USGS Newsroom

From Toxic Dust and Algae to Ill Winds From Africa

OC_Web@usgs.gov (Office of Communications Web Group) — Fri, 20 Nov 2009 10:02:25 EDT

USGS at the Society of Environmental Toxicology and Chemistry

Note to editors: The SETAC conference will be held in New Orleans from Nov. 19-23. For more info on the conference, visit their Web site.

Toxic dust: Toxins in coal-tar-based sealcoats in parking lots may be the culprit in contaminated house dust, according to a USGS study. PAHs – or polycyclic aromatic hydrocarbons – are large molecules found in oil, coal and tar deposits, and can have toxic effects. It’s long been known that PAHs are often found in house dust; however, the specific sources of these PAHs are largely undetermined. Researchers found that dust from indoor areas near parking lots with coal-tar-based sealcoat had substantially elevated concentrations of PAHs. This study, PAHs in house dust and relation to coal-tar-based pavement sealcoat, will be presented on Nov. 20 at 10:20 a.m. in the Belle Chasse Room. For more information, contact Barbara Mahler at bjmahler@usgs.gov or at 512-927-3566.

Eensy-weensy spiders play large role as sentinels of contaminants: Spiders that live near water may be an effective warning system for contaminants in aquatic ecosystems, according to a new USGS and U.S. Environmental Protection Agency study. Scientists examined PCB (polychlorinated biphenyls) levels in shoreline-living spiders at Lake Hartwell, a Superfund site in South Carolina, and used this information to map contaminant concentrations in lake sediment. Future monitoring studies will use the spiders as indicators of ecosystem recovery from PCB contamination. Researchers also made risk maps for a spider-eating bird, the Carolina wren, which could be exposed to PCBs through eating spiders. These spiders rely heavily on adult aquatic insects for food and play a key ecological role in the transfer of contaminants between water and land ecosystems. In spite of this, they are underused as a sentinel species at contaminated sediment sites. This study, using riparian spiders as sentinels of PCB export and risk, will be presented on Nov. 21 at 3:50 p.m. in the Versailles Room. To learn more, contact David Walters at waltersd@usgs.gov or at 970-226-9484.

It’s an ill wind that blows: African dust making it across the ocean: Increasing quantities of African dust have blown across the Atlantic Ocean to the Caribbean and Americas over the past few decades. During that time, the dust’s composition has changed. In this study, African dust air masses in Africa and the Caribbean were analyzed for persistent organic contaminants and metals. These potentially toxic contaminants can originate from the burning of plastics, biomass and waste; widespread use of pesticides, plastics, and pharmaceuticals; and increased industrialization. Multiple pesticides and other contaminants, including carcinogens, suppressors of immune systems, disruptors of endocrine systems, and nervous system or liver toxins were identified from all sample sites. All are known to persist in the environment, accumulate in organisms, and are toxic at very low concentrations. This study, Chasing clouds of dust: transoceanic transport of synthetic organic pollutants and trace metals with African dust, will be presented on Nov. 22 at 11 a.m. in Ballroom D. For more information, contact Ginger Garrison at ginger_garrison@usgs.gov or at 727-803-8747, ext. 3061.

Invasive carp and the secret language of scent: The chemical language of invasive Asian carp may eventually be turned against them in the fight to help eradicate these harmful invaders from the Mississippi River. Asian carp, introduced into the Mississippi River in the 1970s and 80s, are now abundant throughout the lower Missouri, the Mississippi and Ohio rivers, posing a threat to native species. Carp seem to have a chemical language effective for predator defense and reproduction in murky environments, so researchers put this language to the test by subjecting young carp to extracts prepared from the skins of other carp. The result: the young carp, upon detecting the extracts, significantly avoided them by moving from the area, becoming immobile, and schooling. This “alarm substance” may be effective in repelling carp from habitat critical to native species. Young carp were also attracted to the chemical stimuli of schooling carp, which can assist in conventional eradication methods. This study, Use of pheromones to control invasive Asian carp, will be presented on Nov. 20^tat 10:40 a.m. in the Elmwood Room. To learn more, contact Robin Calfee at rcalfee@usgs.gov or at 573-441-2969.

Toxic algae may be harming endangered suckers in Klamath Lake: Preliminary data suggest that algal toxins may be hindering the population growth of endangered Lost River suckers and shortnose suckers in Upper Klamath Lake in southern Oregon. This lake is characterized by high levels of nitrogen and phosphorus, nutrients that promote large, frequent cycles of cyanobacterial or algal blooms from spring through fall. Researchers evaluated the presence and effects of these toxins, specifically microcystins, which are harmful to other aquatic life, in the lake’s water and in fish from the lake. Examination of liver tissues from juvenile suckers revealed adverse physiological effects consistent with tissue damage associated with microcystin exposure. Significant concentrations of the toxins were reported form all field sampling stations in the lake. This study, Cyanobacterial toxins found in Upper Klamath Lake, Oregon: implications for endangered fish, will be presented on Nov. 22 at 1:10 p.m. in Ballroom C. To learn more, contact Kathy Echols at kechols@usgs.gov or at 573-876-1838.

Wading through the sources of lake contamination: Contamination of urban lakes and streams by polycyclic aromatic hydrocarbons (PAHs) is widespread and has been increasing over the last 40 years in the United States. These PAHs can be toxic to bottom-dwelling organisms, can cause tumors in fish, and several are believed to cause cancer in humans. In this study, researchers examined five sources of PAHs in 40 urban lakes from across the United States, including coal-tar-based pavement sealcoat, coal combustion, oil combustion, vehicle emissions and wood combustion. Of the five sources studied, sealcoat was the strongest contributor to PAH contamination in lake sediment. This research can help those trying to reduce pollution levels in the urban environment by providing them with a better understanding of PAH sources. This study, Sources of PAHs to urban lakes in the United States, will be presented on Nov. 23 at 11:20 a.m. in the Jefferson Room. For more information, contact Peter Van Metre at pcvanmet@usgs.gov or at 512-927-3506.

