Results for “Pacific Studies” — Page 50

USGS2003

Late cretaceous foraminifera, paleoenvironments, and paleoceanography of the rosario formation, San Antonio del Mar, Baja California, Mexico

The 315 m of Rosario Formation exposed at the San Antonio del Mar (SADM) section (Baja California, Mexico) contains moderately-to-well preserved benthic and planktic foraminifera, calcareous nannofossils, and molluscs. Nannofossils suggest most of the SADM section was deposited within a narrow interval of the late Campanian (CC21-CC22), whereas foraminifera and molluscs suggest a younger maximum age (younger than the Globotruncana ventricosa Zone) and allow deposition over a longer interval of time. Planktic foraminifera at SADM represent common Tethyan taxa. They are largely restricted to the lower and middle portions of the section and comprise 0-???40% of foraminiferal assemblages. Stable isotopic analyses of Rugoglobigerina rugosa yield ??18OV-PDB values from -2.27%, to -2.82%, corresponding to salinity-corrected paleotemperature estimates of 26-30??C for the Late Cretaceous eastern Pacific. These estimates are as warm as modern tropical temperatures and are similar to tropical paleotemperature estimates from ??18O analyses of exceptionally preserved Maastrichtian samples; however, they are considerably warmer than most tropical Campanian-Maastrichtian estimates. Benthic foraminifera indicate outer shelf paleodepths with a slight increase in depth or decrease in benthic oxygen levels in the upper parts of the interval studied. The change in the benthic assemblage corresponds to an ???1??? positive shift in benthic ??O18, suggesting a relationship between benthic assemblages and an inferred increase in the local intensity of upwelling.

Journal of Foraminiferal Research↗

USGS2011

A Digital Hydrologic Network Supporting NAWQA MRB SPARROW Modeling--MRB_E2RF1

A digital hydrologic network was developed to support SPAtially Referenced Regression on Watershed attributes (SPARROW) models within selected regions of the United States. These regions correspond with the U.S. Geological Survey's National Water Quality Assessment (NAWQA) Program Major River Basin (MRB) study units 2, 3, 4, 5, and 7 (Preston and others, 2009). MRB2, covers the South Atlantic-Gulf and Tennessee River basins. MRB3, covers the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy River basins. MRB4, covers the Missouri River basins. MRB5, covers the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf River basins. MRB7, covers the Pacific Northwest River basins. The digital hydrologic network described here represents surface-water pathways (MRB_E2RF1) and associated catchments (MRB_E2RF1WS). It serves as the fundamental framework to spatially reference and summarize explanatory information supporting nutrient SPARROW models (Brakebill and others, 2011; Wieczorek and LaMotte, 2011). The principal geospatial dataset used to support this regional effort was based on an enhanced version of a 1:500,000 scale digital stream-reach network (ERF1_2) (Nolan et al., 2002). Enhancements included associating over 3,500 water-quality monitoring sites to the reach network, improving physical locations of stream reaches at or near monitoring locations, and generating drainage catchments based on 100m elevation data. A unique number (MRB_ID) identifies each reach as a single unit. This unique number is also shared by the catchment area drained by the reach, thus spatially linking the hydrologically connected streams and the respective drainage area characteristics. In addition, other relevant physical, environmental, and monitoring information can be associated to the common network and accessed using the unique identification number.

