• Geology of the boundary area, Eagle A-1 and Tanacross D-1 quadrangles, east-central Alaska

      Flynn, Roy L. (2003-05)
      Structural relationships and tectonic events in the Boundary area of east-central Alaska shed light on the generally obscure tectonic history of the Yukon-Tanana Upland region. This study used detailed mapping of 160 km², with supporting petrography, geochemical analyses, and ⁴⁰Ar/³⁹Ar dating to define the geology and tectonic history of the Boundary area. A major thrust zone juxtaposes lithotectonic assemblages of metamorphic rocks in the Boundary area, with the Fortymile River assemblage (approximately middle amphibolite facies) thrust over the Nasina and Klondike series (middle to upper greenschist facies), and ultramafic rocks and metagabbro (lower greenschist facies) and epidote-amphibolite-facies gneiss and schist imbricated along the thrust faults. Final thrust imbrication postdates cooling from peak metamorphism in amphibolite-facies lithologies, which appears to be Early Jurassic age. The thrust zone is exposed partially rimming a broad, dome-shaped anticline that encompasses the entire map area. Thermally reset ⁴⁰Ar/³⁹Ar ages in the Boundary area appear to be the result of a short-lived, probably igneous, Mid-Cretaceous reheating event, with widespread and locally variable effects, contemporaneous with intrusion of the Crag Mountain pluton south of the map area. Numerous later high-angle, presumably strike-slip faults transect the Boundary area, with apparently associated latest Cretaceous to Miocene volcanic rocks.
    • Geology of the Caribou Creek area, Big Delta quadrangle, east-central Alaska

      Lessard, Richard R. (2006-12)
      The Caribou Creek area, in the Big Delta C4 Quadrangle, East-Central Alaska, is known for significant placer gold, but no lode source. I present a new 200 km² area geologic map utilizing ground based mapping, airborne geophysical surveys, and follow-up laboratory investigations. Mapping and petrography delineate 10-20 km² blocks containing contrasting rock units and mineral assemblages. Amphibolite facies blocks contain abundant post-kinematic andalusite, with central blocks containing partially replaced kyanite, and blocks to the southeast and west containing post-kinematic sillimanite. Geothermobarometry shows that the amphibolite-facies blocks experienced pressures/temperatures of 11.5 kbars/650°C, followed by a collisional event associated with low-P/variable T post-kinematic recrystallization. The distribution of alumino-silicates suggests the central blocks were down dropped relative to adjacent blocks. Gold occurrences are found in west to northwest trending, steeply dipping quartz veins with stibnite ± arsenopyrite. Located in the central blocks, they are separated from a barren granodiorite pluton by a sinistral, northeast trending, high-angle fault. This study has shown the existence of major faults with significant vertical and horizontal movement, making gold source determination difficult. Future lode gold exploration in the area must take the high-angle faulting into consideration.
    • The geology of three extrusive bodies in central Alaska Range

      Albanese, Mary; Turner, Don; Swanson, Samuel; Gilbert, Wyatt; Kienle, Juergen; Stone, David (1980-05)
      The Buzzard Creek basalt, Jumbo Dome, and Sugar Loaf Mountain occur in the Central Alaska Range. The purpose of this study is to determine the age, nature, geothermal potential, and possible genetic relationships between these igneous bodies. The areas were investigated by mapping, radiometric dating, and petrologic studies. The Buzzard Creek basalt appears to have formed by a maar eruption about 3,000 years ago. Seismic evidence suggests this basalt may be related to current subduction in the area. Jumbo Dome consists of calc-alkaline andesite and is probably Pleistocene in age. Sugar Loaf Mountain is composed of Mid-Tertiary rhyolite. Geochemistry suggests that the Sugar Loaf Mountain rhyolite and Jumbo Dome andesite may also be subduction-related. Differences in age and geochemistry indicate there is no genetic relationship between the rocks of the three areas. The ages, type of volcanic features', and snow melt patterns suggest that these three areas have low geothermal potential.
    • A geometric analysis of thrust-truncated asymmetric folds, Upper Marsh Fork area, eastern Brooks Range, Alaska

