Submitted by: Lipa Nkwalale Helmholtz Center for Environmental Research (UFZ) lipa.nkwalale@ufz.de
Abstract:
The implications of climate change on water quality and aquatic ecosystems are occurring at several interacting modes of action. Thermal structures of lakes display this interaction, with projected increases in water temperatures and changes to stratification phenology set to initiate chains of biogeochemical and ecological processes detrimental to water quality. Dissolved oxygen (DO) depletion leads to unwanted hypoxic/anoxic conditions, highlighting climate induced water quality changes. However, predicting oxygen dynamics is difficult, with in situ oxygen depletion rates showing considerable lake dependent variability, and different mechanisms at play. For example, climate warming leads to stratification elongation and potential increases in hypolimnion temperature, resulting in linearly and exponentially increasing DO depletion, respectively. Using DO depletion rates from literature reflecting variability in trophic state, we quantified the typical DO depletion rates ranges for oligotrophic, mesotrophic, and eutrophic lakes and included their sensitivity against temperature for a broader climate-impact assessment. We achieved that through a simple model for predicting hypolimnetic DO concentration trajectories over the stratified season and hypoxia/anoxia risks depending on the given conditions for trophic state, stratification duration, and hypolimnion temperature. We were not only able to quantify the relative importance of these three influencing factors but also deduce the applicability of this approach through the use of observational data from 13 German lakes.
Primary Session Choice: CS016 Environmental Change
Authors:
Lipa Nkwalale, Helmholtz Center for Environmental Research (UFZ) (lipa.nkwalale@ufz.de)
Robert Schwefel, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (robert.schwefel@igb-berlin.de)
Mahtab Yaghouti, University of Stirling (mahtab.yaghouti@stir.ac.uk)
Karsten Rinke, Helmholtz Center for Environmental Research (UFZ) (karsten.rinke@ufz.de)
SIMPLE MODEL FOR PREDICTING OXYGEN DEPLETION OF LAKES UNDER CLIMATE CHANGE
Category
Scientific Sessions > CS016 Environmental Change
Description
Preference: Oral