvania Game Commission, who has been using this technique since 2010. “It was difficult to have to euthanize bats to diagnose WNS when the disease itself was killing so many. This was a way to get a good indication of which bats were infected and take a small biopsy for testing rather than sacrifice the whole bat.”

Millions of bats in the United States have died from the fungal disease called White nose syndrome which is caused by the fungus Pseudogymnoascus (Geomyces) destructans (Pd). White-nose syndrome was first seen in New York during the winter of 2006. Since then, the disease has spread to 25 US states and 5 Canadian provinces.

A significant problem in studying WNS has been the unreliability of visual onsite inspection when checking for WNS in bats during hibernation; the only way to confirm presence of disease was to euthanize the bats and send them back to a laboratory for testing.

“Ultraviolet light was first used in 1925 to look for ringworm fungal infections in humans,” said Carol Meteyer, USGS scientist and one of the lead authors on the paper. “The fact that this technique could be transferred to bats and have such remarkable precision for indicating lesions positive for Pd invasion is very exciting.”

To test the UV light’s effectiveness, bats with and without white-nose syndrome in North America were tested by the U.S. Geological Survey’s National Wildlife Health Center, first using UV light, then using traditional histological techniques to verify the UV light’s accuracy.

In the USGS lab testing, 98.8 percent of bats with the orange-yellow fluorescence tested positive for white-nose syndrome, whereas 100 percent of those that did not fluoresce tested negative for the disease. Targeted biopsies showed that pinpoint areas of fluorescence coincided with the microscopic wing lesions that are characteristic for WNS.

Researchers in the Czech Republic then tested the UV light-assisted biopsy technique in the field, using it to collect small samples from areas of bat wing that fluoresced under UV light. In this study, 95.5 percent of wing biopsies that targeted areas of fluorescence were microscopically positive for WNS lesions, while again 100 percent of bats that did not fluoresce were negative for WNS.

Combining research from two continents demonstrates that UV diagnostics might be applicable worldwide with great sensitivity and specificity in detecting WNS.

“Moreover, the technique hurts the animal minimally and bats fly away after providing data for research,” said Natalia Martinkova from the Academy of Sciences of the Czech Republic. “This makes UV fluorescence an ideal tool for studying endangered species.”

This effort included partners in the USFWS, state and federal biologists, the Czech Science Foundation, and the National Speleological Society of the USA.

This research article, “Nonlethal Screening of Bat-wing Skin with the Use of Ultraviolet Fluorescence to Detect Lesions Indicative of White-Nose Syndrome,” was recently published in the Journal of Wildlife Diseases. More information may be found on USGS research on white-nose syndrome here.

Hurricane Sandy Impacts Did Not Contribute to Subsequent Storm Flooding

USGS Newsroom - Tue, 05/27/2014 - 11:00
Summary: Flooding in coastal areas bordering Great South Bay, N.Y. and Barnegat Bay, N.J. caused by winter storms that occurred following Hurricane Sandy was not influenced by changes Sandy made to barrier islands or other bay features, according to a new U.S. Geological Survey study Study looks at Great South Bay and Barnegat Bay

Contact Information:

Alfredo Aretxabaleta ( Phone: 508-457-2204 ); Bradford Butman ( Phone: 508-457-2212 ); Neil Ganju ( Phone: 508-457-2252 );



WOODS HOLE, Mass. —Flooding in coastal areas bordering Great South Bay, N.Y. and Barnegat Bay, N.J. caused by winter storms that occurred following Hurricane Sandy was not influenced by changes Sandy made to barrier islands or other bay features, according to a new U.S. Geological Survey study.

The study of Barnegat Bay and Great South Bay looked at data from November 2012 to October 2013, when winter storms brought water levels in these bays to among the 20 highest storm water levels reached from October 2007- October 2013.

“The frequent and extreme high-water levels caused by storms in these two bays in the months after Hurricane Sandy led to perceptions the mainland was more vulnerable to flooding,” said USGS oceanographer and coauthor of the study Neil Ganju. “This study shows that changes to bay features caused by Hurricane Sandy did not influence these post Sandy storm water levels.”

Hurricane Sandy caused extreme floods along portions of the northeast coast of the U.S. and cut new inlets across barrier islands in New Jersey and New York. Scientists investigated whether Hurricane Sandy had in some way reduced the protection provided by the barrier islands and the bays, leaving the mainland more vulnerable to flooding.

The study compared water level measurements made at stations within Great South Bay and Barnegat Bay to ocean water levels before and after Hurricane Sandy. Both are back barrier bays -- bodies of water behind barrier islands and connected to the ocean through one or more inlets.

