| Introduction | Cell states | Physical conditions |
These are proposed cell states with the physiological activities and physical conditions in which they might normally occur.
| CELL STATE NAME |
Can move to: | DEFINING PHYSIOLOGICAL CONDITIONS | PHYSICAL CONDITIONS |
| Balanced Growth | cyclic |
growth achieved through balanced allocation to the cell components three versions:
|
well mixed, euphotic zone |
Cyclic - periodic attractor for photosynthesis
|
balanced down-reg |
photosynthetic output (O2) and efficiency (PAM) varies with time at fixed lights (on about a 30 second period) | dense surface scum |
Down Regulation
|
cyclic balanced death-spiral |
shunting NADPH to detoxify ROS | surface with high UVR |
Lipid peroxidation death spiral
|
dead-end state | high ROS and RON lead to breakdown of lipids in the cell membrane which leads to an autocatalytic collapse of the population
|
calm, high UVR surface waters |
| Sinkers | balanced movers? collapsed |
excess photosynthetic carbon production creates ballast and cells tend to sink | super-optimal light but below damaging light with gentle vertical mixing profile
|
| Floaters | balanced movers? |
low ballast and high gas vescicle content | deeper water moving up to get more light
|
| Movers | balanced sinkers floaters |
Colonies that have the ability to move up and down faster than would be expected from sinking and floating driven by ballast and buoyancy. (Maybe from the squishing of vescicles by osmotic regulation.)
|
in the steep density gradient set up by thermal stratification and low shear forces (i.e. low mixing) |
Collapsed
|
dead-end state | Colonies that have collapsed vescicles and sink rapidly with no buoyancy. The collapse can be caused from high internal osmotic pressure or external hydrostatic pressure or a combination of these. | May see cells leading up to this as a function of high light and then getting mixed to depth. These colonies should end up at the bottom.
|
last modified February 7, 2010