      Jadamec, Margarete A. (2003-08)
      A new surveying technique was developed to document the geometry of eight km size thrust-related folds in the eastern Brooks Range, Alaska. This method combines data from a theodolite and reflectorless laser rangefinder to construct cross sections that are more precise than those based on field map data. In the study area, weakly to non-metamorphosed Carboniferous carbonates typically form northeast-trending, northwest-vergent, asymmetric thrust-truncated folds. The geometry of most of the folds is consistent with a detachment fold model that allows local thickness changes. The anticlines typically display interlimb angles of less than 90,̊ structurally thickened hinge zones, and overturned forelimbs that dip steeply to moderately, suggesting the folds are over-tightened. Furthermore, structural disruption of bedding in the anticlinal forelimbs suggests that strain was localized in this region of the fold and is interpreted to be a record of the transition from folding to thrust faulting within each fold.
    • The geometry and flow of Fireweed Rock Glacier, Alaska

      Bucki, Adam Kyle (2002-05)
      Little is known about the geometry, internal structure or flow of rock glaciers. Geophysical investigations were carried out on Fireweed Rock Glacier to define its geometry. Transient electromagnetic (TEM) methods were effective in determining its shape and depth as well as re-enforcing results of radar and seismic. All of these methods suggest a discontinuity at 15 to 30 m depth. The geometry acquired from these geophysical surveys was used to investigate the motion of the rock glacier. Analysis indicates that motion is concentrated in a pseudo-rectangular subsection of the larger valley on a 'shear plane' at about 27 m depth. We infer that both deformation above and 'sliding' along this shear plane contribute to the observed surface motion. This rock glacier flows relatively quickly for a rock glacier, and has seasonal and annual variations in speed. Some of the variations are related to the quasi-periodic calving at the terminus.
    • Geometry and kinematics of the Yakataga anticline, Icy Bay, Alaska

      Broadwell, Michael Scott; Wallace, Wes; McCarthy, Paul; Hanks, Cathy (2001-05)
      The Yakataga incline is a well-exposed asymmetrical fold with a ramp tip beneath the forelimb. Uncomformities in the backlimb and forelimb indicate that both limbs rotated during fold growth. The stratigraphic character and evidence for deformation before full lithification suggest non-parallel folding by distributed strain rather than flexural slip. These characteristics of the natural fold do not fit existing models for thrust-related folds and I suggest two models for the Yakataga anticline's growth: 1) the fold formed as a non-parallel detachment fold modified by fault-propagation folding in the forelimb; and 2) the fold formed as a rotating-limb fault-propagation fold. The first of these models seems to fit the natural fold better because: 1) this model accounts for the subsidiary fold in the forelimb; and 2) rotation of the backlimb in the fault-propagation fold model requires a fanning of the bedding, a feature not observed in the natural fold.
    • Geometry and kinematics of thrust-truncated and/or flattened asymmetrical folds in the eastern Brooks Range, Alaska

      Bailey, Rebecca D. (2007-08)
      Exceptional exposures of thrust-related folds within carbonate rocks of the Lisburne Group of the Brooks Range of northern Alaska are classified into four groups: unbroken/parallel folds, thrust-truncated/parallel folds, unbroken/flattened folds and thrust-truncated/flattened folds. The geometry of these folds varies greatly along strike, suggesting that serial sections do not represent successive stages in fold evolution. Geometric and kinematic modeling of individual folds reveals that no single fault-related fold model can reproduce the geometry of a given fold. Instead, successful forward modeling of the folds requires some combination of detachment folding with fault-bend folding or fault-propagation folding. All folds followed one of two kinematic paths: the initially parallel folds either broke through without flattening or flattened first and then broke through. Preferred hypothesis for why folds would deform by one path verses the other include: I) Original asymmetry will promote breakthrough over flattening, so that originally asymmetric folds will break through without flattening while initially symmetric folds will flatten before breaking through; and 2) A thin detachment unit may limit fold growth resulting in breakthrough without flattening, while a thick detachment units will not limit fold growth, allowing folds to shorten via flattening before breaking through.
    • The geometry in geometric algebra

