Photosystem II Electron Transport Rates and Oxygen Production in Natural Waterblooms of Freshwater Cyanobacteria During a Diel Cycle

Masojídek, Jiří

doi:10.1093/plankt/23.1.57

Cited by 70 publications

(63 citation statements)

References 50 publications

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“…The electron transport rate (ETR) can provide supplementary information about the status of photosynthetic apparatus at the level of photosystemIIdependent electron transport (Masojídek et al, 2001). In the present study, significant variations of ETR max and I k in Scenedesmus reflected the harmful effect of darkness and low temperature on the structure of photosystem II (Fig.…”

Section: Discussionmentioning

confidence: 52%

Different tolerances and responses to low temperature and darkness between waterbloom forming cyanobacterium Microcystis and a green alga Scenedesmus

Song

2007

Hydrobiologia

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The dynamics of planktonic cyanobacteria in eutrophicated freshwaters play an important role in formation of annual summer blooms, yet overwintering mechanisms of these water bloom forming cyanobacteria remain unknown. The responses to darkness and low temperature of three strains (unicellular Microcystis aeruginosa FACHB-905, colonial M. aeruginosa FACHB-938, and a green alga Scenedesmus quadricauda FACHB-45) were investigated in the present study. After a 30-day incubation under darkness and low temperature, cell morphology, cell numbers, chlorophyll a, photosynthetic activity (ETR max and I k ), and malodialdehyde (MDA) content exhibited significant changes in Scenedesmus. In contrast, Microcystis aeruginosa cells did not change markedly in morphology, chlorophyll a, photosynthetic activity, and MDA content. The stress caused by low temperature and darkness resulted in an increase of the antioxidative enzymecatalase (CAT) in all three strains. When the three strains re-grew under routine cultivated condition subjected to darkness and low temperature, specific growth rate of Scenedesmus was lower than that of Microcystis. Flow cytometry (FCM) examination indicated that two distinct types of metabolic response to darkness and low temperature existed in the three strains. The results from the present study reveal that the cyanobacterium Microcystis, especially colonial Microcystis, has greater endurance and adaptation ability to the stress of darkness and low temperature than the green alga Scenedesmus.

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Section: Discussionmentioning

confidence: 52%

Different tolerances and responses to low temperature and darkness between waterbloom forming cyanobacterium Microcystis and a green alga Scenedesmus

Song

2007

Hydrobiologia

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“…They considered the three effects to be related to each other but were not necessarily caused by the same mechanism. The ETR can provide supplementary information about the status of the photosynthetic apparatus at the level of PSII-dependent electron transport (Masojídek et al, 2001). The increased value of ETR max in non-axenic M. aeruginosa demonstrates that heterotrophic bacteria impart positive effect on the structure of PSII in M. aeruginosa.…”

Section: Chlorophyll a Content And Chlorophyll Fluorescence Parametersmentioning

confidence: 99%

Morphological and physiological changes in Microcystis aeruginosa as a result of interactions with heterotrophic bacteria

et al. 2011

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SUMMARY1. To reveal the role of aquatic heterotrophic bacteria in the process of development of Microcystis blooms in natural waters, we cocultured unicellular Microcystis aeruginosa with a natural Microcystis-associated heterotrophic bacterial community. 2. Unicellular M. aeruginosa at different initial cell densities aggregated into colonies in the presence of heterotrophic bacteria, while axenic Microcystis continued to grow as single cells. The specific growth rate, the chl a content, the maximum electron transport rate (ETR max ) and the synthesis and secretion of extracellular polysaccharide (EPS) were higher in non-axenic M. aeruginosa than in axenic M. aeruginosa after cell aggregation, whereas axenic and non-axenic M. aeruginosa displayed the same physiological characteristic before aggregation. 3. Heterotrophic bacterial community composition was analysed by PCR-denaturing gradient gel electrophoresis (PCR-DGGE) fingerprinting. The biomass of heterotrophic bacteria strongly increased in the coinoculated cultures, but the DGGE banding patterns in coinoculated cultures were distinctly dissimilar to those in control cultures with only heterotrophic bacteria. Sequencing of DGGE bands suggested that Porphyrobacter, Flavobacteriaceae and one uncultured bacterium could be specialist bacteria responsible for the aggregation of M. aeruginosa. 4. The production of EPS in non-axenic M. aeruginosa created microenvironments that probably served to link both cyanobacterial cells and their associated bacterial cells into mutually beneficial colonies. Microcystis colony formation facilitates the maintenance of high biomass for a long time, and the growth of heterotrophic bacteria was enhanced by EPS secretion from M. aeruginosa. 5. The results from our study suggest that natural heterotrophic bacterial communities have a role in the development of Microcystis blooms in natural waters. The mechanisms behind the changes of the bacterial community and interaction between cyanobacteria and heterotrophic bacteria need further investigations.

