A New Trophic State Index for Lagoons

Table 2

TSI and corresponding values of Chl-a, NO₂-N, and SDD computed using Model A. It is noticeable that this model gives negative numbers (shown as “—” dash), which implies the nonapplicability of this model for Chl-a concentrations less than 0.04 mg m⁻³ and NO₂-N concentrations less than 0.71 𝜇g L⁻¹.

TSI	SDD computed (cm)	NO2-N computed (𝜇g L^−1)	Chl-a computed (mg m^−3)
0	6400	—	—
10	3200	—	—
20	1600	—	—
30	800	—	—
40	400	—	0.04
50	200	—	0.32
60	100	—	0.89
70	50	0.71	2.03
80	25	3.29	4.31
90	12	8.44	8.88
100	6	18.75	18.00