Meadow vole rests in its habitat. (High resolution image)
ANCHORAGE, Alaska — A new scientific study predicts that some of Alaska’s mammal species will respond to future climate warming by concentrating in northern areas such as the Arctic National Wildlife Refuge and the National Petroleum Reserve of Alaska. If true, for many species, this would be a significant northward shift into tundra habitats where they are currently absent.
“Small mammal species such as shrews and voles, and larger species like wolverine and marmots have been in Alaska for many thousands of years and have responded to past climate cycles just as they are responding to the current warming trend,” said Dr. Andrew Hope, lead author of the study and former researcher with the U.S. Geological Survey.
“Since these mammals experienced past climate cycles, we were able to interpret signatures of population level responses to those climate events recorded in their DNA, and then also use that information to predict likely shifts in animal distributions throughout Alaska into the future,” said Hope.
Researchers that participated in the study with Hope examined at total of 28 mammal species including those from both northern tundra and relatively more southern boreal forest habitats. The scientists determined the northern movement by looking at current geographic distribution of the animals, coupled with their historical range, and then interpreted from genetic signatures of response to past climate changes to predict where they will likely be found in 2050 and 2080.
Hope worked on the project with researchers from the USGS, the U.S. Fish and Wildlife Service’s Arctic National Wildlife Refuge, the City College of New York, the University of Nevada-Reno, and the University of New Mexico. The study leveraged genetic data collected over the past several decades in multiple laboratories.
“This approach allowed us to examine the consistency among predicted changes to mammal distributions and determine if there are differences in management implications across regions," said David Payer, chair of the Arctic Landscape Conservation Cooperative and a co-author of the study.
This study highlights the value of analyzing many species associated with discrete ecological communities that each share different evolutionary histories.
Hope conducted the research as a post-doctoral fellow at the USGS.
The study was published in the Ecological Society of America’s journal Ecosphere.
Visit the USGS Alaska Science Center for more information.Map shows land management status, ecoregions, and predictions for changes in small mammal biodiversity through time based on all 28 species. Lands highlighted in the map include the Arctic Network of National Parks administered by the National Park Service (NPS; square), Arctic National Wildlife Refuge (administered by the USFWS; circle) and National Petroleum Reserve – Alaska (NPR-A; administered by the BLM; triangle). Biodiversity predictions were based on Last Interglacial (LIG), Last Glacial Maximum (LGM), current (Now), 2050s, and 2070s climate projections. The color gradient reflects areas of low (blue) to high (red) species richness. . (High resolution image)
Marisa Lubeck ( Phone: 303-526-6694 );
Many grassland bird species in the Bakken shale region, including some seriously declining populations, are displaced from their habitats as a result of oil and gas development, according to new U.S. Geological Survey research.
During 2012-2014, USGS and U.S. Fish and Wildlife Service scientists studied Bakken grassland sites in northern North Dakota containing oil well pads, which are the gravel surfaces that house all oil extraction infrastructures. Overall, grassland birds avoided areas within 150 meters, or about 492 feet of gravel roads, 267 meters (about 876 feet) of single-bore well pads and 150 meters of pads with more than one well. These results suggest that detrimental effects of oil extraction on habitat extend considerably beyond the immediate oil well sites.
"Quantifying environmental degradation caused by oil development is a critical step in understanding how to better mitigate harm to valuable wildlife populations," said USGS scientist Sarah Thompson, the lead author of the report. "Our findings can help managers and developers determine the best locations for future infrastructure."
The study focused on sites developed with unconventional methods, such as horizontal drilling and hydraulic fracturing, or fracking. The most commonly detected species were the grasshopper sparrow, Savannah sparrow, clay-colored sparrow, bobolink, chestnut-collared longspur, western meadowlark, brown-headed cowbird, Baird's sparrow, Sprague's pipit and red-winged blackbird.
Specific findings include:
- Individual species showed varying tolerance for oil wells.
- Reduced population densities of the Baird’s sparrow, chestnut-collared longspur and grasshopper sparrow were observed as far as 550 meters from single-bore wells, which were the farthest distances surveyed.
- Clay-colored sparrows and brown-headed cowbirds were tolerant of oil-related infrastructure.
- Sprague’s pipit, which is a candidate species for listing under the Endangered Species Act, showed reduced density within 350 meters of single-bore wells.
"Our findings suggest that reducing new road construction, concentrating wells along developed corridors, combining numerous wells on multi-bore pads and placing wells near existing roads could help minimize loss of suitable habitat for birds," Thompson said.
The Bakken oil-producing regions of North Dakota, Montana and Canada are home to a particularly high density and diversity of grassland bird species that are declining across North America. For more information on USGS ecosystem research in the Bakken, please visit the USGS Northern Prairie Wildlife Research Center website.
Arlene Compher ( Phone: 703-648-4282 );
To honor groundbreaking earthquake research by U.S. Geological Survey seismologist Dr. Lucile “Lucy” Jones, U.S. Secretary of the Interior Sally Jewell will present Jones with the prestigious Samuel J. Heyman Service to America Medal (Sammies) at an awards ceremony this evening at the Andrew W. Mellon Auditorium.
USGS Estimates 21 Million Barrels of Oil and 27 Billion Cubic Feet of Gas in the Monterey Formation of the San Joaquin Basin, California
The Monterey Formation in the deepest parts of California’s San Joaquin Basin contains an estimated mean volumes of 21 million barrels of oil, 27 billion cubic feet of gas, and 1 million barrels of natural gas liquids, according to the first USGS assessment of continuous (unconventional), technically recoverable resources in the Monterey Formation.
“Understanding our domestic oil and gas resource potential is important for many reasons, including helping policy makers to make informed decisions about energy policy, leasing of federal lands, and impact on other resources such as water,” said Vito Nuccio, Acting USGS Energy Resources Program Coordinator. “That’s why the USGS maintains a strong oil and gas assessment team whose goal is to assess new domestic and global areas and continually update previous assessments as warranted.”
The volume estimated in the new study is small, compared to previous USGS estimates of conventionally trapped recoverable oil in the Monterey Formation in the San Joaquin Basin. Those earlier estimates were for oil that could come either from producing more Monterey oil from existing fields, or from discovering new conventional resources in the Monterey Formation.
The area of the potential continuous accumulation assessed in this study is limited to where the Monterey Formation is deeply buried, thermally mature, and thought to be generating oil.
The assessment team concluded that most of the petroleum that has originated from shale of the Monterey Formation in the assessment area has migrated from the source rock, so there is probably relatively little recoverable oil or gas remaining there, and most exploratory wells in the deep basin are unlikely to be successful.
Geological data from more than 80 older wells that penetrated the deep Monterey Formation indicate that retention of oil or gas in the Monterey Formation shale source rock is poor, probably because of natural fracturing, faulting, and folding.