Report↗

USGS2011

A Digital Hydrologic Network Supporting NAWQA MRB SPARROW Modeling--MRB_E2RF1WS

A digital hydrologic network was developed to support SPAtially Referenced Regression on Watershed attributes (SPARROW) models within selected regions of the United States. These regions correspond with the U.S. Geological Survey's National Water Quality Assessment (NAWQA) Program Major River Basin (MRB) study units 2, 3, 4, 5, and 7 (Preston and others, 2009). MRB2, covers the South Atlantic-Gulf and Tennessee River basins. MRB3, covers the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy River basins. MRB4, covers the Missouri River basins. MRB5, covers the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf River basins. MRB7, covers the Pacific Northwest River basins. The digital hydrologic network described here represents surface-water pathways (MRB_E2RF1) and associated catchments (MRB_E2RF1WS). It serves as the fundamental framework to spatially reference and summarize explanatory information supporting nutrient SPARROW models (Brakebill and others, 2011; Wieczorek and LaMotte, 2011). The principal geospatial dataset used to support this regional effort was based on an enhanced version of a 1:500,000 scale digital stream-reach network (ERF1_2) (Nolan et al., 2002). Enhancements included associating over 3,500 water-quality monitoring sites to the reach network, improving physical locations of stream reaches at or near monitoring locations, and generating drainage catchments based on 100m elevation data. A unique number (MRB_ID) identifies each reach as a single unit. This unique number is also shared by the catchment area drained by the reach, thus spatially linking the hydrologically connected streams and the respective drainage area characteristics. In addition, other relevant physical, environmental, and monitoring information can be associated to the common network and accessed using the unique identification number.

Report↗

USGS2011

A Digital Hydrologic Network Supporting NAWQA MRB SPARROW Modeling--MRB_E2RF1WS

A digital hydrologic network was developed to support SPAtially Referenced Regression on Watershed attributes (SPARROW) models within selected regions of the United States. These regions correspond with the U.S. Geological Survey's National Water Quality Assessment (NAWQA) Program Major River Basin (MRB) study units 2, 3, 4, 5, and 7 (Preston and others, 2009). MRB2, covers the South Atlantic-Gulf and Tennessee River basins. MRB3, covers the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy River basins. MRB4, covers the Missouri River basins. MRB5, covers the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf River basins. MRB7, covers the Pacific Northwest River basins. The digital hydrologic network described here represents surface-water pathways (MRB_E2RF1) and associated catchments (MRB_E2RF1WS). It serves as the fundamental framework to spatially reference and summarize explanatory information supporting nutrient SPARROW models (Brakebill and others, 2011; Wieczorek and LaMotte, 2011). The principal geospatial dataset used to support this regional effort was based on an enhanced version of a 1:500,000 scale digital stream-reach network (ERF1_2) (Nolan et al., 2002). Enhancements included associating over 3,500 water-quality monitoring sites to the reach network, improving physical locations of stream reaches at or near monitoring locations, and generating drainage catchments based on 100m elevation data. A unique number (MRB_ID) identifies each reach as a single unit. This unique number is also shared by the catchment area drained by the reach, thus spatially linking the hydrologically connected streams and the respective drainage area characteristics. In addition, other relevant physical, environmental, and monitoring information can be associated to the common network and accessed using the unique identification number.

General Information↗

USGS2020

Fish assemblages in eelgrass beds of Bellingham Bay, Washington, Northern Puget Sound, 2019

Puget Sound is a critical part of the Pacific Northwest, both culturally and economically. Eelgrass beds are an important feature of Puget Sound and are known to influence fish assemblages. As part of a larger site-characterization effort, and to gain a better understanding of the fish assemblages in Bellingham Bay, Washington, four eelgrass beds ( Zostera marina ) along the shoreline were surveyed. Fish were captured from 24 through 26 September 2019 by using three beach-seine hauls per eelgrass bed. In total, 12 hauls yielded 2,135 fish that comprised 20 species from 14 families. Shiner perch ( Cymatogaster aggregata ) accounted for 52 percent of the total catch. The other common species included three-spine stickleback ( Gasterosteus aculeatus ), bay pipefish ( Syngnathus leptorhynchus ), saddleback gunnel ( Pholis ornata ), Pacific staghorn sculpin ( Leptocottus armatus ), and Pacific sand lance ( Ammodytes personatus ). Total catch and species richness were highest at the two locations closest to the urban center of Bellingham; however, species diversity and evenness were highest at the two eelgrass beds farthest from the city center. Descriptions of fish assemblages in eelgrass beds are expected to be useful in the development of future process-based investigations by study partners and will focus on the movements of sediments and contaminants and their influence on biota.