      Kilpatrick, Kristopher N.; Maxwell, David A.; Williams, Gordon I.; Rhodes, John A. (2014-12)
      We present an axiomatic development of geometric algebra. One may think of a geometric algebra as allowing one to add and multiply subspaces of a vector space. Properties of the geometric product are proven and derived products called the wedge and contraction product are introduced. Linear algebraic and geometric concepts such as linear independence and orthogonality may be expressed through the above derived products. Some examples with geometric algebra are then given.
    • A geostatistical model based on Brownian motion to Krige regions in R2 with irregular boundaries and holes

      Bernard, Jordy; McIntyre, Julie; Barry, Ron; Goddard, Scott (2019-05)
      Kriging is a geostatistical interpolation method that produces predictions and prediction intervals. Classical kriging models use Euclidean (straight line) distance when modeling spatial autocorrelation. However, for estuaries, inlets, and bays, shortest-in-water distance may capture the system’s proximity dependencies better than Euclidean distance when boundary constraints are present. Shortest-in-water distance has been used to krige such regions (Little et al., 1997; Rathbun, 1998); however, the variance-covariance matrices used in these models have not been shown to be mathematically valid. In this project, a new kriging model is developed for irregularly shaped regions in R 2 . This model incorporates the notion of flow connected distance into a valid variance-covariance matrix through the use of a random walk on a lattice, process convolutions, and the non-stationary kriging equations. The model developed in this paper is compared to existing methods of spatial prediction over irregularly shaped regions using water quality data from Puget Sound.
    • Glacier contribution to lowland streamflow: a multi-year, geochemical hydrograph separation study in sub-Arctic Alaska

      Gatesman, Tiffany A.; Trainor, Thomas P.; Liljedahl, Anna K.; Douglas, Thomas A. (2017-12)
      Glacier melt affects the geochemical composition of rivers; however, quantifying the glacier contribution to subarctic watershed-scale runoff has attracted limited attention. To estimate glacier contribution, we conducted a 6-year geochemical hydrograph separation study in a geologically heterogeneous glacierized watershed in Interior Alaska. Water samples were collected daily from Jarvis Creek during late April through September. Source waters were collected synoptically each year from rain, snow, baseflow (winter discharge), and the glacier terminus discharge. All samples were analyzed for stable water isotopes and dissolved ion concentrations. Stream surface water samples have large seasonal and inter-annual geochemical variation, however, source waters show distinct chemical signatures allowing the application of a geochemical hydrograph separation model to quantify relative source contribution to lowland streamflow. Considerable inter-annual differences within source water signatures emphasize the importance in informing the model with source waters sampled for each season. We estimated a seasonal average of 35% (20 to 44%) glacier terminus discharge contribution with a daily range of 2 (May) to 80% (September). If glacier contribution was to cease completely, stream discharge would be reduced by 48% and 22% in low and high rainfall summers, respectively. Combined with the documented shrinkage of glaciers, our findings emphasizes the need for further research on glacial wastage effect on subarctic watersheds.
    • Global and local contributors to the historical and projected regional climate change on the North Slope of Alaska

