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--Original- "Purple Sulfur Bacteria"

The purple sulfur bacteria are a group of Proteobacteria capable of photosynthesis, collectively referred to as purple bacteria. They are anaerobic or microaerophilic, and are often found in hot springs or stagnant water. Unlike plants, algae, and cyanobacteria, they do not use water as their reducing agent, so do not produce oxygen. Instead, they use hydrogen sulfide, which is oxidized to produce granules of elemental sulfur. This, in turn, may be oxidized to form sulfuric acid.

The purple sulfur bacteria are divided into two families, the Chromatiaceae and the Ectothiorhodospiraceae, which respectively produce internal and external sulfur granules, and show differences in the structure of their internal membranes. They make up the order Chromatiales, included in the gamma subdivision of the Proteobacteria. The genus Halothiobacillus is also included in the Chromatiales, in its own family, but it is not photosynthetic.

Purple sulfur bacteria are generally found in illuminated anoxic zones of lakes and other aquatic habitats where hydrogen sulfide accumulates and also in "sulfur springs" where geochemically or biologically produced hydrogen sulfide can trigger the formation of blooms of purple sulfur bacteria. Anoxic conditions are required for photosynthesis; these bacteria cannot thrive in oxygenated environments.[1]

The most favorable lakes for the development of purple sulfur bacteria are meromictic (permanently stratified) lakes. Meromictic lakes stratify because they have denser (usually saline) water in the bottom and less dense (usually fresh water) nearer the surface. If sufficient sulfate is present to support sulfate reduction, the sulfide, produced in the sediments, diffuses upward into the anoxic bottom waters, where purple sulfur bacteria can form dense cell masses, called blooms, usually in association with green phototrophic bacteria.

Purple sulfur bacteria are also a prominent component in intertidal microbial mats, such as the Sippewissett Microbial Mat, which have a dynamic environment due to the flow of the tides and incoming fresh water and gives them a similar favorable environment as meromictic lakes. Purple sulphur bacteria have bacteriopurpurin pigment. It uses inorganic sulphur substances as electron and H+ donors.

Biomarkers[edit]

Purple sulfur bacteria make conjugated pigments called carotenoids that function in the light harvesting complex. When these organisms die and sink, some pigment molecules are preserved in modified form in the sediments. One carotenoid molecule produced, okenone, is diagenetically altered to the biomarker okenane. The discovery of okenane in marine sediments implies the presence of purple sulfur bacteria during the time of burial. So far, okenane has only been identified in one sedimentary outcrop from Northern Australia dating to 1640 million years ago.[2] The authors of the study concluded that, based on the presence of purple sulfur bacteria's biomarker, the Paleoproterozoic ocean must have been anoxic and sulfidic at depth. This finding provides evidence for the Canfield Ocean hypothesis.



Edit- "Purple Sulfur Bacteria"

The purple sulfur bacteria (PSB) are part of a group of Proteobacteria capable of photosynthesis, collectively referred to as purple bacteria. They are anaerobic or microaerophilic, and are often found in stratified water environments including hot springs, stagnant water bodies, as well as microbial mats in intertidal zones[3]. Unlike plants, algae, and cyanobacteria, they do not use water as their reducing agent, so do not produce oxygen. Instead, they can use sulfur in the form of sulphide, or thiosulfate (as well some species can use H2, Fe2+, or NO2-) as the electron donor in their photosynthetic pathways[4]. The forms of sulfur are oxidized to produce granules of elemental sulfur. This, in turn, may be oxidized to form sulfuric acid.

The purple sulfur bacteria are divided into two families, the Chromatiaceae and the Ectothiorhodospiraceae, which produce internal and external sulfur granules respectively, and show differences in the structure of their internal membranes[5]. They make up the order Chromatiales, included in the gamma subdivision of the Proteobacteria. The genus Halothiobacillus is also included in the Chromatiales, in its own family, but it is not photosynthetic.

