Chapter 21 Flashcards
(38 cards)
Which CO2 is the most rapidly fixed
Atmosphere
Ways that CO2 is returned to the atmosphere
respiration, microbial decomposition (biggest return)
Photosynthesis Reaction
-CO2 +H2O –> (CH2O) + O2
Respiration Reaction
-(CH2O) + O2 –> CO2 + H2O
Two major end products of decompositio
-CH4 & CO2
How is methane effective in cold seeps/deep-sea ecosystems?
CH4 under high pressure low temperature becomes trapped
-nourishes anaerobic Arch. and Bac.
(CH4 endosymbionts)
Which two cycles are closely coupled?
-Carbon and NItrogen Cycle
KNOW CARBON CYCLE
KNOW CARBON CYCLE
KNOW THE COUPLED CYCLE
KNOW THE COUPLED CYCLE
What is methanogenesis?
central to C cycling in in anoxic environments
i) Reduce CO2 to CH4 with H2 as e- donor
ii) Some can reduce other substrates to CH4
How do methanogensis symbionts benefit the host?
by consuming H2 (generated from glucose fermentation)
What is another H2 consuming process besides methanogensis?
Acetogenesis (less favorable)
List the Major Nitrogen transformations
- nitrification
- denitrification
- anammox
- nitrogen fixation
how is nitrogen made
reduction of NO3- to NH3
what is responsible for 85% N loss
denitrification
KNOW THE NITROGEN CYCLE
KNOW THE NITROGEN CYCLE
What is nitrogen fixation?
the ability to use N2 (few prokaryotes have this ability)
What is denitrification?
i) Reduction of NO3 to gaseous N products
ii) Primary way N2 is produced biologically
Two ways NH3 can be made from N
- N-fixation
2. ammonification
what changes NH3 to N2 gas
Anammox-anoxic oxidation
KNOW NITRATE REDUCTION FLOW CHART
KNOW NITRATE REDUCTION FLOW CHART
Focus a lot of nitrate reduction and its various stuff
Focus a lot of nitrate reduction and its various stuff
Which cycle has to most significant oxidation states
Sulfur (-2, 0, 6)
Major sulfur reservoirs
- sediments and rocks
2. ocean (as sulfate SO4-2)