Tiny particles with big effects: Industrially produced nanoparticles are being dispersed into the environment from a range of everyday human activities. Use of consumer nanoproducts, such as sunscreen with zinc oxide or bed sheets and socks containing silver nanoparticles, all have the potential to release metals into the environment. Some of these particles can be toxic, but little is known about how nanoparticles will accumulate in the environment. Interactions between nanoparticles and living organisms are influenced by the unique physico-chemical properties of each kind of nanoparticle. This study introduces a new approach to evaluate the toxicity of nanoparticles with metal as an ingredient, and offers a way to begin to understand potential beneficial uses and potential environmental risks. This study, Characterizing the bioavailability and toxicity of engineered nanoparticles using enriched isotope tracers and biodynamic modeling, will be presented on Nov. 22 at 10 a.m. in the Oak Alley Room. For more information, contact Marie-Noele Croteau at mcroteau@usgs.gov or at 650-329-4424.

Cause of feminized male sturgeon remains elusive: The number of male shovelnose sturgeon with female characteristics in the Missouri River has increased from about 3 percent in 1968 to 15 percent in 2001. USGS researchers examined the levels of PCBs (polychlorinated biphenyls) and organochlorine pesticides in normal and intersex fish to see whether these hormone-mimicking compounds were associated with the condition. Although the compounds were all present in sturgeon at levels of concern, no differences in levels between intersex male fish and normal male fish were detected. Still, reproductive development is complex and can depend on many factors, including a fish’s age at its first exposure. These fish are also exposed to many other compounds that have not yet been tested. Recent findings of intersex in endangered pallid sturgeon underscore the need to find the cause of this condition. This study, Intersex gonads in Missouri River shovelnose sturgeon: occurrence, severity, and association with contaminants, will be presented on Nov. 22 at 8:40 a.m. in Ballroom A. To learn more, contact Diane Papoulias at dpapoulias@usgs.gov or at 573-999-1788.

Waves of Survival in American Samoa

OC_Web@usgs.gov (Office of Communications Web Group) — Wed, 18 Nov 2009 13:06:46 EDT

Pete Gurr, a resident of American Samoa, was on his way to work when he felt an earthquake that originated 110 miles out at sea. Because of tsunami training he had received, he knew about the possibility of a deadly wave and drove down to the closest coastal village, where he warned the residents. Similarly, Tina Pule knew the earthquake was stronger than usual and told her parents to go inland.

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Although they had just 10 to 15 minutes between the end of the shaking and the arrival of the first deadly wave to shore, many other American Samoa locals have similar stories of survival that USGS researchers heard when they arrived on the island to collect data immediately following the tsunami.

“Thanks to education efforts, thousands of locals had the knowledge to get to higher ground as soon as they felt shaking,” said Bruce Jaffe, a USGS oceanographer, who traveled to American Samoa with a rapid response team of tsunami scientists. “This research on water levels and sediment deposits immediately following a tsunami is an essential part of future education efforts because it is used to improve tsunami models — these are vital for designing evacuation routes, building stronger structures and determining the best areas for building.”

The USGS team also collected information to help interpret the geologic record to determine how frequently tsunamis of this magnitude are likely to strike American Samoa. Scientists can determine this frequency by examining sediment, because each tsunami that hits the area leaves a distinct, new sand layer or boulder deposit.

“We don’t know how often similarly large tsunamis strike American Samoa and whether larger tsunamis have hit the island in the past,” said Jaffe. “There are advantages to living on the coast, so people may live with the risk if it’s not likely that a tsunami this destructive will strike for a long period of time. This research helps us determine that risk.”

If the scientists had waited any longer than a week after the tsunami to collect this information, much of it would have been lost forever to clean-up efforts and natural processes. Just days after the tsunami, people were already scrubbing water marks from homes and removing debris, two of the best sources for determining where and how high the water flowed.

By continuing research on this tsunami, the USGS is working to improve the ability to interpret tsunami characteristics from the resulting deposits, determine the role coral reefs play in protecting the shore, and document and model how reef channels affect the tsunamis.

In addition to tsunami research, the USGS also sent a field party to deploy portable seismometers in American Samoa to detect aftershocks and collect valuable data for determining how ground motions vary in different parts of the island. This is a key parameter for making a seismic hazard assessment for American Samoa.

“Although we have come a long way in studying tsunamis in the last two decades, we must continue to focus on this kind of research because tsunamis are still poorly understood,” said USGS tsunami scientist Guy Gelfenbaum, who also traveled to American Samoa following the tsunami. “Having a better understanding of how a tsunami’s height and speed change as it moves onshore through this research will contribute to keeping people safe.”

Interviews with survivors, pictures of the damage, and maps of water heights used to make tsunami models can be found in “notes from the field” from this USGS team. The USGS team will continue to update this page as new information comes in.

Listen to episode 110 of the USGS CoreCast for an interview with Bruce Jaffe, and check out the USGS Multimedia Gallery for high resolution photos of the effects of this tsunami.