The oil and gas readily migrates from the deep Monterey Formation to fill the many shallower conventional reservoirs in the basin, including some in fractured Monterey Formation shale, and accounts for the prolific production there.
Although the data suggest that there is apparently not a large volume of unconventional oil and gas resources in the Monterey in the deep part of the basin, there are still substantial volumes of additional conventional oil and gas resources oil in the Monterey Formation in the shallower conventional traps in the San Joaquin Basin, as indicated by earlier assessments.
In 2003, USGS conducted an assessment of conventional oil and gas in the San Joaquin Basin, estimating a mean of 121 million barrels of oil recoverable from the Monterey. In addition, in 2012, USGS assessed the potential volume of oil that could be added to reserves in the San Joaquin Basin from increasing recovery in existing fields. The results of that study suggested that a mean of about 3 billion barrels of oil might eventually be added to reserves from Monterey reservoirs in conventional traps, mostly from a type of rock in the Monterey called diatomite, which has recently been producing over 20 million barrels of oil per year.
The estimate of undiscovered continuous oil in the deep Monterey ranges from 3 million to 53 million barrels (95 percent to 5 percent probability, respectively). The estimate of natural gas ranges from 5 to 72 billion cubic feet (95 percent to 5 percent probability, respectively), and the estimate of natural gas liquids ranges from 0 to 3 million barrels (95 percent to 5 percent probability, respectively).
These new estimates are for technically recoverable oil and gas resources, which are those quantities of oil and gas producible using currently available technology and industry practices, regardless of economic or accessibility considerations.
USGS is the only provider of publicly available estimates of undiscovered technically recoverable oil and gas resources of onshore lands and offshore state waters. The USGS Monterey Formation assessment was undertaken as part of a nationwide project assessing domestic petroleum basins using standardized methodology and protocol.
The new assessment of the Monterey Formation in the San Joaquin Basin 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.A map showing the extent of the San Joaquin Basin, as well as the location of the two assessment units of the Monterey Formation that were included. (High resolution image)
USGS coastal scientists visit Nags Head in the Outer Banks to examine coastal erosion impacts that occurred from Hurricane Isabel in 2003. (High resolution image)
As the path of Hurricane Joaquin continues to move farther offshore, making landfall in the U.S. less likely, U.S. Geological Survey coastal change experts say there’s still a high probability of dune erosion along parts of the Atlantic coast, from the North Carolina Outer Banks to Cape Cod.
“The storm’s winds are generating ocean swells capable of causing coastal erosion along the Outer banks, Virginia, and Maryland, as well as areas of the New England, most likely to see the effects,” said Nathaniel Plant, a USGS research oceanographer. “Isolated locations along the New Jersey and New York coast, areas that were hit hard by Hurricane Sandy, could also experience dune erosion.”
As the hurricane’s track has shifted farther offshore, overwash due to wave runup overtopping the dunes is not currently expected to occur, except at isolated locations where dunes are relatively low.
The USGS coastal-change forecasts, which integrate information produced by both the USGS and National Oceanic and Atmospheric Administration and its National Hurricane Center, will continue to be updated daily and results will be posted to the Coastal Change Hazards Portal. The portal provides a wealth of information for coastal residents, emergency managers and community leaders. To access current forecasts, click on the Portal’s ‘Active Storm’ tab located on the upper right corner of the portal’s web page.
“We are collaborating with NOAA to explain what weather and storm conditions mean for coastal communities. Combining weather data with coastal process information enables us to make detailed predictions of the runup of waves along the coast” said Plant. “We are also developing a time series forecast of predicted high water levels, which we can use to forecast the timing and likelihood that storm waves will erode beaches, damage dunes, overtop the dunes and inundate the land with seawater or open breaches in barrier islands. The expected storm impacts from Joaquin are particularly interesting because high water levels are primarily due to Joaquin’s waves rather than storm surge.”
The researchers indicate that Joaquin is a perfect storm to test the accuracy of the coastal erosion forecasts. Within the USGS, water scientists who are collecting wave and storm surge data from sensors developed using supplemental funding following Hurricane Sandy, along with scientists from the coastal-change hazards team, will be working together to evaluate and improve the accuracy of future coastal-change forecasts.
The forecasts and updated information collected from Joaquin will better position the USGS to support emergency managers, coastal planners and community leaders, who can combine the information found on the portal with other data to identify where hazards pose the greatest risks to their communities, thereby allowing them to develop specific plans of action before a storm’s impacts threaten homes, schools, businesses and critical habitats.Screenshot of portal entry page. (high resolution image) Forecast probability of overwash is reduced. (high resolution image) Forecast probability of dune erosion is still high in many areas from Outer Banks to Cape Cod. (high resolution image)
USGS scientist Carlos Rodriguez, deploying a sensor at Newmarket Creek at Mercury Boulevard in Hampton, VA. Credit: USGS(High resolution image)
USGS field crews will be out deploying storm tide sensors along the Virginia coast near Virginia Beach, along the Western Chesapeake Bay, and on the Eastern Shore ahead of Hurricane Joaquin. Storm tide sensors measure the tidal fluctuations and height of the tide relative to land surface.
Currently, Hurricane Joaquin’s track remains uncertain, and the National Hurricane Center is providing updates on potential future movement.
USGS is deploying storm tide sensors along the Virginia coast in an effort to measure storm-tides, which are expected to be above normal even if Hurricane Joaquin does not make landfall. The information these sensors collect is important to future models of coastal impacts from storms.
These sensors are part of a relatively new USGS mobile network of rapidly deployable, experimental instruments that are used to observe and document hurricane-induced storm-surge, waves and tides as they make landfall and interact with coastal features.
This network, known as USGS SWATH, consists of water-level and barometric-pressure monitoring devices that are deployed in the days and hours just prior to a potential widespread storm-surge event, and then retrieved shortly after event occurrence. The network also includes a smaller number of Rapid Deployment Gauges, which are temporary water-stage sensors with autonomous data-transmission capacity. RDGs are set up in advance of an event to provide short-term water-level and meteorological data during the event for areas that are particularly vulnerable to the effects of storm surge.
The SWATH Network was supported by Congressional funding provided to the Department of the Interior post superstorm Sandy (2012).
WHO: USGS field crews
WHAT: Reporters are invited to join USGS field crews deploying tidal sensors in advance of Hurricane Joaquin.
WHEN: Friday, October 2, 2015
WHERE: Virginia Beach, along the Western Chesapeake Bay, and on the Eastern Shore
Photograph showing the impact of a large wave at the south shore of Laysan Island, with endangered Laysan teal in the foreground. (High resolution image)
SANTA CRUZ, Calif. — A new study shows that the combined effect of storm-induced wave-driven flooding and sea level rise on island atolls may be more severe and happen sooner than previous estimates of inundation predicted by passive “bathtub” modeling for low-lying atoll islands, and especially at higher sea levels forecasted for the future due to climate change. More than half a million people live on atolls throughout the Pacific and Indian Oceans, and although the modeling was based on the Northwestern Hawaiian Islands, the results from the study apply to almost all atolls.
