15 Flashcards
photosynth
reduction of o2
what are the two most dominant energy pathways in ocean
photosynth and respiration
enxymes, delta g and Ea
dont change delta g but decrease activation energy
what biological processes are highest in regions where redox species are farthest from eqm
euphotic zone
hydrothermal vents
sediment interface
N fixation by heterotrophs
less efficient
most important reducing agent in ocea
organic matter
nitrogen fixation
imp bc n important for growth in porteins, DNA, RNA
4/5 air is N but in unusable N2
lots of E so much be coupled w photosynth
what organisms couple N fixation w photosynth
cyanobacteria
global cycle
transfer of E through redox rxns
phototrophs transfer E from CO2 and water to oraganic c and O2 and then heterotrpohs restore reduced compounds and oxidized compounds back to their states
solar energy converted to
chemical energy
oxidizing agent for heterotrophs
organic matter bc its thermodynamically unstable in prseence of oxygen
small amount of co2 to organic c
by chemoautolithotrophs
where is energy derived from in the ocean
not from currents or heat
all from inorganic chemicals or sunlight
how is light absorbed
by chromophores that absorb uv or visible light to excite an electron that can then do rxns
form highly reactive species like superoxide or free radicals
free radicals
better oxidizing agent than o2
short half lives and limited to surface waters bc light is needed for thier formation
transient photoxidants
