Group-specific effects on coastal bacterioplankton of polyunsaturated aldehydes produced by diatoms

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 63:123-131 (2011) - DOI: https://doi.org/10.3354/ame01486 Group-specific effects on coastal bacterioplankton of polyunsaturated aldehydes produced by diatoms Cecilia Balestra1, Laura Alonso-Sáez2,3, Josep M. Gasol2, Raffaella Casotti1,* 1Stazione Zoologica A. Dohrn, Villa Comunale, 80121 Naples, Italy 2Institut de Ciències del Mar, CSIC, Passeig Maritim de la Barceloneta 37–49, 08003 Barcelona, Catalonia, Spain 3Present address: Centro Oceanográfico de Xixón, Instituto Español de Oceanografía, Camín del L'Arbeyal s/n, 33212 Xixón, Spain *Corresponding author. Email: raffa@szn.it ABSTRACT: Polyunsaturated aldehydes (PUAs), produced as secondary metabolites by diatoms, have been shown to induce toxic effects on a variety of organisms, including copepods and phyto- and bacterioplankton. However, the nature of and the players in this interaction remain poorly understood. We tested the effect of 3 PUAs commonly produced by marine diatoms—2E,4E/Z-heptadienal (HEPTA), 2E,4E/Z-octadienal (OCTA), 2E,4E/Z-decadienal (DECA) and a mix of HEPTA and OCTA (MIX)—on a natural bacterial community from a coastal area of the NW Mediterranean Sea (Blanes Bay, Spain). Little effect on total or relative cell abundance or bulk bacterial production was observed after 6 or 24 h exposure to 7.5 nM of the 3 different PUAs for the different bacterial phylogenetic groups (Gammaproteobacteria, Bacteroidetes, Rhodobacteraceae and SAR11), assessed by catalysed reporter deposition (CARD)-fluorescence in situ hybridisation (FISH). Metabolic activity, i.e. single-cell activity as determined by microautoradiography combined with CARD-FISH (MAR-CARD-FISH), was least affected by the addition of single PUAs in Gammaproteobacteria, markedly in Bacteroidetes and most markedly in Rhodobacteraceae, leading to a decrease in Rhodobacteraceae abundance by 21% (by 38% of the active cells assessed by leucine uptake) compared to the control. Bacteroidetes, although markedly affected in single-cell activity, were the most abundant group (54% of total cell counts). The addition of a mixture of OCTA and HEPTA produced a more pronounced decrease in the metabolic activity of all groups than the incubation with the single PUAs, suggesting a synergistic effect. Our results demonstrate that PUAs have a differential effect on the single-cell activity of distinct bacterial groups in natural communities. PUAs may therefore play an important role in shaping bacterial community composition by conferring a competitive advantage to PUA-resistant groups, allowing them to preferentially use the organic matter released by diatoms. KEY WORDS: PUAs · Bacterial composition · Metabolism · MAR-CARD-FISH · Diatoms Full text in pdf format PreviousNextCite this article as: Balestra C, Alonso-Sáez L, Gasol JM, Casotti R (2011) Group-specific effects on coastal bacterioplankton of polyunsaturated aldehydes produced by diatoms. Aquat Microb Ecol 63:123-131. https://doi.org/10.3354/ame01486 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 63, No. 2. Online publication date: March 31, 2011 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2011 Inter-Research.