Biogeosciences Meeting Report

Winter Conditions Are Changing Rapidly in Alpine Lake Ecosystems

LimnoAlp Workshop; Lake Cadagno, Switzerland, 10–15 September 2017

By , Martin Kainz, and Mauro Tonolla

Alpine freshwater ecosystems are affected by multifaceted environmental change, including more frequent extreme weather events, generally warmer winters, and direct human impacts. Changes in winter conditions might be particularly pronounced and affect alpine lakes, for instance, through the timing of ice on and ice off. Such impacts may lead to drastic changes in biotic communities and food webs, with repercussions for key ecosystem processes and services, including the cycling of carbon and dietary nutrients.

Despite their relevance, the ecological consequences of changing winter conditions in alpine lake catchments are still poorly understood. Because of the complexity of these changes and the variety of alpine lake catchments, studying the consequences of changing winter conditions requires a concerted, international research program on a large spatial scale; however, this type of program does not exist at present.

Such a program should apply a standardized methodology in various alpine lake catchments. Chosen catchments should vary in vulnerability to environmental change and comprise a range of human impacts on local and regional scales (e.g., hydrological alterations, fish stocking, atmospheric pollution, and catchment management). They should also differ in natural features, such as geology, lake morphometry, stratification patterns, and biotic community composition.

To pave the way toward such a research program, an international team of freshwater ecologists met for a workshop at Lake Cadagno in the Piora valley of the Swiss Alps. The workshop aimed at identifying research questions pertinent to current changes in alpine freshwater ecosystems and their consequences on aquatic communities and ecosystem processes. The workshop also identified nonacademic stakeholders affected by these environmental issues and laid the cornerstones of an international research and training program.

Fifteen scientists, drawn from LimnoAlp, an existing network of limnologists around the Alps, and ranging from postdocs to professors, engaged in lively discussions around the clock at the local Alpine Biology Center. Lake Cadagno, at the center’s doorstep, provided valuable inspiration for identifying and developing research questions, as did research projects simultaneously carried out by Ph.D. students and postdocs.

Lago Nero, shown here shortly after its ice cover broke up in spring, is a monitored alpine lake on the southern slopes of the Swiss Alps. Climate warming is rapidly changing winter conditions for alpine lakes and their vulnerable ecosystems
Lago Nero, shown here shortly after its ice cover broke up in spring, is a monitored alpine lake on the southern slopes of the Swiss Alps. Climate warming is rapidly changing winter conditions for alpine lakes and their vulnerable ecosystems. Credit: Stefano Rioggi

Presentations and discussions revealed—among other insights—the following important issues of environmental change in alpine lake catchments due to changing winter conditions:

  • Lake hydrodynamics. Water stratification within lakes may respond to changes in snow cover and snowmelt as well as to the length of ice cover in winter and heat accumulation during summer. These factors may influence the mixing patterns of lakes and, in turn, ecosystem metabolism and biogeochemical cycles.
  • Aquatic food webs and biodiversity. These may respond drastically to the loss or establishment of keystone species as a consequence of environmental change, affecting the stability of biotic communities and processes they govern.
  • Ecosystem services, management, and training. Pronounced changes in ecosystem features may have repercussions for important ecosystem services, including recreation, provision of clean water, and hydroelectricity. Concerted experiments and monitoring in alpine lake catchments along spatial and altitudinal gradients are thus required to test the generality and dependence of these issues and to train future ecosystem managers and scientists.

Workshop participants identified the European Commission’s Innovative Training Network as the appropriate funding option for a research program to address these issues. If you are interested in this initiative or the LimnoAlp network, please contact one of the authors. The workshop was supported by the Swiss National Science Foundation.

—Andreas Bruder (email: [email protected]), Institute of Earth Sciences, University of Applied Sciences and Arts of Southern Switzerland (SUPSI), Canobbio, Switzerland; Martin Kainz, Inter-university Center for Aquatic Ecosystem Research WasserCluster Lunz, Lunz am See, Austria; and Mauro Tonolla, Laboratory of Applied Microbiology, SUPSI, Bellinzona, Switzerland

Citation: Bruder, A., M. Kainz, and M. Tonolla (2018), Winter conditions are changing rapidly in Alpine Lake ecosystems, Eos, 99, Published on 27 March 2018.
© 2018. The authors. CC BY-NC-ND 3.0