Concentrations of low molecular weight carboxylic acids and carbonyl compounds in the Aegean Sea (Eastern Mediterranean) and the turnover of pyruvate

Author(s)
Ingrid Obernosterer, Gijsbert Kraay, Elisabeth De Ranitz, Gerhard J. Herndl
Abstract

In situ concentrations of low molecular weight carboxylic acids and carbonyl compounds were determined in the upper 100 m water column in the Eastern Mediterranean Sea in September 1997. Concentrations ranged from 1 to 13 nM for pyruvate, 1 to 11 nM for glyoxylate and 30 to 70 nM for glycolaldehyde. No distinct diurnal pattern in the depth distribution of carboxylic acids and carbonyl compounds was detectable. Exposure of surface water to solar radiation, however, resulted in photochemical production of acetaldehyde (10 nmol l-1 h-1), acetone/acrolein (6 nmol l-1 h-1) and pyruvate (3 nmol l-1 h-1). Depth profiles of the optical properties of the total organic carbon (TOC) exhibited low TOC-normalized fluorescence (excitation 350 nm, emission 450 nm) and absorbance (abs365nm) in the top 25 m, both increasing with depth. This indicates an increasing contribution of refractory molecules to the TOC pool with depth. Uptake rates of pyruvate by heterotrophic bacterioplankton ranged from 0.022 to 0.185 nmol l-1 h-1 and contributed ∼10% to the total bacterial carbon production as measured by [3H]leucine incorporation. Bio-assay experiments with surface water amended with either 1 μM NO3, 0.4 μM PO4 or 1 μM glucose or in combination decreased pyruvate uptake as compared to the unamended control. Our results reveal that pyruvate might be an important source of carbon for bacterioplankton, with turnover times of pyruvate of 0.7 to 24 d.

Organisation(s)
Functional and Evolutionary Ecology
External organisation(s)
Royal Netherlands Institute for Sea Research
Journal
Aquatic Microbial Ecology
Volume
20
Pages
147-156
No. of pages
10
ISSN
0948-3055
DOI
https://doi.org/10.3354/ame020147
Publication date
12-1999
Peer reviewed
Yes
Austrian Fields of Science 2012
106021 Marine biology
Keywords
ASJC Scopus subject areas
Ecology, Evolution, Behavior and Systematics, Aquatic Science
Sustainable Development Goals
SDG 14 - Life Below Water
Portal url
https://ucris.univie.ac.at/portal/en/publications/concentrations-of-low-molecular-weight-carboxylic-acids-and-carbonyl-compounds-in-the-aegean-sea-eastern-mediterranean-and-the-turnover-of-pyruvate(00f917ae-8555-4b23-bc36-92ab3104bf91).html