Measurement of Photosynthesis Using <scp>PAM</scp> Technology in a Purple Sulfur Bacterium <i>Thermochromatium tepidum</i> (Chromatiaceae)

Ritchie, Raymond J.; Mekjinda, Nutsara

doi:10.1111/php.12413

Cited by 18 publications

(22 citation statements)

References 64 publications

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“…Table 11 shows estimates of potential primary activity of photosynthetic bacterial mats using equations (11) and (12) on Earth ( in Bold ) and on Proxima Centauri b ( in Italics ). A representative E opt value of 200 µmol photons m −2 s −1 and absorptance of 0.7 were used which was based on RAT measurements of algae filtered onto glass fibre discs (Ritchie 2013; Ritchie & Runcie 2013; Ritchie & Mekjinda 2015). The quantum efficiency ( Q ) of rhodopseudomonads is known to be 0.95 or higher (see Ritchie 2013; Ritchie & Runcie 2013; Ritchie & Mekjinda 2015).…”

Section: Resultsmentioning

confidence: 99%

“…The required reducing equivalents (NADH 2 and/or NADPH 2 ) need to be made using an indirect method (reverse electron flow, Raven 2009). Hence, without a quantum efficiency value (γ) it is very difficult to estimate carbon fixation rates from photosynthetic ETRs in the case of photosynthetic bacteria with an RC-2 photosystem (Ritchie 2013; Ritchie and Runcie 2013; Ritchie and Mekjinda 2015). French (1937a, b) obtained quanta/fixed CO 2 (γ) values of 11 and 17 on a purple photosynthetic bacterium ‘ Streptococcus varians C11’ that is now known as Rhodobacter capsulatus (ATCC 11166) (Syn.…”

Section: Theoretical Development Of a Primary Productivity Modelmentioning

confidence: 99%

“…At supraoptimal irradiance the rate of photosynthesis decreases but more slowly than the rate of photosynthesis increases as irradiance increases at sub-optimal irradiances: the curve is therefore asymmetric in shape around the optimum irradiance. Such light curves are characteristic of both oxygenic and anoxygenic photosynthetic organisms (Ritchie 2008; Ritchie 2013; Ritchie and Larkum 2013; Ritchie and Runcie 2013; Ritchie and Mekjinda 2015).…”

Section: Theoretical Development Of a Primary Productivity Modelmentioning

confidence: 99%

“…Primary production by both oxygenic and anoxygenic photosynthesis is not linearly proportional to irradiance because there are saturation effects at quite modest irradiances and photoinhibition occurs at supra-optimal irradiances (Falkowski et al , 1994; Falkowski & Raven 2007; Jones & Vaughan 2010; Ritchie 2010, 2013; Kirk 2011; Ritchie & Larkum 2013; Ritchie & Runcie 2013; Ritchie & Mekjinda 2015). The shape of photosynthesis versus irradiance curves is discussed in detail in the Appendix.…”

Section: Introductionmentioning

confidence: 99%

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Could photosynthesis function on Proxima Centauri b?