U.S. Geological Survey scientists and their colleagues at the Deltares Institute in the Netherlands, and the Hawaii Cooperative Studies Unit at University of Hawaii, Hilo report that numerical modeling reveals waves will synergistically interact with sea level rise, causing twice as much land forecast to be flooded for a given future sea level than currently predicted by models that do not take wave-driven water levels into account.
Observations show global sea level is rising due to climate change, with the highest rates in the tropical Pacific Ocean where many of the world’s low-lying atolls are located. Sea level rise is particularly critical for low-lying coral reef-lined atoll islands; these islands have limited land and water available for human habitation, limited food sources and ecosystems that are vulnerable to inundation from sea level rise. Sea level rise will result in larger waves and higher wave-driven water levels along atoll islands’ shorelines than at present.
“Many atoll islands will be flooded annually, contaminating the limited freshwater resources with saltwater, and likely forcing inhabitants to abandon their islands in decades, not centuries, as previously thought,” said USGS geologist and lead author of the study, Curt Storlazzi.
The study explored the combined effect of storm-induced wave-driven flooding and sea level rise on atoll islands within the Northwestern Hawaiian Islands, including Laysan and Midway Islands, which are home to many threatened and endangered endemic species. The same modeling approach is applicable to most populated atolls around the world.
The study, “Many Atolls May Be Uninhabitable Within Decades Due to Climate Change,” was recently published in Nature’s Scientific Reports journal, and is available online.
Water quality can be substantially diminished for several years after wildfire in response to relatively common local thunderstorms, according to a recent USGS study.
USGS scientists led by research hydrologist Sheila Murphy collected extensive streamflow and water-quality data for three years after the Fourmile Canyon Fire, Colo., in a geographic setting typical of the American southwest. They then correlated the results with data from a high-density rain gage network.
“Unfortunately, wildfires have become a common occurrence in the western United States,” said William Werkheiser, USGS Associate Director for Water. “We need to better understand the drivers of post-wildfire water quality and find ways to adjust to this challenge.”
About half of the water supply in the southwestern U.S. is supplied by water conveyed from forests, which generally yield higher quality water than any other land use. However, forests are vulnerable to wildfire; more than 12 million acres of land, including important forested water-supply watersheds, have burned in the southwestern U.S. in the past 30 years. Wildfires increase susceptibility of watersheds to both flooding and erosion, and thus can impair water supplies.
The USGS investigators found that hydrologic and water-quality responses downstream of the burned area were primarily driven by small, brief convective storms that had relatively high, but not unusual, rainfall intensity. Suspended sediment, dissolved organic carbon, nitrate, and manganese concentrations were 10-156 times higher downstream of the burned area compared to upstream, and reached concentrations that could impair the ability of water-treatment plants to effectively treat water for human consumption.
Results from this study quantitatively demonstrate that water quality can be altered for several years after wildfire, even in a watershed that was only 23% burned. Because wildfire frequency and size, and possibly storm frequency and intensity, are projected to increase in the southwestern U.S. in the future, post-wildfire water-quality impacts may become more common, compounding water supply and quality problems related to projected decreases in runoff and continued population growth.
Recently published in the journal Environmental Research Letters, the study suggests potential adaptation strategies to avoid the introduction of problematic constituents into water-treatment facilities or reservoirs after wildfire.
Populations of bats diminished by white-nose syndrome (WNS), a disease of hibernating bats, are unlikely to return to healthy levels in the near future, according to new U.S. Geological Survey research.
USGS and U.S. Fish and Wildlife Service scientists recently evaluated the potential for populations of little brown bats in the eastern United States that survive WNS outbreaks to repopulate. The scientists estimated that between 2016 and 2018, little brown bat populations that once contained millions of bats could decrease to lower than 100,000 animals. Also, some populations may not begin to increase again until around 2023. Populations east of the 100th meridian, the designation between the drier western and wetter eastern states, would likely consist of sparse remnant communities, some of which may be less than 1.5 percent of their original sizes.
This scarcity of surviving bats can negatively affect reproduction rates and make survivors more vulnerable to threats.
“With so few surviving animals, little brown bats could cease to be a dominant bat species in the eastern United States,” said USGS scientist Robin Russell, the lead author of the report. “These small bat population sizes are problematic because they are more likely to be wiped out by events such as poor weather conditions and landscape development.”
Animals in small communities could also have trouble finding mates. Female bats gathering in maternity roosts during the summer can include several hundred bats, and the inability to form these colonies due to reduced populations may negatively impact overall reproduction rates.
Bats pollinate plants, spread seeds and save us billions of dollars in pest control each year by eating harmful insects. WNS, caused by the Pseudogymnoascus destructans fungus, can cause up to 100 percent mortality in some little brown bat populations. It has already killed millions of hibernating bats in North America and continues to spread.
As part of a coordinated response to WNS, scientists from around the world are working to further understand the disease and conserve bat species affected by it. The USGS and USFWS are among numerous state, federal, tribal, private and university partners engaged in WNS research and response. Members of this community are pursuing multiple approaches to manage the disease, with treatment strategies to both reduce impacts of the disease and to improve the potential for bat populations to survive and eventually recover. This new study emphasizes the importance of continuing research on bat species affected by WNS to finding a solution for managing the disease.
For more information about USGS WNS research, please visit the USGS National Wildlife Health Center website.
A hepatitis B-like virus has been found for the first time in fish. A team of USGS researchers found the virus in white sucker from the Great Lakes Region using gene-sequencing technologies.
How the recently discovered hepatitis B-like virus is transmitted between fish is not yet understood, and it is unlikely to be communicable to humans.
“To date, a hepatitis B virus has never been found before in fish and we now have evidence that it infects fish in geographically distant river systems in the Great Lakes region,” said lead author Cassidy Hahn, a USGS scientist and graduate student at the University of West Virginia. “This new virus is similar, but also very different from hepatitis B-like viruses found in mammals and birds, and may be a new genus.”
The hepatitis B virus is a small, spherical, enveloped virus, previously known only in two groups--one that infects humans and other mammals including orangutan, gibbons, gorillas and chimpanzee; and the other that infects birds.
The white sucker is considered an indicator species, which is native to river systems in the Midwestern and Northeastern United States. Their widespread distribution and life-history have made them a target species in numerous contaminant monitoring and effects studies. White sucker are bottom feeders, spending most of their lives in close proximity to the bottom of rivers, because of this they are in contact with contaminants associated with the river bottom.
