Glacier change in western North America: influences on hydrology, geomorphic hazards and water quality

Moore, R. D.; Fleming, Sean W.; Menounos, Brian; Wheate, Roger; Fountain, Andrew G.; Stahl, Kerstin; Holm, Kris; Jakob, Matthias

doi:10.1002/hyp.7162

Cited by 336 publications

(299 citation statements)

References 143 publications

(127 reference statements)

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“…This contrasts to SF watersheds, where snowmelt percolates through soils before reaching streams. Additionally, nitrification of snow and icemelt NH 4 + in subglacial environments is a mechanism for NO 3 -production. Isotopic studies of aqueous NO 3 -in an Arctic glacier system on Svalbard revealed that this mechanism explained more than 80% of the increase in NO 3 -concentrations observed between supra-and subglacial streams, whereas contributions from rock-derived NH 4 + appeared minimal (38).…”

Section: Low Nomentioning

confidence: 99%

“…Additionally, nitrification of snow and icemelt NH 4 + in subglacial environments is a mechanism for NO 3 -production. Isotopic studies of aqueous NO 3 -in an Arctic glacier system on Svalbard revealed that this mechanism explained more than 80% of the increase in NO 3 -concentrations observed between supra-and subglacial streams, whereas contributions from rock-derived NH 4 + appeared minimal (38). Additional hypotheses, including those involving rock glaciers and landscape development, are discussed elsewhere (7,13,39,40), although we note that our analysis of watershed characteristics did not reveal significantly different NO 3 -contributions associated with the extent of talus or vegetation types across GSF versus SF watersheds.…”

Section: Low Nomentioning

confidence: 99%

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Melting Alpine Glaciers Enrich High-Elevation Lakes with Reactive Nitrogen

Saros

Rose

Clow

et al. 2010

Environ. Sci. Technol.

113

107

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See next page for additional authorsFollow this and additional works at: https://digitalcommons.unl.edu/geosciencefacpub Part of the Earth Sciences CommonsThis Article is brought to you for free and open access by the Earth and Atmospheric Sciences, Department of at DigitalCommons@University of Nebraska -Lincoln. It has been accepted for inclusion in Papers in the Earth and Atmospheric Sciences by an authorized administrator of DigitalCommons@University of Nebraska -Lincoln. Alpine glaciers have receded substantially over the last century in many regions of the world. Resulting changes in glacial runoff not only affect the hydrological cycle, but can also alter the physical (i.e., turbidity from glacial flour) and biogeochemical properties of downstream ecosystems. Here we compare nutrient concentrations, transparency gradients, algal biomass, and fossil diatom species richness in two sets of high-elevation lakes: those fed by snowpack melt alone (SF lakes) and those fed by both glacial and snowpack meltwaters (GSF lakes). We found that nitrate (NO 3 -) concentrations in the GSF lakes were 1-2 orders of magnitude higher than in SF lakes. Although nitrogen (N) limitation is common in alpine lakes, algal biomass was lower in highly N-enriched GSF lakes than in the N-poor SF lakes. Contrary to expectations, GSF lakes were more transparent than SF lakes to ultraviolet and equally transparent to photosynthetically active radiation. Sediment diatom assemblages had lower taxonomic richness in the GSF lakes, a feature that has persisted over the last century. Our results demonstrate that the presence of glaciers on alpine watersheds more strongly influences NO 3 -concentrations in high-elevation lake ecosystems than any other geomorphic or biogeographic characteristic. Melting Alpine Glaciers Enrich High-Elevation Lakes with Reactive Nitrogen

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Section: Low Nomentioning

confidence: 99%

Section: Low Nomentioning

confidence: 99%

Melting Alpine Glaciers Enrich High-Elevation Lakes with Reactive Nitrogen

Saros

Rose

Clow

et al. 2010

Environ. Sci. Technol.

