Now showing items 1-20 of 66

    • Geochemical Weathering Variability in High Latitude Watersheds

      Jenckes, Jordan (Wiley, 2023)
      High latitude regions across the globe are undergoing severe modifications due to changing climate. A high latitude region of concern is the Gulf of Alaska (GoA) where these changes in hydroclimate undoubtedly effect the hydrogeochemistry of freshwater discharging to the nearshore ecosystems of the region. To fill the knowledge gap of our understanding of freshwater stream geochemistry with the GoA, we compile stream water chemistry data from 162 stream sites across the region. With an inverse model we estimate fractional contributions to solute fluxes from weathering of silicate, carbonate, and sulfide minerals, and precipitation. We asses weathering rates across the region and compare against global river yields. Median fractional contribution of carbonate weathering to total weathering products is 78% across all stream sites, however, there are several streams where silicate weathering is a dominant source of solutes. Weathering by sulfuric acid is elevated in glacierized watersheds. Finally, cation weathering rates are lower in GoA streams compared to the world’s largest rivers, however, weathering rates are similar when compared to a global dataset of glacier fed streams. Due to the climate sensitivity of chemical weathering, we expect future changes to the hydrogeochemistry of river water flux to nearshore ecosystems. We suggest that hydrologic changes driven by glacier ice loss and increased precipitation will alter river water quality and chemical weathering regimes such that silicate weathering may become a more important source of solutes and sulfide oxidation may decrease. This contribution provides a platform to build from for future investigations into changes to stream water chemistry in the region and other high latitude watersheds.
    • Hydroclimate Drives Seasonal Riverine Export Across a Gradient of Glacierized High-Latitude Coastal Catchments

      Jenckes, Jordan (2023-01)
      Glacierized coastal catchments of the Gulf of Alaska are undergoing rapid hydrologic fluctuations in response to climate change. These catchments deliver dissolved and suspended inorganic and organic matter to nearshore marine environments, however, these glacierized coastal catchments are relatively understudied and little is known about total solute fluxes to the ocean. We present hydrologic, physical, and geochemical data collected during April-October 2019-2021 from 10 streams along gradients of glacial fed to non-glacial (i.e., precipitation) fed, in one Southcentral and one Southeast Alaska region. Hydrologic data reveal that glaciers have a dominating influence on seasonal runoff patterns. The ẟ18O signature and specific conductance show distinctive seasonal variations in stream water sources between the two study regions apparently due to the large amounts of rain in Southeast Alaska. Total dissolved solids concentrations and yields were elevated in the Southcentral region, due to lithologic influence on dissolved loads. Hydroclimate is the primary driver of the timing of dissolved and suspended yields in both regions of the Gulf of Alaska. We show the yields of dissolved organic carbon is higher and that the δ13CPOC is enriched in the Southeast streams illustrating contrasts in organic carbon export across the Gulf of Alaska. Furthermore, we illustrate how future yields of solutes and sediments to the Gulf of Alaska may change as watersheds evolve from glacial influenced to precipitation dominated. This integrated analysis provides insights into how watershed characteristics beyond glacier coverage control the properties of freshwater inputs to the Gulf of Alaska and the importance of expanding study regions to multiple hydroclimate regimes.
    • Lithium Storage and Release from Lacustrine Sediments: Implications for Lithium Enrichment and Sustainability in Continental Brines

