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Re: Algae:plant competition and carbon

> Date: Sat, 28 Apr 2001 09:54:11 -0600
> From: Roger S. Miller
> Subject: Re: Algae:plant competition and carbon
> Tom Barr wrote:
> > I have been looking up some competing ideas for certain algae groups
> > Often you'll see something called the Redfield ratio in chemical
> > oceanography. It'll have a ratio of something like Carbons: 106:
> > 16 and P: 1. This is also about the same ratio in phytoplankton.
> >
> > But looking at something such as Macrocystis, a larger brown kelp, you
> > this ratio is now 500 carbon to 15 N's and 1 P. So why is this? Why
would it
> > need more Carbon?
> > It's larger and needs more support. The smaller phytoplanktons do not
> > this support like the larger beast, Macrocystis.

> In discussing variations among the algae, Raven suggested a correlation
> between the high C content of the larger algaes to the presence of a
> thicker cell wall.
> Where are our typical nuisance algae relative to the types shown here?
> Green water is phytoplankton, so that's fairly clear.  Diatoms aren't
> addressed.  My guess is that our tough, attached and filamentous algaes
> have thick cells walls and are more similar to the macroalgaes than they
> are to the phytoplankton.  Either way, carbon would still be higher in
> plants than in algae.

Or could it be that, if we carry this on through the evolutionary chain to
sweet potatoes, it shows the beginnings of cell specialization and the
ability to produce and store _excess_ energy?

> Certainly it seems possible that carbon could limit
> plant growth in cases where it doesn't limit algae growth.

Farmers play with the balance of nitrogen to carbon (and phosphorus) all the
time in order to control growth patterns, vegetative patterns being
different from reproductive patterns. It used to be portrayed to the
neophyte farmer in terms of the "Carbon- Nitrogen 'Cycle'" to give some
underlying meaning and logic to fertilization regimes.

Perhaps you guys are using a microscope to examine an elephant?

Nor would I be as quick to discard a lot of terrestrial studies for
"relevancy" as is sometimes the case on the list. There _are_ times when the
final product is as important a clue as anything else in trying to discover
the means to an evolutionary end...


David A. Youngker
nestor10 at mindspring_com