Photoreactivity and bacterioplankton availability of aliphatic versus aromatic amino acids and a protein

Author(s)
Bettina Reitner, Alois Herzig, Gerhard J. Herndl
Abstract

In batch culture experiments with natural bacerial assemblages collected from a humic-rich lake (Lake Neusiedl, Austria), labile organic nitrogen containing model substrates (alanine [Ala], an aliphatic amino acid, tryptophan [Trp], an aromatic amino acid, and bovine serum albumin [BSA], as protein) were added to 0.2 μm filtered lake water prior to exposure (for 9 h) to surface levels of the full range of solar radiation or being held in the dark. These organic nitrogen species were chosen to investigate compound-specific differences in the photochemical transformation of labile dissolved organic matter (DOM) and its subsequent availability to bacteria. 'Photocoloring' or humification in the Trp-amended water exposed to natural solar radiation and significant dissolved organic carbon (DOC) loss (120 μM C over 9 h exposure) resulted, after inoculation of the natural bacterial assemblage, in a lower maximum bacterial abundance in the previously solar radiation-exposed treatments as compared to the dark control. In contrast, the absorbance characteristics of solar-irradiated Ala- and BSA-amended water were almost identical to the unamended control and to the Ala- and BSA-amended treatments kept in the dark. Also, no significant difference in the maximum bacterial abundance of the solar radiation-exposed Ala- and BSA-amended treatments was detectable as compared to the corresponding dark controls. Our data indicate that Trp is a potential source of solar radiation-mediated humification in Lake Neusiedl.

Organisation(s)
Department of Botany and Biodiversity Research, Functional and Evolutionary Ecology
External organisation(s)
Royal Netherlands Institute for Sea Research
Journal
Aquatic Microbial Ecology
Volume
26
Pages
305-311
No. of pages
7
ISSN
0948-3055
Publication date
01-2002
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/photoreactivity-and-bacterioplankton-availability-of-aliphatic-versus-aromatic-amino-acids-and-a-protein(b4944520-877b-40ef-b64f-39a6367d81ed).html