      Cai, Lei; Alexeev, Vladimir A.; Arp, Christopher D.; Bhatt, Uma S.; Liljedahl, Anna K. (2018-05)
      This thesis includes four studies that explore and compare the impacts of four contributing factors resulting in regional climate change on the North Slope of Alaska based on a numerical simulation approach. These four contributing factors include global warming due to changes in radiative forcing, sea ice decline, earlier Arctic lake ice-off, and atmospheric circulation change over the Arctic. A set of dynamically downscaled regional climate products has been developed for the North Slope of Alaska over the period from 1950 up to 2100. A fine grid spacing (10 km) is employed to develop products that resolve detailed mesoscale features in the temperature and precipitation fields on the North Slope of Alaska. Processes resolved include the effects of topography on regional climate and extreme precipitation events. The Representative Concentration Pathway (RCP) 4.5 scenario projects lower rates of precipitation and temperature increase than RCP8.5 compared to the historical product. The increases of precipitation and temperature trends in the RCP8.5 projection are higher in fall and winter compared to the historical product and the RCP4.5 projection. The impacts of sea ice decline are addressed by conducting sensitivity experiments employing both an atmospheric model and a permafrost model. The sea ice decline impacts are most pronounced in late fall and early winter. The near surface atmospheric warming in late spring and early summer due to sea ice decline are projected to be stronger in the 21st century. Such a warming effect also reduces the total cloud cover on the North Slope of Alaska in summer by destabilizing the atmospheric boundary layer. The sea ice decline warms the atmosphere and the permafrost on the North Slope of Alaska less strongly than the global warming does, while it primarily results in higher seasonal variability of the positive temperature trend that is bigger in late fall and early winter than in other seasons. The ongoing and projected earlier melt of the Arctic lake ice also contributes to regional climate change on the Northern coast of Alaska, though only on a local and seasonal scale. Heat and moisture released from the opened lake surface primarily propagate downwind of the lakes. The impacts of the earlier lake ice-off on both the atmosphere and the permafrost underneath are comparable to those of the sea ice decline in late spring and early summer, while they are roughly six times weaker than those of sea ice decline in late fall and early winter. The permafrost warming resulted from the earlier lake ice-off is speculated to be stronger with more snowfall expected in the 21st century, while the overall atmospheric warming of global origin is speculated to continue growing. Two major Arctic summer-time climatic variability patterns, the Arctic Oscillation (AO) and the Arctic Dipole (AD), are evaluated in 12 global climate models in Coupled Model Intercomparison Program Phase 5 (CMIP5). A combined metric ranking approach ranks the models by the Pattern Correlation Coefficients (PCCs) and explained variances calculated from the model-produced summer AO and AD over the historical period. Higher-ranked models more consistently project a positive trend of the summer AO index and a negative trend of summer AD index in their RCP8.5 projections. Such long-term trends of large-scale climate patterns will inhibit the increase in air temperature while favoring the increase in precipitation on the North Slope of Alaska. In summary, this thesis bridges the gaps by quantifying the relative importance of multiple contributing factors to the regional climate change on the North Slope of Alaska. Global warming is the leading contributing factor, while other factors primarily contribute to the spatial and temporal asymmetries of the regional climate change. The results of this thesis lead to a better understanding of the physical mechanisms behind the climatic impacts to the hydrological and ecological changes of the North Slope of Alaska that have been become more severe and more frequent. They, together with the developed downscaling data products, serve as the climatic background information in such fields of study.
    • Glucose transporter-4 in mononuclear cells of sled dogs

      Schnurr, Theresia Maria; Dunlap, Kriya; Reynolds, Arleigh; Duffy, Lawrence (2013-12)
      The glucose transporter-4 (GLUT4) is the glucose transporter most responsive to insulin and has been thought to exist predominately in muscle and adipose cells. There have been findings that the glucose transporter-4 isoform is also expressed in subpopulations of white blood cells such as mononuclear cells. This study was designed to validate the presence of GLUT4 in subpopulations of white blood cells of sled dogs and to investigate whether changes in GLUT4 protein levels in white blood cells might be associated with age and stage of conditioning, as it has been reported in muscle. Our initial results have shown the ability to detect GLUT4 in white blood cells of sled dogs with a non-significant trend observed in GLUT4 levels based on age. Subsequent testing showed a statistically significant difference in GLUT4 levels in mononuclear cells based on conditioning in sled dogs. Using sled dogs as a model should enhance our understanding of GLUT4 expression on the surface of subpopulations of white blood cells. The presented projects are groundbreaking for the development of an easy, reliable and minimally invasive diagnostic tool for insulin sensitivity. Our next step in this research is to examine whether the conditioning response of GLUT4 is also observed in human mononuclear cells.
    • Glucose transporter-4 on peripheral blood mononuclear cells in conditioned vs. sedentary college students