Habitats[edit]

Purple sulfur bacteria are generally found in illuminated anoxic zones of lakes and other aquatic habitats where hydrogen sulfide accumulates and also in "sulfur springs" where geochemically or biologically produced hydrogen sulfide can trigger the formation of blooms of purple sulfur bacteria. Anoxic conditions are required for photosynthesis; these bacteria cannot thrive in oxygenated environments.[6]

The most favorable lakes for the development of purple sulfur bacteria are meromictic (permanently stratified) lakes. Meromictic lakes stratify because they have denser (usually saline) water in the bottom and less dense (usually fresh water) nearer the surface. If sufficient sulfate is present to support sulfate reduction, the sulfide, produced in the sediments, diffuses upward into the anoxic bottom waters, where purple sulfur bacteria can form dense cell masses, called blooms, usually in association with green phototrophic bacteria.

Presence and Effect in Microbial Mats[edit]

Purple sulfur bacteria are also a prominent component in intertidal microbial mats, such as the Sippewissett Microbial Mat, which have a dynamic environment due to the flow of the tides and incoming fresh water and leads to a similar stratified environment as meromictic lakes. Purple sulfur bacteria growth is enabled as sulfur is supplied from the death and decomposition of microorganisms located above them[7]. The PSB can help stabilize these microbial mat environment sediments through the secretion of their extracellular polymeric substances which can bind the sediments[8][9].

Biomarkers[edit]

Purple sulfur bacteria make conjugated pigments called carotenoids that function in the light harvesting complex. When these organisms die and sink, some pigment molecules are preserved in modified form in the sediments. One carotenoid molecule produced, okenone, is diagenetically altered to the biomarker okenane. The discovery of okenane in marine sediments implies the presence of purple sulfur bacteria during the time of burial. So far, okenane has only been identified in one sedimentary outcrop from Northern Australia dating to 1640 million years ago.[10] The authors of the study concluded that, based on the presence of purple sulfur bacteria's biomarker, the Paleoproterozoic ocean must have been anoxic and sulfidic at depth. This finding provides evidence for the Canfield Ocean hypothesis.

Bioremediation[edit]

Purple sulfur bacteria are known to grow in manure wastewater lagoons and contribute to a reduction of the odor emitted as well as the concentration of environmentally harmful organic compounds. The process of photosynthesis by PSB can lead to a reduction in the concentration of simple organic compounds thus reducing the potential effects of pollution caused by the compounds in the lagoons. The reduction of organic compounds is due to the photoassimilation of them in the presence of sulfide during photosynthesis. As well the reduction of odor can be attributed to the PSB also assimilating compounds known to stink, thereby removing the stench from the lagoon.[11][12].

References[edit]