[Access images for this release at: &amp;lt;a href="http://gallery.usgs.gov/tags/CoreCast110" mce_href="http://gallery.usgs.gov/tags/CoreCast110"&amp;gt;http://gallery.usgs.gov/tags/CoreCast110&amp;lt;/a&amp;gt;]

Free U.S. Earth Imagery Sharpens Shared View of Global Challenges

OC_Web@usgs.gov (Office of Communications Web Group) — Mon, 16 Nov 2009 16:55:02 EDT

USGS Director McNutt a Leader in U.S. Delegation at International Conference

Free, easily accessible U.S. satellite data enables any citizen, scientist, or analyst who can use the information to contribute to a shared vision of the challenges facing our planet.

That's the message the newly-appointed director of the U.S. Geological Survey, Dr. Marcia McNutt, plans to deliver when representatives of 80 governments and over 50 participating organizations convene at the international Group on Earth Observations (GEO-VI) meeting, November 16-17, in Washington, D.C.

“Our policy of providing free Landsat data supports a central GEO goal: to promote global distribution of earth observation data,” said McNutt. "With a continuous record of earth observation since 1972, Landsat provides the most complete set of land surface information as well as a vital historical perspective for researchers, decision makers, and commercial users around the world.”

From over 400 miles above Earth, the scale of Landsat imagery makes it particularly useful in understanding natural and human-induced changes to the planet. The data enable a wide array of investigations — from supporting disaster relief efforts to making agricultural crop assessments to correlating environmental conditions with famine, biodiversity, and human health.

Beginning with the launch of Landsat 1 in 1972, Landsat, a joint operation of USGS and NASA, has produced over two million space-based, moderate-resolution, land remote sensing images. The massive data archive is maintained at the USGS-EROS facility in Sioux Falls, S.D.

“As the world’s increasing population is compelled to face the effects of climate change and the limitations of water, petroleum, and other vital resources, the broad availability of images from Landsat and other earth observation satellites benefits both developing and developed countries,” said Dr. McNutt. McNutt became the 15^th USGS Director on November 5.

USGEO, the American contribution to GEO, is sponsored by 15 federal agencies and two White House offices.

“I am very pleased to note that it was the agency I now direct, USGS, that opened the Landsat archive to the world free of charge,” McNutt continued. “Since the archive was opened, over 1 million images have been provided to users from 180 countries — a resounding success.”

For further information, visit:

Pesticide Levels Decline in Corn Belt Rivers

OC_Web@usgs.gov (Office of Communications Web Group) — Mon, 9 Nov 2009 11:00:00 EDT

Concentrations of several major pesticides mostly declined or stayed the same in “Corn Belt” rivers and streams from 1996 to 2006, according to a new U.S. Geological Survey study.

The declines in pesticide concentrations closely followed declines in their annual applications, indicating that reducing pesticide use is an effective and reliable strategy for reducing pesticide contamination in streams.

Declines in concentrations of the agricultural herbicides cyanazine, alachlor and metolachlor show the effectiveness of U.S. Environmental Protection Agency (EPA) regulatory actions as well as the influence of new pesticide products. In addition, declines from 2000 to 2006 in concentrations of the insecticide diazinon correspond to the EPA’s national phase-out of nonagricultural uses. The USGS works closely with the EPA, which uses USGS findings on pesticide trends to track the effectiveness of changes in pesticide regulations and use.

Scientists studied 11 herbicides and insecticides frequently detected in the Corn Belt region, which generally includes Illinois, Indiana, Iowa, Nebraska and Ohio, as well as parts of adjoining states. This area has among the highest pesticide use in the nation — mostly herbicides used for weed control in corn and soybeans. As a result, these pesticides are widespread in the region’s streams and rivers, largely resulting from runoff from cropland and urban areas.

Elevated concentrations can affect aquatic organisms in streams as well as the quality of drinking water in some high-use areas where surface water is used for municipal supply. Four of the 11 pesticides evaluated for trends were among those most often found in previous USGS studies to occur at levels of potential concern for healthy aquatic life. Atrazine, the most frequently detected, is also regulated in drinking water.

“Pesticide use is constantly changing in response to such factors as regulations, market forces, and advances in science,” said Dan Sullivan, lead scientist for the study. “For example, acetochlor was registered by the EPA in 1994 with a goal of reducing use of alachlor and other major corn herbicides — acetochlor use rapidly increased to a constant level by about 1996, and alachlor use declined. Cyanazine use also decreased rapidly from 1992 to 2000, as it was phased out because of environmental concerns. Metolachlor use did not markedly decrease until about 1998, when S-metolachlor, a more effective version that requires lower application rates, was introduced. Each of these declines in use was accompanied by similar declines in concentrations.”

Although trends in concentration and use almost always closely corresponded, concentrations of atrazine and metolachlor each declined in one stream more rapidly than their estimated use. According to Skip Vecchia, senior author of the report on this analysis, “The steeper decline in these instances may be caused by agricultural management practices that have reduced pesticide transport, but data on management practices are not adequate to definitively answer the question. Overall, use is the most dominant factor driving changes in concentrations.”

Only one pesticide — simazine, which is used for both agricultural and urban weed control — increased from 1996 to 2006. Concentrations of simazine in some streams increased more sharply than its trend in agricultural use, suggesting that non-agricultural uses of this herbicide, such as for controlling weeds in residential areas and along roadsides, increased during the study period.

The USGS study is based on analysis of 11 pesticides for 31 stream sites in the Corn Belt for two partially overlapping time periods: 1996 to 2002 and 2000 to 2006. Pesticides included in the trend analyses were the herbicides atrazine, acetochlor, metolachlor, alachlor, cyanazine, EPTC, simazine, metribuzin and prometon, and the insecticides chlorpyrifos and diazinon. Additional detailed analyses of relations between concentrations and use focused on four herbicides mainly used for weed control in corn (atrazine, acetochlor, metolachlor and alachlor) at a subset of 11 sites on the main rivers and selected large tributaries in the Ohio, Upper Mississippi and Missouri River basins.