The DNA of an organism is like a recipe book for making all of the proteins necessary for life. Those instructions are coded as genes and are conveyed to protein making factories in the cell via messenger ribonucleic acid molecules. In order to develop tools to evaluate how these fish were utilizing their DNA (responding to their environment), the RNA from liver tissue was sequenced using contemporary high throughput RNA-sequencing methods. This approach allows for decoding the usage of this blueprint.
In general, hepatitis-B viruses have a narrow host range and infection manifests in various ways. In mammals, these viruses infect and multiply in liver cells and are typically associated with acute and chronic liver diseases including fibrosis, cirrhosis, bile duct cancer, and hepatocellular carcinoma. It is estimated that 350 million people are chronically infected with HBV. Hepatitis B viruses in birds are not normally associated with these liver diseases. The potential effects on fish are currently unknown.
According to the research team, the hepatitis “B-like” virus found in the fish is about as similar to the human hepatitis B virus as it is to the bird hepatitis B viruses.
“This new virus may improve our understanding of the evolutionary history of hepatitis B-like viruses,” said USGS biologist Luke Iwanowicz, study coauthor. “There have been considerable scientific efforts focused on identifying the origins of hepatitis B -like viruses. The genome of this new virus has features not present in any known virus from this family. It is a very exciting discovery.”
According to the researchers, the study may offer the opportunity to develop a new model system to investigate host – pathogen interactions and benefit human medical research.
Part of a joint U.S. Fish and Wildlife/USGS Great Lakes Initiative Project, the study, Characterization of a Novel Hepadnavirus in the White Sucker (Catostomus commersonii) from the Great Lakes Region of the USA, by Cassidy M. Hahn, Luke R. Iwanowicz, Robert S. Cornman, Carla M. Conway, James R. Winton, and Vicki S. Blazer is available in the Journal of Virology online.
Additional contact: Tracey Cooper, Waikato, +64-7-858-5014, email@example.comSevere bluff erosion, along the southern end of Ocean Beach, San Francisco, California, including damage to the guard rail of the Great Highway (Calif. Hwy.1). The severe winter erosion led to lane closures of the highway and an emergency, $5 million revetment along the base of this bluff. This storm damage occurred during the 2009-2010 El Niño, which, on average, eroded the shoreline 55 meters that winter. (High resolution image) Severe coastal bluff erosion, along the southern end of Ocean Beach, San Francisco, California. This storm damage occurred during the 2009-2010 El Niño, which, on average, eroded the shoreline 55 meters that winter. (High resolution image)
SANTA CRUZ, Calif. — The projected upsurge of severe El Niño and La Niña events will cause an increase in storm events leading to extreme coastal flooding and erosion in populated regions across the Pacific Ocean, according to a multi-agency study published today in Nature Geoscience.
“This study significantly advances the scientific knowledge of the impacts of El Niño and La Niña,” said Patrick Barnard, USGS coastal geologist and the lead author of the study. “Understanding the effects of severe storms fueled by El Niño or La Niña helps coastal managers prepare communities for the expected erosion and flooding associated with this climate cycle.”
The impact of these storms is not presently included in most studies on future coastal vulnerability, which look primarily at sea level rise. New research data, from 48 beaches across three continents and five countries bordering the Pacific Ocean, suggest the predicted increase will exacerbate coastal erosion irrespective of sea level rise affecting the region.
Researchers from 13 different institutions, including the U.S. Geological Survey, University of Sydney, the University of New South Wales and the University of Waikato (New Zealand) analyzed coastal data from across the Pacific Ocean basin from 1979 to 2012. The scientists sought to determine if patterns in coastal change could be connected to major climate cycles. Data came from beaches in the mainland United States and Canada, Japan, Australia, New Zealand and Hawaii.
Although previous studies have analyzed coastal impacts at local and regional levels, this is the first to pull together data from across the Pacific to determine basin-wide patterns. The research group determined all Pacific Ocean regions investigated were affected during either an El Niño or La Niña year. When the west coast of the U.S. mainland and Canada, Hawaii, and northern Japan felt the coastal impacts of El Niño, characterized by bigger waves, different wave direction, higher water levels and/or erosion, the opposite region in the Southern Hemisphere of New Zealand and Australia experienced “suppression,” such as smaller waves and less erosion. The pattern then generally flips: during La Niña, the Southern Hemisphere experienced more severe conditions.
The study also investigated the coastal response of other climate cycles, such as the Southern Annular Mode, which has impacts at the same time in both hemispheres of the Pacific. The data revealed that when the Southern Annular Mode trended towards Antarctica, culminating in more powerful storms in the Southern Ocean, wave energy and coastal erosion in New Zealand and Australia increased, as did the wave energy along the west coast of North America. Other modes of climate variability, such as the Pacific North American pattern, which relates to atmospheric circulation in the North Pacific, are linked to coastal impacts that are more tightly restricted to the northern hemisphere.
Linking coastal erosion to natural climate patterns, such as El Niño/Southern Oscillation and the Southern Annular Mode, can be challenging.
“Shoreline behavior can be controlled by so many different factors, both locally and regionally, that it’s been difficult to isolate the signal until now. However, utilizing the many years of data we were able pull together in this study enabled us to definitively identify how the major climate drivers affect coastal hazards across the Pacific,” said Patrick Barnard. “This will greatly enhance our ability to predict the broader impacts of climate change at the coast.”
A co-author of the paper, Professor Andrew Short from the University of Sydney, says forecast increases in the strength of El Niño and La Niña weather events driven by global climate change means coastal erosion on many Australian beaches could be worse than currently predicted based on sea level rise alone.
“Coastlines of the Pacific are particularly dynamic as they are exposed to storm waves generated often thousands of miles away. This research is of particular importance as it can help Pacific coastal communities prepare for the effects of changing storm regimes driven by climate oscillations like El Niño and La Niña. To help us complete the puzzle, for the next step we would like to look at regions of the Pacific like South America and the Pacific Islands where very limited shoreline data currently exists,” said Mitchell Harley of UNSW Australia, and a coauthor of the paper.
“It's not just El Niño we should be concerned about," said Ian Walker, professor of Geography at the University of Victoria and coauthor of the study. “Our research shows that severe coastal erosion and flooding can occur along the British Columbia coast during both El Niño and La Niña storm seasons unlike further south in California. We need to prepare not only for this winter, but also what could follow when La Niña comes.”
The published paper, “Coastal vulnerability across the Pacific dominated by El Niño/Southern Oscillation” is available online.
This southern sea otter is settling down to rest in a small patch of Egregia (feather boa kelp). (High resolution image)
SANTA CRUZ, Calif. — The recovery of southern sea otters appears to have taken an upturn, according to results from the annual California sea otter survey released by the U.S. Geological Survey today. Yet despite an overall increase in sea otter abundance, sharks have been “taking a bite” out of the portion of the population that could fuel expansion into new areas.
