Methane on Mars.pptx

Methane on Mars

Methane on MarsIs there life on Mars?

Curiosity Rover Finds Methane on Mars: What It Could Mean for Lifehttp://www.space.com/28019-mars-methane-disovery-curiosity-rover.html

SummaryCuriosity discovered a spike in methane levels around its landing siteBackground methane levels are ~ 0.7 part per billion by volume4 measurements across 2 months showed 10-fold spikes in methane levelsMethane is commonly produced by biological processesGeological processes also produce itDifferent isotopes of methane can be analyzed to determine its producerNew tools are needed to probe the Martian atmosphere

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Cellular RespirationCellular RespirationADENOSINE TRIPHOSPHATE (ATP)

Cellular Respiration

GlycolysisAvailable OxygenAerobicKrebs cyclee- transport chainchemiosmosis

No OxygenAnaerobicfermentationmethanogenesis

GlycolysisAlways carried out in cytoplasm10-step process: 1 glucose 2 pyruvate Net 2 ATPs (substrate-level phosphorylation)Requires free NAD+ to store e- for ETC

Cellular Respiration



Mitochondria

Krebs/Citric Acid cycleTwice in stroma (once/pyruvate)Extract energy from pyruvates in e- formFinal results:6 NADH2 FADH22 ATPs6 CO2

Electron Transport Chain (ETC)e- from NADH and FADH2 create H+ gradientelectronegative O2 drives and terminates chain (O2 + 4H+ + 4e- 2H2O)

ChemiosmosisH+ travels DOWN H+ gradientATP synthaseOxidative phosphorylation90% of ATPs produced

Aerobic RespirationGlycolysis Krebs cycle ETC chemiosmosisRequires O2 as final electron acceptorUP TO 36-38 ATPs phosphorylated

C6H12O6 + 6O2 6CO2 + 6H2O G = -686kJ/mol

Complicated?

Controlled method of extracting energy.Problem? What if theres no oxygen?NADH (e- carrier) cannot be converted back to NAD+ for glycolysis Glycolysis shuts down DEATH

Anaerobic RespirationCellular Respiration



FermentationAlcohol fermentationpyruvate becomes:ethyl alcoholCO2NADH NAD+Baking (CO2)Beer (ethyl alcohol)Lactic acid fermentationpyruvate becomes:lactic acidNADH NAD+Muscle fatigue b/c lack of O2

PhotosynthesisPhotosynthesisConverting light energy into chemical energyReactants: carbon dioxide, waterProducts: glucose, oxygenRequires light energy (i.e. from sun)

Relevance to MarsConfirmed presence of water on MarsMostly ice, some in vapour formPolar ice capsPossible to support plant life on MarsAnimal life?

Methanogens

What are Methanogens?Microbes, ArchaebacteriaBacteria that produce methaneAble to survive in a variety of environmentsi.e. Low-oxygenMethanogenesisForm of anaerobic respirationCO2 + 4 H2 CH4 + 2 H2O (hydrogenotrophic)Fairly complicatedRequires number of coenzymes, cofactors

What does this mean?Carbon dioxide is used to formylate methanofuran into formylmethanofuranFormyl group (i.e. aldehyde) is donated to tetrahydrosarcinapterinformyl-H4SPtCondenses into methenyl groupMethenyl then reducedmethenyl methylene methylMethyl group donated to coenzyme MReacts with coenzyme BBoth have sulfhydride group, form disulfide bond

CH3SCoM + HSCoB CH4 + CoBSSCoM

Therefore, methane is released

Methane CycleMethane CycleTied to the carbon cycleThe methane cycle on Mars is practically unknownBased upon conditions on EarthMethane produced by anaerobic digestion or mineralisation of organic matterC6H12O6 3CO2 + 3CH4Organic matter does not have to come from living thingsDiagram

Natural SourcesTypically represented through sources and sinksSome natural sources on Earth includeWetlandsOceansMethane hydratesGrazing animalsTermitesNatural sources contribute to about 30% of Earths yearly methane productionAround 100 200 Tg per year (1011 21011 kg)

Human SourcesHuman SourcesAgricultureWaste disposalBurning biomassHuman made sources generate around 70% of the worlds yearly methane production or between 250 450 teragrams per year

Methane Sources71% Anthropogenic (human)29% NaturalMethane SinksSinks generally fall into 3 categoriesReactions with hydroxyl radicals present in the environment (~90%)Deposition in the atmosphere (~5%)Trapped in the soil (~5%)Each year approximately 560 Tg of methane are deposited in sinks

Methane EmissionsOn Earth, around 70 80% of our atmospheric methane comes from biological sourcesNatural and cultivated submerged soil contribute about 55% of the methane emittedSoils out of water are responsible for about 5% of emitted methaneMethane CycleWetlands contribute more methane thanHighlands

Geological MethaneGeological MethaneSeveral geological processes produce methane as a by-productSerpentinization:The olivine mineral group (quite common on Mars) exhibits this process when water is forced into the crystal structureInvolves the mineral being moved from an area of high temperature and pressure to an area of low temperature and pressureThis forces out carbon atoms and causes them to bind with the hydrogen in the added water

H2OCH4Production ProcessesSurface Organics:Bombarding organic materials with UV rays may cause it to decomposeEarths ozone layer limits processUV radiation can freely bombard the Martian surface due to very thin atmosphereMethane ClathratesClathrates:Methane is insoluble and will form a solid if trapped in ice or sedimentsMethane trapped in solid lattice (ice-like)Significant deposits have been found at extreme depths and under oceansPermafrost and glaciers on Earth contain deposits of methane which originated from geological sourcesSignificant amount of methane clathrate stored in Martian soil

Life on Mars?Mars has been volcanically inactive for millions of yearsSome scientists believe that the primary source is methanogen bacteriaMethane produced in the past may still be stored beneath the surfaceLife on Mars still ambiguous

BiasWritten by Space.com, there is some slight bias towards the space communityThis only seeks to discredit critics of space explorationSupports NASA in ongoing budgetary fights with CongressOverall pro-science

Future ResearchAdditional probes can be sent to further our understanding of the Martian atmosphereMore drilling can be done using current roversExperiments using the Mars Reconnaissance Orbiter can be carried out with respect to organicsThe newly arrived MAVEN can be used to return additional dataMars Atmosphere and Volatile EvolutionNObservations from Earth can be effected using space or land based telescopesRecreation of possible sources of Mars methane can be attemptedActivityYou are representing a broke biology teacher, Walter Black, in Tuscan, New Mexico who wants to make and sell methane to raise money to cure his arthritis.He wants to make sure that the buyers of his 99.6% pure methane knows about the science behind it.To do this, he came up with a list of questions, progressively allowing a buyer to buy more methane.However, due to his high-school-dropout partner, James Blueman, not understanding how basic biological interactions work, he has lost his answers to an RV fire.It is now your job to come up with the answers so he can continue to sell his methane.To make it more fun, his partner is also competing.DiscussionA human expedition to Mars by the 2030s is seen as highly likelyNASA intends to send humans to Mars orbit in the 2030sSpaceX is developing the Mars Colonial Transporter, aiming for a first flight in the 2020sMars colonization efforts are estimated to begin shortly after landingsConsidering that Martian life is likely to be present, should we send human expeditions knowing that they may contaminate Martian organisms?

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Methane on Mars.pptx