Geology Reports⌕ Search

SEARCH · Geology Reports

Results for “Science Activities”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,009 records · Page 56Linked to original sources
USGS2020

The Long-term effect of bleeding for Limulus amebocyte lysate on annual survival and recapture of tagged horseshoe crabs

In the U.S., 525,000 horseshoe crabs ( Limulus polyphemus ) per year have been captured during 2013–2017, brought to biomedical facilities, and bled to produce Limulus amebocyte lysate (LAL), then mostly released to the area of capture. The Atlantic States Marine Fisheries Commission estimates short-term bleeding-induced mortality to be 15% (4% to 30%), resulting in mortality of approximately 78,750 horseshoe crabs annually in recent years comprising a minor portion (<13%) of the up to one million annual coastwide landings dominated by harvest for bait. However, the long-term effect of bleeding for LAL on annual survival and spawning behavior is unknown; thus, results from short-term studies alone might underestimate bleeding effects at the population level. To address this knowledge gap, we analyzed data from the U.S. Fish and Wildlife horseshoe crab tagging database to estimate the differences in survival and recapture rates of bled and not bled horseshoe crabs tagged in the same years and geographic area. Contrary to expectation, survival was not lower for bled crabs compared to unbled crabs. Differences varied, but survival estimates tended to be higher for bled crabs than for unbled crabs. However, biomedical culling and selection for younger or healthier animals could have resulted in biomedically tagged individuals representing a healthier subset of the overall population with subsequent higher survival. Furthermore, the tagging analysis revealed a post-bleeding reduction in capture probability, which could indicate decreased spawning activity, evident in males more than females. Continued tagging of bled and unbled crabs in the same geographic area while recording age class and sex will contribute to the further resolution of LAL production’s effect on horseshoe crab populations.

Delaware, Maryland, New Jersey, Virginia↗
USGS2007

The Washington Biologists' Field Club : Its members and its history (1900-2006)

This book is based on the interesting one-hundred-plus-year history of the Club and its members. Plummers Island and the historic cabin on the Island have served as a common meeting area where the Club members have conducted research and held many social activities for over a century. The history has been written and revised over the years by members, and the biographical sketches also have been collected and written by the members. The Club was formed in 1900 and incorporated as a society in 1901 for scientists in the Washington, D.C., area. In recent years the Club has sponsored research by many non-member local scientists with grants totaling over $305,000. The cumulative total of 267 members represents all branches of natural science, with a strong emphasis on biology as the Club name indicates. In addition to the biologists there have been famous naturalists (e.g., John Burroughs), high-level administrators (e.g., Ira Gabrielson), and well-known artists (e.g., Roger Tory Peterson). Most members have been biological scientists, working for agencies in the Washington, D.C., area, who have published many articles and books dealing with biology and related subjects. The book is publIshed mainly for the benefit of the living Club members and for relatives of the deceased members. The members hope that the book will find its way into libraries across the country and that in the future, persons interested in some of the pioneer scientists, in the various professional areas of science, can obtain biographical information from a well-documented source. Most of the 542 illustrations of the members, cabin, and the Island have not been published previously. It is hopeful that the biographical sketches, pictures, and other information presented in this book can generate new information for future publications and for the website of the Washington Biologists' Field Club, which is updated frequently.

Book↗
USGS2010

Geologic controls on the recent evolution of oyster reefs in Apalachicola Bay and St. George Sound, Florida

