Preston, DL, Caine, N, McKnight, DM, Williams, MW, Hell, K, Miller, MP, Hart, SJ, Johnson, PTJ
AGU-Geophysical Research Letters
NWT Accession Number: NWT1872
High-elevation aquatic ecosystems are highly vulnerable to climate change, yet relatively few
records are available to characterize shifts in ecosystem structure or their underlying mechanisms. Using a
long-term data set on seven alpine lakes (3126 to 3620 m) in Colorado, USA, we show that ice-off dates have
shifted 7 days earlier over the past 33 years and that spring weather conditions—especially snowfall—drive
yearly variation in ice-off timing. In the most well studied lake, earlier ice-off associated with increases in
water residence times, thermal stratification, ion concentrations, dissolved nitrogen, pH, and chlorophyll a.
Mechanistically, low spring snowfall and warm temperatures reduce summer stream flow (increasing lake
residence times) but enhance melting of glacial and permafrost ice (increasing lake solute inputs). The
observed links among hydrological, chemical, and biological responses to climate factors highlight the
potential for major shifts in the functioning of alpine lakes due to forecasted climate change.
Ice-off, Spring Snowfall, water residence times, thermal stratification, ion concentrations, dissolved nitrogen, pH, and chlorophyll a, Climate Change
Preston, DL, Caine, N, McKnight, DM, Williams, MW, Hell, K, Miller, MP, Hart, SJ, Johnson, PTJ, (2016) Climate regulates alpine lake ice cover phenology and aquatic ecosystem structure. AGU-Geophysical Research Letters , DOI: 10.1002/2016GL069036
This material is based upon work supported by the National Science Foundation under Cooperative Agreement #DEB-1637686. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necesarily reflect the views of the National Science Foundation.
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