Photoheterotrophic Marine Prokaryotes

Béjà, Oded; Suzuki, Marcelino T.

doi:10.1002/9780470281840.ch5

Cited by 24 publications

(7 citation statements)

References 93 publications

(77 reference statements)

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“…The magnitude of response of BP to the incubation conditions might be related to the composition of communities and to the degree of dissimilarity between the initial samples. Higher values of BP in the laboratory dark condition are consistent with those obtained in other studies (Morán et al 2001;AlonsoSaez et al 2006;Béjà and Suzuki 2008). However, another study observed BP stimulation in laboratory conditions, but when bacteria were exposure to PAR, not in the dark control as in our study (Ruiz-González et al (2012).…”

Section: Impact Of Incubation Conditions On Bacterial Production Detesupporting

confidence: 94%

“…However, this technique has some limitations such as the dark incubations of the samples (Aas et al 1996;Pakulski et al 1998;Morán et al 2001), which intend to avoid reproduction of the levels of ambient light (Morán et al 2001), removing the stimulatory effects of primary production and eliminate the harmful effects of solar radiation on bacteria (Aas et al 1996). Several studies have been published about this subject; however, there is no agreement on the ideal incubation condition since, in some works, there is stimulation of leucine incorporation rates by PAR (photosynthetically active radiation, 400-700 nm) light irradiation (Mary et al 2008;Ruiz-González et al 2012), and in others, there is a strong inhibition (Morán et al 2001;Alonso-Saez et al 2006;Béjà and Suzuki 2008).…”

Section: Introductionmentioning

confidence: 97%

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Influence of incubation conditions on bacterial production estimates in an estuarine system

et al. 2014

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This study aimed to assess the influence of incubation conditions in the determination of bacterial production (BP). In order to achieve that goal, experimental setups were performed in situ and in the laboratory under both dark and light conditions. To test spatial and seasonal variations and the different natural light exposure of microorganisms, sampling was performed in two distinct zones of the estuary Ria de Aveiro (Portugal), typifying the marine and brackish water zones of the estuarine system. Denaturing gradient gel electrophoresis analysis of 16S rRNA gene fragments was used to monitor possible alterations in bacterial community composition induced by the incubation conditions. The results showed that BP determined in situ conditions significantly differed from in the laboratory. In the marine zone, a defined pattern of variation was detected, with consistent higher values of BP in laboratory dark conditions. This trend was not present in the brackish water zone. The seasonal and spatial variability of BP observed in field incubations was related to the physical-chemical proprieties of the water column, irradiance levels and the original community composition. The metabolic active profiles of bacteria were substantially different in the several incubation conditions, suggesting that methodological procedure influences the bacterial community composition, and the values of BP reported for aquatic ecosystems could be quite different from the real ones. In the light of these results, we suggest that BP determinations should be conducted under in situ conditions. However, due to execution limitations, BP needs to be frequently determined in the laboratory, and in this case, dark incubations provide more approximate values. This is the method routinely used, and although this incubation condition can cause stimulation of BP, the structure of the bacterial community is more similar to the one obtained with the in situ incubations.

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Section: Impact Of Incubation Conditions On Bacterial Production Detesupporting

confidence: 94%

Section: Introductionmentioning

confidence: 97%

Influence of incubation conditions on bacterial production estimates in an estuarine system

et al. 2014

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“…In photoheterotrophs, the proton motive force generated by light can be used to drive active transport, motility, and ATP synthesis but is not used for C fixation; these microbes require organic C for growth. AAP bacteria have bacteriochlorophyll and make up 1-30% of the bacteria in surface waters (Béja & Suzuki 2008, Kirchman & Hanson 2013. They belong to the alpha, beta, and gamma subclasses of the Proteobacteria, and common marine genera include Roseobacter, Erythrobacter, and the gammaproteobacterial clade OM60; these bacteria occur in estuaries, bays, and the open ocean (Eiler 2006, Béja & Suzuki 2008.…”

Section: Photoheterotrophic Bacteria and Archaeamentioning

confidence: 99%

Mixotrophy in the Marine Plankton

Stoecker

Hansen

Caron

et al. 2017

Annu. Rev. Mar. Sci.

432

392

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Mixotrophs are important components of the bacterioplankton, phytoplankton, microzooplankton, and (sometimes) zooplankton in coastal and oceanic waters. Bacterivory among the phytoplankton may be important for alleviating inorganic nutrient stress and may increase primary production in oligotrophic waters. Mixotrophic phytoflagellates and dinoflagellates are often dominant components of the plankton during seasonal stratification. Many of the microzooplankton grazers, including ciliates and Rhizaria, are mixotrophic owing to their retention of functional algal organelles or maintenance of algal endosymbionts. Phototrophy among the microzooplankton may increase gross growth efficiency and carbon transfer through the microzooplankton to higher trophic levels. Characteristic assemblages of mixotrophs are associated with warm, temperate, and cold seas and with stratification, fronts, and upwelling zones. Modeling has indicated that mixotrophy has a profound impact on marine planktonic ecosystems and may enhance primary production, biomass transfer to higher trophic levels, and the functioning of the biological carbon pump.

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“…Many species of bacteria (e.g., Pierson et al, 1985;Madigan and Ormerod, 1995;Be ´ja et al, 2000;Rappe ét al., 2002;Bryant et al, 2007;Zeng et al, 2014;Zervas et al, 2019) as well as some fungi (Gleason et al, 2019), zooplankton (Stoecker et al, 2017), and aphids (Valmalette et al, 2012) are pure photoheterotrophs, using light solely to generate metabolic energy and gathering carbon from other sources. A range of photosynthetic organisms can also switch to a photoheterotrophic metabolism if organic carbon is available in their environment (Be ´ja `and Suzuki, 2008;Stoecker et al, 2017). Thus, on Earth, the use of light solely as a source of energy, and not to power the generation of electrons to reduce CO 2 , is widespread.…”

Section: Energymentioning

confidence: 99%

Venus' Atmospheric Chemistry and Cloud Characteristics Are Compatible with Venusian Life

2024

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Venus is Earth's sister planet, with similar mass and density but an uninhabitably hot surface, an atmosphere with a water activity 50-100 times lower than anywhere on Earths' surface, and clouds believed to be made of concentrated sulfuric acid. These features have been taken to imply that the chances of finding life on Venus are vanishingly small, with several authors describing Venus' clouds as ''uninhabitable,'' and that apparent signs of life there must therefore be abiotic, or artefactual. In this article, we argue that although many features of Venus can rule out the possibility that Earth life could live there, none rule out the possibility of all life based on what we know of the physical principle of life on Earth. Specifically, there is abundant energy, the energy requirements for retaining water and capturing hydrogen atoms to build biomass are not excessive, defenses against sulfuric acid are conceivable and have terrestrial precedent, and the speculative possibility that life uses concentrated sulfuric acid as a solvent instead of water remains. Metals are likely to be available in limited supply, and the radiation environment is benign. The clouds can support a biomass that could readily be detectable by future astrobiology-focused space missions from its impact on the atmosphere. Although we consider the prospects for finding life on Venus to be speculative, they are not absent. The scientific reward from finding life in such an un-Earthlike environment justifies considering how observations and missions should be designed to be capable of detecting life if it is there.

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Photoheterotrophic Marine Prokaryotes

Cited by 24 publications

References 93 publications

Influence of incubation conditions on bacterial production estimates in an estuarine system

Influence of incubation conditions on bacterial production estimates in an estuarine system

Mixotrophy in the Marine Plankton

Venus' Atmospheric Chemistry and Cloud Characteristics Are Compatible with Venusian Life

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