“There’s much more to the story here than the main finding would suggest,” said Dr. Tim Tinker, a research ecologist who leads the USGS sea otter research program, “We are looking into various factors that may be affecting the survey results, including a boom in urchin abundance from Big Sur to Monterey that may explain the uptick in numbers in the range center, and high levels of shark bite mortality that are likely responsible for continued declines at the north and south ends of the range.”
This year’s survey results suggest an increasing trend over the last five years of almost 2 percent per year and the population index, a statistical representation of the entire population calculated as the three-year running average of census counts, has climbed to 3,054 from 2,711 in 2010. The growth is accounted for by an unexpected jump in numbers in the center of the sea otter’s range, an area that spans from Monterey south to Cambria.
“It appears that the high pup counts from the last few years might be translating into higher numbers of juveniles and adults in the center of the range,” said Brian Hatfield, the USGS biologist who coordinates the annual census. “This makes sense if there are significantly more sea urchin prey available to them in those areas. However, our long-term census data suggests the elevated numbers of otters seen during this survey along the Monterey-Big Sur coast may not persist.”
While the population index continues to trend upward, the northern and southern subsets of the population continue a negative five-year decline, dropping 2 percent and 3.4 percent per year, respectively, numbers consistent with increased shark bite induced mortality in these same areas. The increase in white shark bites became evident after 2005 and now appears to be impacting the growth and expansion of the population at the peripheries of the range, as described in a recent publication.
Since the 1980s, USGS scientists have computed the annual population index and evaluated trends in the southern sea otter, “Enhydra lutris nereis,” a federally listed threatened species found in California. For southern sea otters to be considered for removal from threatened species listing under the Endangered Species Act, the population index would have to exceed 3,090 for three consecutive years, according to the threshold established under the Southern Sea Otter Recovery Plan by the U.S. Fish and Wildlife Service. To reach its optimum sustainable population level under the Marine Mammal Protection Act, the number of animals that will result in the maximum productivity of the population, keeping in mind the carrying capacity of the habitat and the health of the ecosystem, the southern sea otter population would have to reach a much higher bar, probably at least 8,400 animals in California according to the Recovery Plan.
“On the surface it appears that the population is climbing towards recovery,” said Lilian Carswell, Southern Sea Otter Recovery Coordinator for USFWS, “but it’s clear the underlying trends in different regions must be taken into consideration. Full recovery of the population will ultimately require range expansion to the north and south.”
Statewide Trends and Local Questions
In addition to conducting the annual survey, USGS scientists also annually update a database of sea otter strandings which tallies the number of dead, sick or injured sea otters recovered along California’s coast each year. In 2014, scientists from California Department of Fish and Wildlife, known as CDFW, USGS, Monterey Bay Aquarium and other institutions recovered or documented a total of 386 stranded sea otters.
This stranding number only accounts for sea otters that people find, and past research indicates that possibly less than 50 percent of sea otters that die in the wild end up on the beach. But efforts are made to examine each reported sea otter carcass, and a subset of fresh carcasses are sent to the CDFW Marine Wildlife Veterinary Care and Research Center, where scientists conduct necropsies to determine the primary causes of death and identify factors that may have contributed to the death of each animal.
Data from both living and deceased sea otters continues to shed light on sea otter population ecology in different parts of the California coast. For example, a high proportion of sea otter carcasses recovered between Cayucos and Pismo Beach in recent years have white shark- bite wounds, a potential explanation for the downward trend in sea otter numbers in that area.
“Before the early 2000s we did not see very many shark bitten otters south of Monterey,” says Mike Harris, a biologist with CDFW, “but in the last few years, shark bite cases have become very common and now explain about 70 percent of the total strandings in this area.”
The sea otter survey and stranding programs are just one part of a larger research program investigating sea otters and their role as predators in coastal ecosystems. In Elkhorn Slough, a recent study suggests that sea otters’ appetite for crabs can improve the health of seagrass beds, and USGS scientists are collaborating with biologists from the Monterey Bay Aquarium, the Elkhorn Slough National Estuarine Research Reserve, University of California Santa Cruz and CDFW to study the population in this unique habitat. And a new study near Monterey by UCSC and USGS, in collaboration with Monterey Bay Aquarium, will investigate how sea otters are responding to a glut of sea urchins that may be in part a result of the loss of sea star predators from wasting disease.
– The annual population index is calculated from visual surveys conducted via telescope observations from shore and via low-flying aircraft along the California coastline by researchers, students and volunteers from USGS, CDFW’s Office of Spill Prevention and Response, Monterey Bay Aquarium, UC Santa Cruz, USFWS, and U.S. Bureau of Ocean Energy Management.
– This year, the surveyed coastline spanned from Pillar Point in San Mateo County, south to Rincon Point near the Santa Barbara/Ventura County line, and also included San Nicolas Island.
Sea Otter Facts
– Sea otters were presumed extinct in California after the fur trade years, but were rediscovered in the 1930s by the public, when as few as 50 animals were documented persisting in nearshore areas off the coast of Big Sur.
– Sea otters are considered a keystone species of rocky sub-tidal ecosystems because they prey on herbivorous invertebrates that, if left unchecked, can decimate kelp beds and the fish habitat they provide.
– Scientists also study sea otters as an indicator of nearshore ecosystem health, since sea otters feed and live near the coast and often are the first predators exposed to pollutants and pathogens washed down from coastlands, such as the microbial toxin microcystin.
– The public can report sightings of stranded sea otters to institutions listed on this webpage.
The report “Spring 2015 California Sea Otter Census Results” is available online.
Reporters: Do you want to accompany USGS crews as they measure flooding? Please contact Jennifer LaVista or Heidi Koontz. Photos of the crews are available online.
U.S. Geological Survey real-time monitoring captured flash flooding in southwest Utah that occurred as a result of intense thunderstorms with rainfall rates estimated as high as three inches per hour. Particularly hard hit was the town of Hildale, Utah and Zion National Park. The flash flood has resulted in 16 deaths.
Two USGS field crews are making streamflow measurements at gages in the area and are determining how high and how fast the water moved during the flash flood event.
“Events like this are not uncommon in southwestern Utah,” said Cory Angeroth, hydrologist with the USGS. “Our crews are providing real-time streamflow information to emergency managers and National Weather Service (NWS) flood forecasters so that they can make informed flood management decisions as thunderstorms continue to move through the area.”
USGS scientists collect critical streamflow data that are vital for protection of life, property and the environment. These data are used by the NWS to develop flood forecasts; the Bureau of Reclamation and the U.S. Army Corps of Engineers to manage flood control; and local and state emergency management in their flood response activities. More information is available on the USGS Utah Water Science Center website.
