Phytoplankton of the seasonal surveys of 1977, and further pre- vs. post-operational comparisons at Cook Nuclear Plant / John C. Ayers, Susan J. Wiley.

where S is the number of species, n is the total number of phytoplankton in
cells/ml, n. is the number of phytoplankton of the i species. Diversity as
1
presented here is not the true diversity since not all forms encountered can
be identified to the species level. Therefore, this diversity must be viewed
with caution. However, since these diversities do mean something about
community structure they will be used to illustrate changes occurring within
the phytoplankton population from year to year and for the derivation of
redundancies.
Redundancy is a measure of the dominance of one or a few species within
a given population. As presented by Wilhm and Dorris (1968) it is:
d -d
max
r = _ -
d - d
max mmin
where d is the observed diversity as calculated above, d is the maximum
max
diversity for a particular community, and dmin is the minimum possible
diversity for a particular community. d is calculated using the following
max
equation:
dma = (1/n)(log2 n! - s log2 [n/S]!)
and dmin is calculated using the equation:
dmin = (1/n)(log2 n! - s log2 [n-(S-1)]!)
The values of r range between 0 and 1. An r equal to 0 implies that the
species encountered in a community each have the same number of cells. An r
equal to 1 implies that one species dominates the community of phytoplankton.
Since redundancy values are not given in Appendix B, it is necessary to give
them here (Table 6). The values for years 1970 - 1976 have been reported by
Ayers (1978). Table 6 also presents the means, standard errors, and numbers of
observations of redundancies in Cook Plant major surveys during 1977 stratified
by seasons, depth zones, and inner and outer station groups. The means and

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