zonation and cell surface reactivity Flashcards
microbial mat process
solid particles in water (surface for cell attachment)
biofilm develops, thickens and more species over time
vertically stratified
EPS
extracellular polymeric substances
holds mat together
has enzymes that break down organic substances
buffers environ change
stage one; early microbial mat
produce organic carbon
cyanobacteria, diatoms, N2 fixers, autotrophs
stage 2; microbial mats
Fermentative and heterotrophic bacteria colonize
Aerobic respirers, denitrifiers, SRB, methanogens
stage 3:mats
Aerobic heterotrophs deplete O2, SRB produce H2S
stage 4; microbial mats
Chemolithotrophs join the party
S oxidisers, colourless and purple S bacteria (PSB) use the H2S
End up sandwiched between cyanobacteria and SRB
Protected from high O2, also PSB like low-light for photosynthesis
<1% H2S escapes mat to atmosphere
developed mats steady state
photoauto and chemoauto at top fix C and N, balanced by hetero decomposition
microbial metabolic reactions in the environment …
change the environment
marine sediment zonation
process
depositied
diagenesis
OM (plankton), inorganic detritus(clay, sand), minerals from water
Particulate organic carbon
POC degraded by aerobic chemoheter
Diagensis
compaction of sediments
microbes degrade OM (co2 and ch4
sediment get cemented
where do cells live
water
aqueous chemical reactions
EPS for cells
extracellular polymeric substance
protects cell from FLUXTUATIONS
keeps things together
s-layer
more structured protect from large molecules
diff surface charges so different interactions (w metals)
what gives microbial surfaces an electrical charge
ionization of functional groups in cell walls
