Most of the animals and plants living in the lagoons are to be found on and around the pinnacles.

The natural populations of pearl oysters also grow on the pinnacles.

Whether a pinnacle survives or disappears depends on the competition between the organisms responsible for its construction (bioconstruction) and its erosion (bioerosion) and the work of the waves.

Bioaccretion / bioerosion balances can be drawn up by calculating the net rate of calcification. For this purpose, the increase (due to bioerosion) or decrease (due to bioaccretion) in the alkalinity of the waters passing over a pinnacle is measured.

The net level of organic production by the communities of algae covering the pinnacles can be assessed by measuring the variations in the dissolved oxygen content of the waters passing over a pinnacle.

In order to assess the bioconstruction and pinnacle production rates, the alkalinity, pH and dissolved oxygen levels are measured on the windward and leeward sides of a pinnacle.

On the atoll of Tikehau, for example, there are approximately 500 pinnacles occupying roughly  0.3 % of the total area of the lagoon.

We have established that the pinnacles investigated were losing more via bioerosion than they were gaining via bioaccretion and that their constitutive carbonates were being dissolved at a rate of  37 g per m2 of lagoon per day. 

The net production of organic matter is negative (-3.2 g of carbon per m2 of lagoon per day): the pinnacles are consuming more organic matter than they are producing.

Examples of the curves obtained on Tikehau: changes in the total alkalinity balance  between the leeward and windward sides of a pinnacle and the net oxygen production between the leeward and windward sides of a pinnacle.

Details of these calculations can be consulted in : Calculation of the fluxes , Equation for calculating the CO2 levels, Equation for calculating the carbon production, Equation for calculating the rate of calcification.