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22 Cards in this Set
- Front
- Back
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What are the main reservoirs of carbon on Earth (and what turnover times do they have)
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-Atmosphere, land, oceans, sediments, rocks and biomass.
-Reservoir size and turnover time are important parameters in understanding the cycling of elements |
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How do you predict that potential global warming scenarios could affect methane reservoirs?
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Global warming could result in additional release of methane ( and could have triggered the Premian - Triassic extinctions)
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Photosynthesis vs Respiration
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Photosynthesisand respiration are part of redox cycle for Carbon
Photosynthesis CO2 + H2O => (CH2O) + O2 Respiration (CH2O) + O2 => CO2 + H2O |
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What makes cold seeps unique as ecosystem?
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Methane hydrates fuel deep-seaecosystems called coldseeps(communities of methane-oxidizing Archaeaand endosymbioticmicrobes)
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How are carbon and nitrogen cycles coupled?
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-All nutrient cycles areinterconnected and feed back upon one another
-Major changes in one cycle affectthe functioning of other cycles -The carbon cycle and the nitrogencycle are very closely coupled |
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Methanogenesis
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Iscentral to carbon cycling in anoxic environments
-Mostmethanogens reduce CO2to CH4with H2as an electron donor; some can reduce other substrates to CH4 (e.g., acetate) - Methanogens team up with partners(syntrophs) that supply them with necessary substrates |
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Microbial Syntrophy
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A process in which two or more organisms cooperate in the anaerobic degradation of organic compounds
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What are some of the major processes for nitrogen fixation?
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•Nitrification
•Denitrification •Anammox •Nitrogen fixation |
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Sulfur Reservoirs
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Theoceans is the most significant reservoir of sulfur (as sulfate) in thebiosphere
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How could ocean acidification affect marine calcifies?
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Acidification will be detrimental to marine calcifies and in the long will reduce the capacity of the ocean to absorb more atmospheric CO2
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Redox cycles for sulfur
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-Sulfurtransformations by microorganisms are complex.
-Thebulk of sulfur on Earth occurs in sediments and rocks as sulfate and sulfideminerals (e.g., gypsum, pyrite) |
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Iron and Magnesium redox cycles
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-Theredox reactions in the iron cycle include both oxidations and reductions
- Manganeseis also oxidized and reduced |
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Phosphorous cycle
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- Organic and inorganic phosphates
- Cycles through living organisms,water, and soil -Phosphates often limiting factor infreshwater (obtained from weathering of rocks) |
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Why is Ca2+ important for many marine eukaryotic phytoplankton (e.g Coccolithophores and Foraminerfera)
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Marinephototrophic microorganisms use Ca2+to form exoskeleton
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Marine Calcium Cycle
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-Major reservoirs are calcareousrocks and oceans
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Marine Silica Cycle
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The marine silica cycle iscontrolled by unicellular eukaryotes that build cell skeletons called frustules
Examples: diatoms,silicoflagellates, and radiolarians |
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Biological pump
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Reduces ocean productivity and It is important in the long term removal of carbon from the atmosphere
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Mercury as pollutant and bioaccumulation in food webs
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- Mercury– human pollutant (e.g. electronic, pesticides, mining)
- Mercuryhas a tendency to concentrate in living tissues and is highly toxic |
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Mercury transformation and mercury redox cycle
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Themajor form of mercury in the atmosphere is elementalmercury (Hg),which is volatile and oxidized to mercuric ion (Hg2+) photochemically.
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How can mercury-resistant bacteria be used for potential of mercury pollution in the enviroment?
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- Bacterial resistance to mercury is often linked to specific plasmids that encode enzymes capable of detoxifying or pumping out the metals
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Global warming and release of greenhouse gases in the atmosphere?
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Greenhouse effect: The ability of these gasses to trap the infrared radiation emitted by the Earth
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Hydrogen Sulfide
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Is amajor volatile sulfur gas that is produced by bacteria via sulfate reduction oremitted from geochemical sources
* Sulfideis toxic to many plants and animals and reacts with numerous metals |
