Filters: Tags: ecosystem functions (X) > partyWithName: LCC Network Data Steward (X)
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Floods, spatially complex water flows, and organism movements all generate important fluxes of aquatic-derived materials into terrestrial habitats, counteracting the gravity-driven downhill transport of matter from terrestrial-to-aquatic ecosystems. The magnitude of these aquatic subsidies isoften smaller than terrestrial subsidies to aquatic ecosystems but higher in nutritional quality, energy density, and nutrient concentration. The lateral extent of biological aquatic subsidies is typically small, extending only a few meters into riparian habitat; however, terrestrial consumers often aggregate on shorelines to capitalize on these high-quality resources. Although the ecological effects of aquatic subsidies remain...
Categories: Data,
Publication;
Types: Citation,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: ECOSYSTEM FUNCTIONS,
ECOSYSTEM FUNCTIONS,
Federal resource managers,
LCC Network Science Catalog,
Publication,
How local geomorphic and hydrologic features mediate the sensitivity of stream thermal regimes to variation in climatic conditions remains a critical uncertainty in understanding aquatic ecosystem responses to climate change. We used stable isotopes of hydrogen and oxygen to estimate contributions of snow and rainfall to 80 boreal streams and show that differences in snow contribution are controlled by watershed topography. Time series analysis of stream thermal regimes revealed that streams in rain-dominated, low-elevation watersheds were 5–8 times more sensitive to variation in summer air temperature compared to streams draining steeper topography whose flows were dominated by snowmelt. This effect was more pronounced...
Categories: Data,
Publication;
Types: Citation,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: ECOSYSTEM FUNCTIONS,
ECOSYSTEM FUNCTIONS,
Federal resource managers,
LCC Network Science Catalog,
Publication,
Interactions and feedbacks between abundant surface waters and permafrost fundamentally shapelowland Arctic landscapes. Sublake permafrost is maintained when the maximum ice thickness (MIT) exceedslake depth and mean annual bed temperatures (MABTs) remain below freezing. However, decliningMIT since the1970s is likely causing talik development below shallow lakes. Here we show high-temperature sensitivity towinter ice growth at the water-sediment interface of shallow lakes based on year-round lake sensor data.Empirical model experiments suggest that shallow (1m depth) lakes have warmed substantially over the last30years (2.4°C), withMABT above freezing5 of the last 7years.This is incomparison to slower ratesofwarming...
In this first worldwide synthesis of in situ and satellite-derived lake data, we find that lakesummer surface water temperatures rose rapidly (global mean = 0.34°C decade1) between 1985 and2009. Our analyses show that surface water warming rates are dependent on combinations of climate andlocal characteristics, rather than just lake location, leading to the counterintuitive result that regionalconsistency in lake warming is the exception, rather than the rule. The most rapidly warming lakes are widelygeographically distributed, and their warming is associated with interactions among different climatic factors—from seasonally ice-covered lakes in areas where temperature and solar radiation are increasing whilecloud...
Categories: Data,
Publication;
Types: Citation,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: ECOSYSTEM FUNCTIONS,
ECOSYSTEM FUNCTIONS,
Federal resource managers,
LCC Network Science Catalog,
Publication,
Webinar given by the lead PI about findings associated with project: Water Temperature Regimes in the Togiak NWR and Wood-Tikchik State Park
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: ECOSYSTEM FUNCTIONS,
ECOSYSTEM FUNCTIONS,
Federal resource managers,
LCC Network Science Catalog,
Regional & county planners,
This project provides a better understanding how linkages among surface-water availability, connectivity, and temperature mediate habitat and trophic dynamics of the Fish Creek Watershed (FCW). These interrelated processes form a shifting mosaic of freshwater habitats across the landscape that can be classified, mapped, understood, and modeled in response to past and future climate and land-use change in a spatial and temporal context. Developing scenarios of freshwater habitat change in this context provides managers and scientists with a flexible template to evaluate a range of potential responses to climate and land-use change. Applying this approach in the FCW is made feasible because of the availability of...
Categories: Data,
Project;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Academics & scientific researchers,
Datasets/Database,
ECOSYSTEM FUNCTIONS,
ECOSYSTEM FUNCTIONS,
Federal resource managers,
The Yukon-Kuskokwim Delta (YKD) encompasses the southernmost, warmest parts of the arctic tundra biome and is renowned for its high biological productivity and large subsistence-based human population. Ice-rich permafrost currently is widespread and strongly influences terrestrial and aquatic habitats, including local topography, vegetation, soil hydrology, and the water balance of lakes. Ground temperatures are near the freezing point, however, and recent projections indicate that the YKD is poised for widespread loss of permafrost by the end of this century. This has implications for the region’s extensive and heretofore stable terrestrial and aquatic habitats. Tundra wildfire is a common ecological “pulse” disturbance...