Washington↗

USGS1989

The brown tree snake, an introduced pest species in the central Pacific Islands

The reproduction of endangered Mariana crows ( Corvus kubaryi ) is intensively monitored, nests are protected, and (when necessary) eggs or young are moved to the safety of lab conditions until they are less vulnerable to the threats in natural habitats. Barriers on tree trunks and judicious pruning of adjacent trees are used in attempts to exclude snakes from nest trees. Two birds unique to Guam--the Micronesian kingfisher ( Halcyon cinnamomina cinnamomina ) and Guam rail ( Gallirallus owstoni )-- are maintained at captive propagation facilities on Guam and in mainland zoos. Studies of these and other species, in captivity and on nearby islands, are underway to bolster our biological understanding of their behavior, reproduction, habitat use, and population biology.

Endangered Species Technical Bulletin↗

USGS2009

Coastal Circulation and Sediment Dynamics in War-in-the-Pacific National Historical Park, Guam; measurements of waves, currents, temperature, salinity, and turbidity, June 2007-January 2008

Flow in and around coral reefs affects a number of physical, chemical and biologic processes that influence the health and sustainability of coral reef ecosystems. These range from the residence time of sediment and contaminants to nutrient uptake and larval retention and dispersal. As currents approach a coast they diverge to flow around reef structures, causing high horizontal and vertical shear. This can result in either the rapid advection of material in localized jets, or the retention of material in eddies that form in the lee of bathymetric features. The high complexity and diversity both within and between reefs, in conjunction with past technical restrictions, has limited our understanding of the nature of flow and the resulting flux of physical, chemical, and biologic material in these fragile ecosystems. Sediment, nutrients, and other pollutants from a variety of land-based activities adversely impact many coral reef ecosystems in the U.S. and around the world. These pollutants are transported in surface water runoff, groundwater seepage, and atmospheric fallout into coastal waters, and there is compelling evidence that the sources have increased globally as a result of human-induced changes to watersheds. In Guam, and elsewhere on U.S. high islands in the Pacific and Caribbean, significant changes in the drainage basins due to agriculture, feral grazing, fires, and urbanization have in turn altered the character and volume of land-based pollution released to coral reefs. Terrigenous sediment run-off (and the associated nutrients and contaminants often absorbed to it) and deposition on coral reefs are recognized to potentially have significant impact on coral health by blocking light and inhibiting photosynthesis, directly smothering and abrading coral, and triggering increases in macro algae. Studies that combine information on watershed, surface water- and groundwater-flow, transport and fate of sediment and other pollutants in the reef environment, and their impact on reef health and ecology are essential for effective reef management. Two of the main anthropogenic activities along west-central Guam's coastline that may impact the region's coral reef ecosystems include pollution and coastal land use/development, as discussed in the review by Porter and others (2005). The pollution threats include point-sources, such as municipal wastewater (Northern District, Hagatna, Naval Station Guam, and Agat-Santa Rita Waster Water Treatment Plants), cooling water (Tanguisson Steam and Cabras Power Plants), and numerous storm water, ballast water, and tank bottom draw outfalls; nonpoint sources include septic systems, urban runoff, illegal dumping, and groundwater discharges. Poor land-use practices include development without the use of runoff management measures, increased areal extent of impervious surfaces and decreased extent of vegetative barriers, and recreational off-road vehicle use. Furthermore, feral ungulates and illegal wildfires remove protective vegetative cover and generally result in increased soil erosion. While anthropogenic point-sources have been reduced in many areas due to better management practices, nonpoint sources have either stayed constant or increased. Between 1975 and 1999, it is estimated that Guam lost more than a quarter of its tree cover, and more than 750 wildfires each year have resulted in a greater proportion of badlands and other erosion-prone land surfaces with high erosion rates (Forestry and Soil Resources Division, 1999). Approximately 1.8 square kilometers (km2) of Asan Bay, west-central Guam, lies within the National Park Service's (NPS) War-in-the-Pacific National Historical Park's (WAPA) Asan Unit; the bay is the sink for material coming out of the Asan watershed. Anthropogenic modifications of the watersheds adjacent to Asan Bay, which include intentionally-set wildfires, construction, and agriculture (Minton, 2005), are believed to have increased over the past 25

