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photosynthesis--latency period?

Edward Doran edoran at u.washington.edu
Wed Jul 5 13:41:28 EST 1995

	Well it may depend on the length of time after the "go!" that you 
want. There has been quite a bit of debate, given the hydrography of the 
water mass and the physiology of phytoplankton, when if ever (in some cases) 
they reach steady state.  One thing to think about though, is short term 
exposures to high light levels can result in photosynthetic rates that are 
higher than would be predicted from a standard P vs.I curve (so photosynthesis
varies with time, irradiance, and physiology). So the length of time you watch
after the "go!" and what you end up calling the maximum photosynthetic rate is
actually quite important.
	In the interest of full disclosure I'll tell you that I am only a 
graduate student.  My work is focused on studying how light regimes and 
perturbations interact with the molecular biology (gene expression, cell cycle
progression) of phytoplankton.

On 5 Jul 1995, BruceRat wrote:

> QUESTION:  How long after algae is exposed to full sunlight does it reach
> its maximum photosynthetic rate?  Is it like, say, the LAC operon, where
> certain enzymes need to be synthesized first (so, 5-10 minutes)? 
> I am working on a project with pond primary productivity.  I have been
> keeping ponds in sunlight, or dark, and measuring dissolved oxygen
> production.  If you have any experience timing the process from the "GO!",
> please advise.
> Bruce Ratcliffe  (BruceRat at AOL.COM)

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