There are 154 USGS-operated streamgages in Utah that measure water levels, streamflow and rainfall. Current streamflow conditions are available online.
More detailed information on flooding in Utah is available on the WaterWatch flood page.
For more than 125 years, the USGS has monitored flow in selected streams and rivers across the U.S. The information is routinely used for water supply and management, monitoring floods and droughts, bridge and road design, determination of flood risk and for many recreational activities.
Access current flood and high flow conditions across the country by visiting the USGS WaterWatch website. Receive instant, customized updates about water conditions in your area via text message or email by signing up for USGS WaterAlert.
A new interactive mapping tool provides predicted concentrations for 108 pesticides in streams and rivers across the Nation and identifies which streams are most likely to exceed water-quality guidelines for human health or aquatic life.
Citizens and water managers can create maps showing where pesticides are likely to occur in local streams and rivers and evaluate the likelihood of concentrations exceeding water-quality guidelines. The predictions can also be used to design cost-effective monitoring programs.
“Because pesticide monitoring is very expensive, we cannot afford to directly measure pesticides in all streams and rivers,” said William Werkeiser, USGS Associate Director for Water. “This model can be used to estimate pesticide levels at unmonitored locations to provide a national assessment of pesticide occurrence.”
“The USGS pesticide model is a valuable tool that we can use, along with other modeling and analytical tools, to evaluate data as we complete ecological risk assessments for pesticides,” said Dr. Donald J. Brady, Director, Environmental Fate and Effects Division, Office of Pesticide Programs, U.S. Environmental Protection Agency.
“Streams and rivers most vulnerable to pesticides can be assessed,” said Wes Stone, USGS hydrologist and lead developer of the model. “For instance, many streams in the Corn Belt region are predicted to have a greater than 50 percent probability that one or more pesticides exceed aquatic-life benchmarks.
The online mapping tool is based on a USGS statistical model — referred to as Watershed Regression for Pesticides (or “WARP”) — which provides key statistics for thousands of streams, including the probability that a pesticide may exceed a water-quality benchmark and the reliability of each prediction.
The WARP model estimates concentrations using information on the physical and chemical properties of pesticides, agricultural pesticide use, soil characteristics, hydrology, and climate.
The model used by the mapping tool is based on data from USGS monitoring of pesticides in streams across the Nation since 1992 as part of the National Water-Quality Assessment (NAWQA) Program. Since 1991, NAWQA has been a primary source of nationally consistent data and information on the quality of the Nation’s streams and groundwater. Objective and nationally consistent water-quality data and models provide answers to where, when, and why the Nation’s water quality is degraded and what can be done to improve it for human and ecosystem needs.
Interactive mapping of predicted pesticide levels for streams in the U.S. are available online.
National maps and trend graphs of agricultural use of 459 pesticides from 1992 to 2012 for the conterminous U.S. are also available online.
Modeled national perspective of the prevalence of the insecticide chlorpyrifos, 2012 data
Chlorpyrifos is an insecticide used commonly on cotton, corn, citrus, and almond crops. For 2012, streams in the Midwest, central Texas, southwest Florida, and the Central Valley in California were predicted to have chlorpyrifos levels with a greater likelihood of exceeding the acute fish aquatic life benchmark. Use the online mapper to view the spatial variability of over 100 pesticides. (High resolution image)
Several of the 1,028 new US Topo quadrangles for Florida now display parts of the Florida National Scenic Trail (FNST) and other designated public trails. For Gulf Coast residents, recreationalists and visitors who want to explore the featured Florida trails by biking, hiking, horseback or other means, the new trail features on the US Topo maps will be useful.
The FNST is a congressionally-designated, long-distance hiking trail that weaves its way across more than 1,000 miles of Florida from Big Cypress National Preserve in the south to Gulf Islands National Seashore in the western end of Florida’s panhandle. The Trail is a national treasure, being one of only 11 National Scenic Trails in the country, and one of three contained entirely within a single state.
“As administrators of the Florida National Scenic Trail, we work with a variety of partners to ensure that the trail is managed, and interpreted, consistently across changing landscapes and management boundaries,” said Shawn Thomas, Florida National Scenic Trail Program Manager. “Illustrating the FNST on the widely accessible US Topo maps will not only further this management purpose, but allow more recreationists and potential resource stewards to learn about the Florida National Scenic Trail and enjoy the natural, scenic, cultural, and historical resources the Trail corridor has to offer.”
The USGS partnered with the U.S. Forest Service to incorporate the trail data onto the revised Florida US Topo maps. The Florida National Scenic Trail, joins the Appalachian National Scenic Trail, Arizona National Scenic Trail, Continental Divide National Scenic Trail, Ice Age National Scenic Trail, Natchez Trace National Scenic Trail, New England National Scenic Trail, North Country National Scenic Trail, Pacific Crest National Scenic Trail, and the Pacific Northwest National Scenic Trail, as being featured on the new US Topo quads. The USGS plans to eventually include all National Scenic Trails in The National Map products.
The U.S. Forest Service has provided boundary and road data for the US Topo map series for the past five years, and is now working on a national dataset of recreational trails.
Some of the other data for new trails on the maps is provided to the USGS through a nationwide “crowdsourcing” project managed by the International Mountain Biking Association (IMBA). This unique crowdsourcing venture has increased the amount and diversity of trail data available through The National Map mobile and web apps, and the revised US Topo maps.
During the past two years the IMBA, in a partnership with the MTB Project, has been building a detailed national database of trails. This activity allows local IMBA chapters, IMBA members, and the public to provide trail data and descriptions through their website. MTB Project and IMBA then verify the quality of the trail data provided, ensure accuracy and confirm the trail is officially designated for public use.
Further significant additions to the new quadrangles include map symbol redesign, enhanced railroad information and new road source data.
The new 2015 US Topo map coverage over Florida replaces the first edition US Topo maps for the Sunshine State and are available for free download from The National Map, the USGS Map Locator & Downloader website , and several other USGS applications.
To compare change over time, scans of legacy USGS topo maps, some dating back to the late 1800s, can be downloaded from the USGS Historical Topographic Map Collection.
For more information on US Topo maps: http://nationalmap.gov/ustopo/.Updated 2015 version of the Spring Creek US Topo quadrangle with orthoimage turned on. (1:24,000 scale) (Larger image) Updated 2015 version of the Spring Creek US Topo quadrangle with orthoimage turned off to better show trails. (1:24,000 scale) (Larger image) Scan of the 1940 legacy topographic map quadrangle of the Spring Creek area (Arran quad, 1:62,500 scale) from the USGS Historic Topographic Map Collection. (Larger image) The Florida National Scenic Trail is currently more than 1,000 miles long, with 1,300 total miles planned. The U.S. Forest Service has divided the Trail into four main geographic regions: the Southern region, the Central region, the Northern region, and the Panhandle region. (Larger image)
A series of 100 photos may reduce the risk of Native Americans and Alaska Natives being exposed to or consuming water or food containing harmful cyanobacteria.
