Publication Details

Category Text Publication
Reference Category Journals
DOI 10.5194/bg-19-5343-2022
Licence creative commons licence
Title (Primary) Mineralization of autochthonous particulate organic carbon is a fast channel of organic matter turnover in Germany's largest drinking water reservoir
Author Dordoni, M.; Seewald, M.; Rinke, K.; Friese, K.; van Geldern, R.; Schmidmeier, J.; Barth, J.A.C.
Source Titel Biogeosciences
Year 2022
Department SEEFO
Volume 19
Issue 22
Page From 5343
Page To 5355
Language englisch
Topic T5 Future Landscapes
Supplements https://bg.copernicus.org/articles/19/5343/2022/bg-19-5343-2022-supplement.zip
https://doi.org/10.5194/bg-19-5343-2022-supplement
Abstract Turnover of organic matter (OM) is an essential ecological function in inland water bodies and relevant for water quality. This is especially important for the potential of dissolved organic carbon (DOC) removal as well as for emissions of CO2. In this study, we investigated various phases of OM including DOC, autochthonous particulate organic carbon (auto-POC), allochthonous particulate organic carbon (allo-POC), and sedimentary matter (SED) in a temperate drinking water reservoir (Rappbode Reservoir, Germany) by means of dissolved inorganic carbon (DIC) concentrations and carbon stable isotope ratios. In order to best outline carbon turnover, we focused on the metalimnion and the hypolimnion of the reservoir, where respiration is expected to be dominant and hardly disturbed by atmospheric exchange or photosynthesis. DIC concentrations ranged between 0.30 and 0.53 mmol L−1, while δ13CDIC values ranged between −15.1 ‰ and −7.2 ‰ versus the VPDB (Vienna PeeDee Belemnite) standard. Values of δ13CDOC and δ13Cauto-POC ranged between −28.8 ‰ and −27.6 ‰ and between −35.2 ‰ and −26.8 ‰, respectively. Isotope compositions of sedimentary material and allochthonous POC were inferred from the literature and from measurements from previous studies with δ13C ‰ and δ13Callo-POC ranging from −31.8 ‰ to −28.6 ‰. Comparison of DIC concentration gains and stable isotope mass balances showed that auto-POC from primary producers was the main contributor to increases in the DIC pool. Calculated OM turnover rates (0.01 to 1.3 µmol L−1 d−1) were within the range for oligotrophic water bodies. Some higher values in the metalimnion are likely due to increased availability of settling auto-POC from the photic zone. Samples from a metalimnetic oxygen minimum (MOM) also showed dominance of respiration over photosynthesis. Our work shows that respiration in temperate lentic water bodies largely depends on auto-POC production as a major carbon source. Such dependencies can influence the vulnerabilities of these aqueous systems.
Persistent UFZ Identifier https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=26841
Dordoni, M., Seewald, M., Rinke, K., Friese, K., van Geldern, R., Schmidmeier, J., Barth, J.A.C. (2022):
Mineralization of autochthonous particulate organic carbon is a fast channel of organic matter turnover in Germany's largest drinking water reservoir
Biogeosciences 19 (22), 5343 - 5355 10.5194/bg-19-5343-2022