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At least 883 records · Page 49Linked to original sources

USGS2006

Trends in snowfall versus rainfall in the western United States

The water resources of the western United States depend heavily on snowpack to store part of the wintertime precipitation into the drier summer months. A well-documented shift toward earlier runoff in recent decades has been attributed to 1) more precipitation falling as rain instead of snow and 2) earlier snowmelt. The present study addresses the former, documenting a regional trend toward smaller ratios of winter-total snowfall water equivalent (SFE) to winter-total precipitation (P) during the period 1949-2004. The trends toward reduce d SFE are a response to warming across the region, with the most significant reductions occurring where winter wet-day minimum temperatures, averaged over the study period, were warmer than -5??C. Most SFE reductions were associated with winter wet-day temperature increases between 0?? and +3??C over the study period. Warmings larger than this occurred mainly at sites where the mean temperatures were cool enough that the precipitation form was less susceptible to warming trends. The trends toward reduced SFE/P ratios w ere most pronounced in March regionwide and in January near the West Coast, corresponding, to widespread warming in these months. While mean temperatures in March were sufficiently high to allow the warming, trend to produce SFE/P declines across the study region, mean January temperatures were cooler. with the result that January SFE/P impacts were restricted to the lower elevations near the West Coast. Extending the analysis back to 1920 sho ws that although the trends presented here may be partially attributable to interdecadal climate variability associated with the Pacific decadal oscillation. they also appear to result from still longer-term climate shifts.

Journal of Climate↗

USGS2017

Geologic field trip guide to Mount Mazama and Crater Lake Caldera, Oregon

Crater Lake partly fills one of the most spectacular calderas of the world—an 8 by 10 kilometer (km) basin more than 1 km deep formed by collapse of the Mount Mazama volcano during a rapid series of explosive eruptions ~7,700 years ago. Having a maximum depth of 594 meters (m), Crater Lake is the deepest lake in the United States. Crater Lake National Park, dedicated in 1902, encompasses 645 square kilometers (km 2 ) of pristine forested and alpine terrain, including the lake itself, and virtually all of Mount Mazama. The geology of the area was first described in detail by Diller and Patton (1902) and later by Williams (1942), whose vivid account led to international recognition of Crater Lake as the classic collapse caldera. Because of excellent preservation and access, Mount Mazama, Crater Lake caldera, and the deposits formed by the climactic eruption constitute a natural laboratory for study of volcanic and magmatic processes. For example, the climactic ejecta are renowned among volcanologists as evidence for systematic compositional zonation within a subterranean magma chamber. Mount Mazama’s climactic eruption also is important as the source of the widespread Mazama ash, a useful Holocene stratigraphic marker throughout the Pacific Northwest United States, adjacent Canada, and offshore. A detailed bathymetric survey of the floor of Crater Lake in 2000 (Bacon and others, 2002) provides a unique record of postcaldera eruptions, the interplay between volcanism and filling of the lake, and sediment transport within this closed basin. Knowledge of the geology and eruptive history of the Mount Mazama edifice, enhanced by the caldera wall exposures, gives exceptional insight into how large volcanoes of magmatic arcs grow and evolve. In addition, many smaller volcanoes of the High Cascades beyond the limits of Mount Mazama provide information on the flux of mantle-derived magma through the region. General principles of magmatic and eruptive processes revealed by geologic research at Crater Lake have been incorporated not only in scientific investigations elsewhere, but also in the practical evaluation of local hazards (Bacon and others, 1997b) and geothermal resources (Bacon and Nathenson, 1996). The 1:24,000-scale geologic map of Mount Mazama and Crater Lake caldera (Bacon, 2008) is unusual because it portrays bedrock (outcrop), surficial, and lake floor geology. Caldera wall geology is depicted in detail on the accompanying geologic panoramas, and bedrock geology is shown in a 1:50,000-scale geologic map. This field guide supersedes earlier geology guides of Crater Lake (Bacon, 1987, 1989).

Oregon↗

USGS2020

Climate change causes river network contraction and disconnection in the H.J. Andrews Experimental Forest, Oregon, USA

Headwater streams account for more than 89% of global river networks and provide numerous ecosystem services that benefit downstream ecosystems and human water uses. It has been established that changes in climate have shifted the timing and magnitude of observed precipitation, which, at specific gages, have been directly linked to long-term reductions in large river discharge. However, climate impacts on ungaged headwater streams, where ecosystem function is tightly coupled to flow permanence along the river corridor, remain unknown due to the lack of data sets and ability to model and predict flow permanence. We analyzed a network of 10 gages with 38–69 years of records across a 5th-order river basin in the U.S. Pacific Northwest, finding increasing frequency of lower low-flow conditions across the basin. Next, we simulated river network expansion and contraction for a 65-year period of record, revealing 24% and 9% declines in flowing and contiguous network length, respectively, during the driest months of the year. This study is the first to mechanistically simulate network expansion and contraction at the scale of a large river basin, informing if and how climate change is altering connectivity along river networks. While the heuristic model presented here yields basin-specific conclusions, this approach is generalizable and transferable to the study of other large river basins. Finally, we interpret our model results in the context of regulations based on flow permanence, demonstrating the complications of static regulatory definitions in the face of non-stationary climate.

