The Sierra Baguales Mountain Range, forming the eastern foothills of the Southern Patagonian Andes, has well-developed alpine-glaciated landforms which present an ideal opportunity to study climatic and non-climatic factors that control cirque development and morphology. One hundred and forty-three glacial cirques were studied with reference to 14 morphometric attributes which were analyzed using statistical analysis and GIS methodologies. The cirques were classified into two types using cluster analysis complimented with a composite map based on the attributes, the latter technique that is applied to glacial cirque analysis for the first time. Type 1 cirques are associated with glacial processes isolated from the Southern Patagonian Ice Field (SPIF), developed under locally cold and dry climatic conditions. Type 2 glacial cirques are associated with older, more extensive glacial processes controlled by regional-scale climate variables and the presence of the Pleistocene Ice Sheet. The results show that the development of most of the glacial cirques has been controlled mainly by their aspect, exposure to solar radiation, Southern Hemisphere Westerly winds, and cirque floor slope. Finally, we concluded that our analyses show the evolution of cirques in the Sierra Baguales Mountain Range was not uniform. Cirque glaciers that developed to the west, close to the Southern Patagonian Ice field, have been more dynamic, and therefore their cirques experienced more erosion than those located to the east. 
                        more » 
                        « less   
                    
                            
                            Stream water chemistry data for Arikaree cirque, 1984 - ongoing.
                        
                    
    
            This is a summary of major ion concentrations for stream water samples collected from the stream draining the Arikaree Cirque. Sampling location varied from the channel at the lip of the cirque, where it is first exposed by snowmelt, at the beginning of the season to the outlet from the pond at the foot of the glacier (usually around early July). 
        more » 
        « less   
        
    
                            - Award ID(s):
- 2224439
- PAR ID:
- 10632813
- Publisher / Repository:
- Environmental Data Initiative
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
- 
            