  1. ^ Proctor, Lita M. (1997). "Nitrogen-fixing, photosynthetic, anaerobic bacteria associated with pelagic copepods," Aquatic Microbial Ecology Vol. 12, 105-113.
  2. ^ Brocks, Jochen J.; Schaeffer, Philippe (2008-03-01). "Okenane, a biomarker for purple sulfur bacteria (Chromatiaceae), and other new carotenoid derivatives from the 1640 Ma Barney Creek Formation". Geochimica et Cosmochimica Acta. 72 (5): 1396–1414. doi:10.1016/j.gca.2007.12.006.
  3. ^ (Daldal, Fevzi, Marion C. Thurnauer, and C. N. Hunter. https://link.springer.com/content/pdf/10.1007%2F978-1-4020-8815-5.pdf Advances in Photosynthesis and Respiration, 28: Purple Phototrophic Bacteria. Springer, 2008.)
  4. ^ (Daldal, Fevzi, Marion C. Thurnauer, and C. N. Hunter. https://link.springer.com/content/pdf/10.1007%2F978-1-4020-8815-5.pdf Advances in Photosynthesis and Respiration, 28: Purple Phototrophic Bacteria. Springer, 2008.)
  5. ^ (Daldal, Fevzi, Marion C. Thurnauer, and C. N. Hunter. https://link.springer.com/content/pdf/10.1007%2F978-1-4020-8815-5.pdf Advances in Photosynthesis and Respiration, 28: Purple Phototrophic Bacteria. Springer, 2008.)
  6. ^ Proctor, Lita M. (1997). "Nitrogen-fixing, photosynthetic, anaerobic bacteria associated with pelagic copepods," Aquatic Microbial Ecology Vol. 12, 105-113.
  7. ^ (Daldal, Fevzi, Marion C. Thurnauer, and C. N. Hunter. https://link.springer.com/content/pdf/10.1007%2F978-1-4020-8815-5.pdf Advances in Photosynthesis and Respiration, 28: Purple Phototrophic Bacteria. Springer, 2008.)
  8. ^ (Hubas, Cedric, et al. "Proliferation of Purple Sulphur Bacteria at the Sediment Surface Affects Intertidal Mat Diversity and Functionality: E82329." Plos One, vol. 8, no. 12, 2013.)
  9. ^ Stal LJ (2010) Microphytobenthos as a biogeomorphological force in intertidal sediment stabilization. Ecol Eng 36: 236–245. doi:10.1016/ j.ecoleng.2008.12.032.
  10. ^ Brocks, Jochen J.; Schaeffer, Philippe (2008-03-01). "Okenane, a biomarker for purple sulfur bacteria (Chromatiaceae), and other new carotenoid derivatives from the 1640 Ma Barney Creek Formation". Geochimica et Cosmochimica Acta. 72 (5): 1396–1414. doi:10.1016/j.gca.2007.12.006.
  11. ^ Caumette, P. 1993. Ecology and physiology of phototrophic bacteria and sulfate-reducing bacteria in marine salterns. Experientia 49:473–481. doi:10.1007/BF01955148
  12. ^ (Dungan, RS, and AB Leytem. "Detection of Purple Sulfur Bacteria in Purple and Non-Purple Dairy Wastewaters." Journal of Environmental Quality, vol. 44, no. 5, 2015, pp. 1550-1555)

Joshdalmann (talk) 04:24, 9 October 2017 (UTC)[reply]

Josh Dalmann's Peer Review[edit]

Overall, the edited text is highly relevant and the structural changes have added clarity to the article. The division of the original article into multiple headings gives the article more clarity and better organization, which allows for a better understanding of the article. However, I would suggest the section discussing microbial mats be incorporated into the habitat section. The lead of the article lists hot springs, stagnant waters and microbial mats as the PSB habitats. Therefore, the rest of the article should remain consistent and include microbial mats under the habitat heading.

The added text regarding bioremediation is a wonderful addition to the article because of its relevance to current environmental issues. However, this section could be improved by further elaborating on the specific types of organic compounds that are harmful to the environment and what effects they have on the environment.

The information in the bioremediation section is presented in a logical order. However, the run on sentences and punctuation errors distract from the information presented. For instance, the first sentence could be broken into two or three separate sentences. Additionally, the wording could be more formal. Rather than using the word “stink”, phrasing the sentences to use “foul odour” would be more appropriate for a Wikipedia article. Nonetheless, the article is well written with a neutral point of view.

After checking the references, they all come from reputable textbooks and journals; however the formatting in the references section does not include hyperlinks to the article. This creates the challenge for readers to check sources. In addition, the same Daldal et al. reference is used four times, I would suggest finding additional sources rather than relying on the single source to balance out the article.

Tylertam (talk) 07:09, 8 November 2017 (UTC)[reply]


Final Edit- "Purple Sulfur Bacteria"

The purple sulfur bacteria (PSB) are part of a group of Proteobacteria capable of photosynthesis, collectively referred to as purple bacteria. They are anaerobic or microaerophilic, and are often found in stratified water environments including hot springs, stagnant water bodies, as well as microbial mats in intertidal zones[1]. Unlike plants, algae, and cyanobacteria, they do not use water as their reducing agent, and therefore do not produce oxygen. Instead, they can use sulfur in the form of sulfide, or thiosulfate (as well, some species can use H2, Fe2+, or NO2-) as the electron donor in their photosynthetic pathways[2]. The sulfur is oxidized to produce granules of elemental sulfur. This, in turn, may be oxidized to form sulfuric acid.

