User:Ajohnson439/sandbox

Evaluating content.
''1 paragraph: Is everything in the article relevant to the article topic? Is there anything that distracted you? Is any information out of date? Is anything missing that could be added? What else could be improved? Is scientific information presented clearly, accurately, and without jargon? Does the article link to other Wikipedia articles for related topics?''

Everything in the Methane wiki article is related to methane and links to many other wiki articles. In general, the article is fairly well written and accurate with minor grammatical errors throughout the page; some sections are more jargon-heavy than others. I'm unaware of whether the majority of the article information is up-to-date since I'm not up-to-date with most of the literature for many of the article's sections: methane's properties, chemical reactions, and its uses. I am, however, more knowledgable on how methane is formed and recycled in nature; the sections that cover this are "Generation", "Occurrence", and "Anaerobic oxidation of methane". The "Generation" section gives an incomplete and confusing description of the geologic production of methane in addition to a very short biological route explanation, which could be expanded. The "Occurrence" section includes information on clathrate hydrates, and is largely based on a news article discussing a newly discovered source of methane in the Arctic and the section doesn't address the other prevalent sources. Finally, there's a one sentence description of AOM, which could be expanded and moved to the biological route subsection under generation; the biological route subsection could then be split into methanogenesis and methanotrophy. I plan update these sections for my wikipedia project.

Evaluating tone.
''1 sentence: Is the article neutral? Are there any claims that appear heavily biased toward a particular position? Are there viewpoints that are overrepresented, or underrepresented?''

The article appears to be neutral in all sections. However, there seems to be an imbalance; methane's industrial utility is overrepresented compared to its prevalence in nature and its importance in carbon's biogeochemical cycle.

Evaluating sources.
''1 sentence: Check a few citations. Do the links work? Does the source support the claims in the article? Is each fact referenced with an appropriate, reliable reference? Where does the information come from? Are these neutral sources? If biased, is that bias noted?''

The links to the citations indeed work and are mostly appropriate, reliable references. I have noted several press release citations that should probably be updated. I have also noted a section (the entire first paragraph of the "Safety" section) that does not include a single reference.

Evaluating talk page.
''1 sentence: Now take a look at how others are talking about this article on the talk page. What kinds of conversations, if any, are going on behind the scenes about how to represent this topic? How is the article rated? Is it a part of any WikiProjects?''

It's interesting to see how the article has evolved over time. They've talked about all aspects of methane and what types of information to include, especially relating to methane's relationship to climate. There are some comments stating that parts of the article are "simply unintelligible" in past versions of the article. The article is a level-4 vital article and is rated as B-Class; it's part of three WikiProjects: Chemicals/Core, Energy, and Molecular and Cell Biology.

Adding to the talk page.
Choose at least one of the four evaluation comments you wrote in your sandbox and leave at least one paragraph of evaluation on the article's Talk page. Be sure to sign your feedback with four tildes ~.

Bibliography - 10 citations
https://doi.org/10.1007/978-3-319-54529-5_6-1.

Reeburgh, William S. (2007). “Oceanic methane biogeochemistry”. Chemical Reviews. 107 (2): 486-513. https://doi.org/10.1021/cr050362v.

Etiope, Giuseppe; Lollar, Barbara Sherwood (2013). "Abiotic methane on Earth". Reviews of Geophysics. 51 (2): 276-99. http://dx.doi.org/10.1002/rog.20011.

Whiticar, M. J. (1999). “Carbon and hydrogen isotope systematics of bacterial formation and oxidation of methane". Chemical Geology. 161: 291-314. https://doi.org/10.1016/S0009-2541(99)00092-3.

Serrano-Silva, N.; Sarria-Guzmán, Y.; Dendooven, L.; Luna-Guido, M. (2014). “Methanogenesis and methanotrophy in soil: a review”. Pedosphere. 24: 291-307. http://dx.doi.org/10.1016/S1002-0160(14)60016-3.