Oregon↗

USGS2018

Paleoclimate Records: Providing context and understanding of current Arctic change

At present, the Arctic Ocean is experiencing changes in ocean surface temperature and sea ice extent that are unprecedented in the era of satellite observations, which extend from the 1980s to the present (see sections 5c,d). To provide context for current changes, scientists turn to paleoclimate records to document and study anthropogenic influence and natural decadal and multidecadal climate variability in the Arctic system. Paleoceanographic records extend limited Arctic instrumental measurements back in time and are central to improving our understanding of climate dynamics and the predictive capability of climate models. By comparing paleoceanographic records with modern observations, scientists can place the rates and magnitudes of modern Arctic change in the context of those inferred from the geological record. Over geological time, paleoceanographic reconstructions using, for instance, marine sediment cores indicate that the Arctic has experienced huge sea ice fluctuations. These fluctuations range from nearly completely ice-free to totally ice-covered conditions. The appearance of ice-rafted debris and sea ice-dependent diatoms in Arctic marine sediments indicate that the first Arctic sea ice formed approxi-mately 47 million years ago (St. John 2008; Stickley et al. 2009; Fig. SB5.1), coincident with an interval of declining atmospheric carbon dioxide (CO2) concentration, global climate cooling, and expansion of Earths cryosphere during the middle Eocene. The development of year-round (i.e., perennial) sea ice in the central Arctic Ocean, similar to conditions that exist today, is evident in sediment records as early as 1418 million years ago (Darby 2008). These records suggest that transitions in sea ice cover occur over many millennia and often vary in concert with the waxing and waning of circum-Arctic land ice sheets, ice shelves, and long-term fluctuations in ocean and atmospheric temperature and atmospheric CO2 concentrations (Stein et al. 2012; Jakobsson et al. 2014). Over shorter time scales, shallow sediment records from Arctic Ocean continental shelves allow more detailed, higher-resolution (hundreds of years resolution) reconstructions of sea ice history extending through the Holocene (11 700 years ago to present), the most recent interglacial period. A notable feature of these records is an early Holocene sea ice minimum, corresponding to a thermal maximum (warm) period from 11 000 to 5000 years ago, when the Arctic may have been warmer and had less summertime sea ice than today (Kaufman et al. 2004). However, it is not clear that the Arctic was ice-free at any point during the Holocene (Polyak et al. 2010). High-resolution paleosea ice records from the western Arctic in the Chukchi and East Siberian Seas indicate that sea ice concentrations increased through the Holocene in concert with decreasing summer solar insolation (sunlight). Sea ice extent in this region also varied in response to the volume of Pacific water delivered via the Bering Strait into the Arctic Basin (Stein et al. 2017; Polyak et al. 2016). Records from the Fram Strait (Mller et al. 2012), Laptev Sea (Hrner et al. 2016), and Canadian Arctic Archipelago (Vare et al. 2009) also indicate a similar long-term expansion of sea ice and suggest sea ice extent in these regions is modulated by the varying influx of warm Atlantic water into the Arctic Basin (e.g., Werner et al. 2013). Taken together, available records support a circum-Arctic sea ice expansion during the late Holocene. A notably high-resolution summer sea ice history (<5-year resolution) has been established for the last 1450 years using a network of terrestrial records (tree ring , lake sediment, and ice core records) located around the margins of the Arctic Ocean (Kinnard et al. 2011). Results summarized in Fig. SB5.2 indicate a pronounced decline in summer sea ice extent beginning in the 20th century, with exceptionally low ice extent recorded since the mid-1990s, consistent with the satellite record (see section 5d). While several episodes of reduced and expanded sea ice extent occur in association with climate anomalies such as the Medieval Climate Warm Period (AD 8001300) and the Little Ice Age (AD 14501850), the magnitude and pace of the modern decline in sea ice is outside of the range of natural variability and unprecedented in the 1450-year reconstruction (Kinnard et al. 2011). A radiocarbon-dated driftwood record of the Ellesmere ice shelf in the Canadian High Arctic, the oldest landfast ice in the Northern Hemisphere, also demonstrates a substantial reduction in ice extents over the 20th century (England et al. 2017). A supporting sediment record indicates that inflowing Atlantic water in Fram Strait has warmed by 2C since 1900, driving break up and melt of sea ice (Spielhagen et al. 2011). Complementary mooring and satellite observations show the Atlantification of the eastern Arctic due to enhanced inflow of warm saline water through Fram Strait (Nilsen et al. 2016) and nutrient-rich Pacific water via the Bering has increased by more than 50% (Woodgate et al. 2012), further driving sea ice melt and warming seas. Similar high-resolution proxy records from Arctic regions also indicate that the modern rate of increasing annual surface air temperatures has not been observed over at least the last 2000 years (McKay and Kaufman 2014). Scientists conclude that broad-scale sea ice variations recorded in the paleo record were dominantly driven by changes in basin-scale changes in atmospheric circulation patterns, fluctuations in air temperature, strength of incoming solar radiation, and changes in the inflow of warm water via Pacific and Atlantic inflows (Polyak et al. 2010). There is general consensus that ice-free Arctic summers are likely before the end of the 21st century (e.g., Stroeve et al. 2007; Massonnet et al. 2012), while some climate model projections suggest ice-free Arctic summers as early as 2030 (Wang and Overland 2009). Paleoclimate studies and observational time series attribute the decline in sea ice extent and thickness over the last decade to both enhanced greenhouse warming and natural climate variability. While understanding the interplay of these factors is critical for future projections of Arctic sea ice and ecosystems, most observational time series records cover only a few decades. This highlights the need for additional paleoceanographic reconstructions across multiple spatial and temporal domains to better understand the drivers and implications of present and future Arctic Ocean change.

