Publication Details

Category Text Publication
Reference Category Journals
DOI 10.3390/w12061577
Licence creative commons licence
Title (Primary) Quality of dissolved organic matter driven by autotrophic and heterotrophic microbial processes in a large river
Author Kamjunke, N.; Lechtenfeld, O.J. ORCID logo ; Herzsprung, P.
Source Titel Water
Year 2020
Department SEEFO; FLOEK; ANA
Volume 12
Issue 6
Page From art. 1577
Language englisch
Supplements 10.3390/w12061577
Keywords Dissolved organic matter (DOM); Fourier transform-ion cyclotron resonance mass spectroscopy (FT-ICR MS); phytoplankton; bacteria; bacterial production
UFZ wide themes ProVIS;
Abstract Rivers are regarded as important sites for processing of dissolved organic matter (DOM) from terrestrial sources on its way to the ocean. However, little is known about the longitudinal change of DOM molecular composition in large rivers. Here we performed a Lagrangian sampling in the lower part of the Middle Elbe at low discharge conditions to test how DOM composition changes along the river stretch and how this is related to microbial processes. The concentration of dissolved organic carbon and fluorescence indices showed only subtle longitudinal differences. In contrast, ultra-high-resolution mass spectrometry analysis of riverine DOM detected pronounced changes in molecular composition. Also, chlorophyll a concentration, bacterial abundance, and bacterial production all increased downstream. The three microbial parameters were positively related to intensities of CHO and CHNO molecular formulas with high hydrogen/carbon and low oxygen/carbon ratios but negatively to several CHOS surfactants. To disentangle the role of autotrophic and heterotrophic processes, we developed a new approach and compared slopes from linear regression of DOM compound intensities versus chlorophyll a concentration and bacteria abundance. As a result, most of the positive related DOM compounds were produced by bacteria. In conclusion, longitudinal changes of river DOM seemed to be largely driven by microbial processes.
Persistent UFZ Identifier
Kamjunke, N., Lechtenfeld, O.J., Herzsprung, P. (2020):
Quality of dissolved organic matter driven by autotrophic and heterotrophic microbial processes in a large river
Water 12 (6), art. 1577 10.3390/w12061577