The colorful images are part of a new field and laboratory guide developed by the U.S. Geological Survey to help Native American and Alaska Native communities develop an awareness of what harmful algal blooms look like in the field and be able to distinguish them from non-toxic blooms.
Harmful algal blooms that are dominated by certain cyanobacteria are known to produce a variety of toxins that can negatively affect fish, wildlife and people. Exposure to these toxins can cause a range of effects from simple skin rashes to liver and nerve damage and even death, although rarely in people.
The issue may be increasing in importance, as scientists indicate warming global temperatures may exacerbate the growth of harmful algal blooms.
“We are likely to see more cyanobacterial blooms in the future as waters continue to warm,” said Barry Rosen, a USGS biologist and author of the guide. “Cyanobacteria proliferate in warm water temperatures, generally about 25 degrees Celsius (77 F), and are more tolerant of these warmer conditions than their competitors, such as green algae. We expect numerous other physiological adaptations will give cyanobacteria an advantage as global climate changes occur.”
While there are communities worldwide that may find the field and laboratory guide of use, those with people in direct contact with surface water or who consume fish and shellfish may find it particularly helpful.
“In the U.S., Native American and Alaska Native communities, especially those reliant on subsistence fishing or who have frequent contact with surface water, have an increased risk of exposure to cyanotoxins,” said Monique Fordham, the USGS National Tribal Liaison. “This guide will give them a new resource to use to monitor the waters they rely on and protect their people.”
Algae serve as the base of the food web in aquatic habitats. When algae cause a “problem,” typically a surface scum or accumulation on or near a shoreline, it is given the name “algae bloom” and many times is called a harmful algae bloom. An algae bloom forms under the correct environmental conditions, including nutrient abundance, stability of the water column, ample light, and optimal temperatures.
Although many different types of algae are responsible for harmful algae blooms, cyanobacteria, which produce natural cyanotoxins, pose the greatest problem and are the focus of this guide. The guide includes photos of what cyanobacteria blooms look like in a waterbody as well as photos of cyanobacteria taken through the microscope, which is needed to determine the type of bloom that is present.
The publication, “Field and Laboratory Guide to Freshwater Cyanobacteria Harmful Algal Blooms for Native American and Alaska Native Communities,” by Barry H. Rosen and Ann St. Amand, is available online.
Rosen, B.H., and St. Amand, Ann, Field and laboratory guide to freshwater cyanobacteria harmful algal blooms for Native American and Alaska Native Communities: U.S. Geological Survey Open-File Report 2015–1164.
Slowing fire-related population declines in greater sage-grouse in the Great Basin over the next 30 years may depend on the intensity of fire suppression efforts in core breeding areas and long-term patterns of precipitation, according to a just-published USGS-led study.
The authors conducted an extensive analysis of wildfire and climatic effects on greater sage-grouse population growth derived from 30 years (1984-2013) of breeding area-count data, along with wildfire and precipitation patterns. They constructed a model that also simulated different post-fire recovery times for sagebrush habitats based on soil attributes -- soil moisture and temperature maps -- that strongly influence resilience to wildfire and resistance to invasive grass species.
This research links multi-decadal patterns of wildfire across the Great Basin with multi-decadal data on greater sage-grouse population dynamics and climate.
If the current trend in wildfire continues unabated, model results predicted steady and substantial declines of greater sage-grouse populations across the Great Basin, with an average of about half of current population numbers being lost by the mid-2040s.
The researchers also found that greater sage-grouse populations increased following periods of above-average precipitation; however the long-lasting effects of wildfire in greater sage-grouse breeding areas negated the positive effects associated with precipitation.
Forecasted climate change may result in less precipitation and warmer, drier soils in sagebrush ecosystems, leaving greater sage-grouse habitat vulnerable to increasingly frequent wildfires. Fire is a natural process in sagebrush ecosystems, but burn size and frequency in the Great Basin have increased over the past few decades in response to the increasing expansion of invasive grasses, primarily cheatgrass.
Wildfires kill nearly all native species of sagebrush, which can transform the habitat into landscapes dominated by invasive grasses when soils are warm and dry. In turn, the presence of invasive grasses can prevent sagebrush from returning and, by serving as tinder, result in a positive feedback loop that promotes more wildfires in future years.
“Greater sage-grouse population persistence may be compromised as sagebrush ecosystems and sage-grouse habitat become more impacted by fire and a changing climate,” said Peter Coates, a research scientist with the USGS Western Ecological Research Center. “Our research shows that targeted fire suppression in core sage-grouse areas is vital to help conserve large blocks of the best habitat for sage-grouse in the Great Basin,”
Scientists also examined different management scenarios that could help offset adverse wildfire effects on greater sage-grouse populations, especially when focused on areas with the best sage-grouse habitat and the greatest number of breeding sage-grouse.
For example, reducing the trend in annual cumulative burned area near leks sites within 3.1 miles (5 km) by 25 percent in identified greater sage-grouse core areas is predicted to do little to prevent population declines over the next 30 years, but reducing it by 75 percent in the same period would substantially slow the decline even under below-average precipitation conditions, stabilize it under normal conditions and result in population growth under above-average conditions.
Coates noted that further long-term research can help identify populations that are most at risk from wildfire or changing climate and lead to more effective targeting of management resources for conservation of sagebrush and greater sage-grouse populations.
This peer-reviewed research, Long-term effects of wildfire on sage-grouse populations: an integration of population and ecosystem ecology for management in the Great Basin, was authored by Peter Coates, USGS; M.A. Ricca, USGS; B.G. Prochazka, USGS; , K.E. Doherty, USFWS; M.L. Brooks, USGS; and M.L. Casazza, USGS.
About Greater Sage-Grouse and the Great Basin
The Great Basin comprises more than 72.7 million hectares (more than 179 million acres) across five states: Nevada, Utah, Idaho, Oregon and California. Wildfire has been identified as a primary disturbance in the Great Basin.
Greater sage-grouse occur in parts of 11 U.S. states and 2 Canadian provinces in western North America. The U.S. Fish and Wildlife Service is formally reviewing the status of greater sage-grouse to determine if the species is warranted for listing under the Endangered Species Act.
MENLO PARK, Calif. — Some of the inner workings of Earth’s subduction zones and their “megathrust” faults are revealed in a paper published today in the journal “Science.” U.S. Geological Survey scientist Jeanne Hardebeck calculated the frictional strength of subduction zone faults worldwide, and the stresses they are under. Stresses in subduction zones are found to be low, although the smaller amount of stress can still lead to a great earthquake.