113

107

View full text Add to dashboard Cite

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“…Storm surges enhanced by sea-ice retreat have led to increased coastal erosion and salinization (Jones et al 2009). Glacier melting has exposed new barren alpine areas subject to primary succession (Arendt et al 2009) and affected the geomorphology of glacier-fed river systems (Moore et al 2009). Increasing human populations and industrial activities also contribute to environmental changes (Walker et al 1987).…”

Section: Introductionmentioning

confidence: 99%

Projected changes in diverse ecosystems from climate warming and biophysical drivers in northwest Alaska

Jorgenson¹,

Marcot

Swanson

et al. 2015

Climatic Change

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Climate warming affects arctic and boreal ecosystems by interacting with numerous biophysical factors across heterogeneous landscapes. To assess potential effects of warming on diverse local-scale ecosystems (ecotypes) across northwest Alaska, we compiled data on historical areal changes over the last 25-50 years. Based on historical rates of change relative to time and temperature, we developed three state-transition models to project future changes in area for 60 ecotypes involving 243 potential transitions during three 30-year periods (ending 2040, 2070, 2100). The time model, assuming changes over the past 30 years continue at the same rate, projected a net change, or directional shift, of 6 % by 2100. The temperature model, using past rates of change relative to the past increase in regional mean annual air temperatures (1°C/30 year), projected a net change of 17 % in response to expected warming of 2, 4, and 6°C at the end of the three periods. A rate-adjusted temperature model, which adjusted transition rates (±50 %) based on assigned feedbacks associated with 23 biophysical drivers, estimated a net change of 13 %, with 33 ecotypes gaining and 23 ecotypes losing area. Major drivers included shrub and tree expansion, fire, succession, and thermokarst. Overall, projected A. R. DeGange Alaska Climate Science Center, U. S. Geological Survey, 4210 University Drive, Anchorage, AK 99508, USA changes will be modest over the next century even though climate warming increased transition rates up to 9 fold. The strength of this state-transition modeling is that it used a large dataset of past changes to provide a comprehensive assessment of likely future changes associated with numerous drivers affecting the full diversity of ecosystems across a broad region.

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“…In western North America, notable area and volume loss of glaciers (Larsen et al, 2007;Schiefer et al, 2007;Berthier et al, 2010;Bolch et al, 2010) and decreased late-summer flows in glacier-fed rivers (Stahl and Moore, 2006;Moore et al, 2009) have already been observed. On annual timescales, surface runoff in glacierized basins is affected by glacier mass change (Moore and Demuth, 2001) which supplements streamflow in years with thin snowpack or dry summers.…”

Section: Introductionmentioning

confidence: 99%

An approach to derive regional snow lines and glacier mass change from MODIS imagery, western North America

et al. 2013

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Abstract. We describe a method to calculate regional snow line elevations and annual equilibrium line altitudes (ELAs) from daily MODIS imagery (MOD02QKM) on large glaciers and icefields in western North America. An automated cluster analysis of the cloud-masked visible and near-infrared bands at 250 m resolution is used to delineate glacier facies (snow and ice) for ten glacierized regions between 2000-2011. For each region and season, the maximum observed value of the 20th percentile of snowcovered pixels (Z S(20) ) is used to define a regional ELA proxy (ELA est ). Our results indicate significant increases in the regional ELA proxy at two continental sites (Peyto Glacier and Gulkana Glacier) over the period of observation, though no statistically significant trends are identified at other sites. To evaluate the utility of regional ELA proxies derived from MOD02QKM imagery, we compare standard geodetic estimates of glacier mass change with estimates derived from historical mass balance gradients and observations of Z S(20) at three large icefields. Our approach yields estimates of mass change that more negative than traditional geodetic approaches, though MODIS-derived estimates are within the margins of error at all three sites. Both estimates of glacier mass change corroborate the continued mass loss of glaciers in western North America. Between 2000 and 2009, the geodetic change approach yields mean annual rates of surface elevation change for the Columbia, Lillooet, and Sittakanay icefields of −0.29 ± 0.05, −0.26 ± 0.05, and −0.63 ± 0.17 m a −1 , respectively. This study provides a new technique for glacier facies detection at daily timescales, and contributes to the development of regional estimates of glacier mass change, both of which are critical for studies of glacier contributions to streamflow and global sea level rise.

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Glacier change in western North America: influences on hydrology, geomorphic hazards and water quality

Cited by 336 publications

References 143 publications

Melting Alpine Glaciers Enrich High-Elevation Lakes with Reactive Nitrogen

Melting Alpine Glaciers Enrich High-Elevation Lakes with Reactive Nitrogen

Projected changes in diverse ecosystems from climate warming and biophysical drivers in northwest Alaska

An approach to derive regional snow lines and glacier mass change from MODIS imagery, western North America

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