Categories: Data,
Project;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: 2016,
AK-00,
Academics & scientific researchers,
Academics & scientific researchers,
Conservation NGOs,
Lakes are dominant and diverse landscapefeatures in the Arctic, but conventional land coverclassification schemes typically map them as a singleuniform class. Here, we present a detailed lake-centricgeospatial database for an Arctic watershed in northernAlaska. We developed a GIS dataset consisting of 4362lakes that provides information on lake morphometry,hydrologic connectivity, surface area dynamics,surrounding terrestrial ecotypes, and other importantconditions describing Arctic lakes. Analyzing thegeospatial database relative to fish and bird survey datashows relations to lake depth and hydrologic connectivity,which are being used to guide research and aid in themanagement of aquatic resources in the NationalPetroleum...
This project integrates projections from two climate downscaling approaches into a series of future climate scenarios that will be used to assess the vulnerability of resources and ecosystem services within the Aleutian and Bering Sea Islands LCC. It consists of 4 phases: 1) downscaled climate model integration and synthesis, and engagement with key researchers; 2) the development of a set of likely future climate scenarios based on common model projections; 3) an evaluation and synthesis of vulnerabilities of key resources and ecosystem services; and 4) presentation of results and engagement of regional managers and stakeholders in a dialogue about further research and implications. This project will occur as collaboration...
Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structureand function. Recent studies have suggested significant warming of water temperatures in individual lakesacross many different regions around the world. However, the spatial and temporal coherence associatedwith the magnitude of these trends remains unclear. Thus, a global data set of water temperature isrequired to understand and synthesize global, long-term trends in surface water temperatures of inlandbodies of water. We assembled a database of summer lake surface temperatures for 291 lakes collectedin situ and/or by satellites for the period 1985–2009. In addition, corresponding climatic drivers (airtemperatures,...
Categories: Data,
Publication;
Types: Citation,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: ECOSYSTEM FUNCTIONS,
ECOSYSTEM FUNCTIONS,
Federal resource managers,
LCC Network Science Catalog,
Publication,
Beaded streams are widespread in permafrost regionsand are considered a common thermokarst landform.However, little is known about their distribution, how andunder what conditions they form, and how their intriguingmorphology translates to ecosystem functions and habitat.Here we report on a circum-Arctic survey of beaded streamsand a watershed-scale analysis in northern Alaska using remotesensing and field studies.We mapped over 400 channelnetworks with beaded morphology throughout the continuouspermafrost zone of northern Alaska, Canada, and Russiaand found the highest abundance associated with mediumto high ground-ice content permafrost in moderately slopingterrain. In one Arctic coastal plain watershed, beaded...
Lakes are prevalent in the Arctic and thus play a key role in regional hydrology. Since manyArctic lakes are shallow and ice grows thick (historically 2 m or greater), seasonal ice commonly freezes tothe lake bed (bedfast ice) by winter’s end. Bedfast ice fundamentally alters lake energy balance and meltoutprocesses compared to deeper lakes that exceed the maximum ice thickness (floating ice) and maintainperennial liquid water below floating ice. Our analysis of lakes in northern Alaska indicated that ice-out ofbedfast ice lakes occurred on average 17 days earlier (22 June) than ice-out on adjacent floating ice lakes (9July). Earlier ice-free conditions in bedfast ice lakes caused higher open-water evaporation,...
Southwest Alaska is one of the fastest warming regions on Earth and its aquatic resources are at distinct risk from changing climate. Previous work has demonstrated that a variety of physical and biological processes are sensitive to changing climate regimes in this region, including those that support wildlife and fisheries that are of substantial importance for subsistence and commercial activities. This collaborative project resulted in the compilation of a database of existing stream, river and lake temperatures that is unmatched anywhere else in Alaska in terms of its spatial and temporal coverage. Analysis of these data resulted in refinement of the monitoring plan developed to characterize thermal responses...