Concentrations of many other pesticides that were less prevalent than the 11 included in the study were below analytical detection limits in most samples and thus could not be analyzed for trends. Glyphosate, an herbicide which has had rapidly increasing use on new genetically modified varieties of soybeans and corn, and which now is the most heavily used herbicide in the nation, was not measured until late in the study and thus had insufficient data for analysis of trends.

A USGS Scientific Investigations Report, ”Trends in Pesticide Concentrations in Corn-Belt Streams, 1996-2006,” (Analysis of concentration trends for 11 pesticides at 31 stream and river sites) and a journal article in the Environmental Science and Technology journal, “Trends in Concentrations and Use of Agricultural Herbicides for Corn Belt Rivers” (Analysis of concentration and use trends for 4 herbicides at 11 major river sites) is available online. Additional information, including data, reports and maps on pesticide status, trends and use may be found at the USGS Pesticide National Synthesis Project Web site.

Atlanta Floods Extremely Rare

OC_Web@usgs.gov (Office of Communications Web Group) — Wed, 4 Nov 2009 14:37:07 EDT

The epic flooding that hit the Atlanta area in September was so extremely rare that, six weeks later this event has defied attempts to describe it. Scientists have reviewed the numbers and they are stunning.

“At some sites, the annual chance of a flood of this magnitude was so significantly less than 1 in 500 that, given the relatively short length of streamgaging records (well less than 100 years), the U.S. Geological Survey cannot accurately characterize the probability due to its extreme rarity," said Robert Holmes, USGS National Flood Program Coordinator. “Nationwide, given that our oldest streamgaging records span about 100 years, the USGS does not cite probabilities for floods that are beyond a 0.2 percent (500-year) flood.”

“If a 0.2 percent (500-year) flood was a cup of coffee, this one brewed a full pot,” said Brian McCallum, Assistant Director for the USGS Georgia Water Science Center in Atlanta. “This flood overtopped 20 USGS streamgages – one by 12 feet. The closest numbers we have seen like these in Georgia were from Tropical Storm Alberto in 1994. This flood was off the charts.”

The rains returned water levels in the region’s two largest reservoirs, Lake Lanier and Allatoona Lake, to pre-drought levels. Lake Lanier rose by more than three feet to 1068 feet by Sept. 25 and returned to full pool in October. Allatoona Lake rose to 853.25 feet on Sept 23, more than 13 feet over full pool of 840 feet.

“The flooding in Atlanta is certainly near the top of the list of the worst floods in the United States during the past 100 years,” said Holmes. “For comparable drainage areas, the magnitude of this flood was worse than the 1977 Kansas City flood, which caused tremendous destruction and loss of life. It is a testament to the diligence of county officials and emergency management teams that more lives were not lost in Georgia.”

Significant property losses, however, were a near certainty from this event. According to the National Weather Service, some locations recorded up to 20 inches of rain from 8:00 pm on Sept. 20 to 8:00 pm the following day. Culverts and sewers are not usually designed for events of this magnitude because they are so rare and it is cost prohibitive.

“Applying rainfall frequency calculations, we have determined that the chance of 10 inches or more occurring at any given point are less than one hundredth of one percent”, said Kent Frantz, Senior Service Hydrologist for the National Weather Service at Peachtree City. “This means that the chance of an event like this occurring is 1 in 10,000.”

For this analysis, USGS reviewed high-water-mark surveys and indirect peak discharge computations throughout the flood-affected region. Scientists gather these data from the field during floods and in their immediate aftermath to supplement or in this case, to provide data after a gage is destroyed. Some notable results:

In Cobb County, Sweetwater, Noonday, Butler, and Powder Springs creeks flooded so severely that the annual chance of a worse event is far smaller than 0.2 percent (500-year) flood. On Sweetwater Creek near Austell, Ga., high-water marks showed a peak stage of 30.8 feet. The peak flow (31,500 cubic feet per second) was more than double the previous peak flow recorded at this site during the last 73 years. The previous peak, caused by the remnants of Hurricane Dennis in July 2005, was almost 10 feet lower at 21.87 feet.

In Douglas County, the Dog River near Fairplay overtopped the USGS stream gage by 12 feet. The peak stage was 33.8 feet, with a peak discharge of 59,900 cubic feet per second. This is well beyond the 0.2 percent annual exceedence probability (500-year) flood.

Gwinnett, DeKalb and Rockdale counties also had record flooding. Suwanee Creek floods were beyond the 0.2 percent annual exceedence probability (500-year) flood.

On the Chattahoochee, the USGS gage at Vinings reached a peak stage of 28.12 feet with 40,900 cubic feet per second, which represents between a between a 1.0 to 0.5 percent annual exceedence probability (100- to 200-year) flood.

In Georgia the USGS maintains a network of nearly 300 streamgages that provide data in real time. Data from these streamgages are used by local, state and federal officials for numerous purposes, including public safety and flood forecasting by the National Weather Service. A map of these gages and graphs of discharge for the last seven days is available online.

The USGS works in cooperation with other Federal, state, and local agencies, throughout Georgia that measure water level (stage), streamflow (discharge), lake levels and rainfall.

Users can access current flood and high flow conditions across the country at the USGS WaterWatch Web site.

More information on USGS flood-related activities is available at the USGS Surface Water Information Web site.

November Science Picks -- Hot News about Cool Science

OC_Web@usgs.gov (Office of Communications Web Group) — Wed, 4 Nov 2009 00:00:00 EDT

Did you know that that the United States uses less water today than 35 years ago and that there might be caves on Mars? In this edition of Science Picks, learn more about these stories, as well as the latest on carbon storage in the Arctic and faulty wallboard from China that may be making Florida residents sick. Also, discover why bats are dying near wind turbines and how endangered whooping cranes are being saved.