      Coffey, Daniel; Munk, Lee Ann; Ibarra, Daniel; Butler, Kristina; Boutt, David; Jenckes, Jordan (2021)
      Despite current and projected future reliance on lithium as a resource, deficiencies remain in genesis models of closed-basin Li brines. Subsurface geochemical interactions between water and bulk solid phases from lacustrine sediments, are shown here to be the most important process for brine genesis and sustainability of the Clayton Valley, NV brine deposit. A new subsurface basin model was developed and used to select Li-bearing solids to test the release mechanisms for Li. Ash (20-350 ppm Li) and bulk sediments (1000-1700 ppm Li) samples across depths in the basin represent the majority of the subsurface Li-bearing materials. Temperature dependent (25-95 oC) batch reaction experiments using low-salinity groundwater from the basin indicate a positive relationship between the amount of Li released and temperature. Four-step sequential extractions on a subset of bulk sediments indicate most Li is released from water and weak acid-soluble portions with approximately 30% of the total Li contained in the sediments released overall. We conceptualize that lithium is released from these samples via three mechanisms: 1) release of adsorbed Li; 2) cation exchange of Li and Mg and; 3) possible minor release from silicate structure at elevated temperatures. Based on these results and the abundance of Li-bearing sediments in the subsurface we estimate the mean Li mass in the basin materials to be between 24.4 to 58.0 Mt. This Li provides a continuous supply from water-rock interactions. This is now the largest known accumulation of Li in a basin-fill continental setting on a global scale.
    • Concentration-Discharge Patterns Across the Gulf of Alaska Reveal Geomorphological and Glacierization Controls on Stream Water Solute Generation and Export

      Jenckes, Jordan; Ibarra, Daniel; Munk, Lee (2021-10-19)
      High latitude glacierized coastal catchments of the Gulf of Alaska (GoA) are undergoing rapid hydrologic changes in response to climate change and glacial recession. These catchments deliver important nutrients in the form of both inorganic and organic matter to the nearshore marine environment, yet are relatively understudied with respect to characterization of the sediment and solute generation processes and total yields. Using multiple linear regression informed by Bayesian Information Criterion analysis we empirically demonstrate how watershed characteristics affect suspended sediment and solute generation as represented by concentration-discharge relationships. We find that watershed mean slope and relief control solute generation and that solute yields are influenced most by glacier coverage. We contribute a new flux and concentration-discharge based conceptualization for understanding solute cycles across a hydroclimatic gradient of GoA watersheds that can be used to better understand future watershed responses to rapid hydrologic change.
    • Rabies Alaska and Canada

      Huettmann, Falk; Huettmann, Falk (2021)
    • Data Submission Package for Manuscript 'Model-predicting Matschie's Tree Kangaroo in Papua New Guinea'

      Falk Huettmann et al. (30-Jul-20)
      These are the GIS data used for modeling Matschie's Tree Kangaroo (Huon Tree Kangaroo) in Papua New Guinea PNG; for details please see metadata. THe manuscript is currently in revision phase.
    • Metadata of six NCEAS data sets in Elith et al. 2020

      Elith, J.; Graham, C.H.; Valavi, R.; Abegg, M.; Bruce, C.; Ford, A.; Guisan, A.; Hijmans, R.J.; Huettmann, F.; Lohmann, L.G.; et al. (7/29/2020)
      The publication by Elith et al. 2020 publishes data from Elith et al. 2006 and consists of six data set; metadata descriptions provided here. Data are found in OSF and as an R package; details provided in Elith et al. 2020 and/or with authors.
    • Data (Appendix) for Book Chapter 43: Citizen Science Experience in Lumbini/Nepali for Sarus Cranes and Lesser Adjudants (Storks) with Regmi and Huettmann 2020 Hindu Kush Himalaya: Watersheds Downhill, Springer

      Karmacharya, D.K.; Duwal, R.; Yadav, S.K. (4/2/2020)
      This dataset consist of an appendix of citizen science data for the Sarus Crane and Adjudant storks in Lumbini and Jagdishpur Reservoir, Nepal. It's a plain MS Excel sheet.
    • Data (Appendix) for Book Chapter 33: Persistent Langur (Semnopithecus) decline in Nepal with Regmi and Huettmann 2020 Hindu Kush Himalaya: Watersheds Downhill, Springer