Bulletin American Meteorological Society↗

USGS1980

Paleoecological evaluation of Late Eocene biostratigraphic zonations of the Pacific Coast of North America

The late Eocene zonal criteria of the west coast of North America are to a large extent controlled by paleoecology and, therefore, the correlation of coeval but environmentally different benthic foraminiferal faunas cannot be achieved before paleoecological control of the biostratigraphy is understood. The faunal trends, morphology, characteristic occurrences and estimated upper depth limits of the benthic foraminifers and associated microfossils in the Oregon and Washington study sections lead to the recognition of paleoecologic facies. The interpretation of these late Eocene facies as bathymetric and low-oxygen facies is based on analogous late Eocene and Holocene assemblages. The paleoecologic facies criteria are often identical to the stage and zonal criteria. In the California zonal schemes, the Narizian zones are identified by lower and middle bathyal faunas whereas the Refugian zones are identified by outer neritic and upper bathyal faunas. The Washington late Eocene zones are identified by middle bathyal and transported neritic faunas. Modifications of the existing zonal schemes such that time and not paleoecology is the controlling factor results in a zonation that synthesizes the existing zonal schemes, recognizes regional stratigraphic ranges of diagnostic species, and removes paleoecologically controlled species occurrences. The late Narizian encompasses a bathyal and a neritic facies. The bathyal facies is correlative with a modified Bulimina corrugata Zone of California and the Uvigerina cf. U. yazooensis Zone of Washington. The neritic late Narizian facies corresponds to a modified Bulimina schencki-Plectofrondicularia cf. P. jenkinsi Zone of Washington and a modified Amphimorphina jenkinsi Zone of California. The Refugian can also be divided into a neritic and a bathyal facies. Although the early and late subdivisions of this stage are tentative, the early Refugian is equivalent to the modified versions of the Cibicides haydoni and the Uvigerina atwilli Subzones of the Valvulineria tumeyensis Zone and the Uvigerina vicksburgensis Zone (in part) of California and the modified version of the Sigmomorphina schencki Zone of Washington. The late Refugian is equivalent to modified versions of the California Uvigerina vicksburgensis Zone (in part) and the Washington Cassidulina galvinensis Zone. The Cibicides haydoni Subzone is the neritic facies of the Refugian Stage, whereas the faunas of the Uvigerina atwilli Subzone and the Uvigerina vicksburgensis, Sigmomorphina schencki and Cassidulina galvinensis Zones represent the bathyal Refugian facies.

Paleontological Monograph↗

USGS2020

Trends and biological effects of environmental contaminants in lamprey

Environmental contamination is of global concern. Lamprey are scientifically, ecologically, culturally, and economically important fishes. Our study represents the first synthesis ever on environmental contamination in lamprey. Objectives of this study include: (1) evaluate lethal and sublethal effects of environmental contaminants on lamprey, thereby providing insight into the potential for environmental contaminants to affect lamprey abundance, (2) highlight the unique characteristics of contaminant accumulation in lamprey, (3) determine whether spatial and temporal trends observed in contaminant concentrations of other top predators of aquatic food webs are reflected in the spatial and temporal trends of contaminant concentrations of lamprey, (4) identify key environmental contaminants affecting consumption advisories for people eating lamprey, and (5) identify important gaps in our knowledge of environmental contamination in lamprey. The geographic scope of this synthesis is worldwide. We conclude that, in general, the environmental contaminant concentrations that have been experienced by lamprey in the wild appear to be nonlethal to lamprey. However, environmental contaminants exert sublethal effects on lamprey. Sea lamprey ( Petromyzon marinus ) and Pacific lamprey ( Entosphenus tridentatus ) are relatively high in total mercury (Hg) concentration compared with other fishes. Compared with other top predators, lamprey are relatively low in polychlorinated biphenyl (PCB) concentration and concentrations of organochlorine pesticides. We also conclude that regulations on the use of PCBs, beginning in the 1970s, were effective in dramatically reducing PCB concentration in lamprey since the 1970s. Emerging contaminants, such as pharmaceuticals, microplastics, and per- and polyfluorinated alkyl substances (PFAS), have yet to be studied in lamprey.