Open-File Report↗

USGS2019

Species insurance trumps spatial insurance in stabilizing biomass of a marine macroalgal metacommunity

Because natural ecosystems are complex, it is difficult to predict how their variability scales across space and levels of organization. The species‐insurance hypothesis predicts that asynchronous dynamics among species should reduce variability when biomass is aggregated either from local species populations to local multispecies communities, or from metapopulations to metacommunities. Similarly, the spatial‐insurance hypothesis predicts that asynchronous spatial dynamics among either local populations or local communities should stabilize metapopulation biomass and metacommunity biomass, respectively. In combination, both species and spatial insurance reduce variation in metacommunity biomass over time, yet these insurances are rarely considered together in natural systems. We partitioned the extent that species insurance and spatial insurance reduced the annual variation in macroalgal biomass in a southern California kelp forest. We quantified variability and synchrony at two levels of organization (population and community) and two spatial scales (local plots and region) and quantified the strength of species and spatial insurance by comparing observed variability and synchrony in aggregate biomass to null models of independent species or spatial dynamics based on cyclic‐shift permutation. Spatial insurance was weak, presumably because large‐scale oceanographic processes in the study region led to high spatial synchrony at both population‐ and community‐level biomass. Species insurance was stronger due to asynchronous dynamics among the metapopulations of a few common species. In particular, a regional decline in the dominant understory kelp species Pterygophora californica was compensated for by the rise of three subdominant species. These compensatory dynamics were associated with positive values of the Pacific Decadal Oscillation, indicating that differential species tolerances to warmer temperature and nutrient‐poor conditions may underlie species insurance in this system. Our results illustrate how species insurance can stabilize aggregate community properties in natural ecosystems where environmental conditions vary over broad spatial scales.

Ecology↗

USGS2015

Decomposition of sea lamprey Petromyzon marinus carcasses: temperature effects, nutrient dynamics, and implications for stream food webs

Anadromous fishes serve as vectors of marine-derived nutrients into freshwaters that are incorporated into aquatic and terrestrial food webs. Pacific salmonines Oncorhynchus spp. exemplify the importance of migratory fish as links between marine and freshwater systems; however, little attention has been given to sea lamprey ( Petromyzon marinus Linnaeus, 1758) in Atlantic coastal systems. A first step to understanding the role of sea lamprey in freshwater food webs is to characterize the composition and rate of nutrient inputs. We conducted laboratory and field studies characterizing the elemental composition and the decay rates and subsequent water enriching effects of sea lamprey carcasses. Proximate tissue analysis demonstrated lamprey carcass nitrogen:phosphorus ratios of 20.2:1 (±1.18 SE). In the laboratory, carcass decay resulted in liberation of phosphorus within 1 week and nitrogen within 3 weeks. Nutrient liberation was accelerated at higher temperatures. In a natural stream, carcass decomposition resulted in an exponential decline in biomass, and after 24 days, the proportion of initial biomass remaining was 27% (±3.0% SE). We provide quantitative results as to the temporal dynamics of sea lamprey carcass decomposition and subsequent nutrient liberation. These nutrient subsidies may arrive at a critical time to maximize enrichment of stream food webs.

Hydrobiologia↗

USGS2016

Assessing wildlife benefits and carbon storage from restored and natural coastal marshes in the Nisqually River Delta: Determining marsh net ecosystem carbon balance

Working in partnership since 1996, the U.S. Fish and Wildlife Service and the Nisqually Indian Tribe have restored 902 acres of tidally influenced coastal marsh in the Nisqually River Delta (NRD), making it the largest estuary-restoration project in the Pacific Northwest to date. Marsh restoration increases the capacity of the estuary to support a diversity of wildlife species. Restoration also increases carbon (C) production of marsh plant communities that support food webs for wildlife and can help mitigate climate change through long-term C storage in marsh soils. In 2015, an interdisciplinary team of U.S. Geological Survey (USGS) researchers began to study the benefits of carbon for wetland wildlife and storage in the NRD. Our primary goals are (1) to identify the relative importance of the different carbon sources that support juvenile chinook ( Oncorhynchus tshawytscha ) food webs and contribute to current and historic peat formation, (2) to determine the net ecosystem carbon balance (NECB) in a reference marsh and a restoration marsh site, and (3) to model the sustainability of the reference and restoration marshes under projected sea-level rise conditions along with historical vegetation change. In this fact sheet, we focus on the main C sources and exchanges to determine NECB, including carbon dioxide (CO 2 ) uptake through plant photosynthesis, the loss of CO 2 through plant and soil respiration, emissions of methane (CH 4 ), and the lateral movement or leaching loss of C in tidal waters.

