Twentieth Century Glacier Change on Mount Adams, Washington, USA

Sitts, Danielle J.; Fountain, Andrew G.; Hoffman, Matthew J.

doi:10.3955/046.084.0407

Cited by 15 publications

(9 citation statements)

References 26 publications

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“…Three main sources of uncertainty are encountered when defining the outline of G&PS: georectification, digitizing, and interpretation (DeBeer and Sharp, 2007;Sitts et al, 2010;Thompson et al, 2011). Georectification uncertainty refers to the quality of the imagery or maps being analyzed.…”

Section: Uncertaintymentioning

confidence: 97%

A century of glacier change in the Wind River Range, WY

DeVisser

Fountain

2015

Geomorphology

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Section: Uncertaintymentioning

confidence: 97%

A century of glacier change in the Wind River Range, WY

DeVisser

Fountain

2015

Geomorphology

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“…It has over 200 perennial snow and ice features and twelve glaciers. Total glacier area on Mount Adams has decreased 49% since 1904 (Sitts, Fountain, & Hoffman, 2010). Gotchen and Mazama Glaciers are located on the southeastern side of Mount Adams.…”

mentioning

confidence: 99%

Primary productivity of snow algae communities on stratovolcanoes of the Pacific Northwest

Hamilton

Havig

2016

Geobiology

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The majority of geomicrobiological research conducted on glacial systems to date has focused on glaciers that override primarily carbonate or granitic bedrock types, with little known of the processes that support microbial life in glacial systems overriding volcanic terrains (e.g., basalt or andesite). To better constrain the role of the supraglacial ecosystems in the carbon and nitrogen cycles, to gain insight into microbiome composition and function in alpine glacial systems overriding volcanic terrains, and to constrain potential elemental sequestration or release through weathering processes associated with snow algae communities, we examined the microbial community structure and primary productivity of snow algae communities on stratovolcanoes in the Cascade Range of the Pacific Northwest. Here, we present the first published values for carbon fixation rates of snow algae communities on glaciers in the Pacific Northwest. We observed varying levels of light‐dependent carbon fixation on supraglacial and periglacial snowfields at Mt. Hood, Mt. Adams, and North Sister. Recovery of abundant 18S rRNA transcripts affiliated with photoautotrophs and 16S rRNA transcripts affiliated with heterotrophic bacteria is consistent with previous studies indicating the majority of primary productivity on snow and ice can be attributed to photoautotrophs. In contrast to previous observations of glacial ecosystems, our geochemical, isotopic, and microcosm data suggest these assemblages are not limited by phosphorus or fixed nitrogen availability. Furthermore, our data indicate these snow algae communities actively sequester Fe, Mn, and P leached from minerals sourced from the local rocks. Our observations of light‐dependent primary productivity on snow are consistent with similar studies in polar ecosystems; however, our data may suggest that DIC may be a limiting nutrient in contrast to phosphorus or fixed nitrogen as has been observed in other glacial ecosystems. Our data underscore the need for similar studies on glacier surfaces and seasonal snowfields to better constrain the role of local bedrock and nutrient delivery on carbon fixation and biogeochemical cycling in these ecosystems.

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“…Total glacier area on Mount Baker has generally been decreasing since reaching a Little Ice Age maxima sometime in the nineteenth century (Dick, ; Harper, ), with a period of particularly rapid retreat from about 1930 to 1945 followed by readvances from 1945 to 1980 (Figure ). A similar sequence of glacial retreat and advance has occurred on the other regional stratovolcanoes (Jackson & Fountain, ; Nylen, ; Sitts et al, ) as well as in southwest British Columbia (Menounos, ; Koch et al, ). Since around 1930, these trends in glacier extent are well explained by variations in regional climate, and, consequently, changes in glacier extent also correlate well with records of channel change.…”

Section: Resultsmentioning

confidence: 60%

Downstream‐Propagating Channel Responses to Decadal‐Scale Climate Variability in a Glaciated River Basin

Anderson

Konrad

2019

JGR Earth Surface

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Regional climate is an important control on the rate of coarse sediment mobilization and transport in alpine river systems. Changes in climate are then expected to cause a cascade of geomorphic responses, including adjustments in downstream channel morphology. However, the mechanics and sensitivity of channel response to short‐term climate variability remain poorly documented. In the Nooksack River, which drains a glaciated stratovolcano in Washington State, bed elevation changes were inferred from shifting stage‐discharge relations at seven U.S Geological Survey stream gages. Decadal‐scale elevation trends can be explained as a downstream‐propagating channel response to regional climate variability, where periods of persistent warm, dry (cool and wet) conditions corresponded to periods of aggradation (incision). The channel elevation response propagated downstream at a rate of 1 to 4 km per year; propagation rate scaled closely with channel slope. Historical trends in glacier extent and flood intensity both show some potential to explain climate‐sediment linkages, though assessing causation is complicated by the shared climate signal in both records. Results show the influence of the Pacific Decadal Oscillation, with relatively high coarse sediment yields prior to 1950 and since 1980, and notably lower sediment yields from 1950 to 1980. Measured sediment yields from nearby glaciated basins corroborate this history, suggesting a regional consistency to these climate‐sediment linkages. These results document consistent relations between climate, sediment supply, and downstream channel response at the basin scale, with channel responses propagating downstream over periods of decades with little apparent attenuation.

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Twentieth Century Glacier Change on Mount Adams, Washington, USA

Cited by 15 publications

References 26 publications

A century of glacier change in the Wind River Range, WY

A century of glacier change in the Wind River Range, WY

Primary productivity of snow algae communities on stratovolcanoes of the Pacific Northwest

Downstream‐Propagating Channel Responses to Decadal‐Scale Climate Variability in a Glaciated River Basin

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