Apalachicola Bay and St. George Sound contain the largest oyster fishery in Florida, and the growth and distribution of the numerous oyster reefs here are the combined product of modern estuarine conditions in the bay and its late Holocene evolution. Sidescan-sonar imagery, bathymetry, high-resolution seismic profiles, and sediment cores show that oyster beds occupy the crests of a series of shoals that range from 1 to 7 km in length, trend roughly north-south perpendicular to the long axes of the bay and sound, and are asymmetrical with steeper sides facing to the west. Surface sediment samples show that the oyster beds consist of shelly sand, while much of the remainder of the bay floor is covered by mud delivered by the Apalachicola River. The present oyster reefs rest on sandy delta systems that advanced southward across the region between 6400 and 4400 yr BP when sea level was 4–6 m lower than present. Oysters started to colonize the region around 5100 yr BP and became extensive by 1200 and 2400 yr BP. Since 1200 yr BP, their aerial extent has decreased due to burial of the edges of the reefs by the prodelta mud that continues to be supplied by the Apalachicola River. Oyster reefs that are still active are narrower than the original beds, have grown vertically, and become asymmetrical in cross-section. Their internal bedding indicates they have migrated westward, suggesting a net westerly transport of sediment in the bay.

Florida↗
USGS2021

In vitro effects-based method and water quality screening model for use in pre- and post-distribution treated waters

Recent urban public water supply contamination events emphasize the importance of screening treated drinking water quality after distribution. In vitro bioassays, when run concurrently with analytical chemistry methods, are effective tools to evaluating the efficacy of water treatment processes and water quality. We tested 49 water samples representing the Chicago Department of Water Management service areas for estrogen, (anti)androgen, glucocorticoid receptor-activating contaminants and cytotoxicity. We present a tiered screening approach suitable to samples with anticipated low-level activity and initially tested all extracts for statistically identifiable endocrine activity; performing a secondary dilution-response analysis to determine sample EC 50 and biological equivalency values (BioEq). Estrogenic activity was detected in untreated Lake Michigan intake water samples using mammalian (5/49; median: 0.21 ng E2Eq/L) and yeast cell (5/49; 1.78 ng E2Eq/L) bioassays. A highly sensitive (anti)androgenic activity bioassay was applied for the first time to water quality screening and androgenic activity was detected in untreated intake and treated pre-distribution samples (4/49; 0.93 ng DHTEq/L). No activity was identified above method detection limits in the yeast androgenic, mammalian anti-androgenic, and both glucocorticoid bioassays. Known estrogen receptor agonists were detected using HPLC/MS-MS (estrone: 0.72-1.4 ng/L; 17α-estradiol: 1.3-1.5 ng/L; 17β-estradiol: 1.4 ng/L; equol: 8.8 ng/L), however occurrence did not correlate with estrogenic bioassay results. Many studies have applied bioassays to water quality monitoring using only relatively small samples sets often collected from surface and/or wastewater effluent. However, to realistically adapt these tools to treated water quality monitoring, water quality managers must have the capacity to screen potentially hundreds of samples in short timeframes. Therefore, we provided a tiered screening model that increased sample screening speed, without sacrificing statistical stringency, and detected estrogenic and androgenic activity only in pre-distribution Chicago area samples.

Illinois, Indiana↗
USGS2020

Factors affecting nitrate concentrations in stream base flow

Elevated nitrogen concentrations in streams and rivers in the Chesapeake Bay watershed have adversely affected the ecosystem health of the bay. Much of this nitrogen is derived as nitrate from groundwater that discharges to streams as base flow. In this study, boosted regression trees (BRTs) were used to relate nitrate concentrations in base flow ( n = 156) to explanatory variables describing nitrogen sources, geology, and soil and catchment characteristics. From these relations, a BRT model was developed to predict base flow nitrate concentrations in streams throughout the Chesapeake Bay watershed. The highest base flow nitrate concentrations were associated with intensive agricultural land use, carbonate geology, and sparse riparian canopy, which suggested that reduced nitrogen inputs, particularly over carbonate terrane, are critical for limiting nitrate concentrations. The lowest nitrate concentrations in the BRT model were associated with extensive riparian canopy, high levels of organic carbon in soils, and suboxic conditions at shallow depths, which suggested that denitrification in the subsurface, particularly in the riparian zone, is limiting base flow nitrate concentrations. Nitrate transport from aquifers to streams can take decades to occur, resulting in decades-long lag times between the time when a land-use activity is implemented and when its effects are fully observed in streams. Predictive models of base flow nitrate concentrations in streams will help identify which portions of a watershed are likely to have large fractions of total stream nitrogen load derived from pathways with significant lag times.