Sirohi, S. K.; Pandey, N.; Singh, B.; Puniya, A. K. (2010). “Rumen methanogens: a review”. Indian J Microbiol. 50 (3): 253-262. https://doi.org/10.1007/s12088-010-0061-6.

Knittel, K.; Wegener, G.; Boetius, A. (2019), McGenity, Terry J., ed., “Anaerobic Methane Oxidizers”, Microbial Communities Utilizing Hydrocarbons and Lipids: Members, Metagenomics and Ecophysiology, Handbook of Hydrocarbon and Lipid Microbiology, Springer International Publishing, pp. 1-21. https://doi.org/10.1007/978-3-319-60063-5_7-1.

Bohrmann, Gerhard; Torres, Marta E. (2006), Schulz, Horst D.; Zabel, Matthias, eds., “Gas Hydrates in Marine Sediments”, Marine Geochemistry, Springer Berlin Heidelberg, pp. 481-512,   https://doi.org/10.1007/3-540-32144-6_14.

Dean, J. F.et al.(2018). “Methane feedbacks to the global climate system in a warmer world”. Reviews of Geophysics. 56: 207-250. https://doi.org/10.1002/2017RG000559.

Moore, T. A. (2012). “Coalbed methane: A review”. International Journal of Coal Geology. 101: 36-81, http://dx.doi.org/10.1016/j.coal.2012.05.011.

Current Text:
"Methane ( or ) is a chemical compound with the chemical formula (one atom of carbon and four atoms of hydrogen). It is a group-14 hydride and the simplest alkane, and is the main constituent of natural gas. The relative abundance of methane on Earth makes it an attractive fuel, although capturing and storing it poses challenges due to its gaseous state under normal conditions for temperature and pressure.

Natural methane is found both below ground and under the sea floor. When it reaches the surface and the atmosphere, it is known as atmospheric methane. The Earth's atmospheric methane concentration has increased by about 150% since 1750, and it accounts for 20% of the total radiative forcing from all of the long-lived and globally mixed greenhouse gases. "

Updated Text: The lead sentence was fine - I added to the second paragraph of lead section to include generation and occurrence info; added Etiope 2013 citation
Methane(or ) is a chemical compound with the chemical formula (one atom of carbon and four atoms of hydrogen). It is a group-14 hydride and the simplest alkane, and is the main constituent of natural gas. The relative abundance of methane on Earth makes it an attractive fuel, although capturing and storing it poses challenges due to its gaseous state under normal conditions for temperature and pressure.

Natural occurring methane is found both below ground and under the sea floor, and is formed by both geological and biological processes. The largest reservoir of methane is under the seafloor in the form of methane clathrates. When methane reaches the surface and the atmosphere, it is known as atmospheric methane. The Earth's atmospheric methane concentration has increased by about 150% since 1750, and it accounts for 20% of the total radiative forcing from all of the long-lived and globally mixed greenhouse gases. Methane has also been detected on other planets, including Mars, which has implications for astrobiology research.

To-do list
- expand on the biological route explanation

- someone moved the AOM reaction from “Occurrence” to “selective oxidation”; mention AOM again in methanotrophy and expand on the consortium with sulfate reducing bacteria

"Geological routes
The two main routes for geological methane generation are (i) organic (thermogenic) and (ii) inorganic (abiotic, meaning non-living). Thermally generated methane, referred to as thermogenic, originates from deeper sedimentary strata. Thermogenic methane (CH4) formation occurs due to the breakup of organic matter, forced by elevated temperatures and pressures. This type of methane is considered to be the primary methane type in sedimentary basins, and from an economical perspective the most important source of natural gas. Thermogenic methane components are generally considered to be relic (from an earlier time). Generally, formation of thermogenic methane (at depth) can occur through organic matter breakup, or organic synthesis. Both ways can involve microorganisms (methanogenesis) but may also occur inorganically. The involved anaerobic and aerobic processes can also consume methane, with and without microorganisms. The more important source of methane at depth (crystalline bedrock) is abiotic. Abiotic means that the methane formation took place involving inorganic compounds, without biological activity, magmatic or created at low temperatures and pressures through water-rock reactions.