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: ECOSYSTEM FUNCTIONS,
ECOSYSTEM FUNCTIONS,
Federal resource managers,
LCC Network Science Catalog,
Regional & county planners,
In Arctic ecosystems, freshwater fish migrateseasonally between productive shallow water habitatsthat freeze in winter and deep overwinter refuge in riversand lakes. How these movements relate to seasonal hydrologyis not well understood.We used passive integratedtransponder tags and stream wide antennae to track1035 Arctic grayling in Crea Creek, a seasonally flowingbeaded stream on the Arctic Coastal Plain, Alaska. Migrationof juvenile and adult fish into Crea Creek peakedin June immediately after ice break-up in the stream. Fishthat entered the stream during periods of high flow andcold stream temperature traveled farther upstream thanthose entering during periods of lower flow and warmertemperature. We used generalized...
Numerous studies utilizing remote sensing imagery and other methods have documented that thermokarst lakes are undergoing varied hydrological transitions in response to recent climate changes, from surface area expansion to drainage and evaporative desiccation. Here, we provide a synthesis of hydrological conditions for 376 lakes of mainly thermokarst origin across high-latitude North America. We assemble surface water isotope compositions measured during the past decade at five lake-rich landscapes including Arctic Coastal Plain (Alaska), Yukon Flats (Alaska), Old Crow Flats (Yukon), northwestern Hudson Bay Lowlands (Manitoba), and Nunavik (Quebec). These landscapes represent the broad range of thermokarst environments...
Field measurements, satellite observations, and models document a thinning trend in seasonal Arcticlake ice growth, causing a shift from bedfast to floating ice conditions. September sea iceconcentrations in the Arctic Ocean since 1991 correlate well (r=+0.69, p<0.001) to this lakeregime shift. To understand how and to what extent sea ice affects lakes, we conducted modelexperiments to simulate winters with years of high (1991/92) and low (2007/08) sea ice extent forwhich we also had field measurements and satellite imagery characterizing lake ice conditions. Alakeice growth model forced with Weather Research and Forecasting model output produced a 7%decrease in lake ice growth when 2007/08 sea ice was imposed on...
Spawning migrations of Pacific salmon (Oncorhynchus spp.) to coastal watersheds provide a rich resource subsidy to freshwater consumers. However, variation in thermal regimes and spawning activity across the landscape constrain the ability of poikilothermic consumers to assimilate eggs and carcasses. We investigated how sockeye salmon (Oncorhynchus nerka) spawning density and stream temperature affect the growth, body condition, and fatty acid composition of juvenile coho salmon (Oncorhynchus kisutch), a known egg predator, in seven tributaries of the Wood River in Southwest Alaska. We compared mean body size of juvenile coho salmon in late summer among 3–7 years per stream and found that the largest mean size occurred...
Categories: Data,
Publication;
Types: Citation,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: ECOSYSTEM FUNCTIONS,
ECOSYSTEM FUNCTIONS,
Federal resource managers,
LCC Network Science Catalog,
Publication,
Lake polygons within the Fish Creek Watershed, Alaska were created and classified for a number of variables relevant to size, depth, hydrology, connectivity etc. Products derived from a 5m resolution IfSAR digital surface model by calculating a zero slope. Each feature was expanded by one pixel around the entire perimeter since all waterbodies were truncated by this during the slope calculation. Lakes >=1ha were manually extracted from the dataset and their perimeters further corrected using 2002 CIR orthophotography.
The Fish Creek Watershed encompasses diverse aquatic habitats representative of much of the Arctic Coastal Plain of northern Alaska. Beyond surface water and permafrost responses caused by changes in climate, this landscape is also subject to potential land-use impacts related to petroleum development in the National Petroleum Reserve – Alaska (NPR-A). Thus, this region is an ideal setting to address aquatic habitat questions of longstanding interest to Arctic resource managers, scientists, and other stakeholders. Our multidisciplinary team is focusing on broad hypothesis that surface-water availability, connectivity, and temperature mediate aquatic habitats and trophic dynamics. We are working to understand and...
These data are the result of a geospatial analysis involving multi-year SAR-based lake ice regime classification using sigma-naught backscatter intensity from calibrated space-borne C-band SAR for thousands of lakes in 7 lake districts in Alaska, USA, detailed in Engram et al., (in review). Historically, radar backscatter from space-borne and airborne platforms shows a lower backscatter return from bedfast lake ice and a higher backscatter return from floating ice (where liquid phase water exists under the ice) (Jeffries, Morris, Weeks, & Wakabayashi, 1994; Weeks, 1977). We used a threshold method where the threshold to differentiate floating and bedfast ice regimes was determined for each year from the frequency...
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