      Sticka, Kendra D.; Knall, Cindy M.; Dunlap, Kriya L.; Krebs, Jocelyn E.; Duffy, Lawrence K. (2016-05)
      Glucose transporter 4 (GLUT-4) plays a key role in the pathophysiology of type 2 diabetes. GLUT-4 is upregulated in response to exercise, enhancing cellular glucose transport in skeletal muscle tissue. This mechanism appears to remain intact in individuals with insulin resistance. There is evidence of increased translocation of GLUT-4 and increased transcription of SLC2A, the gene which codes for GLUT-4. Details of the mechanism are poorly understood and are challenging to study due to the invasive nature of muscle biopsy. Peripheral blood mononuclear cells (PBMC) have documented insulin-sensitive GLUT-4 activity and may serve as a proxy tissue for studying skeletal muscle GLUT-4. The purpose of this study was to investigate whether GLUT-4 on PBMC is affected by exercise in a similar fashion to myocytes. Additionally, correlations between PBMC GLUT-4 and common indicators of insulin resistance and dietary patterns were examined. The results show a trend toward higher PBMC GLUT-4 levels in conditioned athletes than in their sedentary counterparts, similar to what has been documented in myocytes. Females were shown to have higher PBMC GLUT-4 levels than males. SLC2A4 mRNA analysis demonstrates a difference in mean gene expression between the conditioned and sedentary participants. Correlations between levels of PBMC GLUT-4 and hemoglobin A1c (HbA1c), glucose, insulin, HOMA-IR, BMI, or body fat were not detected. Relationships between specific nutrients and GLUT-4 were also not detected. This study provides evidence to support exploration of PBMC as a proxy tissue for studying GLUT-4 response to exercise or other non-insulin factors. This could provide important treatment avenues for individuals with insulin resistance and type 2 diabetes.
    • Gold and base metal mineralization of the Dolphin intrusion-related gold deposit, Fairbanks Mining District, Alaska