Journal of Great Lakes Research↗

USGS2021

Expected warning times from the ShakeAlert earthquake early warning system for earthquakes in the Pacific Northwest

The ShakeAlert® earthquake early warning system has been live since October 2019 for the testing of public alerting to mobile devices in California and will soon begin testing this modality in Oregon and Washington. The Pacific Northwest presents new challenges and opportunities for ShakeAlert owing to the different types of earthquakes that occur in the Cascadia subduction zone. Many locations in the Pacific Northwest are expected to experience shaking from shallow crustal earthquakes (similar to those in California), earthquakes that occur deep within the subducted slab, and large megathrust earthquakes that occur primarily offshore. The different geometries and maximum magnitudes associated with these types of earthquakes lead to a range of warning times that are possible between when the initial ShakeAlert Message is issued and when a user experiences strong shaking. After an earthquake begins, the strategy of the ShakeAlert system for public alerting is to warn people who are located close enough to the fault that the system estimates they will experience at least weak to moderate shaking. By alerting the public at these low levels of expected shaking, it is possible to provide sufficient warning times for some users to take protective actions before strong shaking begins. In this study, we present an analysis of past ShakeAlert Messages as well as simulations of historical earthquakes and potential future Cascadia earthquakes to quantify the range of warning times that users who experience strong or worse shaking are likely to receive. Additional applications for ShakeAlert involve initiation of automatic protective actions prior to the onset of shaking, such as slowing trains, shutting water supplies, and opening firehouse doors, which are beyond the scope of this paper. Users in the Pacific Northwest should expect that the majority of alerts they receive will be from shallow crustal and intraslab earthquakes. In these cases, users will only have a few seconds of warning before strong shaking begins. This remains true even during infrequent, offshore great (magnitude ≥8) megathrust earthquakes, where warning times will generally range from seconds to tens of seconds, depending on the user’s location and the intensity of predicted shaking that a user chooses to be alerted for, with the longest warning times of 50–80 seconds possible only for users located at considerable distance from the epicenter. ShakeAlert thus requires short, readily understood alerts stating that earthquake shaking is imminent and suggesting protective actions users should take. Extensive education and outreach efforts that emphasize the need to take actions quickly will be required for ShakeAlert to successfully reduce injuries and losses.

California, Oregon, Washington↗

USGS2021

Plant community succession following ungulate exclusion in a temperate rainforest

Ecosystem structure and processes of coastal temperate rainforests of the Pacific Northwest are thought to be strongly influenced by herbivory primarily of Roosevelt elk ( Cervus elaphus roosevelti ) and secondarily of Columbian black-tailed deer ( Odocoileus hemionus columbianus ). Two large (0.5-ha) exclosures were built in old-growth coniferous rainforest communities in Olympic National Park, Washington, during 1979 to study these effects. Cover of shrubs, ferns, herbs, and graminoids and numbers of tree seedlings were described over 36 yr. Results show a sequence following ungulate exclusion of early release of shrubs, ferns, and herbs followed by eventual dominance of shrubs as other vegetation layers become shaded. Short-term responses of individual species reflected functional traits related to ability to avoid or tolerate herbivory. Over the longer term, effects reflected changing competitive relationships among vegetation layers and other ecosystem dynamics such as the provision of fallen trees in the appropriate decay class to serve as establishment substrate for tree seedlings. In aggregate, vegetation composition shifted after 36 yr from a system dominated by herbaceous cover with a major graminoid component to one dominated by shrubs (5- to 6-fold absolute increase) and ferns (5–7% increase in absolute cover), less absolute herb cover (15–20% loss), and almost no graminoids (<1.5% cover remaining in any plot) after 36 yr. These changes represented a substantial loss in plant community diversity with a loss of 46 of 74 species. Elk abundance outside of the exclosures began to decline in the 1990s leading to parallel changes in plant community trajectories outside of exclosures to those initially seen inside. While this suggests plant community responses inside the exclosures were also driven by elk exclusion, the strength of this response depends on elk abundance.

Washington↗

USGS1992

Pliocene paleoclimatic interpretation of DSDP Site 580 (NW Pacific) using diatoms

High-resolution quantitative diatom data are tabulated for the early part of the late Pliocene (3.25 to 2.08 Ma) at DSDP Site 580 in the northwestern Pacific. Sample spacing averages 11 k.y. between 3.1 and 2.8 Ma, but increases to 14 to 19 k.y. prior to 3.1 Ma and after 2.8 Ma. Q-mode factor analysis of the middle Pliocene assemblage reveals four factors which explain 92.4% of the total variance of the 47 samples studied between 3.25 and 2.55 Ma. Three of the factors are closely related to modern subarctic, transitional, and subtropical elements, while the fourth factor, which is dominated by Coscinodiscus marginatus and the extinct Pliocene species Neodenticula kamtschatica , appears to correspond to a middle Pliocene precursor of the subarctic water mass. Knowledge of the modern and generalized Pliocene paleoclimatic relationships of various diatom taxa is used to generate a paleoclimate curve (“Twt”) based on the ratio of warm-water (subtropical) to cold-water diatoms with warm-water transitional taxa ( Thalassionema nitzschioides, Thalassiosira oestrupii , and Coscinodiscus radiatus ) factored into the equation at an intermediate (0.5) value. The “Twt” ratios at more southerly DSDP Sites 579 and 578 are consistently higher (warmer) than those at Site 580 throughout the Pliocene, suggesting the validity of the ratio as a paleoclimatic index. Diatom paleoclimatic data reveal a middle Pliocene (3.1 to 3.0 Ma) warm interval at Site 580 during which paleotemperatures may have exceeded maximum Holocene values by 3°–5.5°C at least three times. This middle Pliocene warm interval is also recognized by planktic foraminifers in the North Atlantic, and it appears to correspond with generalized depleted oxygen isotope values suggesting polar warming. The diatom “Twt” curve for Site 580 compares fairly well with radiolarian and silicoflagellate paleoclimatic curves for Site 580, planktic foraminiferal sea-surface temperature estimates for the North Atlantic, and benthic oxygen isotope curves for late Pliocene, although higher resolution studies on paired samples are required to test the correspondence of these various paleoclimatic indices.