Washington↗

USGS2002

Publications of Western Earth Surface Processes Team 2001

The Western Earth Surface Processes Team (WESPT) of the U.S. Geological Survey (USGS) conducts geologic mapping and related topical earth-science studies in the Western United States. This work is focused on areas where modern geologic maps and associated earth-science data are needed to address key societal and environmental issues, such as ground-water quality, landslides and other potential geologic hazards, and land-use decisions. Areas of primary emphasis in 2001 included southern California, the San Francisco Bay region, the Pacific Northwest, and the Las Vegas urban corridor. The team has its headquarters in Menlo Park, California, and maintains smaller field offices at several other locations in the Western United States. The results of research conducted by the WESPT are released to the public as a variety of databases, maps, text reports, and abstracts, both through the internal publication system of the USGS and in diverse external publications such as scientific journals and books. This report lists publications of the WESPT released in 2001, as well as additional 1999 and 2000 publications that were not included in the previous list (USGS Open-File Report 00–215 and USGS Open-File Report 01–198). Most of the publications listed were authored or coauthored by WESPT staff. The list also includes some publications authored by non-USGS cooperators with the WESPT, as well as some authored by USGS staff outside the WESPT in cooperation with WESPT projects. Several of the publications listed are available on the World Wide Web; for these, URL addresses are provided. Many of these web publications are USGS Open-File Reports that contain large digital databases of geologic map and related information.

Open-File Report↗

USGS2003

Publications of the Western Earth Surface Processes Team 2002

The Western Earth Surface Processes Team (WESPT) of the U.S. Geological Survey (USGS) conducts geologic mapping and related topical earth science studies in the western United States. This work is focused on areas where modern geologic maps and associated earth-science data are needed to address key societal and environmental issues such as ground-water quality, landslides and other potential geologic hazards, and land-use decisions. Areas of primary emphasis in 2001 included southern California, the San Francisco Bay region, the Pacific Northwest, and the Las Vegas urban corridor. The team has its headquarters in Menlo Park, California, and maintains smaller field offices at several other locations in the western United States. The results of research conducted by the WESPT are released to the public as a variety of databases, maps, text reports, and abstracts, both through the internal publication system of the USGS and in diverse external publications such as scientific journals and books. This report lists publications of the WESPT released in 2002 as well as additional 1998 and 2001 publications that were not included in the previous list (USGS Open-File Report 00-215, USGS Open-File Report 01-198, and USGS Open-File Report 02-269). Most of the publications listed were authored or coauthored by WESPT staff. The list also includes some publications authored by non-USGS cooperators with the WESPT, as well as some authored by USGS staff outside the WESPT in cooperation with WESPT projects. Several of the publications listed are available on the World Wide Web; for these, URL addresses are provided. Many of these web publications are USGS open-file reports that contain large digital databases of geologic map and related information. Information on ordering USGS publications can be found on the World Wide Web or by calling 1-888-ASK-USGS. The U.S. Geological Survey’s web server for geologic information in the western United States is located at http://geology.wr.usgs.gov. More information is available about the WESPT is available on-line at the team website.

Open-File Report↗

USGS2016

Ground-penetrating radar and differential global positioning system data collected from Long Beach Island, New Jersey, April 2015

Scientists from the United States Geological Survey, St. Petersburg Coastal and Marine Science Center, U.S. Geological Survey Pacific Coastal and Marine Science Center, and students from the University of Hawaii at Manoa collected sediment cores, sediment surface grab samples, ground-penetrating radar (GPR) and Differential Global Positioning System (DGPS) data from within the Edwin B. Forsythe National Wildlife Refuge–Holgate Unit located on the southern end of Long Beach Island, New Jersey, in April 2015 ( FAN 2015-611-FA ). The study’s objective was to identify washover deposits in the stratigraphic record to aid in understanding barrier island evolution. This report is an archive of GPR and DGPS data collected from Long Beach Island in 2015. Data products, including raw GPR and processed DGPS data, elevation corrected GPR profiles, and accompanying Federal Geographic Data Committee metadata can be downloaded from the Data Downloads page.