Biological routes
Methane is mainly produced by methanogenesis. This multistep process is used by microorganisms as an energy source. The net reaction is


 * CO2 + 8 H+ + 8 e− → CH4 + 2 H2O

The final step in the process is catalyzed by the enzyme Coenzyme-B sulfoethylthiotransferase. Methanogenesis is a form of anaerobic respiration used by organisms that occupy landfill (producing biogas), ruminants (for example cows or cattle), and the guts of termites. Rice fields also generate large amounts of methane during plant growth.

Ruminants
Cattle belch methane, accounting for 16% of the world's annual methane emissions to the atmosphere. One study reported that the livestock sector in general (primarily cattle, chickens, and pigs) produces 37% of all human-induced methane. Early research has found a number of medical treatments and dietary adjustments that help slightly limit the production of methane in ruminants. A 2009 study found that at a conservative estimate, at least 51% of global greenhouse gas emissions were attributable to the life cycle and supply chain of livestock products, meaning all meat, dairy, and by-products, and their transportation. A 2013 study estimated that livestock accounted for 44 percent of human-induced methane and 14.5 percent of human-induced greenhouse gas emissions. Many efforts are underway to reduce livestock methane production and trap the gas to use as energy. The state of California has been particularly active in this area. "

Geological routes
The two main routes for geological methane generation are (i) organic (thermogenic) and (ii) inorganic (abiotic, meaning non-living). Thermally generated methane, referred to as thermogenic, originates from deeper sedimentary strata. Thermogenic methane (CH4) formation occurs due to the breakup of organic matter, forced by elevated temperatures and pressures. This type of methane is considered to be the primary methane type in sedimentary basins, and from an economical perspective the most important source of natural gas. Thermogenic methane components are generally considered to be relic (from an earlier time). Generally, formation of thermogenic methane (at depth) can occur through organic matter breakup, or organic synthesis. Both ways can involve microorganisms (methanogenesis) but may also occur inorganically. The involved anaerobic and aerobic processes can also consume methane, with and without microorganisms. The more important source of methane at depth (crystalline bedrock) is abiotic. Abiotic means that the methane formation took place involving inorganic compounds, without biological activity, magmatic or created at low temperatures and pressures through water-rock reactions.

Biological routes
Main article: methanogenesis

Most of Earth's methane is biogenic and is produced by methanogenesis, a process only known to be conducted by members of the domain, Archaea. This multistep process is used by these microorganisms as an energy source. The net reaction is:


 * CO2 + 8 H+ + 8 e− → CH4 + 2 H2O

The final step in the process is catalyzed by the enzyme Coenzyme-B sulfoethylthiotransferase.

Methanogenesis is a form of anaerobic respiration used by Archaea (the extremophiles) that occupy landfill s (producing biogas) and other soils, ruminants (for example cows or cattle) , the guts of termites, and the anoxic sediments below the seafloor and the bottom of lakes. Rice fields also generate large amounts of methane during plant growth.

Ruminants
Cattle belch methane, accounting for 16% of the world's annual methane emissions to the atmosphere. One study reported that the livestock sector in general (primarily cattle, chickens, and pigs) produces 37% of all human-induced methane. Early research has found a number of medical treatments and dietary adjustments that help slightly limit the production of methane in ruminants. A 2009 study found that at a conservative estimate, at least 51% of global greenhouse gas emissions were attributable to the life cycle and supply chain of livestock products, meaning all meat, dairy, and by-products, and their transportation. A 2013 study estimated that livestock accounted for 44 percent of human-induced methane and 14.5 percent of human-induced greenhouse gas emissions. Many efforts are underway to reduce livestock methane production and trap the gas to use as energy. The state of California has been particularly active in this area.

