Effects of Changing Environmental Conditions on Lagoon Ecology - Coastal Lagoons: Ecosystem Processes and Modeling for Sustainable Use and Development - page 212

Another classification system, also related to water renewal rate and water
constituents, but independent of salinity, was suggested by Guelorget and Per-
thuisot. 108 They define the term “confinement” as a measure of the degree of isolation
related to the renewal rates and the impoverishment of substances (“vitamins”) of
marine origin (Figure 5.8). Biological gradients such as biomass, abundance, and
diversity that can be found in coastal lagoons are explained as a function of con-
finement (see also Guelorget et al., 109 Bianchi, 107,110 and Carrada and Fresi 111 ).
However, the distribution of organisms in coastal lagoons responds to more than
one parameter. 89,107,110,112,113 For example, the distribution of some communities and

Hyposaline

Continental domain

VI VI

VI

S% S%

V

V

IV

IV

III

III

II

II

I

Marine domain S%

Biomass

Chl a ( µ g L − 1 ) Dry weight (g m − 2 )

Phytoplankton

Benthos

I II III IV V VI

VI V IV III II

evaporation

continental input

FIGURE 5.8 Diagram showing the biological zonation (I to VI ) in coastal lagoons according
to the confinement model and the associated variation in benthic and phytoplankton biomass.
(Adapted from Guelorget, O. and Perthuisot, J.P., Trav. Lab. Geol., 16: 1, 1983. With
permission.)