Shannon – Weaver diversity (H) and Sorenson’s indices
Shannon Weaver diversity index of phytoplankton species within the different sites was determined using:
H^1=∑▒(p_i ) (log_n〖P_i 〗 ) (Magaurran), 1988)
Where : H1 = Index of species diversity (information content of sample, bits or individuals); pi = Proportion of total sample belonging to ith species, and i = Number of species.
Sorensen’s similarity index
Modified Sorensen (1948) was used to show species similarity in the different sites in terms of species distribution. It is expressed as:
C_n=2a/(2a+b+c)
Where: Cn = Sorensen’s similarity coefficient; a, b, c = number of individuals per sites.