Ritchie

Larkum

Ribas

2017

International Journal of Astrobiology

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Could oxygenic and/or anoxygenic photosynthesis exist on planet Proxima Centauri b? Proxima Centauri (spectral type – M5.5 V, 3050 K) is a red dwarf, whereas the Sun is type G2 V (5780 K). The light regimes on Earth and Proxima Centauri b are compared with estimates of the planet's suitability for Chlorophyll a (Chl a) and Chl d-based oxygenic photosynthesis and for bacteriochlorophyll (BChl)-based anoxygenic photosynthesis. Proxima Centauri b has low irradiance in the oxygenic photosynthesis range (400–749 nm: 64–132 µmol quanta m−2 s−1). Much larger amounts of light would be available for BChl-based anoxygenic photosynthesis (350–1100 nm: 724–1538 µmol quanta m−2 s−1). We estimated primary production under these light regimes. We used the oxygenic algae Synechocystis PCC6803, Prochlorothrix hollandica, Acaryochloris marina, Chlorella vulgaris, Rhodomonas sp. and Phaeodactylum tricornutum and the anoxygenic photosynthetic bacteria Rhodopseudomonas palustris (BChl a), Afifella marina (BChl a), Thermochromatium tepidum (BChl a), Chlorobaculum tepidum (BChl a + c) and Blastochloris viridis (BChl b) as representative photosynthetic organisms. Proxima Centauri b has only ≈3% of the PAR (400–700 nm) of Earth irradiance, but we found that potential gross photosynthesis (Pg) on Proxima Centauri b could be surprisingly high (oxygenic photosynthesis: earth ≈0.8 gC m−2 h−1; Proxima Centauri b ≈0.14 gC m−2 h−1). The proportion of PAR irradiance useable by oxygenic photosynthetic organisms (the sum of Blue + Red irradiance) is similar for the Earth and Proxima Centauri b. The oxygenic photic zone would be only ≈10 m deep in water compared with ≈200 m on Earth. The Pg of an anoxic Earth (gC m−2 h−1) is ≈0.34–0.59 (land) and could be as high as ≈0.29–0.44 on Proxima Centauri b. 1 m of water does not affect oxygenic or anoxygenic photosynthesis on Earth, but on Proxima Centauri b oxygenic Pg is reduced by ≈50%. Effective elimination of near IR limits Pg by photosynthetic bacteria (<10% of the surface value). The spectrum of Proxima Centauri b is unfavourable for anoxygenic aquatic photosynthesis. Nevertheless, a substantial aerobic or anaerobic ecology is possible on Proxima Centauri b. Protocols to recognize the biogenic signature of anoxygenic photosynthesis are needed.

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Section: Resultsmentioning

confidence: 99%

Section: Theoretical Development Of a Primary Productivity Modelmentioning

confidence: 99%

Section: Theoretical Development Of a Primary Productivity Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Could photosynthesis function on Proxima Centauri b?

Ritchie

Larkum

Ribas

2017

International Journal of Astrobiology

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“…No information is available in the use probiotic bacteria of purple non-sulfur bacteria to utilize fish hatchery waste in the decomposition process to improve the nutritional values of media. Purple non-sulfur bacteria (PNSB) Rhodopseudomonas palustris and Rhodovulum sulfidophilum are potential species in the utilization of food waste, effectively in the utilization of organic matter [3] [4]. Growth characteristic of PNSB, Afifella marina strain ME (KC205142), as well as production of exo-polymeric substances like enzymes and nucleic acid has been documented [5].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Finfish Hatchery Waste for Value Added Product

Azad¹,

Lal²,

Benjamin³

2020

ABB

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Commercial fish hatchery generates waste both organic and inorganic; the sources are primarily from uneaten food and fish feces. Conventional methods of treating hatchery wastes will increase the operating cost and become extra burden in production. It is necessary to develop a new research application of this nonconventional resource and reduce the negative impacts of hatchery waste on the environment. The whole project is to utilize hatchery waste through bioprocess for probiotic fortified live feed production. In this study, the chemical composition of hatchery waste was determined to understand the suitability waste to get value-added derived products through bioprocess. Composite samples were collected everyday and dried in an oven at a temperature of 65˚C until complete dryness. Dried samples were mixed well and grinded into fine powder. The analytical parameters like total solids, ammonium nitrogen, nitrite, nitrate and phosphate were determined from the freshly collected samples. Total nitrogen, total phosphorus and total potassium were determined from the dry samples. Total solids, ammonium nitrogen, nitrite, nitrate and phosphate-phosphorus were observed in the ranged from 75-82 mg/L, 0.25-8.5 mg/L, 0.05-1.9 mg/L, 0.04-6.7 mg/L and 4.1-16.7 mg/L respectively. On the other hand, the mean content of 3.75% total nitrogen, 1.80% total phosphorus and 0.15% potassium were determined in dry hatchery wastes. The analytical parameters are useful and demonstrate that the nutrients in both fresh and dry waste will be supportive for the growth of microbes in the bioprocess system.

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Measurement of chlorophylls a and b and bacteriochlorophyll a in organisms from hypereutrophic auxinic waters

Ritchie

2018

J Appl Phycol

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Measurement of Photosynthesis Using PAM Technology in a Purple Sulfur Bacterium Thermochromatium tepidum (Chromatiaceae)

Cited by 18 publications

References 64 publications

Could photosynthesis function on Proxima Centauri b?

Could photosynthesis function on Proxima Centauri b?

Characterization of Finfish Hatchery Waste for Value Added Product

Measurement of chlorophylls a and b and bacteriochlorophyll a in organisms from hypereutrophic auxinic waters

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