      Ale, Purna Bahadur; Regmi, Ganga Ram; Huettmann, Falk (4/2/2020)
      This dataset consists of an appendix of a GIS map of langur sp information in Nepal. The datasets are locations, presences and absences from a value-added GBIF.org query, transect data by the authors and literature data Details are specified in the book chapter by Ale et al in Regmi and Huettmann 2020. This is the first and best compiled data for this species in Nepal and shows national declines with large conservation management implications.
    • Data (Appendix) for Book Chapter 25: Museum Data holdings and Libraries in Nepal and Hindu Kush Himalaya region with Regmi and Huettmann 2020 Hindu Kush Himalaya: Watersheds Downhill, Springer

      Huettmann, Falk (4/2/2020)
      This compiled dataset consists of a value-added analysed GBIF data set in the wider Hindu Kush-Himalaya (HKH) region. The original data source is from individual national contributors found in GBIF. Data are used here for research purposes for the wider HKH region watersheds and to show institutional spread and distribution. Some major outside museums internationally are mentioned too. The dataset consists of MS Excel sheets Methods and details are specified in the book chapter by Huettmann in Regmi and Huettmann 2020. This is the first and best compiled data for the study area and is to set a start of such views and investigations towards a better and more fair access to data, as part of a better and more democratic decision-making process.
    • Data (Appendix) for Book Chapter 22: Rapid Assessment of Urban Birds and GIS models of Kathmandu and Pokhara, Nepal with Regmi and Huettmann 2020 Hindu Kush Himalaya: Watersheds Downhill, Springer

      Hansen, Lindsay; Huettmann, Falk (4/2/2020)
      This compiled dataset consists of a field data from rapid assessment of common birds found in urban areas of Kathmandu and Pokhara, Nepal, Hindu Kush-Himalaya (HKH) region.The dataset consists of 31 bird and animal species from a detection survey of 2 transects and photos in MS Excel sheets. It is overlaid with Open Street GIS map predictors for the study areas, and model predicted with GIS. We used the following 6 layers:waterways, natural places, shop polygons, land use, roads and highways and computed proximities for each in GIS. Methods and details are specified in the book chapter by Huettmann in Regmi and Huettmann 2020. This is the first and best compiled field and GIS data for the study area and is to set a start of such views and investigations towards a better and more fair access to data, as part of a better and more democratic decision-making process. Here an example is presented using avian species and GIS habitat layers.
    • Data (Appendix) for Book Chapter 37: 'Road, Railroad and Airport data for the Hindu Kush Himalaya region' with Regmi and Huettmann 2020 Hindu Kush Himalaya: Watersheds Downhill, Springer

      Huettmann, Falk (4/2/2020)
      This compiled dataset consists of an appendix of value-added merged GIS maps for roads, railroads and airports in the wider Hindu Kush-Himalaya (HKH) region. The original data source is from individual national DIVA-GIS files and used here for research purposes for the wider HKH region watersheds. Nations included are: Nepal, India, China, Buthan, Kazachstan, Tajikistan, Kyrgystan, Uzbekistan, Turkmenistan, Afghanistan, Iran, Laos, Myanmar, Thailand, Vietnam, Pakistan, Bangladesh and Cambodia. The dataset consists of 21zip archives of these nations also covering railways and airports. Methods and details are specified in the book chapter by Huettmann in Regmi and Huettmann 2020. This is the first and best compiled data for the study area.
    • Data (Appendix) for Book Chapter 28: Sarus Crane GIS Model with Regmi and Huettmann 2020 Hindu Kush-Himalaya: Watersheds Downhill, Springer

      Karmacharya, D. K.; Huettmann, F.; Mi, C; Han, X; Duwal, R; Yadav, SK; Guo, Y (4/2/2020)
      This dataset consist of an appendix of GIS model predictions of Sarus Cranes (GRus antigone Taxonomic Serial Number TSN: 176181) in Nepal. Details are specified in the book chapter by Karmacharya et al in G.R.Regmi and F. Huettmann 2020. This is the first model for this species and shows conservation management implications for the Terai landscape between Nepal and India.
    • Rabies data for Canada and Alaska/US for GIS model predictions