Seafloor Sediments
Most of the subseafloor is anoxic because oxygen is removed within the first few centimeters of the sediment by aerobic microorganisms. Below the oxygen replete seafloor, methanogens produce methane that is used by other organisms or becomes trapped in the gas hydrates. Other organisms utilize methane for energy and are known as methanotrophs (methane-eating). Consortia of Archaea and Bacteria have been found to oxidize methane via Anaerobic Oxidation of Methane (AOM); the organisms responsible for this are Anaerobic Methanotrophic Archaea (ANME) and Sulfate-Reducing Bacteria (SRB).

To-do list:
- revise clathrate hydrate section

"Clathrates
Significant deposits of methane clathrate have been found under sediments on the ocean floors of Earth at large depths. These deposits are both a potential source of methane fuel as well as a potential contributor to global warming. The depths apply pressure required to stabilize the clathrates, which otherwise disintegrate into the water and methane components. Estimates consider up to 15,000 gigatonnes of carbon may be stored in the form of clathrates (hydrates) in the ocean floor, not accounting for abiotic methane, a relatively newly discovered source of methane, formed below the ocean floor, in the earth crust. It has been suggested that today's methane emission regime from the ocean floor, is potentially similar to that during the period of the Paleocene–Eocene Thermal Maximum (PETM) around 55.5 million years ago.

Arctic methane release from permafrost and methane clathrates is an expected consequence and further cause of global warming. "

Clathrates
Methane clathrates are solid cages of water molecules that trap single molecules of methane. Significant reservoirs of methane clathrates have been found in arctic permafrost and along continental margins beneath the ocean floor at large depths where there are high pressures and low temperatures. The source of methane in methane clathrates can include biogenic methane from methanogens in or below the methane clathrate stability zone, thermogenically derived methane, or a mix of the two. The depths apply pressure required to stabilize the clathrates, which otherwise disintegrate into the water and methane components. These deposits are both a potential source of methane fuel as well as a potential contributor to global warming. Estimates consider up to 15,000 gigatonnes of carbon may be stored in the form of clathrates (hydrates) in the ocean floor, not accounting for abiotic methane, a relatively newly discovered source of methane, formed below the ocean floor, in the earth crust. It has been suggested that today's methane emission regime from the ocean floor, is potentially similar to that during the period of the Paleocene–Eocene Thermal Maximum (PETM) around 55.5 million years ago. Arctic methane release from permafrost and methane clathrates is an expected consequence and further cause of global warming; this is known as the clathrate gun hypothesis.

LEAD SECTION: (CITATIONS ADDED: Etiope 2013)
Methane(or ) is a chemical compound with the chemical formula (one atom of carbon and four atoms of hydrogen). It is a group-14 hydride and the simplest alkane, and is the main constituent of natural gas. The relative abundance of methane on Earth makes it an attractive fuel, although capturing and storing it poses challenges due to its gaseous state under normal conditions for temperature and pressure.

Natural occurring methane is found both below ground and under the sea floor, and is formed by both geological and biological processes. The largest reservoir of methane is under the seafloor in the form of methane clathrates. When methane reaches the surface and the atmosphere, it is known as atmospheric methane. The Earth's atmospheric methane concentration has increased by about 150% since 1750, and it accounts for 20% of the total radiative forcing from all of the long-lived and globally mixed greenhouse gases. Methane has also been detected on other planets, including Mars, which has implications for astrobiology research.

Geological routes
The two main routes for geological methane generation are (i) organic (thermally generated, or thermogenic) and (ii) inorganic (abiotic). Thermogenic methane occurs due to the breakup of organic matter at elevated temperatures and pressures in deep sedimentary strata. Most methane in sedimentary basins is thermogenic; therefore, thermogenic methane is the most important source of natural gas. Thermogenic methane components are typically considered to be relic (from an earlier time). Generally, formation of thermogenic methane (at depth) can occur through organic matter breakup, or organic synthesis. Both ways can involve microorganisms (methanogenesis), but may also occur inorganically. The processes involved can also consume methane, with and without microorganisms. The more important source of methane at depth (crystalline bedrock) is abiotic. Abiotic means that the methane formation took place involving inorganic compounds, without biological activity, either through magmatic processes or via water-rock reactions that occur at low temperatures and pressures, like serpentinization.

