[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Algae:plant competition and Carbon

I have been looking up some competing ideas for certain algae groups lately.
Often you'll see something called the Redfield ratio in chemical
oceanography. It'll have a ratio of something like Carbons: 106: Nitrogen:
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 find
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 need
this support like the larger beast, Macrocystis.

All of the common algae in our tanks are smaller, much like the
phytoplankton. Our plants are much like the larger macro algae. They need
support. This support is mainly in the form of things like cellulose,
hemicellulose, a number of pectins etc. These lack the N:P portion. They are
sugars, carbonhydrates. No P or N.

Now it would seem that the aquatic plants are not different in respects to
this issue as the kelps and we still have the smaller "phytoplankton like"
algae that cause grief for plant tanks.

It would again seem that extra Carbon is the main missing nutrient for the
plants. More than this 106 ratio but close to 5 time that. Plants perhaps
have even a higher C ratio than the kelps. If this is supplied in great
enough quantity the smaller algae will not have the same advantages but the
larger ones will. It makes sense since the majority of the C is used for
support while the algae can get by with far less Carbon.

Still doubtful of the importance of carbon?

Tom Barr