      Hueffer, K.; Huettmann, F. (2020-04)
      This value-added data set is part of a publication by Huettmann and Hueffer (in prep) and includes the GIS layers for rabies and predictions of Canada, assessed with Alaska locations ((taken from Huettmann et al. 2015). This project compiled the best publically available rabies data for Canada, and models them for the Northern part of the the North American continent (Alaska and Arctic Canada). The environmental data sets are in a common GIS format (ESRI and ASCII grids) and are taken from public Open Access sources. The rabies data sets are point data, as rabies was reported by the Canadian Food Inspection Agency, and processed in the lab. The dataset is 5GB in size and consists of 20 files.
    • Camera Trapping Grid Data in Nepal Hindu Kush-Himalaya for regions of Humla 2015 , Manang 2014-2015 and Manang 2016-2017

      Ganga, Regmi; Lama, Rinzin Phunjok; Ghale, Tashi Rapte; Lama, Tenzing; Puri , Ganesh; Huettmann, Falk (2020-04)
      This multi-year, multi-site and multi-species dataset describes Bushnell Camera Trap data from three locations in remote Nepal: Humla 2015, Manang 2014-2015 and Manang 2016-2017. The data from the Hindu Kush-Himalaya region comes from a geo-referenced survey grid and are stored in three MS Excel sheets, also combined and available in CSV consisting of 175658 records and 15 columns with a file size of 19MB. Species covered are Blue Sheep/Bharal (Pseudois nayaur Taxonomic Serial Number TSN 180596 ), Snow Leopard (Panthera unica, Uncia uncia TSN 183811), Beech Marten (Martes foina TSN 621941), Wolf (Canis lupus TSN 180596), birds (Aves Golden Eagle etc.),Pika (Ochotona), Red Fox (Vulpes vulpes TSN 180604), Mountain Weasel (Mustela altaica TSN 621947), Pallas�s Cat (Otocolobus manul, Felis manul TSN 183791), and Golden Jackal (Canis aureus TSN 183817)
    • Red squirrel midden model prediction GIS data

      Robold, Richard; Huettmann, Falk (11/30/2019)
      This dataset features the best-available compilation about Red Squirrels (Tamiasciurus hudsonicus, taxonomic serial number 180168 ) GIS model predictions in a study area in Fairbanks,Alaska. This dataset starts in 20016 and ends in 2017. The data are referenced in time and in space (GPS) and it consist of GIS layers for the UAF campus trails, including LIDAR; the geographic projection is UTM 6N in meters. The dara are compiled from sightings and records by the first author. This dataset represents opportunistic as well as complete sightings for a study area at UAF campus. The actual squirrel data are compiled into an MS Excel sheet and all other data layers are in ESRI format: raster or shapefile Tthe size of the overall data package is app. 21 MB.
    • Distribution and density of the American Red Squirrel (Tamiasciurus hudsonicus ) in the interior Alaskan old-growth forest for 2019

      Huettmann, Falk; Steiner, Moriz (2019-07-31)
      The aim of this project -carried out in July 2019 - was to determine the distribution and density of the American Red Squirrel (Tamiasciurus hudsonicus; taxonomic serial number 180166) in the old-growth forest of interior Alaska; region of Fairbanks. Also the distribution and density of squirrel middens (construction built by the squirrel, which is used for nutrition storing for the winter. Middens also provide as a nest for the squirrel's which can be used as protection from predators. We carried out opportunistic surveys along trails and within forest stands using GPS and notebook. Google Maps were used for navigation and planning help. This work can be used for subsequent model predictions with GIS software and other modelling software programs to obtain the detection rates and the distribution and density of middens in the whole study area (Tanana State Forest).
    • Streetlight Halos

      Tape, Walter (2010)