Delaware, Maryland, New York, North Carolina, Penn↗
USGS2002

Linear solvation energy relationships: "rule of thumb" for estimation of variable values

For the linear solvation energy relationship (LSER), values are listed for each of the variables (V i /100, &pi;*, &beta m , &alpha; m ) for fundamental organic structures and functional groups. We give the guidelines to estimate LSER variable values quickly for a vast array of possible organic compounds such as those found in the environment. The difficulty in generating these variables has greatly discouraged the application of this quantitative structure-activity relationship (QSAR) method. This paper present the first compilation of molecular functional group values together with a utilitarian set of the LSER variable estimation rules. The availability of these variable values and rules should facilitate widespread application of LSER for hazard evaluation of environmental contaminants.

Environmental Science & Technology↗
USGS1985

A heat-flow reconnaissance of southeastern Alaska

Heat flow was measured at nine sites in crystalline and sedimentary rocks of southeastern Alaska. Seven of the sites, located between 115 and 155 km landward of the Queen Charlotte – Fairweather transform fault, have an average heat flow of 59 ± 6 mW m −2 . This value is significantly higher than the mean of 42 mW m −2 in the coastal provinces between Cape Mendocino and the Queen Charlotte Islands, to the south, and is lower than the mean of 72 ± 2 mW m −2 for 81 values within 100 km of the San Andreas transform fault, even farther south. This intermediate value suggests the absence of significant heat sinks associated with Cenozoic subduction and of heat sources related to either late Cenozoic tectono-magmatic events or significant shear-strain heating. At Warm Springs Bay, 75 km from the plate boundary, an anomalously high heat flow of 150 mW m −2 can most plausibly be ascribed to the thermal spring activity from which its name is derived. At Quartz Hill, 240 km landward of the plate boundary, a value of 115 mW m −2 might indicate a transition to a province of high heat flow resulting from late Tertiary and Quaternary extension and volcanism.

Alaska↗
USGS2025

Biologging to identify nesting and non-nesting emergences for four species of imperiled sea turtles

Quantifying sea turtle nesting behavior is essential for recovery planning and evaluating management actions. Traditional monitoring approaches, based on nest counts from beach surveys, can misclassify non-nesting emergences, obscure true fecundity, and underestimate clutch frequency, metrics that directly influence population models and regulatory decisions. Here, we demonstrate that high-resolution acceleration data loggers (ADLs) can reliably discriminate nesting from non-nesting emergences across four imperiled species of sea turtles at sites in the Gulf of America, southeast USA, and Caribbean. From 60 recovered ADL deployments on green ( Chelonia mydas ; N = 10), hawksbill ( Eretmochelys imbricata ; N = 7), Kemp’s ridley ( Lepidochelys kempii ; N = 21), and loggerhead sea turtles ( Caretta caretta ; N = 22) lasting on average 17.5 ± 8.7 days (range 2–43 days), we identified 54 nesting events and 76 non-nesting emergences, with >97% accuracy when compared to direct observations. These data provide the first observer-validated, species-specific behavioral signatures of nesting phases and reveal correlations between egg-laying duration and clutch size. All non-nesting emergences occurred within 72 hours of subsequent nesting, allowing managers to anticipate nest deposition windows. By refining inter-nesting intervals and fecundity estimates, ADLs offer a practical path to reduce error in clutch frequency estimates. The integration of ADL-derived algorithms with satellite-transmitting tags would enable the remote, real-time monitoring of nesting activity, creating a system for the remote monitoring of inter-nesting intervals and nest fecundity that are crucial to quantify the impacts of climate change and other threats to sea turtle nesting habitat.