Marine Micropaleontology↗

USGS2012

Arthropod prey for riparian associated birds in headwater forests of the Oregon Coast Range

Headwater riparian areas occupy a large proportion of the land base in Pacific Northwest forests, and thus are ecologically and economically important. Although a primary goal of management along small headwater streams is the protection of aquatic resources, streamside habitat also is important for many terrestrial wildlife species. However, mechanisms underlying the riparian associations of some terrestrial species have not been well studied, particularly for headwater drainages. We investigated the diets of and food availability for four bird species associated with riparian habitats in montane coastal forests of western Oregon, USA. We examined variation in the availability of arthropod prey as a function of distance from stream. Specifically, we tested the hypotheses that (1) emergent aquatic insects were a food source for insectivorous birds in headwater riparian areas, and (2) the abundances of aquatic and terrestrial arthropod prey did not differ between streamside and upland areas during the bird breeding season. We found that although adult aquatic insects were available for consumption throughout the study period, they represented a relatively small proportion of available prey abundance and biomass and were present in only 1% of the diet samples from only one of the four riparian-associated bird species. Nonetheless, arthropod prey, comprised primarily of insects of terrestrial origin, was more abundant in streamside than upland samples. We conclude that food resources for birds in headwater riparian areas are primarily associated with terrestrial vegetation, and that bird distributions along the gradient from streamside to upland may be related to variation in arthropod prey availability. Because distinct vegetation may distinguish riparian from upland habitats for riparian-associated birds and their terrestrial arthropod prey, we suggest that understory communities be considered when defining management zones for riparian habitat.

Oregon↗

USGS2007

Three-dimensional P wave velocity model for the San Francisco Bay region, California

[1] A new three-dimensional P wave velocity model for the greater San Francisco Bay region has been derived using the double-difference seismic tomography method, using data from about 5,500 chemical explosions or air gun blasts and approximately 6,000 earthquakes. The model region covers 140 km NE-SW by 240 km NW-SE, extending from 20 km south of Monterey to Santa Rosa and reaching from the Pacific coast to the edge of the Great Valley. Our model provides the first regional view of a number of basement highs that are imaged in the uppermost few kilometers of the model, and images a number of velocity anomaly lows associated with known Mesozoic and Cenozoic basins in the study area. High velocity ( V p > 6.5 km/s) features at ∼15-km depth beneath part of the edge of the Great Valley and along the San Francisco peninsula are interpreted as ophiolite bodies. The relocated earthquakes provide a clear picture of the geometry of the major faults in the region, illuminating fault dips that are generally consistent with previous studies. Ninety-five percent of the earthquakes have depths between 2.3 and 15.2 km, and the corresponding seismic velocities at the hypocenters range from 4.8 km/s (presumably corresponding to Franciscan basement or Mesozoic sedimentary rocks of the Great Valley Sequence) to 6.8 km/s. The top of the seismogenic zone is thus largely controlled by basement depth, but the base of the seismogenic zone is not restricted to seismic velocities of ≤6.3 km/s in this region, as had been previously proposed.

