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Originally Posted by Dan_P
Let’s ignore the carbon part of this comparison because CO2 is abundant for phytoplankton and macro algae. The 30:1 and 16:1 N:P ratios both tell a similar story. More nitrogen is needed than phosphorous. That’s the big picture and a generalization of elemental needs.
Organisms can also build up reservoirs of these elements in times of plenty, throwing off the ratio. Similarly, rate of growth disturbs the ratio. The stoichiometric ratio is a rough number of what an organism needs, on average but not necessarily what it absorbs.
Organisms in general absorb material with wide range of stoichiometric ratios and eliminate the excess. Organism use material for biomass, the elements of which are reflected in the stoichiometric ratio. The elements absorbed for energy production may not. The biomass stoichiometry is instructive but does not reflect what an organism absorbs, just what its elemental goal is.
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Spot on. Macro is a sponge and it will absorb what is in the water. “Eliminate the excess” is interesting and explains why some macro is so messy with giving off DOC.
When I first starting growing macro, it was to produce a fresh live food from the sea. Red Ogo, Gracilaria Parvispora, has been a mainstay of Hawaiian diet for centuries. After setting up 10K gallons of tumble culture in my greenhouse, I found out that the high sulfur content of Trinity aquifier water ruined the marketability of Red Ogo as a human food.