Alabama, Florida, North Carolina, Texas↗
USGS2020

The historic events at Kilauea Volcano in 2018: Summit collapse, rift zone eruption, and Mw 6.9 earthquake: Preface to the special issue

Kīlauea Volcano, on the Island of Hawaiʻi, has had a prominent role in the science of volcanology, and a long history of generating new insights into how volcanoes operate (Tilling et al. 2014; Garcia 2015). Native Hawaiians shared ideas on the behavior of the volcano with early Western visitors to Kīlauea, addressing the basic geometry of magma supply and transport (Ellis 1825; Bishop 1827). The recognition that magma originated at the summit and was transferred at shallow levels to the flanks implied that these ideas were rooted in centuries of observation preceding Western contact. The lava lake activity at Kīlauea’s summit in the 1800s and early 1900s fascinated early geologists, such as James Dana (1890), who published one of the first inquiries into the fundamental processes of Hawaiian volcanoes. The sustained activity led to the 1912 founding of the Hawaiian Volcano Observatory, one of the world’s first volcano observatories, by Thomas Jaggar (Tilling et al. 2014). Kīlauea’s activity in the 20th century contributed to the development of many modern volcano monitoring techniques (Tilling et al. 2014), which helped refine conceptual models of how volcanoes behave (Eaton and Murata, 1960).

Hawaii↗
USGS2026

2026–2031 U.S. Geological Survey strategy for a hazard ready Nation—Actionable science for risk reduction

Executive Summary The USGS Strategy for a Hazard Ready Nation provides an approach that U.S. Geological Survey (USGS) researchers and staff can use to deliver actionable, user-focused science that supports risk-informed decision making aimed at reducing risk and losses across the Nation. The Strategy builds upon successful efforts within the USGS and seeks to promote and prioritize similar work in the future under an organized framework. Rooted in four priorities—(1) center end-user needs, (2) enhance research relevance, (3) support product and service development and implementation, and (4) improve communication—the USGS Strategy for a Hazard Ready Nation is designed to focus and guide, not prescribe, activities. Strategic actions are proposed to achieve these four priorities in a timely fashion. The USGS plans to continually build upon the Strategy for a Hazard Ready Nation to deliver actionable information for risk-informed decision making.

Circular↗
USGS2018

Nearshore single-beam bathymetry data collected in 2015, Dauphin Island, Alabama

Dauphin Island, Alabama, is a barrier island located in the northern Gulf of Mexico that supports local residences, tourism, commercial infrastructure, and historic Fort Gaines. During the past decade, Dauphin Island was affected by several major hurricanes—Hurricanes Ivan (2004), Katrina (2005), and Isaac (2012)—and storms, along with sea-level rise, continue to present a threat to island stability. State and Federal managers are using a scientific approach to identify, formulate, and implement a long-term plan to provide restoration options for Dauphin Island, thereby helping increase its resilience against future storms and sea-level rise. Island morphology, including current bathymetry and shoreline data, is one scientific domain being investigated in an effort to produce a comprehensive restoration plan funded by an interagency grant from the National Fish and Wildlife Foundation Gulf Environmental Benefit Fund . In August 2015, the U.S. Geological Survey ( USGS ) St. Petersburg Coastal and Marine Science Center ( SPCMSC ), in cooperation with the U.S. Army Corps of Engineers at the U.S. Army Engineer Research and Development Center, Mobile District, and the State of Alabama, conducted bathymetric surveys of the nearshore waters surrounding Dauphin Island. This report provides a detailed methodology for the data acquisition and post-processing of 1,165-line kilometers (km) of single-beam bathymetry data collected under the USGS–SPCMSC Alabama Barrier Island Restoration Study . These data were acquired and processed under USGS field activity number 2015–326–FA . Data are provided in three datums: (1) the International Terrestrial Reference Frame of 2000, ellipsoid height (from –47.04 meters (m) to –29.36 m); (2) the North American Datum of 1983, CORS96 realization (NAD83 (CORS96)) horizontal, and the North American Vertical Datum 1988 GEOID12A vertical (from –0.24 m to –17.33 m); and (3) NAD83 (CORS96) horizontal, and mean lower low water vertical (from –0.12 m to –17.93 m). The x,y,z point datasets, trackline shapefiles, digital and handwritten Field Activity Collection Systems logs, one 50-m digital elevation model, and formal Federal Geographic Data Committee metadata are obtainable from the Data Downloads page or the associated USGS data release .