California↗

USGS2017

In memoriam - William Toshio (Tosh) Yasutake, 1922-2016

William Toshio (Tosh) Yasutake, 1922-2016 passed away peacefully at home on December 12, 2016, at the age of 94. He is survived by Fumi, his wife of 66 years, as well as four children and six grandchildren. With his death, the fish health community has lost an outstanding scientist as well as a kind, unassuming, and wonderful human being. Tosh was born on June 10, 1922, in Seattle, Washington, to Jack and Hide Yasutake. He was in his first year of studies at the University of Washington when Pearl Harbor was attacked by Imperial Japan on December 7, 1941. Following the attack, Tosh and his family (father, mother, sister, and two brothers) were among the 110,000–120,000 people of Japanese ancestry who were forced from their homes on the Pacific coast and incarcerated in internment camps in the interior. In June 1942, Tosh enlisted in the U.S. Army, serving as an unarmed combat medic in the famed 442nd Regimental Combat Team, the most decorated unit for its size and length of service in the history of American warfare. Wounded in October 1944 during the Vosges Mountains campaign near Bruyères, France, Tosh was evacuated and missed the ensuing battle to rescue the “Lost Battalion,” at which his replacement was killed. Tosh returned to action in Italy in February 1945 and served until the end of the war in Europe, earning both a Purple Heart and a Bronze Star for bravery. In October 2010, the Congressional Gold Medal was awarded to the 442nd Regimental Combat Team, and in 2012 the surviving members were made chevaliers of the French Légion d’Honneur for actions contributing to the liberation of France in World War II. After the war, Tosh returned to the University of Washington on the GI Bill and received a B.S. degree in zoology in 1951. In 1953 he began his research career at the U.S. Fish and Wildlife Service’s Western Fish Nutrition Laboratory at Cook, Washington, where he conducted pioneering research on nutritional fish diseases with John Halver. Tosh was one of the first to recognize hepatomas in hatchery-reared Rainbow Trout and helped to trace the disease to an aflatoxin produced by the mold Aspergillus flavis , which grew during the storage of ingredients for fish diets. In 1960, he transferred to the Western Fisheries Research Center (WFRC) in Seattle (then called the Western Fish Disease Laboratory) to start a fish pathology diagnostic laboratory. There he described the histopathology of diseases of economically important fishes, identified etiologic agents, and worked with hatchery biologists to improve the health, quality, and survival of salmonids released from federal and state hatcheries. Tosh was instrumental in recognizing that the viruses of Oregon sockeye disease and Chinook Salmon virus disease were one entity and in giving the disease its present name: infectious hematopoietic necrosis. In recognition of his pioneering research, Tosh was awarded a doctorate in fish pathology by the University of Tokyo in 1980, the first American to have been so honored. In 1983, he published his classic textbook The Microscopic Anatomy of Salmonids: An Atlas , which quickly became a standard reference work in fish pathology and is still in wide use today. For his outstanding career achievements, in 1987 Tosh received the S. F. Snieszko Distinguished Service Award, the highest honor bestowed by the American Fisheries Society’s Fish Health Section (AFS–FHS). Tosh retired in 1988 but continued his research at the WFRC as a senior scientist emeritus, providing technical assistance to federal and state agencies and to the aquaculture industry worldwide. His culminating project was to digitize his lifetime collection of photomicrographs and prepare an atlas, “Histopathology of Selected Parasitic Salmonid Diseases: A Color Atlas,” that is now posted on the Web sites of the WFRC and the AFS–FHS. Although his presence will be sorely missed, his research contributions have become part of the foundation of today’s knowledge of fisheries biology and have assured him a place in history.

Journal of Aquatic Animal Health↗

USGS2003

Controls on intrusion of near-trench magmas of the Sanak-Baranof Belt, Alaska, during Paleogene ridge subduction, and consequences for forearc evolution

A belt of Paleogene near-trench plutons known as the Sanak-Baranof belt intruded the southern Alaska convergent margin. A compilation of isotopic ages of these plutons shows that they range in age from 61 Ma in the west to ca. 50 Ma in the east. This migrating pulse of magmatism along the continental margin is consistent with North Pacific plate reconstructions that suggests the plutons were generated by migration of a trench-ridge-trench triple junction along the margin. On the Kenai Peninsula the regional lower greenschist metamorphic grade of the turbiditic host rocks, texture of the plutons, contact-metamorphic assemblage, and isotopic and fluid inclusion studies suggest that the plutons were emplaced at pressures of 1.5–3.0 kbars (5.2–10.5 km) into a part of the accretionary wedge with an ambient temperature of 210–300 °C. The presence of kyanite, garnet, and cordierite megacrysts in the plutons indicates that the melts were generated at a depth greater than 20 km and minimum temperature of 650 °C. These megacrysts are probably xenocrystic remnants of a restitic or contact metamorphic phase entrained by the melt during intrusion. However, it is also possible that they are primary magmatic phases crystallized from the peraluminous melt. Plutons of the Sanak-Baranof belt serve as time and strain markers separating kinematic regimes that predate and postdate ridge subduction. Pre-ridge subduction structures are interpreted to be related to the interaction between the leading oceanic plate and the Chugach terrane. These include regional thrust faults, NE-striking map-scale folds with associated axial planar foliation, type-1 mélanges, and an arrayof faults within the contact aureole indicating shortening largely accommodated by layer-parallel extension. Syn-ridge subduction features include the plutons, dikes, and ductile shear zones within contact aureoles with syn-kinematic metamorphic mineral growth and foliation development. Many of the studied plutons have sheeted margins and appear to have intruded along extensional jogs in margin-parallel strike-slip faults, whereas others form significant angles with the main faults and may have been influenced by minor faults of other orientations. Some of the plutons of the Sanak-Baranof belt have their long axes oriented parallel to faults of an orthorhombic fault set, implying that these faults may have provided a conduit for magma emplacement. This orthorhombic set of late faults is interpreted to have initially formed during the ridge subduction event, and continued to be active for a short time after passage of the triple junction. ENE-striking dextral faults of this orthorhombic fault system exhibit mutually crosscutting relationships with Eocene dikes related to ridge subduction, and mineralized strike-slip and normal faults of this system have yielded 40Ar/39Ar ages identical to near-trench intrusives related to ridge subduction. Movement on the orthorhombic fault system accommodated exhumation of deeper levels of the southern Alaska accretionary wedge, which is interpreted as a critical taper adjustment to subduction of younger oceanic lithosphere during ridge subduction. These faults therefore accommodate both deformation of the wedge and assisted emplacement of near-trench plutons. Structures that crosscut the plutons and aureoles include the orthorhombic fault set and dextral strike-slip faults, reflecting a new kinematic regime established after ridge subduction, during underthrusting of the trailing oceanic plate with new dextral-oblique convergence vectors with the overriding plate. The observation that the orthorhombic fault set both cuts and is cut by Eocene intrusives demonstrates the importance of these faults for magma emplacement in the forearc. A younger, ca. 35 Ma suite of plutons intrudes the Chugach terrane in the Prince William Sound region, and their intrusion geometry was strongly influenced by pre-existing faults developed during ridge subduction. The generation of these plutons may be related to the sudden northward migration of the triple junction at ca. 40–33 Ma, as the ridge was being subducted nearly parallel to the trench during this interval. These younger plutons are used to provide additional constraints on the structural evolution of the wedge. Late- to post-ridge subduction fabrics include a pressure solution cleavage and additional movement on the orthorhombic fault system. After triple junction migration, subduction of the trailing oceanic plate involved a significant component of dextral transpression and northward translation of the Chugach terrane. This change in kinematics is recorded by very late gouge-filled dextral faults in the late structures of the accretionary prism.