Subduction zone megathrust faults produce most of the world’s largest earthquakes. The stresses are the forces acting on the subduction zone fault system, and are the forces that drive the earthquakes. Understanding these forces will allow scientists to better model the physical processes of subduction zones, and the results of these physical models may give us more insight into earthquake hazards.
“Even a ‘weak’ fault, meaning a fault with low frictional strength, can accumulate enough stress to produce a large earthquake. It may even be easier for a weak fault to produce a large earthquake, because once an earthquake starts, there aren't as many strongly stuck patches of the fault that could stop the rupture,” explained lead author and USGS geophysicist Hardebeck.
Although the physical properties of these faults are difficult to observe and measure directly, their frictional strength can be estimated indirectly by calculating the directions and relative magnitudes of the stresses that act on them. The frictional strength of a fault determines how much stress it can take before it slips, creating an earthquake.
Evaluating the orientations of thousands of smaller earthquakes surrounding the megathrust fault, Hardebeck calculated the orientation of stress, and from that inferred that all of the faults comprising the subduction zone system have similar strength. Together with prior evidence showing that some subduction zone faults are “weak”, this implies that all of the faults are “weak”, and that subduction zones are “low-stress” environments.
A “strong” fault has the frictional strength equivalent to an artificial fault cut in a rock sample in the laboratory. However, the stress released in earthquakes is only about one tenth of the stress that a “strong” fault should be able to withstand. A “weak” fault, in contrast, has only the strength to hold about one earthquake's worth of stress. A large earthquake on a “weak” fault releases most of the stress, and before the next large earthquake the stress is reloaded due to motion of the Earth’s tectonic plates.
Mark Newell, APR ( Phone: 573-308-3850 );
A new, official height for Denali has been measured at 20,310 feet, just 10 feet less than the previous elevation of 20,320 feet which was established using 1950’s era technology.
With this slightly lower elevation, has the tallest mountain in North America shrunk? No, but advances in technology to better measure the elevation at the surface of the Earth have resulted in a more accurate summit height of Alaska’s natural treasure.
“No place draws more public attention to its exact elevation than the highest peak of a continent. Knowing the height of Denali is precisely 20,310 feet has important value to earth scientists, geographers, airplane pilots, mountaineers and the general public. It is inspiring to think we can measure this magnificent peak with such accuracy," said Suzette Kimball, USGS acting director. "This is a feeling everyone can share, whether you happen to be an armchair explorer or an experienced mountain climber.”
Denali National Park where the mountain is located, was established in 1917 and annually sees more than 500,000 visitors to the six million acres that now make up the park and preserve. About 1,200 mountaineers attempt to summit the mountain each year; typically about half are successful.
"Park rangers have been excited to work with and learn from their USGS colleagues using the latest technology to determine Denali's height,” said Denali NP Superintendent Don Striker. “Climbers and other visitors will be fascinated by this process, and I hope our future park rangers see from this firsthand example how a background in science, technology, engineering and mathematics, and staying physically active in the outdoors can enable them to do some of America's coolest jobs.”
To establish a more accurate summit height, the USGS partnered with NOAA’s National Geodetic Survey (NGS), Dewberry, CompassData, (a subcontractor to Dewberry) and the University of Alaska, Fairbanks, to conduct a precise Global Positioning System (GPS) measurement of a specific point at the mountain’s peak.
A previous 2013 Denali survey was called into question with an elevation measurement of 20,237 feet. That survey was done by an airborne radar measurement collected using an Interferometric Synthetic Aperture Radar (ifsar) sensor. Ifsar is an extremely effective tool for collecting map data in challenging areas such as Alaska, but it does not provide precise spot or point elevations, especially in very steep terrain.
The climbing team of GPS experts and mountaineers reached the Denali summit in mid-June. Since then, they have been processing, analyzing, and evaluating the raw data to arrive at the final number of 20, 310 feet. Unique circumstances and variables such as the depth of the snowpack and establishing the appropriate surface that coincides with mean sea level had to be taken into account before the new apex elevation could be determined.
A USGS feature story has more details about the trek, data collection and calculation methods.A view of Denali from the airplane as the Survey team approached the Kahiltna Glacier to begin their ascent to the mountain’s summit. Photo : Blaine Horner, CompassData) (Larger image) Two of the Survey climbers continue their trek up towards the next base camp, with gear in tow. Much of the climbing was done at night or early morning to take advantage of the frozen ground. (Photo: Blaine Horner, CompassData) (Larger image) Blaine Horner of CompassData probing the snow pack at the highest point in North America along with setting up Global Position System equipment for precise summit elevation data. (Photo: Blaine Horner, CompassData) (Larger image)
A malformed (’teratological’) chitinozoan specimen of the genus Ancyrochitina (a) and a morphologically normal specimen (b) of the same genus. Both of these Silurian microfossils are from the A1-61 well in Libya and are about 415 Ma old. Scale bars are 0.1 mm. (High resolution image)
Toxic metals such as iron, lead and arsenic may have helped cause mass extinctions in the world’s oceans millions of years ago, according to recent research from the U.S. Geological Survey, the National Center for Scientific Research, France; and Ghent University, Belgium. These findings largely came from studying “teratological” or malformed fossil plankton assemblages corresponding to the initial stages of extinction events approximately 420 million years ago that killed off most marine species
At that time, several mass extinction events shaped the evolution of life on our planet. Some of these short-lived events were responsible for eradication of up to 85 percent of marine species, however the exact kill-mechanism responsible for these crises remains poorly understood.
In a paper just published in Nature Communications, the scientists present evidence that malformed fossil remains of 415 million- year-old marine plankton contain highly elevated concentrations of heavy metals of the kind that can cause morphological abnormalities in today’s marine life. This led the authors to conclude that metal poisoning caused the observed malformation and may have contributed to the extinction of these and many other species.
“This paper is a testament to the power of multi-disciplinary research,” said USGS scientist Poul Emsbo, a lead author of the report. “Here, collaboration between a paleontologist and an ore-deposit geochemist has led to new data that unveils new processes that may ultimately explain the cause of catastrophic extinctions in earth history.”
The documented chemical behavior of the toxic metals correlates with previously observed disturbances in oceanic carbon, oxygen and sulfur signatures. Such behavior strongly suggests that these metal increases were a result of decreased oxygen in the ocean.
Thus, metal toxicity, and its expressions in fossilized malformations, could provide the missing link that relates organism extinctions to a widespread absence of ocean oxygen. As part of a series of complex systemic interactions accompanying oceanic geochemical variation, the mobilizations of metals in spreading low-oxygen waters may identify the early phase of the kill-mechanism that led to these catastrophic extinction events.
The recurring correlation between fossil malformations and Ordovician-Silurian extinction events raises the provocative prospect that toxic metal contamination may be a previously unrecognized contributing agent to many, if not all, extinction events in the ancient oceans.