Alabama↗
USGS2025

Trade-offs in designing a participatory acoustic study of bats: Comparison of user engagement and data quality between two ultrasonic detectors

Technology for the acoustic detection of animals has advanced rapidly over the past few decades. Due to ease of use, consistency, and safety, acoustic methods are particularly useful for science applications that engage the public. In this study, we evaluated the technological and educational trade-offs between 2 acoustic bat detectors in a participatory science application along the Colorado River in the Grand Canyon, Arizona. Both devices were deployed simultaneously by commercial river guides in parallel with sampling insect prey for 1 h at dusk on 48 dates between April and October 2022. The detector with higher data quality capabilities recorded more bats overall (a mean of 231 more passes per hour) and more species (19 species, including 4 not detected by the lower quality detector). However, data from both detectors showed a decrease in total bat activity from spring to fall, despite the differences in recording capabilities. We conclude that detector quality matters, but user engagement is important when designing participatory research.

Journal of North American Bat Research↗
USGS2010

The dispersion of fibrous amphiboles by glacial processes in the area surrounding Libby, Montana, USA

Mining operations began at a world-class vermiculite deposit at Vermiculite Mountain near Libby, Montana, circa 1920 and ended in 1990. Fibrous and asbestiform amphiboles intergrown with vermiculite ore are suspected to be a causative factor in an abnormally high number of cases of respiratory diseases in former mine and mill workers, and in residents of Libby. The question addressed in this report is whether some of the amphibole from Vermiculite Mountain could have been dispersed by Pleistocene glacial processes rather than by human activity after vermiculite mining began. The history of Pinedale glaciation in the Libby area provides a framework for estimating the presence and distribution of asbestiform amphiboles derived from Vermiculite Mountain and found in naturally occurring sediments of Glacial Lake Kootenai that underlie the Libby Valley area. There were two situations where sediments derived from Vermiculite Mountain were deposited into Glacial Lake Kootenai: (1) as lake-bottom sediments derived from meltwater flowing down Rainy Creek when the valley south of Vermiculite Mountain was free of ice but active ice still covered Vermiculite Mountain; and (2) as lake-bottom sediments eroded from the Rainy Creek outwash and re-deposited during a re-advance of the Purcell Trench Glacier lobe near Moyie Springs, Idaho.

Montana↗
USGS2019

Point sources and agricultural practices control spatial-temporal patterns of orthophosphate in tributaries to Chesapeake Bay

Orthophosphate (PO 4 ) is the most bioavailable form of phosphorus (P). Excess PO 4 may cause harmful algal blooms in aquatic ecosystems. A major restoration effort is underway for Chesapeake Bay (CB) to reduce P, nitrogen, and sediment loading to CB. Although PO 4 cycling and delivery to streams has been characterized in small-scale studies, regional drivers of PO 4 patterns remain poorly understood because most water quality trend assessment focus on total P. Moreover, these trend assessments are usually at an annual timestep. To address this research gap, we analyzed PO 4 patterns over a 9-year period at 53 monitoring stations across the CB watershed to: 1) characterize the role of PO 4 in total P fluxes and trends; 2) describe spatial and temporal patterns of PO 4 concentrations across seasons and streamflow ; and 3) explore factors explaining these patterns. Agricultural watersheds exported the most total P compared with watersheds under different land uses (e.g., urban or forest), with PO 4 comprising up to 50% of those exports. Although PO 4 exports are declining at many sites, some agricultural regions are experiencing increasing trends at a rate sufficient to drive total P trends. Regression modeling results suggest that point source load reductions are likely responsible for decreasing PO 4 concentrations observed at many sites. Watersheds with more Conservation Reserve Program enrollment had lower summer PO 4 concentrations, highlighting the effectiveness of this practice. Manure inputs strongly predicted PO 4 concentrations at high flows across all seasons. Both manure applications and conservation tillage were correlated with changes in PO 4 concentrations at high flow, suggesting these activities could contribute to increasing PO 4 concentrations. This study highlights the effectiveness of point source control for reducing PO 4 exports and underscores the need for management strategies to target sources, practices, and landscape factors determining PO 4 loss from soils where manure inputs remain high.

