Changes in marine prokaryotic community induced by varying types of dissolved organic matter and subsequent grazing pressure

Alonso‐Sáez, Laura; Unanue, Marian; Latatu, Ainhoa; Azúa, Iñigo; Ayo, Begoña; Artolozaga, Itxaso; Iriberri, Juan

doi:10.1093/plankt/fbp081

Cited by 33 publications

(24 citation statements)

References 44 publications

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“…In this work, beta-Proteobacteria was not the dominant group and their abundance did not change significantly after the appearance of nanoflagellates, probably due to their ability to form small aggregates. This result is partly in line with numerous studies (J€ urgens et al 1999;Simek et al 2001;Burkert et al 2003;Hahn et al 2004;Alonso-S aez et al 2009), in which beta-Proteobacteria, when exposed to high predation pressure, formed aggregates and microcolonies. Here, we also detected small alpha-Proteobacteria cells forming microcolonies in association with beta-Proteobacteria.…”

Section: Discussionsupporting

confidence: 89%

Competition and protist predation are important regulators of riverine bacterial community composition and size distribution

Batani

Pérez

Escalera

et al. 2016

Journal of Freshwater Ecology

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Among the bacterivorous protists, heterotrophic nanoflagellates (HNFs) are considered to be the main grazers of bacteria in freshwaters due to their size-selective grazing. In this work, we assessed the change of a riverine bacterial community in controlled incubations, where HNFs' predation pressure was initially released through filtration. Filtration did not prevent the passage of cysts, which grew in the enrichments afterwards. Data on the composition of the bacterial community were gathered by Catalyzed Reporter Deposition Fluorescent In situ Hybridization (CARD-FISH) using 16S probes targeting phylogenetic groups. Bacterial cell size was also examined using image analysis. Overall, the initial filtration directly (through release of predation pressure) or indirectly (through competition among bacterial groups) affected the bacterial community composition. When nanoflagellate abundance rose, a reduction of bacterial abundance and changes in cell size distribution were observed. Gamma-Proteobacteria and Actinobacteria were the groups showing the greatest reduction in abundance. Beta-Proteobacteria showed a reduction of cell size and were found in aggregates. AlphaProteobacteria and Actinobacteria developed two distinct filamentous morphotypes: short, segmented rods and long chains of rods. Our results showed that the release of the predation pressure and the successive rise of the nanoflagellates changed the bacterial community in terms of composition at large phylogenetic scale. HNF grazing is highly groupspecific and seems to reconstruct the community based on cell size, and thus, not only drastically changing the bacterial community composition, but also increasing its functional diversity.

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Section: Discussionsupporting

confidence: 89%

Competition and protist predation are important regulators of riverine bacterial community composition and size distribution

Batani

Pérez

Escalera

et al. 2016

Journal of Freshwater Ecology

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“…They have also been shown to induce changes in eukaryotic and prokaryotic microbial community composition (Alonso-Sáez et al, 2009;Fagerberg et al, 2010;Sipler et al, unpublished data). These observations suggest that humic substances play a complex, biogeochemically active role in coastal ecosystems (Bronk et al, 2007;See and Bronk, 2005;Steinberg et al, 2004).…”

Section: Humic Substancesmentioning

confidence: 98%

Dynamics of Dissolved Organic Nitrogen

Sipler¹,

Bronk²

2015

Biogeochemistry of Marine Dissolved Organic Matter

119

128

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“…There is evidence that these broad groups of bacteria also differ in their use of organic material (Cottrell & Kirchman 2000, Longnecker et al 2006, Elifantz et al 2007). For example, more cells in the Alphaproteobacteria class use low molecular weight compounds like amino acids or glucose than high molecular weight compounds such as protein or polysaccharides (Cottrell & Kirchman 2000, Alonso-Saez et al 2009). Within the Alphaproteobacteria, more than half of the ubiquitous SAR11 clade incorporated amino acids and dimethylsulfoniopropionate (DMSP) in the North Atlantic (Malmstrom et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Single-cell response of bacterial groups to light and other environmental factors in the Delaware Bay, USA

Straza¹,

Kirchman²

2011

Aquat. Microb. Ecol.

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We examined the incorporation of leucine, protein, and a mixture of 15 amino acids by selected phylogenetic groups in light and dark incubations of coastal waters of the Delaware Bay and Mid-Atlantic Bight. In experiments conducted over 3 yr, the single-cell activity of different groups of bacteria varied with molecular weight of the substrate, photosynthetically active radiation (PAR), and other environmental conditions. The fraction of cells active in using leucine and incorporating protein differed among groups and between summer and fall. About 30% of all cells incorporated the amino acid mixture, while only 10% incorporated protein. PAR availability affected single-cell activity in 20% of all experiments, and PAR conditions prior to sampling correlated with light effects on singlecell activity, varying with the compound (amino acid mixture, leucine or protein). The bacterial group most consistently affected by PAR was the SAR11 clade; 25% more SAR11 bacteria used leucine in the light than the total community. The study illustrates the complex effects of light on single-cell activity of bacterial groups and helps to explain the variability in the impact of light on dissolved organic carbon fluxes. KEY WORDS: Microautoradiography · Bacterial activity · Light · DOM incorporation Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 62: [267][268][269][270][271][272][273][274][275][276][277] 2011 of which vary seasonally (Fuhrman et al. 2006, Henriques et al. 2006. In Blanes Bay in the northwest Mediterranean Sea, more Gammaproteobacteria incorporated amino acids in winter than in summer (AlonsoSaez & Gasol 2007). Active fractions of Gammaproteobacteria and the Sphingobacteria-Flavobacteria group increased with higher concentrations of glucose during a spring phytoplankton bloom in the North Sea (Alonso & Pernthaler 2006). Mortality due to grazing or viral lysis also impacts bacterial activity, and there is some evidence of differing responses by different bacterial groups as well as a greater response in oligotrophic systems (Longnecker et al. 2010). In the California Current System, the fraction of cells in the whole bacterial community using leucine responded to changes in temperature and salinity but there were no differences in the responses of the bacterial groups studied, including Sphingobacteria-Flavobacteria and the Alpha-, Beta-, and Gammaproteobacteria (Longnecker et al. 2006). The environmental factors driving variation in single-cell activity of specific bacterial groups are not well characterized.The ability of some heterotrophic bacteria to use light as an additional source of energy may drive variation in growth and abundance (Kolber et al. 2000, Béjá et al. 2001). Exposure to photosynthetically active radiation (PAR) can stimulate the total community uptake of compounds such as leucine and methionine (Moran et al. 2001, Church et al. 2004, Mary et al. 2008), but the effect may not always be present or the same (Michelou et al. 2007). Some...

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Changes in marine prokaryotic community induced by varying types of dissolved organic matter and subsequent grazing pressure

Cited by 33 publications

References 44 publications

Competition and protist predation are important regulators of riverine bacterial community composition and size distribution

Competition and protist predation are important regulators of riverine bacterial community composition and size distribution

Dynamics of Dissolved Organic Nitrogen

Single-cell response of bacterial groups to light and other environmental factors in the Delaware Bay, USA

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