“Changes in water levels in the back-barrier bays are primarily caused by ocean water levels driving water into or out of the bays through inlets,” said USGS oceanographer and lead author of the study Alfredo Aretxabaleta.  “The study showed that most of the ocean water level fluctuations caused by storms make their way into the bays, while only a fraction of tidal fluctuations do.”

The results showed that alterations to the barrier, inlet, and bay systems caused by Hurricane Sandy did not influence the high water levels caused by storms from November 2012 to October 2013. None of these post-Sandy storms opened new inlets or caused overtopping of the protective dunes and barrier beach systems. Both before and after Sandy, about 80 percent of storm surge—a temporary rise in water level caused by an offshore storm’s winds or low pressure—made its way into the back barrier bays, whereas only about 20 percent of the tidal fluctuations do. This suggests that whether the same storm occurred before or after Hurricane Sandy, the water level in the bays would be the same.   

“While the existing barrier island and inlet system shields the mainland to a great extent from the daily tides, most of the storm surge, and all long-term changes in water level, such as those resulting from sea level rise, reach the mainland” said USGS oceanographer and coauthor Bradford Butman. “These results will inform coastal communities and planners how water levels in back-barrier bays respond to ocean fluctuations.”

Several studies related to Hurricane Sandy recovery, restoration and rebuilding efforts, many of which are funded by Disaster Relief Appropriations Act 2013, are currently underway.

“The USGS is committed to providing the science foundation for federal, state, and local authorities to build more resilient communities,” said John Haines, coordinator of the USGS’ Coastal and Marine Geology Program. “This is one of many studies the USGS is doing to understand the effects of Hurricane Sandy and to evaluate the vulnerability of the coast and its communities to future storms.”

The study, “Water-level response in back-barrier bays unchanged following Hurricane Sandy,” by Aretxabaleta, A.L., Butman, B., and Ganju, N.K., is in the Geophysical Research Letters journal and available online.

Climate Change Accelerates Hybridization between Native and Invasive Species of Trout

USGS Newsroom - Sun, 05/25/2014 - 12:00
Summary: Scientists have discovered that the rapid spread of hybridization between a native species and an invasive species of trout in the wild is strongly linked to changes in climate

Contact Information:

Suzanna Soileau ( Phone: 406-994-7257 ); Clint Muhlfeld ( Phone: 406-600-9686 );



BOZEMAN, Mont. – Scientists have discovered that the rapid spread of hybridization between a native species and an invasive species of trout in the wild is strongly linked to changes in climate.

In the study, stream temperature warming over the past several decades and decreases in spring flow over the same time period contributed to the spread of hybridization between native westslope cutthroat trout and introduced rainbow trout – the world’s most widely introduced invasive fish species –across the Flathead River system in Montana and British Columbia, Canada.

Experts have long predicted that climate change could decrease worldwide biodiversity through cross-breeding between invasive and native species, but this study is the first to directly and scientifically support this assumption. The study, published today in Nature Climate Change, was based on 30 years of research by scientists with the U.S. Geological Survey, University of Montana, and Montana Fish, Wildlife & Parks.

Hybridization has contributed to the decline and extinction of many native fishes worldwide, including all subspecies of cutthroat trout in western North America, which have enormous ecological and socioeconomic value.  The researchers used long-term genetic monitoring data coupled with high-resolution climate and stream temperature predictions to assess whether climate warming enhances interactions between native and nonnative species through hybridization.

“Climatic changes are threatening highly prized native trout as introduced rainbow trout continue to expand their range and hybridize with native populations through climate-induced ‘windows of opportunity,’ putting many populations and species at greater risk than previously thought,” said  project leader and USGS scientist Clint Muhlfeld. “The study illustrates that protecting genetic integrity and diversity of native species will be incredibly challenging when species are threatened with climate-induced invasive hybridization.”

Westslope cutthroat trout and rainbow trout both spawn in the spring and can produce fertile offspring when they interbreed. Over time, a mating population of native and non-native fish will result in only hybrid individuals with substantially reduced fitness because their genomes have been infiltrated by nonnative genes that are maladapted to the local environment. Thus, protecting and maintaining the genetic integrity of native species is important for a species’ ability to be resilient and better adapt to a rapidly changing climate.  

Historical genetic samples revealed that hybridization between the two fish species was largely confined to one downstream Flathead River population. However, the study noted, over the past 30 years, hybridization rapidly spread upstream, irreversibly reducing the genetic integrity of native westslope cutthroat trout populations. Genetically pure populations of westslope cutthroat trout are known to occupy less than 10 percent of their historical range.

The rapid increase in hybridization was highly associated with climatic changes in the region. From 1978 to 2008 the rate of warming nearly tripled in the Flathead basin, resulting in earlier spring runoff, lower spring flooding and flows, and warming summer stream temperatures. Those locations with the greatest changes in stream flow and temperature experienced the greatest increases in hybridization. 