Delaware, Maryland, New York, Pennsylvania, Virgin↗
USGS1998

Chemistry, isotopic composition, and origin of a methane-hydrogen sulfide hydrate at the Cascadia subduction zone

Although the presence of extensive gas hydrate on the Cascadia margin, offshore from the western U.S. and Canada, has been inferred from marine seismic records and pore water chemistry, solid gas hydrate has only been found at one location. At Ocean Drilling Program (ODP) Site 892, offshore from central Oregon, gas hydrate was recovered close to the sediment-water interface at 2–19 m below the seafloor (mbsf) at 670 m water depth. The gas hydrate occurs as elongated platy crystals or crystal aggregates, mostly disseminated irregularly, with higher concentrations occurring in discrete zones, thin layers, and/or veinlets parallel or oblique to the bedding. A 2- to 3-cm thick massive gas hydrate layer, parallel to bedding, was recovered at ∼ 17 mbsf. Gas from a sample of this layer was composed of both CH 4 and H 2 S. This sample is the first mixed-gas hydrate of CH 4 H 2 S documented in ODP; it also contains ethane and minor amounts of CO 2 . Measured temperatures of the recovered core ranged from 2 to −1.8°C and are 6 to 8 degrees lower than in-situ temperatures. These temperature anomalies were caused by the partial dissociation of the CH 4 H 2 S hydrate during recovery without a pressure core sampler.During this dissociation, toxic levels of H 2 S (δ 34 S, +27.4‰) were released. The δ 13 C values of the CH 4 in the gas hydrate, −64.5 to −67.5‰ (PDB) , together with δD values of −197 to −199‰ (SMOW) indicate a primarily microbial source for the CH 4 . The δ 18 O value of the hydrate H 2 O is +2.9‰ (SMOW) , comparable with the experimental fractionation factor for sea-ice. The unusual composition (CH 4 H 2 S) and depth distribution (2–19 mbsf) of this gas hydrate indicate mixing between a methane-rich fluid with a pore fluid enriched in sulfide; at this site the former is advecting along an inclined fault into the active sulfate reduction zone. The facts that the CH 4 H 2 S hydrate is primarily confined to the present day active sulfate reduction zone (2–19 mbsf), and that from here down to the BSR depth (19–68 mbsf) the gas hydrate inferred to exist is a ≥99% CH 4 hydrate, suggest that the mixing of CH 4 and H 2 S is a geologically young process. Because the existence of a mixed CH 4 H 2 S hydrate is indicative of moderate to intense advection of a methane-rich fluid into a near surface active sulfate reduction zone, tectonically active (faulted) margins with organic-rich sediments and moderate to high sedimentation rates are the most likely regions of occurrence. The extension of such a mixed hydrate below the sulfate reduction zone should reflect the time-span of methane advection into the sulfate reduction zone.