If you would like to receive Science Picks via e-mail, would like to change the recipient or no longer want to receive it, please e-mail kcapelli@usgs.gov.

November Highlights:

United States Using Less Water Today
Caves Provide Martians (or Scientists) a New Place to Hide
Thawing Arctic May Mean More Atmospheric Carbon
Wallboard Woes
Welcoming a New Director
Wind Energy: A Scare for Bats and Birds
Whooping Cranes are Flying High!
Hazards Remain After the Smoke Clears
Giant Snakes Threaten Ecosystems
Streamgages: the Silent Superhero
Why Celebrate GIS Day on Nov. 18?
Sand-tastic Beach Management

United States Using Less Water than 35 Years Ago

OC_Web@usgs.gov (Office of Communications Web Group) — Thu, 29 Oct 2009 9:44:21 EDT

WASHINGTON, D.C.--The United States is using less water than during the peak years of 1975 and 1980, according to water use estimates for 2005. Despite a 30 percent population increase during the past 25 years, overall water use has remained fairly stable according to a new U.S. Geological Survey report.

Media Advisory: Water Use: Every Drop Counts

OC_Web@usgs.gov (Office of Communications Web Group) — Wed, 28 Oct 2009 6:26:21 EDT

Water is our single largest commodity, but we don’t account for our water resources as we do for other important commodities. How has our use of water across the United States changed in the past 50 years? Come learn what the USGS and its partners know — and don’t know — about the nation’s use of water.

What:

The media is invited to a congressional briefing on how water is used throughout the country and what still needs to be learned about water use.

Who:

Anne Castle, Assistant Secretary for Water and Science, Department of the Interior
Robert Hirsch, Research Hydrologist, U.S. Geological Survey
Sue Lowry, Interstate Streams Administrator, Wyoming State Engineer’s Office
David Naftzger, Executive Director, Council of Great Lakes Governors

Where:

2261 Rayburn House Office Building
Washington, D.C.

When:

Friday, October 30, 2009
10-11 a.m.

Hosts:

Senator Jim Risch (ID)
Congressman Jim Moran (VA)
Congressman Vernon Ehlers (MI)

Sponsors:

American Water Works Association
Association of Metropolitan Water Agencies

Refreshments will be served.

Global Tree Death Patterns Reveal Emerging Climate Change Risks for Forests

OC_Web@usgs.gov (Office of Communications Web Group) — Mon, 26 Oct 2009 18:19:45 EDT

Recent tree loss, largely driven by climate stress, in forests around the world could portend increased tree mortality under climate change, according to a U.S. Geological Survey (USGS) report recently released online in the journal Forest Ecology and Management.

The USGS-led review suggests that many of the world's forests are sensitive to climate-related drought and heat stress, raising the concern that forests may become increasingly vulnerable to future mortality, even in environments that are not normally considered water-limited. The results suggest risks to ecosystem services that are valuable to forests and societies around the world.

"Trees can die much more quickly than they grow," said Craig D. Allen, USGS scientist and lead author of the report. "The widespread examples of drought and heat-induced tree mortality that we document illustrate how climate can drive abrupt, broad-scale impacts to essential forest services ranging from timber and protection of watersheds and biodiversity to recreational, aesthetic and spiritual benefits."

Although tree mortality episodes occur in the absence of climate change, the report's results are consistent with projections of future increases in tree mortality due to climate-related stresses. These heat and drought stresses could fundamentally alter the composition, structure and biogeography of forests in many regions, as well as affect how forests sequester carbon.

"This work by USGS underscores multiple risks that climate change poses to our forests and our world," said Secretary of the Interior Ken Salazar. "It also illuminates the importance of our efforts to develop practical, on-the-ground land management strategies that will help us adjust to the stresses that climate change is placing on our forests."

The report details 88 cases of significant tree mortality around the world associated with heat and drought since 1970, documenting climate-induced tree losses from Africa, Asia, Australia, Europe, North America and South America.

"From northern forests of spruce, pine or oak to tropical savannas and rainforests, many forest types appear vulnerable to such climate-driven mortality and to forest pests that are also highly sensitive to temperature," Allen said.

The report also identifies key information gaps and scientific uncertainties that currently hinder our ability to identify climate-related trends in tree mortality and to predict future losses in response to climate change, including lack of species-specific knowledge about tree water and temperature stress limits and the absence of a globally coordinated observation system.

However, in conjunction with other recent observational and experimental studies indicating that higher temperatures can drive increases in tree mortality, this article highlights risks that tree mortality could become more frequent and extensive as global climate change progresses.

Saving Sand: South Carolina Beaches Become a Model for Preservation

OC_Web@usgs.gov (Office of Communications Web Group) — Fri, 23 Oct 2009 9:33:00 EDT

The USGS report is available online.

While most people head to Myrtle Beach for vacation, a group of scientists have been hitting the famous South Carolina beach for years to figure out how to keep the sand from washing away.

Although they studied only a limited segment of beach, their work is a model for beach preservation that can apply elsewhere. And with talk of “balancing the sand budget” and money saved on restoration, their findings sound financial.

The study will be presented to scientists from around the world at the International Geological Programs Annual Conference, Oct. 25 to 31 in Myrtle Beach.

“Effective beach preservation requires knowing the beach’s sand budget and understanding the geology that constrains it,” said U.S. Geological Survey lead scientist Walter Barnhardt. “It takes a systematic approach and strong partnerships at all levels of government with neighborhood associations and universities to keep a beach from simply washing away.”