      Raymond, Luke M.; Newberry, Rainer; Larsen, Jessica; Keskinen, Mary (2018-08)
      The Dolphin deposit is an intrusion-related gold deposit (IRGD) located approximately 30 km north of Fairbanks, Alaska. The deposit is in--and adjacent to--a composite mid-Cretaceous pluton intruding amphibolite facies metamorphic rocks. An NI43-101 compliant gold resource estimation for the deposit (utilizing a 0.3 g/t cut-off grade) is 61.5 Million tonnes (Mt) at 0.69 g/t indicated (1.36 million oz = Moz) and 71.5 Mt at 0.69 g/t inferred (1.58 Moz). Due to extensive hydrothermal alteration of the intrusion, identifying rock types in hand sample and thin section, as well as by standard compositional techniques (e.g., SiO₂ vs. Na₂O + K₂O), has proven problematic. By plotting wt % TiO₂ vs. P₂O5 obtained from XRF analyses and four-acid digest ICP-MS data, two distinct population clusters appear. By comparison with least-altered intrusive rock analyses from the Fairbanks district, the igneous units were originally granite and tonalite. Because there is no gradational transition through an intermediate granodiorite unit, they were most likely derived from two separate magmatic bodies rather than in-situ fractionation from a single parent. Tonalite is concentrated along the northern and eastern margins of the stock with granite composing the rest of the body. Tonalite xenoliths in granite and granite dikes intruding tonalite prove that tonalite is the older unit. Investigations of hydrothermal alteration (based on chemical analyses, X-ray diffraction, and thin section examination) show albitic and advanced argillic (kaolinite-quartz) alteration are the dominant styles with sericite common throughout. Advanced argillic is a low temperature (<300°C) low pH alteration style that has not been previously identified in intrusion related gold deposits (IRGDs) in interior Alaska. Albitic alteration probably resulted from higher temperature, more neutral pH fluids. Gold investigations show that gold occurs as coarse-grained Au°, aurostibite, and maldonite in quartz + sulfide veins; fine-grained Au° in the oxide zone; and in many forms in disseminated sulfide. These forms include Au° inclusions in pyrite and arsenopyrite; solid-solution Au within compositionally zoned arsenopyrite; and as Au° nanoparticles in pyrite and probably arsenopyrite. Using UAF's JEOL JXA-8530F microprobe, I found that solid-solution gold occurs only in arsenopyrite with strong compositional zoning. Such grains are always small (< 0.2 mm) and commonly have low As cores; gold- bearing mantles with moderate % As; and higher As rims. In contrast, compositionally homogenous arsenopyrite does not contain detectable solid-solution gold. Pyrite is commonly arsenian and carries dissolved gold (if any) near detection limits. Gold mineralization has not been tied to any one lithology or alteration style; however, gold does seem to correlate with abrupt changes in alteration, especially between sericite + albite and kaolinite + sericite alteration. Gold-bearing, zoned arsenopyrite is predominantly associated with advanced argillic alteration and apparently represents a rapid growth, disequilibrium phenomenon.
    • GPS based tectonic analysis of the Aleutian arc and Bering plate

      Cross, Ryan S. (2007-05)
      Global Positioning System (GPS) measurements enable a quantitative analysis of tectonic deformation in the Aleutian Islands, Alaska. We construct elastic deformation models to calculate coupling on the subduction interface and the interseismic strain recorded at stations throughout the Aleutian arc. Using a grid-search inversion procedure, we determine an arc translation velocity for each region of the arc, revealing south to southwest motions of 4 to 14 mm/yr. In the central Aleutians, there is good agreement between areas of high coupling and areas of large moment release in major seismogenic events. We have combined modeling results from the Aleutians with direct measurements of station velocities of sites in western Alaska and the Bering Sea islands to test the hypothesis of a clockwise rotating Bering plate. The Bering Sea area including the Aleutian arc and western Alaska is fit by an Euler pole located at 42.5°N, 121.3°E with an angular velocity of 6.0°/my, relative to stable North America. The Bering plate's eastern boundary appears to be related to left lateral faulting in interior Alaska as clockwise rotation of the plate results in south-southwest motion relative to the North American plate. The Bering plate's interaction with a counter-clockwise rotating southcentral Alaska block may be responsible for the decreased slip-rate on the western Denali fault. Thrust earthquake slip azimuths expose a systematic discrepancy with Pacific-Bering plate convergence direction. A simple model of slip partitioning and GPS measurements reveal that slip partitioning is present in the forearc throughout the arc but only develops in the back arc west of Amchitka Pass.
    • GRID habitat plot survey data for the nesting sea turtles beach La Flor beach, Pacific, southwestern Nicaragua July of 2013

