Novel evaluations of sources and sinks of dissolved oxygen via stable isotopes in lentic water bodies

Dordoni M, Seewald M, Rinke K, Schmidmeier J, Barth J (2022)

Publication Type: Journal article

Publication year: 2022

Journal

Science of the Total Environment Elsevier

Book Volume: 838

Article Number: 156541

DOI: 10.1016/j.scitotenv.2022.156541

Abstract

Dissolved oxygen (DO) dynamics of a temperate drinking water reservoir in the Harz Mountains (Germany) were investigated over a time period of 18 months. Via depth profiles in a fortnightly sampling resolution we were able to trace DO and temperature dynamics including the formation and breakdown of a Metalimnetic Oxygen Minimum (MOM) by means of DO concentration, saturation patterns and stable isotope ratios of dissolved oxygen (expressed as δ18ODO). Over the evaluation period, 19.4 % of the samples collected had δ18ODO values compatible with atmospheric equilibration (+24.6 ‰ ± 0.4 ‰). With values smaller and larger than this threshold, the remaining δ18ODO values showed that 40.8 % of our samples were dominated by photosynthesis and 39.8 % by respiration. From December to April the reservoir was mixed and DO consumption by respiration exceeded production via photosynthesis. During stratification period, quantification of respiration/photosynthesis rates (R/P) confirmed the epilimnion as a photosynthetic (i.e. net-autotrophic) environment while the hypolimnion was heterotrophic and dominated by respiration at various degrees. Samples of the MOM zone showed the highest R/P ratios and had among the most positive δ18ODO signals caused by respiration. This study showed that combinations of DO concentrations and their isotope ratios are promising to quantify critical zones of respiration and photosynthesis in aquatic environments.

Authors with CRIS profile

Marlene Dordoni Lehrstuhl für Angewandte Geologie Jakob Schmidmeier Lehrstuhl für Angewandte Geologie Johannes Barth Lehrstuhl für Angewandte Geologie

Involved external institutions

Helmholtz-Zentrum für Umweltforschung (UFZ) / Helmholtz Center for Environmental Research DE Germany (DE)

How to cite

APA:

Dordoni, M., Seewald, M., Rinke, K., Schmidmeier, J., & Barth, J. (2022). Novel evaluations of sources and sinks of dissolved oxygen via stable isotopes in lentic water bodies. Science of the Total Environment, 838. https://doi.org/10.1016/j.scitotenv.2022.156541

MLA:

Dordoni, Marlene, et al. "Novel evaluations of sources and sinks of dissolved oxygen via stable isotopes in lentic water bodies." Science of the Total Environment 838 (2022).

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