Relative to cutthroat trout, rainbow trout prefer these climate-induced changes, and tolerate greater environmental disturbance. These conditions have likely enhanced rainbow trout spawning and population numbers, leading to massive expansion of hybridization with westslope cutthroat trout.

“The evolutionary consequences of climate change are one of our greatest areas of uncertainty because empirical data addressing this issue are extraordinarily rare; this study is a tremendous step forward in our understanding of how climate change can influence evolutionary process and ultimately species biodiversity,” said Ryan Kovach, a University of Montana study co-author.

Overall, aquatic ecosystems in western North America are predicted to experience increasingly earlier snowmelt in the spring, reduced late spring and summer flows, warmer and drier summers, and increased water temperatures – all of which spell increased hybridization between these species.

The article, published in Nature Climate Change, is titled “Invasive hybridization in a threatened species is accelerated by climate change” and can be viewed at the following website.  Its authors are Clint Muhlfeld, U.S. Geological Survey; Ryan Kovach, University of Montana; Leslie Jones, U.S. Geological Survey; Robert Al-Chokhachy, U.S. Geological Survey; Matthew Boyer, Montana Fish, Wildlife and Parks; Robb Leary, Montana Fish, Wildlife and Parks; Winsor Lowe, University of Montana; Gordon Luikart, University of Montana; and Fred Allendorf, University of Montana.

This study was supported by the Great Northern Landscape Conservation Cooperative, the Interior Department’s Northwest Climate Science Center, the National Climate Change and Wildlife Science Center, National Science Foundation, and Bonneville Power Administration.   

More information about impacts and prevention of invasive species and hybridization can be found on the USGS Northern Rocky Mountain Science Center website

Genetic Analysis Reveals Fish Eggs Found in Upper Mississippi River are not Asian Carp

USGS Newsroom - Thu, 05/22/2014 - 14:00
Summary: Scientists have extracted DNA from fish eggs found in northern sections of the Upper Mississippi River and have determined that the eggs and larvae are not from Asian carp

Contact Information:

Dave Ozman ( Phone: 303-202-4744 ); Catherine Puckett ( Phone: 352-377-2469 );



Scientists have extracted DNA from fish eggs found in northern sections of the Upper Mississippi River and have determined that the eggs and larvae are not from Asian carp.  Genetic analysis instead shows that the fish eggs collected in the summer of 2013 likely belong to a native North American species in the same family as carp.  All Asian carp species are considered invasive species and belong to the cyprinid fish family.  

To confirm visual identification of the eggs’ species, scientists from the U.S. Geological Survey genetically tested 41 of the 65 eggs and larvae that were collected from the Upper Mississippi River (Pool 9 and Pool 11) in Wisconsin and Iowa.  DNA sequences successfully obtained from 17 eggs revealed that they were similar to those of other cyprinid fishes and did not come from Asian carp.  The one exception was an egg collected from Pool 19 in southern Iowa, which had been visually identified as an Asian carp, and was later genetically confirmed by the USGS as a grass carp, one of the four Asian carp species.  

“What we have learned from this research is that non-Asian carp cyprinid eggs in the northern portions of the Upper Mississippi can closely resemble Asian carp eggs in size and shape,”  said Leon Carl, USGS Midwest Region Director.  “These findings underscore the importance of using genetic testing to confirm the results of visual identification.” 

Researchers were surprised to learn that the large eggs from Pools 9 and 11 belonged to other species in the cyprinid family rather than to Asian carp species.  Such findings are contrary to previously published work that had established that non-Asian carp cyprinids indigenous to the Midwest have considerably smaller eggs compared to the invasive carp that were the focus of the study. 

Detailed visual analysis of the eggs’ size and shape earlier this year indicated that they were consistent with the eggs of Asian carp species and led scientists to believe that invasive carp may have successfully spawned in this northern portion of the Upper Mississippi.  Given the seriousness of the Asian carp spread northward, USGS scientists alerted partners and the general public about that potential in March and decided to pursue genetic testing to confirm the visual findings.

Scientists emphasized that the recent genetic data will modify their application of visual identification methods to distinguish fish eggs and larvae collected in the Upper Mississippi River. The difficulty USGS scientists had in genetically testing the eggs suggests that researchers and managers studying or monitoring Asian carp reproduction in North America should consider separately preserving, for genetic analysis, a subset of collected embryos to confirm visual identification. 

USGS researchers will continue efforts to gain a better understanding of how egg size, location of eggs within the river and flow conditions may help to identify those habitats important to reproduction of native and non-native cyprinids including Asian carp.  Understanding habitat requirements will assist in the development of methods to control invasive Asian carp.