- 
            Abstract. Over the last century, northwestern Canada experienced some of the highest rates of tropospheric warming globally, which caused glaciers in the region to rapidly retreat. Our study seeks to extend the record of glacier fluctuations and assess climate drivers prior to the instrumental record in the Mackenzie and Selwyn mountains of northwestern Canada. We collected 27 10Be surface exposure ages across nine cirque and valley glacier moraines to constrain the timing of their emplacement. Cirque and valley glaciers in this region reached their greatest Holocene extents in the latter half of the Little Ice Age (1600–1850 CE). Four erratic boulders, 10–250 m distal from late Holocene moraines, yielded 10Be exposure ages of 10.9–11.6 ka, demonstrating that by ca. 11 ka, alpine glaciers were no more extensive than during the last several hundred years. Estimated temperature change obtained through reconstruction of equilibrium line altitudes shows that since ca. 1850 CE, mean annual temperatures have risen 0.2–2.3 ∘C. We use our glacier chronology and the Open Global Glacier Model (OGGM) to estimate that from 1000 CE, glaciers in this region reached a maximum total volume of 34–38 km3 between 1765 and 1855 CE and had lost nearly half their ice volume by 2019 CE. OGGM was unable to produce modeled glacier lengths that match the timing or magnitude of the maximum glacier extent indicated by the 10Be chronology. However, when applied to the entire Mackenzie and Selwyn mountain region, past millennium OGGM simulations using the Max Planck Institute Earth System Model (MPI-ESM) and the Community Climate System Model 4 (CCSM4) yield late Holocene glacier volume change temporally consistent with our moraine and remote sensing record, while the Meteorological Research Institute Earth System Model 2 (MRI-ESM2) and the Model for Interdisciplinary Research on Climate (MIROC) fail to produce modeled glacier change consistent with our glacier chronology. Finally, OGGM forced by future climate projections under varying greenhouse gas emission scenarios predicts 85 % to over 97 % glacier volume loss by the end of the 21st century. The loss of glaciers from this region will have profound impacts on local ecosystems and communities that rely on meltwater from glacierized catchments.more » « less
- 
            Abstract Emergent aquatic insects transport aquatic‐derived resources into terrestrial ecosystems but are rarely studied at landscape or regional scales. Here, we investigate how stream network geometry constrains the spatial influence of aquatic insect subsidies in terrestrial ecosystems. We also explore potential factors (i.e., climate, topography, soils, and vegetation) that could produce variation in stream network geometry and thus change the extent of aquatic insect subsidies from one region to another. The stream signature is the percentage of aquatic insect subsidies traveling a given distance into the terrestrial ecosystem, relative to what comes out of the stream. We use this concept to model the spatial extent (area) and distribution (spatial patterning) of aquatic subsidies in terrestrial ecosystems across the contiguous United States. Our findings suggest that at least 8% of the subsidies measured at the aquatic–terrestrial boundary (i.e., the 8% stream signature) are typically transferred throughout the entire watershed and that variation in this spatial extent is largely influenced by the drainage density of the stream network. Moreover, we found stream signatures from individual stream reaches overlap such that the spatial extent of the 8% stream signature often includes inputs from multiple stream reaches. Landscape‐scale stream network characteristics increased the area of overlapping stream signatures more than reach‐scale channel properties. Finally, we found runoff was an important factor influencing stream network geometry suggesting a potential effect of climate on aquatic‐to‐terrestrial linkages that have been understudied.more » « less
- 
            The Hubbard Brook Stream Ecology record is a companion dataset to the Hubbard Brook Watershed Stream and Precipitation Chemistry record. The Stream Ecology record started in 2018 and HBWatER collects ecological samples from seven gauged watersheds: Watersheds 1 through 6 and Watershed 9. HBWatER measures algal biomass, aquatic invertebrate emergence, and stream decomposition by measuring (1) chlorophyll-a on tiles and artificial moss, which approximate algal biomass growth on bare rock and bryophyte mats, (2) preserved algal biomass on artificial moss substrates in Lugol’s Iodine solution, (3) aquatic invertebrate emergence on replicate sticky traps placed above the stream, and (4) stream decomposition through leaf litter pack and cotton strip decay. To complement these ecological records, HBWaTER installed light sensors and field cameras to obtain better information about the light and stream environment daily. Three replicate light sensors that take sub-daily measurements of light level intensity are placed at each watershed at the weir pond (full-sun), and two under the canopy (partial shade). Field cameras take daily photos at noon of the stream canopy and the stream channel. While many studies at Hubbard Brook have measured algal biomass, aquatic invertebrates, and stream decomposition, they are scattered in locations across the valley, were performed at non-continuous times, and use various semi-comparable methods. The HBWatER Stream Ecology record was created to address this gap and systematically measure any long-term changes in the organisms living in the stream. The collection of HBWatER samples is currently sustained by Tammy Wooster (Cary IES) and analyses of these samples has been performed by Heather Malcom (Cary IES), Audrey Thellman (Duke), Steve Anderson (Duke), Geoff Wilson (Cary IES), and Adam Rok (Duke). The dataset is curated and maintained by a team of researchers: Chris Solomon (Cary IES), Emma Rosi (Cary IES), and Emily Bernhardt (Duke). Current Financial Support for HBWatER is provided by NSF LTREB #1907683 and the NSF LTER #XXX (I think you mentioned that you know the LTER fund code for this). Data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.more » « less
- 
            The Hubbard Brook Stream Ecology record is a companion dataset to the Hubbard Brook Watershed Stream and Precipitation Chemistry record. The Stream Ecology record started in 2018 and HBWatER collects ecological samples from seven gauged watersheds: Watersheds 1 through 6 and Watershed 9. HBWatER measures algal biomass, aquatic invertebrate emergence, and stream decomposition by measuring (1) chlorophyll-a on tiles and artificial moss, which approximate algal biomass growth on bare rock and bryophyte mats, (2) preserved algal biomass on artificial moss substrates in Lugol’s Iodine solution, (3) aquatic invertebrate emergence on replicate sticky traps placed above the stream, and (4) stream decomposition through leaf litter pack and cotton strip decay. To complement these ecological records, HBWaTER installed light sensors and field cameras to obtain better information about the light and stream environment daily. Three replicate light sensors that take sub-daily measurements of light level intensity are placed at each watershed at the weir pond (full-sun), and two under the canopy (partial shade). Field cameras take daily photos at noon of the stream canopy and the stream channel. While many studies at Hubbard Brook have measured algal biomass, aquatic invertebrates, and stream decomposition, they are scattered in locations across the valley, were performed at non-continuous times, and use various semi-comparable methods. The HBWatER Stream Ecology record was created to address this gap and systematically measure any long-term changes in the organisms living in the stream. The collection of HBWatER samples is currently sustained by Tammy Wooster (Cary IES) and analyses of these samples has been performed by Heather Malcom (Cary IES), Audrey Thellman (Duke), and Geoff Wilson (Cary IES). The dataset is curated and maintained by a team of researchers: Chris Solomon (Cary IES), Emma Rosi (Cary IES), and Emily Bernhardt (Duke). Current Financial Support for HBWatER is provided by NSF LTREB #1907683 and the NSF LTER #2224545 These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.more » « less
 An official website of the United States government
An official website of the United States government 
				
			 
					 
					