The main objective of this 7-year study, done in cooperation with the South Carolina Sea Grant Consortium, was to improve projections of coastal change by determining the geologic features and ocean processes that control sediment movement along the coast.

“As a result of this work, we were able to identify offshore sand sources that could be used for future beach replenishment without causing a bigger erosion problem elsewhere,” said Barnhardt.

Controlling beach erosion will likely become more difficult as a result of climate change with its attendant sea-level rise and increase in the number and intensity of storms. This is particularly true in places like South Carolina that have a broad, low-elevation coast and a sand shortage.

“The comprehensive nature of this study -- considering the geologic framework, behavior and driving processes regionally -- has resulted in a remarkable baseline for better managing our beach and near- shore resources,” said Paul Gayes, Director of Coastal Carolina University’s Center for Marine and Wetland Studies.

“From inventory of potential future beach nourishment sand resources, to distribution of important hardbottom fish habitat, to models of beach behavior, this study forms the starting point for many present and future efforts. This work is regularly cited as a model approach and result for similar studies and efforts around the country,” said Gayes.

For this study, scientists examined land and marine environments in a 62-mile-long segment of South Carolina’s coast. The swath extends more than 3 miles inland and 6 miles seaward. They tracked waves and sand movement, drilled cores, mapped the topography and geology onshore and offshore, and monitored coastal change.

Key Findings:

Sand is a scarce resource near Myrtle Beach
- The beaches are thin ribbons of sand that sit on top of sedimentary rocks. They receive little or no sand from nearby rivers.
- Offshore, there is little sand to wash ashore and replenish the beach. Large expanses offshore are exposed as hard grounds that are locally overlain by sand less than 3 feet thick.

Sand is transported primarily from northeast to southwest in the area. Large sand deposits have accumulated seaward of Murrell’s Inlet and Winyah Bay, SC. These and other sand deposits could serve as offshore sources of beach nourishment in the future.

Effective beach management requires a regional, systematic effort to
- understand the geology and how it constrains sand supplies and sand movement,
- determine patterns of shoreline change by surveying beaches at regular intervals over several years and
- identify ocean processes that drive coastal erosion.

A detailed record of coastal change provides guidance for land use and a rationale for development decisions such as determining setbacks necessary to protect property.

Climate change will affect many beaches; low elevation beaches are vulnerable over greater inland areas.

Coastal Change Along the Coast of Northeastern South Carolina – The South Carolina Coastal Erosion Study (USGS Circular 1339), is available online. Printed copies are available from the USGS Store (Product #222905)

The USGS conducts regional multidisciplinary studies of coastal erosion to provide impartial scientific information necessary for the protection and management of valuable coastal resources.

Secretary Salazar Applauds Senate's Confirmation of Dr. Marcia McNutt as Director of the U.S. Geological Survey

OC_Web@usgs.gov (Office of Communications Web Group) — Thu, 22 Oct 2009 12:53:00 EDT

WASHINGTON, D.C. – Secretary of the Interior Ken Salazar today praised the Senate’s confirmation of Dr. Marcia McNutt as Director of the U.S. Geological Survey (USGS) and Science Advisor to the Secretary. The President nominated her for the positions in July.

Caves could reveal secrets of life on Mars

OC_Web@usgs.gov (Office of Communications Web Group) — Mon, 19 Oct 2009 10:00:00 EDT

'Virtual spelunking" finds possible cave system in Martian volcano flows

A series of depressions discovered on Mars could be entrances to a cave system that might provide shelter for future Mars missions or shed light on whether microbial life forms have ever existed on the "Red Planet."

Glen Cushing, a physicist with the US Geological Survey, discovered the series of "collapse depressions" in extinct lava flows from a Martian volcano. Cushing describes his discovery as a collection of “long grooves” in the surface with distinctive depressions that appear to be skylight entrances into tunnel-like structures. Some of the grooves are more than 100 kilometers long and could easily extend much further and deeper beneath the surface. Some of the grooves are about 50 to 60 meters wide and are curvy and meandering while others are more linear and 2-3 times wider, suggesting that more than one formation mechanism may have been operating.

The depressions were detected using high-resolution images conveyed through Mars-orbiting satellites.

"By finding caves on Mars, USGS scientists have demonstrated once again that real, cutting-edge science is more exciting than the best science fiction ever written," said U.S. Secretary of the Interior, Ken Salazar.

Current observations can only hint at the characteristics of Martian caves, says Cushing. “We can only estimate the lengths of these tunnels for as far as their surface expressions continue,” says Cushing. “It’s likely that many internal sections have collapsed and may be impassable to explorers.”

The depressions are located in lava flows from a massive volcano named Arsia Mons. Some of the grooves observed by Cushing likely formed when a solid ceiling of cooled material formed over a lava channel during an ancient volcanic eruption. When the eruption ended, an empty tunnel or “lava tube” was left behind. Sections of these ceilings collapsed at some point to form the observed skylight entrances, or caves.

Cushing notes that caves could be of fundamental importance for human explorers on Mars. “Caves can protect human explorers from a range of dangerous conditions that exist on Mars’ surface. If caves are not used for long-term human habitation, then explorers must either transport substantial shelters of their own or build them on site.” The latter options could be prohibitively expensive and perhaps not as safe.

Cushing is confident that Martian caves will become focal points for future robotic and human exploration, because of their implications for microbial life. “Someday, robot explorers will probably visit caves such as these and show us a whole new hidden world.” This new hidden world may be among the only accessible environments capable of preserving evidence of past or present microbial life, if it ever existed on Mars.

Until then, Cushing and his colleagues will continue "virtually spelunking” the caves of Mars.

