EGU21-1693
https://doi.org/10.5194/egusphere-egu21-1693
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Winter limnology: how do hydrodynamics and biogeochemistry shape ecosystems under ice?

Joachim Jansen1,2, Sally MacIntyre3, David Barrett4, Yu-Ping Chin5, Alicia Cortés6, Alexander Forrest6, Allison Hrycik7, Rosemary Martin8, Bailey McMeans8, Milla Rautio9, and Robert Schwefel10
Joachim Jansen et al.
  • 1Uppsala University, Department of Ecology and Genetics / Limnology, Uppsala, Sweden
  • 2Bolin Centre for Climate Research, Stockholm, Sweden
  • 3Marine Science Institute, University of California at Santa Barbara, Santa Barbara, USA
  • 4Department of Biological Sciences, University of Calgary, Calgary, Canada
  • 5Department of Civil and Environmental Engineering, University of Delaware, Newark, USA
  • 6Department of Civil and Environmental Engineering, University of California at Davis, Davis, USA
  • 7Great Lakes Center, SUNY Buffalo State College, Buffalo, USA
  • 8Department of Biology, University of Toronto at Mississauga, Mississauga, Canada
  • 9Département des sciences fondamentales, Université du Québec à Chicoutimi, Chicoutimi, Canada
  • 10Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany

The ice-covered period in lakes is increasingly recognized for its unique hydrodynamic and biogeochemical phenomena and ecological relevance yet it remains poorly studied compared to the ice-free season. Knowledge gaps exist where research areas – hydrodynamics, biogeochemistry and biology – intersect. For example, density-driven circulation under ice coincides with an expansion of the anoxic zone, but abiotic and biotic controls on oxygen depletion have not been disentangled. While heterotrophic microorganisms and migrating phytoplankton often thrive at the oxycline, the extent to which physical processes induce fluxes of heat and substrates that further support under-ice food webs is uncertain. Similarly, radiatively-driven convection under ice in spring can promote growth of motile phytoplankton or diatoms depending on flow velocity, water clarity and mixing depth, but links between functional trait selection, trophic transfer to zooplankton and fish and the prevalence of microbial versus classical food webs in seasonally ice-covered lakes remain unclear. Under-ice processes cascade into and from the ice-free season, and are relevant to annual cycling of energy and carbon through aquatic food webs. Understanding the coupling between state transitions and the reorganization of trophic hierarchies is essential for predicting complex ecosystem responses to climate change. In this presentation, we briefly review existing knowledge regarding physical processes in lakes in winter and the parallel developments in under-ice biogeochemistry and ecology. We then illustrate interactions between these processes, identify extant knowledge gaps whose solution requires interdisciplinary approaches, and present (novel) methods to address outstanding questions.

How to cite: Jansen, J., MacIntyre, S., Barrett, D., Chin, Y.-P., Cortés, A., Forrest, A., Hrycik, A., Martin, R., McMeans, B., Rautio, M., and Schwefel, R.: Winter limnology: how do hydrodynamics and biogeochemistry shape ecosystems under ice?, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1693, https://doi.org/10.5194/egusphere-egu21-1693, 2021.

Corresponding presentation materials formerly uploaded have been withdrawn.