The purple sulfur bacteria are divided into two families, the Chromatiaceae and the Ectothiorhodospiraceae, which produce internal and external sulfur granules respectively, and show differences in the structure of their internal membranes[3]. They make up part of the order Chromatiales, included in the gamma subdivision of the Proteobacteria. The genus Halothiobacillus is also included in the Chromatiales, in its own family, but it is not photosynthetic.

Habitats[edit]

Purple sulfur bacteria are generally found in illuminated anoxic zones of lakes and other aquatic habitats where hydrogen sulfide accumulates. They also reside in "sulfur springs", where geochemically or biologically produced hydrogen sulfide can trigger the formation of blooms of purple sulfur bacteria. As anoxic conditions are required for photosynthesis; these bacteria cannot thrive in oxygenated environments.[4]

The most favorable lakes for the development of purple sulfur bacteria are meromictic (permanently stratified) lakes. Meromictic lakes stratify due to denser (usually saline) water in the bottom and less dense (usually fresh water) nearer the surface. If sufficient sulfate is present to support sulfate reduction, the sulfide, produced in the sediments, diffuses upward into the anoxic bottom waters, where purple sulfur bacteria can form dense cell masses, called blooms, usually in association with green phototrophic bacteria.

Purple sulfur bacteria can also be found and are a prominent component in intertidal microbial mats. Mats, such as the Sippewissett Microbial Mat, have dynamic environments due to the flow of tides and incoming fresh water leading to similarily stratified environments as meromictic lakes. Purple sulfur bacteria growth is enabled as sulfur is supplied from the death and decomposition of microorganisms located above them within these intertidal pools[5]. The stratification and sulfur source allows the PSB to grow in these intertidal pools where the mats occur. The PSB can help stabilize these microbial mat environment sediments through the secretion of extracellular polymeric substances that can bind the sediments in the pools[6] [7].

Biomarkers[edit]

Purple sulfur bacteria make conjugated pigments called carotenoids that function in the light harvesting complex. When these organisms die and sink, some pigment molecules are preserved in modified form in the sediments. One carotenoid molecule produced, okenone, is diagenetically altered to the biomarker okenane. The discovery of okenane in marine sediments implies the presence of purple sulfur bacteria during the time of burial. So far, okenane has only been identified in one sedimentary outcrop from Northern Australia dating to 1640 million years ago.[8] The authors of the study concluded that, based on the presence of purple sulfur bacteria's biomarker, the Paleoproterozoic ocean must have been anoxic and sulfidic at depth. This finding provides evidence for the Canfield Ocean hypothesis.

Bioremediation[edit]

Purple sulfur bacteria can contribute to a reduction of environmentally harmful organic compounds and odour emission in manure wastewater lagoons where they are known to grow. Harmful compounds such as Methane, a greenhouse gas, and Hydrogen sulfide, a pungent, toxic compound, can be found in wastewater lagoons. PSB can help lower the concentration of both, and others. [9]

Harmful organic carbon containing compounds can be removed through photoassimilation, the uptake of carbon by organisms through photosynthesis[10]. When PSB in the lagoons perform photosynthesis they can utilize the carbon from harmful compounds, such as methane[11], as their carbon source. This removes methane, a greenhouse gas, from the lagoon and reduces the lagoons atmospheric pollution affect.

H2S can act as a sulfur source for PSB during these same photosynthetic processes that remove the organic compounds. The use of H2S as a reducing agent by PSB removes it from the lagoon and leads to a reduction of odour and toxicity in the lagoons.[12][13][14].