New Jersey↗

USGS2020

Evaluation of uncertainty intervals for daily, statistically derived streamflow estimates at ungaged basins across the continental U.S.

Streamflow estimation methods that transfer information from an index gage to an ungaged site are commonly used; however, uncertainty in daily streamflow estimates are often not adequately quantified. In this study, daily streamflow was simulated at 1,331 validation streamgages across the continental United States using four transfer-based streamflow estimation methods. Empirical 95 percent uncertainty intervals were computed for estimated daily streamflows. Uncertainty intervals were evaluated for reliability, sharpness, and overall ability to accurately quantify the uncertainty inherent in the estimated daily streamflow. Uncertainty intervals performed reliably in the Eastern U.S. and Pacific Northwest regions of the country, containing a median of 96 and 99 percent of the observed values respectively. Uncertainty intervals were less reliable in the Great Plains and arid Southwest regions, where uncertainty intervals contained a median of 83 and 94 percent of the observed streamflows respectively. Uncertainty interval performance was correlated with gage density and hydrologic similarity near the validation site, as well as the aridity and base-flow indices at the site.

Water↗

USGS1982

Measurements of fall migrant peregrine falcons from Texas and New Jersey

Three subspecies of Peregrine Falcons (Falco peregrinus) breed in North America: F. p. anatum, formerly bred in all eco-geographic regions of North America south of the Arctic tundra, except for the immediate vicinity of the northwest Pacific Coast; F. p. tundrius breeds in the Arctic tundra; and F. p. pealei, a relatively sedentary form, occupies the region of the northwest Pacific coast excluded from the range of F. p. anatum (Fyfe et al. 1976). Compared with tundrius, anatum is larger and darker, and the white auricular area is less extensive in proportion to the black malar stripe (White 1968a). This paper presents morphological information from two migrant populations. Also, measurements are compared with F. p. tundrius described by White (1968a,b), although shrinkage in study skins (the source of White's measurements) was recently documented (Fjelds• 1980) and confounds direct comparison.

Texas, New Jersey↗

USGS2015

Evaluating the status of individuals and populations: Advantages of multiple approaches and time scales

The assessment of population status is a central goal of applied wildlife research and essential to the field of wildlife conservation. “Population status” has a number of definitions, the most widely used having to do with the current trajectory of the population (i.e., growing, stable, or declining), or the probability of persistence (i.e., extinction risk), perhaps without any specific knowledge as to the factors driving a population’s dynamics. In contrast, a population’s status relative to the carrying capacity of the environment ( K ) is an ecologically-based definition that explicitly provides information about a major mechanism of population control. That is, it relates to the relative per capita availability of resources to individuals in a population, which can also be used to infer the state of the environment itself. Sea otters in the North Pacific provide an excellent system with which to examine various approaches to assessing population status relative to K . This is because sea otters were nearly extirpated by historic commercial overexploitation in the eighteenth and nineteenth centuries, followed by natural and translocation-aided population recovery during the twentieth century, and this decline and recovery has been relatively well documented. This provided a unique opportunity to study populations at the extremes of the population status spectrum. Here we describe and review the approaches that have been utilized in sea otter research to understand the status of populations relative to resource abundance. Specifically, we will illustrate the utility of various indices of population status for understanding population dynamics using the case study of a second precipitous sea otter decline in the Western Aleutians. The indices or “tools” described here fit into several broad categories including (1) energetic, (2) morphological, and (3) demographic as well as a fourth category of emerging tools that have not yet been employed in many other situations including dietary diversity, community structure, spatial distribution, and gene expression. Overall, a variety of indices used to measure population status throughout the sea otter’s range have provided insights for understanding the mechanisms driving the trajectory of various sea otter populations, which a single index could not, and we suggest using multiple methods to measure a population’s status at multiple spatial and temporal scales. The work described here also illustrates the usefulness of long-term data sets and/or approaches that can be used to assess population status retrospectively, providing information otherwise not available. While not all systems will be as amenable to using all the approaches presented here, we expect innovative researchers could adapt analogous multi-scale methods to a broad range of habitats and species including apex predators occupying the top trophic levels, which are often of conservation concern.

