How much net carbon can coral sequester?

Question

So I am wondering how much carbon any given coral can sequester given that carbon dioxide dissolves in water and forms carbonic acid, and coral uses that carbonic acid in their own calcification process given by this equation.

$$\ce{Ca^{2+} +2HCO3- -> CaCO3 + H2O + CO2}$$

Given the amount of concentration of carbon dioxide that is in the atmosphere currently, how much net carbon can one coral organism sequester per year?

Just as a note, I am not talking about coral reefs as a whole, but just one coral organism. Obviously a lot of assumptions must be made, so please just include them in your answer please. Thank you!

Answer 1

Corals usually grow 1cm every year, some as slow as 2mm, some faster.

Coral sand density is about 1.5g /cm2, it's not the best estimate of coral weight. So, a coral organism of 10cm^2 produces 150 grams of CaCO3 every year, and 1m2 of coral can absorb 15 kilos.

CO2 is 44.01 g/mol CaCO3 is 100.0869 g/mol

15kg * .44 is the absorbtion of CO2 of a coral organism of 1m2 surface area. that's 6.6kg.

A car produces about 6 tons of CO2 every year.

Coral reefs are estimated to cover 284,300 km2 (109,800 sq mi), just under 0.1% of the oceans' surface area.

There are 1 billion cars, and 9 billion tons of antropogenic CO2.