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“…ETR of algal suspensions is often linearly correlated to O 2 -production or C-fixation at limiting irradiances; however, sometimes at saturating irradiance, ETR can under-or overestimate the maximum rate of photosynthesis (Flameling & Kromkamp 1998, Hartig et al 1998, Masojídek et al 2001. Comparisons of ETR and standard measures for the quantification of undisturbed MPB biofilm photosynthetic rates are rare, and the published results are often contradictory (Barranguet & Kromkamp 2000, Perkins et al 2002, Serôdio 2003.…”

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confidence: 99%

“…According to theory, using either 'multiple' or 'single' turnover saturation kinetics (see Kromkamp & Forster 2003) the effective quantum efficiency of Photosystem II (PSII) (ΔF/F m '), which generally represents the effective quantum efficiency of photosynthesis (Φ P ) (Genty et al 1989), can be derived at a range of irradiances. If ΔF/F m ' is then multiplied by the irradiance absorbed by PSII, the rate of non-cyclic electron transport (ETR) can be calculated (Hofstraat et al 1994, Kromkamp & Forster 2003, which can be converted to a photosynthetic rate by multiplying by the electron use efficiency (Φ e , mol C fixed per mol electrons produced by PSII) (Gilbert et al 2000).ETR of algal suspensions is often linearly correlated to O 2 -production or C-fixation at limiting irradiances; however, sometimes at saturating irradiance, ETR can under-or overestimate the maximum rate of photosynthesis (Flameling & Kromkamp 1998, Hartig et al 1998, Masojídek et al 2001. Comparisons of ETR and standard measures for the quantification of undisturbed MPB biofilm photosynthetic rates are rare, and the published results are often contradictory (Barranguet & Kromkamp 2000, Perkins et al 2002, Serôdio 2003.…”

mentioning

confidence: 99%

Coupling between Photosystem II electron transport and carbon fixation in microphytobenthos

Morris¹,

Forster²,

Peene³

et al. 2008

Aquat. Microb. Ecol.

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Photosynthetic parameters of a microphytobenthic (MPB) biofilm grown in a tidal mesocosm were measured on undisturbed sediment using variable fluorescence-based measurements of electron transport rate (ETR), as well as by ETR and 14 C assimilation measurements in optically thin suspensions of algal cells. Absorption cross-sections of the MPB suspensions were quantified using the quantitative filter technique and by reconstruction using HPLC-derived pigment concentrations. Photosynthetic parameters derived by the 3 methods were compared on 3 days, representing different biofilm growth/[chl a ] conditions, at the start, middle and end of the daytime tidal emersion. Comparisons of ETR and radioisotope-derived photosynthetic parameters measured on optically thin suspensions were not significantly different, confirming that with an appropriate estimation of the irradiance absorbed by Photosystem II (PSII), under optically well-defined conditions, variable fluorescence is a reliable measure of MPB photosynthetic rates. In contrast, significant differences of up to 60% were observed between the maximum photosynthetic capacity (P B max ) measured on undisturbed sediment and in suspensions. These differences were observed at high [chl a] (coinciding with low growth rates) towards the end of emersion periods. Comparison of the effective quantum efficiency (ΔF/F m ') at the highest light steps of photosynthetic-irradiance (P-E) curves suggested that the overestimation was due to the poor definition of the complex sediment optics, which interacted presumably with photo-taxis and/or single species migrations. Definition of the optics within undisturbed sediments, particularly considering the complex effects of migration, is a serious challenge, limiting the application of variable fluorescence techniques in situ on undisturbed sediments.KEY WORDS: Variable fluorescence · 14 C uptake · Microphytobenthos · Maximum photosynthetic capacity · Maximum quantum yield of photosynthesis · Sediment · Absorption cross-section · PAM fluorescence Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 50: [301][302][303][304][305][306][307][308][309][310][311] 2008 with their own specific advantages and disadvantages (reviewed by Underwood & Kromkamp 1999). In situ tracer incubations measure the fixation of 13 C or 14 C from bicarbonate solution applied to the sediment surface (Middelburg et al. 2000); however, calculations of fixation rates can be difficult due to the unknown specific activity of the tracer in the sediment pore water (Vadeboncoeur & Lodge 1998). This problem may be serious in cohesive sediments (Jonsson 1991), or in dense biofilms where drawdown of the porewater DIC pool is extremely fast and atmospheric CO 2 is the main inorganic carbon source. In contrast, photosynthetic measurements using suspensions of MPB cells in a medium (typically filtered seawater) can give useful information about photosynthetic characteristics under controlled temperature and irradiance cond...

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Photosystem II Electron Transport Rates and Oxygen Production in Natural Waterblooms of Freshwater Cyanobacteria During a Diel Cycle

Cited by 70 publications

References 50 publications

Different tolerances and responses to low temperature and darkness between waterbloom forming cyanobacterium Microcystis and a green alga Scenedesmus

Different tolerances and responses to low temperature and darkness between waterbloom forming cyanobacterium Microcystis and a green alga Scenedesmus

Morphological and physiological changes in Microcystis aeruginosa as a result of interactions with heterotrophic bacteria

Coupling between Photosystem II electron transport and carbon fixation in microphytobenthos

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