• Bacteria

• Protists  

• Micro and meso zooplancton

• Trophic food web

Unlike autotrophic producers, heterorotrophic producers require not only mineral materials but also organic matter originating from other organisms to be able to develop.

The heterotrophic producers present in the water column are the bacteria (procaryotes),  the protista and the zooplankton. The latter group can be sub-divided on the basis of size into micro- (35-200 µm), meso- (200-2000 µm) and macro- (> 2000 µm) zooplankton.

The heterotrophic producers present in the benthos can be sub-divided into meiofauna (metazoans ranging between 100 and 2000 µm in size) and macrofauna (metazoans measuring more than 2 mm). These organisms live either within the sediments (in the case of the meiofauna and some of the macrofauna), on top of the sedimentary layer or on the coral pinnacles.

The diagram of the trophic network in the lagoons gives an average overall picture of the situation at a given instant: it gives the biomasses of the various autotrophic and heterotrophic compartments  (expressed in units of biomass per unit volume or area) and the exchanges of matter and energy occurring between compartments (expressed in units of biomass per unit volume or area and per unit of time).