Alaska↗

USGS2015

Up in arms: Immune and nervous system response to sea star wasting disease

Echinoderms, positioned taxonomically at the base of deuterostomes, provide an important system for the study of the evolution of the immune system. However, there is little known about the cellular components and genes associated with echinoderm immunity. The 2013–2014 sea star wasting disease outbreak is an emergent, rapidly spreading disease, which has led to large population declines of asteroids in the North American Pacific. While evidence suggests that the signs of this disease, twisting arms and lesions, may be attributed to a viral infection, the host response to infection is still poorly understood. In order to examine transcriptional responses of the sea star Pycnopodia helianthoides to sea star wasting disease, we injected a viral sized fraction (0.2 μm) homogenate prepared from symptomatic P. helianthoides into apparently healthy stars. Nine days following injection, when all stars were displaying signs of the disease, specimens were sacrificed and coelomocytes were extracted for RNA-seq analyses. A number of immune genes, including those involved in Toll signaling pathways, complement cascade, melanization response, and arachidonic acid metabolism, were differentially expressed. Furthermore, genes involved in nervous system processes and tissue remodeling were also differentially expressed, pointing to transcriptional changes underlying the signs of sea star wasting disease. The genomic resources presented here not only increase understanding of host response to sea star wasting disease, but also provide greater insight into the mechanisms underlying immune function in echinoderms.

PLoS ONE↗

USGS2006

National Assessment of Shoreline Change Part 3: Historical Shoreline Change and Associated Coastal Land Loss Along Sandy Shorelines of the California Coast

Beach erosion is a chronic problem along many open-ocean shores of the United States. As coastal populations continue to grow and community infrastructures are threatened by erosion, there is increased demand for accurate information regarding past and present trends and rates of shoreline movement. There is also a need for a comprehensive analysis of shoreline movement that is consistent from one coastal region to another. To meet these national needs, the U.S. Geological Survey is conducting an analysis of historical shoreline changes along open-ocean sandy shores of the conterminous United States and parts of Hawaii and Alaska. One purpose of this work is to develop standard repeatable methods for mapping and analyzing shoreline movement so that periodic updates regarding coastal erosion and land loss can be made nationally that are systematic and internally consistent. In the case of this study, the shoreline being measured is the boundary between the ocean water surface and the sandy beach. This report on the California Coast represents the first of two reports on long-term sandy shoreline change for the western U.S., the second of which will include the coast of the Pacific NW, including Oregon and Washington. A report for the Gulf of Mexico shoreline was completed in 2004 and is available at: http://pubs.usgs.gov/of/2004/1043/. This report summarizes the methods of analysis, interprets the results, provides explanations regarding long-term and short-term trends and rates of change, and describes how different coastal communities are responding to coastal erosion. Shoreline change evaluations are based on comparing three historical shorelines digitized from maps, with a recent shoreline derived from lidar (Light Detection and Ranging) topographic surveys. The historical shorelines generally represent the following periods: 1800s, 1920s-1930s, and 1950s-1970s, whereas the lidar shoreline is from 1998-2002. Long-term rates of change are calculated using all four shorelines (1800s to lidar shoreline), whereas short-term rates of change are calculated for only the most recent period (1950s-1970s to lidar shoreline). The rates of change presented in this report represent past conditions and therefore are not intended for predicting future shoreline positions or rates of change. Due to the geomorphology of the California Coast (rocky coastline instead of beach) as well as to data gaps in some areas, this report presents beach erosion rates for 45% of California's 1100 km of coast. The average rate of long-term shoreline change for the State of California was 0.2?0.1 m/yr, an accretional trend. This is based on shoreline change rates averaged from 14,562 individual transects, of which 40% were eroding. Of the transects on which the shoreline was eroding, the long-term erosion rates were generally lowest in Southern California where coastal engineering projects have greatly altered the natural shoreline movement. On a regional scale, long-term accretion rates were either equal to (Central California) or greater than (Northern and Southern California) the long-term erosion rates, yielding the net accretional trend for the entire state. This accretional trend is most likely due to changes in the large volumes of sediment that are added to the system from large rivers and to the impact from coastal engineering and beach nourishment projects. The average rate of short-term shoreline change for the state was erosional. The net short-term rate as averaged along 16,142 transects was -0.2?0.4 m/yr. Of the transects used to measure short-term change, 66% had erosional trends. In addition erosion rates were higher in the short-term period, possibly related to the localized artificial nourishment that occurred over much of the 20th century but that has recently slowed or stopped (Flick, 1993; Wiegel, 1994). Short-term accretion rates were highest in Northern California where the overall magnitudes of shoreline change are systematically higher than in Central and Southern California. The most stable (low erosion and accretion rates) California beaches were most commonly found in Central California. Seawalls and/or riprap revetments have been constructed in all three sections of California, although many of these structures were built to protect houses and infrastructures from the erosion of coastal cliffs and bluffs rather than to protect against long-term beach erosion. California permits shoreline stabilization structures where homes, buildings or other community infrastructure are imminently threatened by erosion. A second California report that is following this publication will include analyses and reports on long-term coastal cliff erosion, as this hazard is of equal or greater concern to coastal communities in many areas along the California Coast.

