Bacterial wax esters in recent fluvial sediments

Author(s)
Vesna Micic Batka, Michael Kruge, Bert Engelen, Jürgen Köster, Thilo Hofmann
Abstract

Intensive anthropogenic activities may periodically induce a high nutrient and/or contaminant input to rivers. These fluctuations in environmental conditions affect aquatic organisms and might cause temporary algal blooms, but can also enforce some prokaryotes to accumulate storage compounds as a hedge against starvation. Such an environmental stress can be documented in the molecular record of river sediments.
We investigated the molecular record in Danube River surface and core sediments and identified wax esters (WE) with 28 to 34 carbon atoms, being most likely of bacterial origin.
The identified WE consist of various combinations of linear (n), iso (i), anteiso (ai) aliphatic acid and alcohol moieties, showing different isomeric distributions for compounds with odd and even carbon numbers.

WE concentrations in surface sediments vary from 0 to 741 µg kg-1 with a significant enrichment recorded at locations with high concentrations of organic nitrogen and total phosphorus and a relative high proportion of aquatic vs. terrestrial organic matter, all pointing to high primary productivity. In a 70 cm long core of rapidly deposited sediment WE concentrations decrease significantly with depth following first-order kinetics, suggesting a loss of WE within few years’ time.
Cluster analysis of DGGE band patterns revealed different bacterial community compositions in up- and downstream surface sediments.
WE have seldom been investigated in rivers, but we speculate that they are markers for environmental stress. Which environmental conditions encountered in these sediments cause bacteria to generate wax esters remains, however, unclear.

Organisation(s)
External organisation(s)
Carl von Ossietzky Universität Oldenburg, Montclair State University
Volume
89-90
No. of pages
12
DOI
https://doi.org/10.1016/j.orggeochem.2015.10.003
Publication date
12-2015
Austrian Fields of Science 2012
104015 Organic chemistry, 104023 Environmental chemistry, 104002 Analytical chemistry, 105906 Environmental geosciences
Keywords
ASJC Scopus subject areas
Geochemistry and Petrology
Portal url
https://ucrisportal.univie.ac.at/en/publications/bacterial-wax-esters-in-recent-fluvial-sediments(17f4dc0d-a16b-4edd-9a45-83bc1e1e588b).html