The mission of the USGS Astrogeology Science Center is to serve the Nation, the international planetary science community, and the general public’s pursuit of new knowledge of our Solar System. The Team’s vision is to be a national resource for the integration of planetary geosciences, cartography, and remote sensing. As explorers and surveyors, with a unique heritage of proven expertise and international leadership, USGS astrogeologists enable the ongoing successful investigation of the Solar System for humankind.

Arctic Now Traps 25 Percent of World's Carbon -- But That Could Change

OC_Web@usgs.gov (Office of Communications Web Group) — Wed, 14 Oct 2009 17:20:08 EDT

The arctic could potentially alter the Earth’s climate by becoming a possible source of global atmospheric carbon dioxide. The arctic now traps or absorbs up to 25 percent of this gas but climate change could alter that amount, according to a study published in the November issue of Ecological Monographs.

In their review paper, David McGuire of the U.S. Geological Survey and the University of Alaska at Fairbanks and his colleagues show that the Arctic has been a carbon sink since the end of the last Ice Age, which has recently accounted for between zero and 25 percent, or up to about 800 million metric tons, of the global carbon sink. On average, says McGuire, the Arctic accounts for 10-15 percent of the Earth’s carbon sink. But the rapid rate of climate change in the Arctic – about twice that of lower latitudes – could eliminate the sink and instead, possibly make the Arctic a source of carbon dioxide.

“This study is another example of the important role played by USGS and its partners in providing the scientific research that must be the backbone of any actions related to climate change,” said Secretary of the Interior Ken Salazar.

This figure shows the mean extent of permafrost in the Arctic, estimated for (a) the years 1990-2000 and (b) the years 2090-2100. In (c), the estimation of loss of permafrost by 2100 is overlaid on estimates for the year 2000. Credit: A. David McGuire, USGS (click on the image to see the full size version)

Carbon generally enters the oceans and land masses of the Arctic from the atmosphere and largely accumulates in permafrost, the frozen layer of soil underneath the land’s surface. Unlike active soils, permafrost does not decompose its carbon; thus, the carbon becomes trapped in the frozen soil. Cold conditions at the surface have also slowed the rate of organic matter decomposition, McGuire says, allowing Arctic carbon accumulation to exceed its release.

But recent warming trends could change this balance. Warmer temperatures can accelerate the rate of surface organic matter decomposition, releasing more carbon dioxide into the atmosphere. Of greater concern, says McGuire, is that the permafrost has begun to thaw, exposing previously frozen soil to decomposition and erosion. These changes could reverse the historical role of the Arctic as a sink for carbon dioxide.

“In the short term, warming temperatures could release more Arctic carbon to the atmosphere,” says McGuire. “And with permafrost thawing, there will be more available carbon to release.”

On the scale of a few decades, the thawing permafrost could also result in a more waterlogged Arctic, says McGuire, a situation that could encourage the activity of methane-producing organisms. Currently, the Arctic is a substantial source of methane to the atmosphere: as much as 50 million metric tons of methane are released per year, in comparison to the 400 million metric tons of carbon dioxide the Arctic stores yearly. But methane is a very potent greenhouse gas – about 23 times more effective at trapping heat than carbon dioxide on a 100-year time scale. If the release of Arctic methane accelerates, global warming could increase at much faster rates.

“We don’t understand methane very well, and its releases to the atmosphere are more episodic than the exchanges of carbon dioxide with the atmosphere,” says McGuire. “It’s important to pay attention to methane dynamics because of methane’s substantial potential to accelerate global warming.”

But uncertainties still abound about the response of the Arctic system to climate change. For example, the authors write, global warming may produce longer growing seasons that promote plant photosynthesis, which removes carbon dioxide from the atmosphere. Also, the expansion of shrubs in tundra and the movement of treeline northward could sequester more carbon in vegetation. However, increasingly dry conditions may counteract and overcome these effects. Similarly, dry conditions can lead to increased fire prevalence, releasing even more carbon.

McGuire contends that only specific regional studies can determine which areas are likely to experience changes in response to climate change.

“If the response of the arctic carbon cycle to climate change results in substantial net releases of greenhouse gases, this could compromise proposed mitigation efforts for controlling the carbon cycle,” he says.

The article, Sensitivity of the Carbon Cycle in the Arctic to Climate Change, was published online today in Ecological Monographs. The coordinating lead author is David McGuire, USGS, and the co-authors include internationally renowned scientists from Canada, Germany, Sweden, and the United States. This study was sponsored by the Arctic Monitoring and Assessment Program, the Climate in the Cryosphere Program, and the International Arctic Science Committee.

Report Documents the Risks of Giant Invasive Snakes in the U.S.

OC_Web@usgs.gov (Office of Communications Web Group) — Tue, 13 Oct 2009 12:00:00 EDT

Listen to a podcast: Science Seeks to Stem Snake Surge.

Five giant non-native snake species would pose high risks to the health of ecosystems in the United States should they become established here, according to a U.S. Geological Survey (USGS) report released today.

The USGS report details the risks of nine non-native boa, anaconda and python species that are invasive or potentially invasive in the United States. Because all nine species share characteristics associated with greater risks, none was found to be a low ecological risk. Two of these species are documented as reproducing in the wild in South Florida, with population estimates for Burmese pythons in the tens of thousands.

Based on the biology and known natural history of the giant constrictors, individuals of some species may also pose a small risk to people, although most snakes would not be large enough to consider a person as suitable prey. Mature individuals of the largest species—Burmese, reticulated, and northern and southern African pythons—have been documented as attacking and killing people in the wild in their native range, though such unprovoked attacks appear to be quite rare, the report authors wrote. The snake most associated with unprovoked human fatalities in the wild is the reticulated python. The situation with human risk is similar to that experienced with alligators: attacks in the wild are improbable but possible.