References[edit]

  1. ^ (Daldal, Fevzi, Marion C. Thurnauer, and C. N. Hunter. https://link.springer.com/content/pdf/10.1007%2F978-1-4020-8815-5.pdf Advances in Photosynthesis and Respiration, 28: Purple Phototrophic Bacteria. Springer, 2008.)
  2. ^ (Daldal, Fevzi, Marion C. Thurnauer, and C. N. Hunter. https://link.springer.com/content/pdf/10.1007%2F978-1-4020-8815-5.pdf Advances in Photosynthesis and Respiration, 28: Purple Phototrophic Bacteria. Springer, 2008.)
  3. ^ (Daldal, Fevzi, Marion C. Thurnauer, and C. N. Hunter. https://link.springer.com/content/pdf/10.1007%2F978-1-4020-8815-5.pdf Advances in Photosynthesis and Respiration, 28: Purple Phototrophic Bacteria. Springer, 2008.)
  4. ^ Proctor, Lita M. (1997). "Nitrogen-fixing, photosynthetic, anaerobic bacteria associated with pelagic copepods," Aquatic Microbial Ecology Vol. 12, 105-113.
  5. ^ (Daldal, Fevzi, Marion C. Thurnauer, and C. N. Hunter. https://link.springer.com/content/pdf/10.1007%2F978-1-4020-8815-5.pdf Advances in Photosynthesis and Respiration, 28: Purple Phototrophic Bacteria. Springer, 2008.)
  6. ^ (Hubas, Cedric, et al. "[http://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0082329&type=printable "Proliferation of Purple Sulphur Bacteria at the Sediment Surface Affects Intertidal Mat Diversity and Functionality: E82329." Plos One, vol. 8, no. 12, 2013.)
  7. ^ Stal LJ (2010) https://ac.els-cdn.com/S0925857409000160/1-s2.0-S0925857409000160-main.pdf?_tid=2a3d5a5e-cd79-11e7-aa3b-00000aacb35f&acdnat=1511130774_f1d9f08b3f0de5ea6f90b0d1427800bb Microphytobenthos as a biogeomorphological force in intertidal sediment stabilization. Ecol Eng 36: 236–245. doi:10.1016/ j.ecoleng.2008.12.032.
  8. ^ Brocks, Jochen J.; Schaeffer, Philippe (2008-03-01). "Okenane, a biomarker for purple sulfur bacteria (Chromatiaceae), and other new carotenoid derivatives from the 1640 Ma Barney Creek Formation". Geochimica et Cosmochimica Acta. 72 (5): 1396–1414. doi:10.1016/j.gca.2007.12.006.
  9. ^ McGarvey, JA, et al. http://onlinelibrary.wiley.com/doi/10.1111/j.1472-765X.2009.02683.x/epdf "Induction of Purple Sulfur Bacterial Growth in Dairy Wastewater Lagoons by Circulation." Letters in Applied Microbiology, vol. 49, no. 4, 2009, pp. 427-433.
  10. ^ “Photoassimilation | Definition of photoassimilation in English by Oxford Dictionaries.” https://en.oxforddictionaries.com/definition/photoassimilation Oxford Dictionaries | English, Oxford Dictionaries, en.oxforddictionaries.com/definition/photoassimilation.
  11. ^ Leytem, AB, et al. https://ac.els-cdn.com/S0022030217305799/1-s2.0-S0022030217305799-main.pdf?_tid=a8cdccc8-cd79-11e7-8cad-00000aab0f6c&acdnat=1511130986_0d85d5d96ffb65e1ca976c83f8706f90 "Methane Emissions from Dairy Lagoons in the Western United States."Journal of Dairy Science, vol. 100, no. 8, 2017, pp. 6785-6803.
  12. ^ “Hydrogen sulfide.” http://www.npi.gov.au/resource/hydrogen-sulfide National Pollutant Inventory, Australian Government Department of Environment and Energy, www.npi.gov.au/resource/hydrogen-sulfide.
  13. ^ Caumette, P. 1993. https://link.springer.com/content/pdf/10.1007%2FBF01955148.pdf Ecology and physiology of phototrophic bacteria and sulfate-reducing bacteria in marine salterns. Experientia 49:473–481. doi:10.1007/BF01955148
  14. ^ (Dungan, RS, and AB Leytem. https://dl.sciencesocieties.org/publications/jeq/pdfs/44/5/1550"Detection of Purple Sulfur Bacteria in Purple and Non-Purple Dairy Wastewaters." Journal of Environmental Quality, vol. 44, no. 5, 2015, pp. 1550-1555)
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