Glaciers are physically and biologically connected to the landscapes which they inhabit. From changes in local water chemistry and temperature to their influence on global sea level rise, glaciers affect the lives of people and organisms far beyond their icy margins. The complex web of glacier interactions is an increasingly important area of study as glaciers decline in size and number. In some glacierized regions, agriculture and tourism are affected by hydrologic changes, while elsewhere, native trout species are threatened as a result of warming stream temperatures as glacier-fed streams dry up. Some of the research associated with glacier impacts in the USGS Benchmark Glacier regions is compiled below. While not exhaustive, these examples give some perspective to the importance of glaciers and glacier-related research as glaciers respond to changes in climate.
Gulkana Glacier is situated in the eastern Alaska Range of central Alaska, 200 miles north-east of Anchorage, Alaska. It sits in continental climate where precipitation tends to be lighter than in more coastal areas. Melt of glacial ice provides a seasonal input of cold, sediment-rich water to downstream rivers. Additionally, recent work has shown that melting glaciers increase streamflow in winter as well as summer, through contribution to aquifer recharge (Liljedahl, 2017). This impact has been demonstrated in glacier-fed headwater streams and larger lowland rivers, far downstream of initial glacial input. Glaciers in Interior Alaska are an important source of water to both streams and aquifers, as well as providing nutrients to downstream ecological communities.
Liljedahl, A. et al., 2017, Glacierized headwater streams as aquifer recharge corridors, subarctic Alaska, Geophys. Res. Lett., 44, 6876–6885, doi:10.1002/2017GL073834.
Sperry Glacier is a small alpine glacier located in Glacier National Park in the U.S. Rocky Mountains of Montana. It occupies a broad, shallow cirque along the Continental Divide which results in climatic influences from both maritime and continental air masses. Glaciers in this region have been decreasing in mass and extent during the 20th century in response to altered temperature and precipitation. Meltwater from these glaciers helps to regulate stream temperatures and maintains streamflow during late summer and drought periods when other sources are depleted. As glaciers disappear, summer stream temperatures will increase and may cause the local extinction of temperature sensitive aquatic insects, disrupting the basis of the aquatic food chain. Such changes in stream habitat may also have adverse effects for the threatened native bull trout and increase hybridization of native cutthroat trout, leaving the native population at risk. Loss of a sustained water source may impact vegetation communities and contribute to a dryer, more fire-prone landscape overall. Aside from these and other ecological consequences of losing glaciers, local economies and livelihoods are connected to glaciers in this region as well. Meltwater also contributes to agricultural practices and recreational uses like boating and fishing. Sperry, and the other remaining glaciers in Glacier National Park, also provide an aesthetic and historic component to the local tourism-based economy. The loss of glaciers in this region, and associated ecologic and socioeconomic contributions, are issues that scientists are exploring to assist land managers in determining adaptive strategies.
Clark, Adam M., Joel T. Harper, and Daniel B. Fagre, 2015, Glacier-Derived August Runoff in Northwest Montana. Arctic, Antarctic, and Alpine Research 47(1):1-16.
Muhlfeld, Clint C, J. Joseph Giersch, F. Richard Hauer, Gregory T. Pederson, Gordon Luikart, Douglas P. Peterson, Christopher C. Downs, and Daniel B. Fagre, 2011, Climate change links fate of glaciers and an endemic alpine invertebrate. Climatic Change Letters. DOI 10.1007/s10584-011-0057-1.
Pederson, G.T., L.J. Graumlich, D.B. Fagre, T. Kipfer and C.C. Muhlfeld, 2009, A century of climate and ecosystem change in Western Montana: what do temperature trends portend?. Climatic Change 96: DOI 10.1007/s10584-009-9642-y, 22pp.
Wolverine Glacier is located in the Kenai Mountains of Alaska, 65 miles south of Anchorage. The glacier is located in a maritime climate, within the Nellie Juan river basin. Runoff drains into the Nellie Juan Fjord of Prince William Sound, approximately 9 miles east of the current glacier terminus. Glaciers in in the Gulf of Alaska influence the nearshore marine environment by providing a seasonal pulse of cold, sediment-rich freshwater, impacting coastal ecology and ocean currents. Changes in coastal Alaskan glaciers will have profound impacts on downstream areas, including river and fjord ecology, and nearshore ocean currents.
Beamer, J.P., D.F. Hill, D. McGrath, A. Arendt, and C. Kienholz, 2017, Hydrologic impacts of changes in climate and glacier extent in the Gulf of Alaska watershed, Water Resour. Res., 53, 7502–7520, doi:10.1002/2016WR020033.
O'Neel, S., et al., 2015, Icefield-to-ocean linkages across the Northern Pacific coastal temperate rainforest ecosystem, BioScience, 65, 499– 512, doi:10.1093/biosci/biv027.
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