Biological routes
Main article: methanogenesis

Most of Earth's methane is biogenic and is produced by methanogenesis, a form of anaerobic respiration only known to be conducted by some members of the domain, Archaea. Methanogens occupy landfill s and other soils, ruminants (for example cows or cattle) , the guts of termites, and the anoxic sediments below the seafloor and the bottom of lakes. Rice fields also generate large amounts of methane during plant growth. This multistep process is used by these microorganisms for energy. The net reaction of methanogenesis is:


 * CO2 + 8 H 2 → CH4 + 2 H2O

The final step in the process is catalyzed by the enzyme methyl coenzyme M reductase (MCR).

Ruminants
Ruminants, such as cattle, belch methane, accounting for ~22% of the U.S. annual methane emissions to the atmosphere. One study reported that the livestock sector in general (primarily cattle, chickens, and pigs) produces 37% of all human-induced methane. A 2009 study found that at a conservative estimate, at least 51% of global greenhouse gas emissions were attributable to the life cycle and supply chain of livestock products, meaning all meat, dairy, and by-products, and their transportation. A 2013 study estimated that livestock accounted for 44% of human-induced methane and ~15% of human-induced greenhouse gas emissions. Many efforts are underway to reduce livestock methane production, such as medical treatments and dietary adjustments, and to trap the gas to use as energy. The state of California has been particularly active in this area.

Seafloor Sediments
Most of the subseafloor is anoxic because oxygen is removed by aerobic microorganisms within the first few centimeters of the sediment. Below the oxygen replete seafloor, methanogens produce methane that is either used by other organisms or becomes trapped in gas hydrates. Other organisms utilize methane for energy and are known as methanotrophs (methane-eating). Consortia of Archaea and Bacteria have been found to oxidize methane via Anaerobic Oxidation of Methane (AOM); the organisms responsible for this are Anaerobic Methanotrophic Archaea (ANME) and Sulfate-Reducing Bacteria (SRB).

=== OCCURRENCE SECTION: (ADDED CITATIONS: Bohrmann, Dean 2018, Boswell & Collett 2011; replaced the webpage reference with correct reference - found the primary source as well ) ===

Clathrates
Methane clathrates (also known as methane hydrates) are solid cages of water molecules that trap single molecules of methane. Significant reservoirs of methane clathrates have been found in arctic permafrost and along continental margins beneath the ocean floor within the gas clathrate stability zone, located at high pressures (1 to 100 MPa; lower end requires lower temperature) and low temperatures (< 15 °C; upper end requires higher pressure). Methane clathrates can form from biogenic methane, thermogenic methane, or a mix of the two. These deposits are both a potential source of methane fuel as well as a potential contributor to global warming. The global mass of carbon stored in gas clathrates is still uncertain and has been estimated as high as 12,500 Gt carbon and as low as 500 Gt carbon. The estimate has declined over time with a most recent estimate of ~1800 Gt carbon. A large part of this uncertainty is due to our knowledge gap in sources and sinks of methane and the distribution of methane clathrates at the global scale. For example, a relatively newly discovered source of methane was discovered in an ultraslow spreading ridge in the Arctic. Some climate models suggest that today's methane emission regime from the ocean floor is potentially similar to that during the period of the Paleocene–Eocene Thermal Maximum (PETM) around 55.5 million years ago, although there are no data indicating that methane from clathrate dissociation currently reaches the atmosphere. Arctic methane release from permafrost and seafloor methane clathrates is a potential consequence and further cause of global warming; this is known as the clathrate gun hypothesis.