      Huettmann, Falk (Maderas Rainforest Conservancy, 2013-07-29)
      This GRID habitat plot survey was done at a globally relevant sea turtle nesting beach: La Flor (latitude 11.14282, longitude 85.79418, geographic datum WGS84). This sand beach is located at the Pacific Ocean in southwestern Nicaragua, approx. 20 km far from San Juan Del Sur and approx. 30 km far from the Costa Rican border. We did our grid-based habitat survey on the 11th of July in 2013. The GRID points are geo-referenced by latitude and longitude (decimal degrees, WGS84, +- 10 meters acuracy) and were visited only once (no 3 repeats were done because it consists of sand and private/reserve property) and no species information is provided (sand beach). From 25 regular GRID points 13 were inaccessable because of reserve land holdings or dense bush forests. We took three photos (sky, ground vertical view) for every plot, more details can be seen there. This grid can be used for change detection, shoreline location, develeopment questions, and beach erosion questions over time for turtle nest habitat, for instance. Known sea turtles for this region are predominately Olive`s Ridley sea turtle (Lepidochelys olivacea, TSN 173840), but also Hawksbill (Eretmochelys imbricata TSN 208666) and Leatherback sea turtle (Dermochelys coriacea, TSN 173843).
    • GRID survey habitat data for Playa el Coco beach (nesting sea turtles) - Pacific, southwestern Nicaragua July of 2013

      Huettmann, Falk (Maderas Rainforest Conservancy, 2013-07-29)
      This GRID survey was done at the beach of Playa de Coco - near a globally relevant sea turtle nesting beach (La Flor). Playa el Coco (latitude 11.15382, longitude 85.80051, geographic datum WGS84) is situated at the Pacific Ocean in southwestern Nicaragua, approx. 20 km far from San Juan Del Sur and approx. 30 km far from the Costa Rican border, just adjacent to La Flor. We did our grid-based habitat survey on 8th and 9th of July in 2013. The GRID points are geo-referenced by latitude and longitude (decimal degrees, WGS84, +- 10 meters acuracy) and were visited only once (no 3 repeats because it consists of sand and private property) and no species information (mostly empty sand beach). From 25 regular GRID points 9 were inaccessable because of private land holdings or very bushy forests. We took photos for every point (horizontal, vertical, sky), more details can be seen there. This grid can be used for change detection, shoreline location, develeopment, and beach erosion questions over time for turtle nest habitat, for instance. Known sea turtles for this region are predominately Olive`s Ridley turtle (Lepidochelys olivacea, TSN 17384), other species could potentially occur too. On the beach, we also detected Black-throated Magpie-Jay Calocitta colliei 558992, Balck Vulture Coragyps atratus 175272, Groove-billed Ani Crotophaga sulcirostris 177839, Great Kiskadee Pitangus sulphuratus 178301, Magnificent Frigate Bird Fregata magnificens 174763, Black Oystercatcher Haematopus bachman 176475, Sooty Tern Onychoprion fuscatus 824105, Brown Pelican Pelecanus occidentalis 174685, Neotropical Cormorant Phalacrocorax brasilianus 554375 and Banded Wren Thryothorus pleurostictus 563460). This dataset is an MS Excel format and less than 1MB in size.
    • GRID-based habitat plot data for the public nesting sea turtle beach of Pacuare, Caribean Sea, Costa Rica July of 2013

      Huettmann, Falk (Maderas Rainforest Conservancy, 2013-07-29)
      This GRID habitat survey was done at a globally relevant public sea turtle nesting beach: Pacuare (Playa Vigilada). It is situated at the Caribean Sea in Costa Rica ((latitude10.20123 longitude 83.25925; geographic datum WGS84). We did our grid-based habitat survey on 18th of July in 2013. The individual GRID points are geo-referenced by latitude and longitude (decimal degrees, +- 10 meters acuracy) and were visited only once (no 3 repeats because it consists of sand and private property) and no species information was taken (sand beach habitat). From 25 regular GRID points 15 were inaccessable because the nearby jungle and reserve. We took photos for every point (horizontally, ground and sky), more details can be seen there. This grid can for instance be used for change detection, shoreline location, develeopment, and beach erosion questions over time for turtle nest habitat. Known and observed sea turtles to occur for this region are Leatherback sea turtle (Dermochelys coriacea TSN 173843), and presumably Hawksbill sea turtle (Eretmochelys imbricata TSN 208666) and the Green sea turtle (Chelonia mydas TSN 173833). This dataset is in an MS Excel format and is less than 1MB in size.