“This report clearly reveals that these giant snakes threaten to destabilize some of our most precious ecosystems and parks, primarily through predation on vulnerable native species,” said Dr. Robert Reed, a coauthor of the report and a USGS invasive species scientist and herpetologist.

High-risk species—Burmese pythons, northern and southern African pythons, boa constrictors and yellow anacondas—put larger portions of the U.S. mainland at risk, constitute a greater ecological threat, or are more common in trade and commerce. Medium-risk species—reticulated python, Deschauensee’s anaconda, green anaconda and Beni anaconda—constitute lesser threats in these areas, but still are potentially serious threats.

The USGS scientists who authored the report emphasized that native U.S. birds, mammals, and reptiles in areas of potential invasion have never had to deal with huge predatory snakes before—individuals of the largest three species reach lengths of more than 20 feet and upwards of 200 pounds. The reticulated python is the world’s longest snake, and the green anaconda is the heaviest snake. Both species have been found in the wild in South Florida, although breeding populations are not yet confirmed for either.

Breeding populations have been confirmed in South Florida for Burmese pythons and the boa constrictor, and there is strong evidence that the northern African python may have a breeding population in the wild as well.

“Compounding their risk to native species and ecosystems is that these snakes mature early, produce large numbers of offspring, travel long distances, and have broad diets that allow them to eat most native birds and mammals,” said Dr. Gordon Rodda, a USGS scientist at the Fort Collins Science Center and the other coauthor of the report.

In addition, he said, most of these snakes can inhabit a variety of habitats and are quite tolerant of urban or suburban areas. Boa constrictors and northern African pythons, for example, already live wild in the Miami metropolitan area.

The report notes that there are no control tools yet that seem adequate for eradicating an established population of giant snakes once they have spread over a large area. Making the task of eradication more difficult is that in the wild these snakes are extremely difficult to find since their camouflaged coloration enables them to blend in well with their surroundings.

“We have a cautionary tale with the American island of Guam and the brown treesnake,” said Reed. “Within 40 years of its arrival, this invasive snake has decimated the island’s native wildlife—10 of Guam’s 12 native forest birds, one of its two bat species, and about half of its native lizards are gone. The python introduction to Florida is so recent that the tally of ecological damage cannot yet be made.”

USGS researchers used the best available science to forecast areas of the country most at risk of invasion by these giant snakes. Based on climate alone, many of the species would be limited to the warmest areas of the United States, including parts of Florida, extreme south Texas, Hawaii, and America’s tropical islands, such as Puerto Rico, Guam, and other Pacific islands. For a few species, however, larger areas of the continental United States appear to exhibit suitable climatic conditions. For example, much of the southern U.S. climatic conditions are similar to those experienced by the Burmese python in its native range. However, many factors other than climate alone can influence whether a species can establish a population in a particular location, the report notes.

The Fish and Wildlife Service and the National Park Service will use the report to assist in further development of management actions concerning the snakes when and where these species appear in the wild. In addition, the risk assessment will provide current, science-based information for management authorities to evaluate prospective regulations that might prevent further colonization of the U.S. by these snakes. The 300-page report provides a comprehensive review of the biology of these species as well as the risk assessment.

Resources

View the risk-assessment report
Questions and Answers about this report
View b-roll video and image gallery (below)
Read U.S. Fish and Wildlife Service information on injurious wildlife
Everglade National Park web page for the Burmese Python species profile.

Scientific Names

Indian or Burmese Python (Python molurus)
Northern African Python (Python sebae)
Southern African Python (Python natalensis)
Reticulated Python (Python [or Broghammerus] reticulatus)
Boa Constrictor (Boa constrictor)
Green Anaconda (Eunectes murinus)
Yellow Anaconda (Eunectes notaeus)
Beni or Bolivian Anaconda (Eunectes beniensis)
De Schauensee’s Anaconda (Eunectes deschauenseei)

[Access images for this release at: &amp;amp;amp;lt;a href="http://gallery.usgs.gov/tags/NR2009_10_13" mce_href="http://gallery.usgs.gov/tags/NR2009_10_13"&amp;amp;amp;gt;http://gallery.usgs.gov/tags/NR2009_10_13&amp;amp;amp;lt;/a&amp;amp;amp;gt;]

October Science Picks -- Hot News about Cool Science

OC_Web@usgs.gov (Office of Communications Web Group) — Fri, 2 Oct 2009 00:00:00 EDT

Do you want to know more about the recent Samoa and Sumatra earthquakes? What’s the latest climate change news? Did they really find water on the moon? And can male fish have female features? The answers are in this edition of Science Picks. Also, the nation’s earthquake monitoring system is getting a facelift, and Halloween is coming up, making it the perfect time to read up on bats!

If you would like to receive Science Picks via e-mail, would like to change the recipient or no longer want to receive it, please e-mail kcapelli@usgs.gov.

October Highlights:

Responding to the Samoa and Sumatra Earthquakes
DOI Prepared to Address Climate Change
Water is Out of This World
Gender Line Blurred in Fish
Improvements of Seismic Proportions
Forget the Garlic Necklace! Learn More about Bats and Rabies
Winter Warming Affects Sea Goose Migration
Invading Island Applesnails
Toxic Snow Takes Toll on Tadpoles
Helping Plants and Animals Faced with Arctic Warming
Don't Blow Off Hurricane Sensors
Fighting Fire with Minerals
Country Roads, Take Me … Online!
Hunting for Climate Clues in Lake Champlain
Citizen Scientists Monitor Boise Watershed