The extent and variability of storm-induced epilimnetic temperature changes in lakes using a long-term and high-frequency global dataset

DOUBECK, JP. ; ADRIAN, R. ; ANNEVILLE, O. ; BHATTACHARYA, R. ; DE EYTO, E. ; FEUCHTMAYR, H.; HEJZLAR, J. ; IBELINGS, B. ; JACQUET, S. ; LLAMES, M.E. (10/19); Y OTROS.

Congreso; GLEON 20 All Hands' Meeting; 2018

The intensity, frequency, and duration of storms are expected to increase in manyregions around the world because of climate change. Altered environmental conditionsfollowing storms can lead to shifts in the composition and variability of ecologicalcommunities across terrestrial and aquatic ecosystems. In freshwater lakes andreservoirs, storms can rapidly lower surface water temperatures in several waysincluding precipitation run-off and wind-induced water column mixing of theepilimnion and the hypolimnion. Decreased water column temperatures couldsubsequently impact phytoplankton community structure. Recent laboratoryexperiments suggest that sharp and rapid changes in water temperature (10ºC) couldinfluence phytoplankton communities more than storm-induced increases in nutrientsand decreases in light. We empirically assessed the extent to which epilimnetictemperatures change after storm events, and how any changes may depend on variousenvironmental conditions or morphometric characteristics such as season, lake mixingregime, and origin of the waterbody. We analyzed high-frequency, and long-termdatasets from a global set of lakes from the Global Evaluation of the Impacts of Stormson freshwater Habitat and structure of phytoplankton Assemblages (GEISHA),originated within GLEON Storm-Blitz, to (1) estimate the degree to which storms lowerepilimnetic temperatures, (2) test if the largest epilimnetic temperature decreases wereassociated with the strongest storm events, and (3) quantify what internal or externalcharacteristics of lakes play significant roles in the extent of epilimnetic temperaturechanges. Finally, we discuss the implications of observed changes in epilimnetic temperature as a result of storms for phytoplankton community dynamics, usingfunctional trait approaches.