Earth and Planetary Science Letters↗
USGS2002

Geochemistry of fluid phases and sediments: Relevance to hydrothermal circulation in Middle Valley, ODP Legs 139 and 169

Geochemical and isotopic studies of pore fluids and solid phases recovered from the Dead Dog and Bent Hill hydrothermal sites in Middle Valley (Ocean Drilling Program Leg 169) have been compared with similar data obtained previously from these sites during Ocean Drilling Program Leg 139. Although generally the hydrothermal systems reflect non-steady state conditions, the data allow an assessment of the history of the hydrothermal processes. Sediment K/A1 ratios as well as the distribution of anhydrite in the sediments suggest that the Dead Dog hydrothermal field has been, and still is, active. In contrast, similar data in the Bent Hill hydrothermal field indicate a waning of hydrothermal activity. Pore fluid and hydrothermal vent data in the Dead Dog hydrothermal field are similar in nature to the data collected during ODP Leg 139. In the area of the Bent Hill sulfide deposit, however, the pore water data indicate that recent wholesale flushing of the sediment column with relatively unaltered seawater has obliterated a previous record of hydrothermal activity in the pore fluids. Data from the deepest part of Hole 1035A in the Bent Hill locality show the presence of hydrothermal fluids at greater depths in this area. This suggests the origin of the hydrothermal fluids found to be emanating from Hole 1035F, which constitutes one of the first man made hydrothermal vents in the Middle Valley hydrothermal system. Similarly, CORKed Hole 858G, because of seal failures, has acted as a hydrothermal vent, with sulfide deposits forming inside the CORK. ?? 2002 Elsevier Science Ltd. All rights reserved.

Applied Geochemistry↗
USGS2006

Experimental recovery of sea otter carcasses at Kodiak Island, Alaska, following the Exxon Valdez oil spill

ound, Alaska, spilling approximately 11 million barrels of crude oil. Oil was deposited on beaches nearly 700 km from the spill site (Galt and Payton 1990, Piatt et al. 1990), affecting thousands of hectares of sea otter (Enhydra lutris) habitat. Two of the principal limitations in determining the initial effects of the Exxon Valdez oil spill on sea otter populations were a lack of recent population data, and a lack of information on the proportion of the total number of sea otters killed by the spill that were actually recovered. ound, Alaska, spilling approximately 11 million barrels of crude oil. Oil was deposited on beaches nearly 700 km from the spill site (Galt and Payton 1990, Piatt et al. 1990), affecting thousands of hectares of sea otter (Enhydra lutris) habitat. Two of the principal limitations in determining the initial effects of the Exxon Valdez oil spill on sea otter populations were a lack of recent population data, and a lack of information on the proportion of the total number of sea otters killed by the spill that were actually recovered. On 24 March 1989, the T/V Exxon Valdez ran aground in Prince William Sound, Alaska, spilling approximately 11 million barrels of crude oil. Oil was deposited on beaches nearly 700 km from the spill site (Galt and Payton 1990, Piatt et al . 1990), affecting thousands of hectares of sea otter ( Enhydra lutris ) habitat. Two of the principal limitations in determining the initial effects of the Exxon Valdez oil spill on sea otter populations were a lack of recent population data, and a lack of information on the proportion of the total number of sea otters killed by the spill that were actually recovered. In late April and early May oil spread to the Kodiak Archipelago. With the oil came wildlife rescue, beach cleanup, and other spill-response activities including searches for dead birds and mammals. We took this opportunity to assess experimentally the recovery of sea otter carcasses in the Kodiak Island area. Specifically, we were interested in the proportion of the total number of dead sea otters the recovered carcasses represented.

Alaska↗
USGS2006

Toward "Supervolcano" technology

I n addition to depicting the ultimate volcano-eruption horror story, the recent Discovery Channel/BBC coproduction “Supervolcano” speculates about what technology will be available to the geophysicist in 2025 to monitor active volcanoes. The result is a fictional Virtual Geophysical Laboratory that, when fed the right data, predicts eruption scenarios, thereby providing information to help guide civil emergency-response decisions. On page 821 of this issue, Patanè et al. ( 1 ) report a key step toward realizing such an advanced volcano-monitoring technology.

Science↗