Book chapter↗

USGS2024

Passive acoustic monitoring and convolutional neural networks facilitate high-resolution and broadscale monitoring of a threatened species

Population monitoring is an essential component of biodiversity conservation and management, but low detection probabilities for rare and/or cryptic species makes estimating abundance and occupancy challenging. Passive acoustic monitoring combined with machine learning algorithms represents a potential path forward to effectively and efficiently monitor the occurrence of rare vocalizing species across entire forest landscapes. Our objectives were to develop and implement a convolutional neural network (PNW-Cnet) to identify vocalizations of a rare and threatened forest nesting bird species – the marbled murrelet ( Brachyramphus marmoratus ) – in the Pacific Northwest, U.S.A., 2018–2021. We used PNW-Cnet predictions from broadscale passive acoustic monitoring data to examine spatiotemporal patterns in the distribution of murrelets. PNW-Cnet showed sufficiently high prediction accuracy (overall precision > 0.9) to enable broadscale population monitoring. Spatiotemporal analysis showed that annual peak murrelet call abundance occurs in ordinal weeks 28–32 (late July–Mid August) but this varied by study area. The greatest number of detections typically occurred in the Olympic Peninsula and Oregon Coast Range where late-successional forest dominates and nearer to ocean habitats. We demonstrate that passive acoustic monitoring can be used to understand intensity of use across broad scales for a rare and cryptic species in addition to the typical detection/non-detection data that are often collected. Passive acoustic monitoring combined with PNW-Cnet offers considerable promise for species distribution modeling and long-term population monitoring for rare species.

Oregon, Washington↗

USGS2022

Deep-ocean polymetallic nodules and cobalt-rich ferromanganese crusts in the global ocean: New sources for critical metals

The transition from a global hydrocarbon economy to a green energy economy and the rapidly growing middle class in developing countries are driving the need for considerable new sources of critical materials. Deep-ocean minerals, namely cobalt-rich ferromanganese crusts and polymetallic nodules, are two such new resources generating interest. Polymetallic nodules are essentially two-dimensional mineral deposits sitting on abyssal plain sediments at about 3,500–6,000 m water depths. Metals of economic interest enriched in nodules include nickel, copper, manganese, cobalt and molybdenum. Cobalt-rich ferromanganese crusts are also two-dimensional deposits forming pavements on rock outcrops on seamounts and ridges at water depths of 400–7,000 m. Metals of economic interest for crusts include cobalt, manganese, nickel, molybdenum, tellurium, platinum, vanadium and rare earth elements. A conservative estimate is that 21.1 billion dry tons of polymetallic nodules exist in the Clarion-Clipperton Zone ( CCZ ) manganese nodule field, the largest in area and tonnage of the known global nodule fields. Based on that estimate, tonnages of many critical metals in the CCZ nodules are greater than those found in global terrestrial reserves. About 7.5 billion dry tons of cobalt-rich ferromanganese crusts are estimated to occur in the Pacific Ocean Prime Crust Zone, the area with the highest tonnage of critical-metal-rich crust deposits, with many elements contained therein estimated to be greater than those found in global terrestrial reserves. Deep-ocean mining has not yet been carried out in the Exclusive Economic Zone of any nation, nor in the Areas beyond national jurisdiction, although extensive mineral exploration and environmental studies are being conducted and exploitation regulations codified, indicating that mining activities will likely begin in the near future. If deep-ocean mining follows the evolution of offshore production of petroleum, we can expect that about 35–45 per cent of the demand for critical metals will come from deep-ocean mines by 2065.

Book chapter↗