A New Trophic State Index for Lagoons

Table 3

TSI and corresponding values of Chl-a, NO₂-N, and SDD computed using Model B. It is noticeable that this model gives negative numbers (shown as “—” dash), which implies the nonapplicability of this model for NO₂-N concentrations less than 0.13 𝜇g L⁻¹. Model B shows slight improvement over Model A; however, the values of computed indices are underestimated in this model.

TSI	SDD computed (cm)	NO2-N computed (𝜇g L^−1)	Chl-a computed (mg m^−3)
0	200	—	0.32
10	128	—	0.65
20	82	—	1.15
30	52	—	1.94
40	33	—	3.17
50	21	0.13	5.11
60	14	0.70	8.13
70	9	1.28	12.86
80	6	1.86	20.27
90	4	2.44	31.86
100	2	3.01	50.00