Open-File Report↗

USGS1987

Did the 1982-1983 El Niño-Southern Oscillation Affect Seabirds in Alaska?

The causes and effects of the oceanographic and atmospheric phenomena known as El Nino and the Southern Oscillation (ENSO) have been studied intensively in recent years (Cane 1983, Rasmusson and Wallace 1983, Barber and Chave 1983, Cane and Zebiak 1985). ENSOs occur at semiregular intervals of 3-4 years, and the stronger events have important biological consequences, including reduced breeding success and survival of seabirds in the central and eastern tropical Pacific Boersma 1978, Barber and Chavez 983, Schreiber and Schreiber 1984, Duffy 1986). The ENSO event of 1982-1983 was perhaps the strongest of this century Cane 1983), and there is evidence that seabird populations as far north as the Oregon coast (42-46'N) were adversely affected (Hodder and Graybill 1985, Bayer 1986). Here I examine evidence for similar effects on seabirds along the Alaskan coast.

Alaska↗

USGS2021

Migration strategies supporting salmonids in Arctic Rivers: A case study of Arctic Cisco and Dolly Varden

Amphidromous fish such as Dolly Varden (Salvelinus malma) and Arctic Cisco (Coregonus autumnalis) have distinct life histories that facilitate their success in Arctic environments. Both species spawn in freshwater and make annual migrations between marine, brackish, or freshwater environments. Dolly Varden rear for one or more years in freshwater before migrating to sea whereas Arctic Cisco migrate to sea during their first summer. By contrast, Pacific salmon (Oncorhynchus spp.) spawn in freshwater, but once they smolt and go to sea they remain there until they mature and return to spawn. Salmon migrate at variable ages depending on species. Arctic marine environments offer productive food resources during summer, but during winter they are too cold for salmonids that lack antifreeze proteins. To avoid the cold sea during winter, Dolly Varden return to freshwater while Arctic Cisco overwinter in brackish estuaries. The lack of migration back to freshwater for overwintering helps explain why Pacific salmon success is limited in Arctic waters and suggests major increases in success will not be realized until Arctic seas provide suitable overwinter conditions. In this paper we contrast these migration strategies, discuss potential changes in a warming Arctic, and highlight information needs especially for juvenile fish.

Alaska↗

USGS2021

Disentangling stationary and dynamic estuarine fish habitat to inform conservation: Species-specific responses to physical habitat and water quality in San Francisco Estuary

Estuaries represent critical aquatic habitat that connects surface water distributed between Earth’s landmasses and oceans. They are dynamic transitional ecosystems, which provide important habitat for fishes and other aquatic organisms. Effective conservation of species inhabiting estuaries requires knowledge of the habitat features that drive their abundance and distribution. We sought to elucidate how stationary (i.e., wetlands, shoals, and channels) and dynamic (i.e., salinity, temperature, turbidity, and chlorophyll concentration) habitat features interact to drive distributions of individual fish species. The Pacific coast of the conterminous United States has over 400 estuaries of various types. The largest (historical surface area) is San Francisco Estuary, California. We conducted extensive field observations of fishes in the central San Francisco Estuary among stationary habitat types (i.e., wetland, shoal, and channel) over a 19-month period encompassing substantial variability in dynamic water quality conditions. Most of the species observed, especially native species of special management interest, were associated with tidal wetland habitat. Few species exhibited associations with water quality conditions driven by seasonal (temperature) or a combination of broad- and fine-scale ecosystem processes (salinity and turbidity). Our study provides (1) an empirical demonstration of how researchers can deal with the complex and dynamic expressions of habitat in estuarine systems to address urgent natural resource problems and (2) a clear demonstration of the urgent need for habitat restoration and its likely outcome in systems such as San Francisco Estuary. Restoration of suitable tidal wetland habitat on the West Coast of the United States is likely to be an effective conservation tool to support estuarine fishes given that over 90% of historical tidal wetland habitat in San Francisco Estuary and 85% of vegetated wetland habitat along the Pacific coast of the United States has been lost due to human modification.

California↗