L9: Biogeochemical Cycles I Flashcards
What are interconversions/ what do they catalyse
REDOX substrates consume/produce molecules that contribute to flow of nutrients
Resevoir
part of biosphere with alot of of an element
Define source
resevoir that releases more of an element that it consumes
Sink
resevoir that takes in more of an element than it releases
What is flux, -, +
F: net rate of change in the amount of an element
+: sink, gaining
-: source, loosing
Main Carbon fluxes
- photosynthesis
- respiration
- marine uptake
- marine release
Carbon resevoirs
- vegetation
- soils
- hydrocarbons + minerals
- atosmphere
- oceans
- marine biota
What is the biggest terrestial resevoir
soil
Discuss availability of carbon
- some is readily available
- most is not due to occlusion/sortion making it short-term unavailable
What are the trends in microboal respiration + carbon
- more respiration = less soil carbon
- as soon carbon goes into the ground it is fixed, dies and respires to atmosphere
- in the arctic its slow, meaning carbon hang out there
What is the latitude / depth trend
- equtorial has low surface carbon cus of respiration
- as u go deeper = more carbon cus less respiration
DRAW the carbon cycle
:)
Name 6 Carbon Cycle pathways
- Carbon fixation
- Heterotrophic respitation
- methonogenesis
- methanotrophy
- ANME
Explore Carbon fixation
uses energy to make organic carbon from CO2
Heteropthic respiration
- fermentation
- aeorbic/anaerobic of carbon makes CO2
- many carbon sources available
Methanogensis, EA, ED, where, enzymes
- obligatory anarobes use reduce C to make CH4
- when other EA: nitrate, sulfate are not acceable
- archea
Possible EA
* acetates, CO2, methanol (other 1 carbon compounds)
possible ED
* CO2
Key enzymes:
* methanofuran
* methanoprerin
* Coenzyme M
Happens with fermentation cus Fermentation releases H2/CO2, which can be used for methanogensis (guts)
Methanotrophy
- use methane as energy source of carbon/energy
- after oxidation methane needs energy + oxygen so it
- … becomes biomass (requires energy)
- …carbon oxidsed more used for ETC/NADH (produces energy + CO2
where
* aerobic, cus O needed for first oxidation step
* above methanotrophs
Enzyme
* methan monoozygenase
Two pathways for biomass
* gammaproteobacteria + alphaproteobacteria
ANME
- methane oxidation without oxygen
- many forms
EA
* Nitrate, sulfate, nitrite, sulfite
Name key components of carbon cyle + global change
- Temperature dependant microbial processes
* photo increase in higher temp to maximum
* reperations increase in higher temp continuanlly
* when respiration esceeds, soil carbon get released to atmosphere and soil becomes a soil not sink - Temperature-dependant CO2 soluability
* CO2 soluable in warm water
* when warmer: CO2 will leave water
* less dissolved CO2 is available, autotrophic products becomes less domintant than hetetrotrophic
Discuss permafrost carbon feedback
- contains a lot of carbon
- inactive when frozen but becomes available when thaws
*
– - Hetetrophic activity in thawd permafrost decomposes the thawed organic matter
- aerobic decomposition = CO2 released
- fermentation releases CO2 + H2 for methanogensis
- menthotrophs attenutate CH4 release by converting Ch4 to Co2
How do themokrast lakes form
- rapid thawing leads to lake in slumped land
- lakes underlined by talik which is unfrozen layer
- because of the talik, which is unfrozen year round,
- water stores heat with limited oxygen
- becomes hotspot of carbon emmisions
What we need to know
- knowing more information about microbial community + thawing environemnt we can predict rates and products
- determinsitic selection makes them more predicable, knowing what makes it deterministic is important
Determitisc characterisitcs
- slow thawing, moderate slective pressure, functional reducances, large spacial scales
