Zooplankton diversity in four Norwegian fjords

The zooplankton diversity in four Norwegian fjords is presented and discussed. There is a highly significant correlation between the Shannon-Wiener index (H) and the Simpson index (λ), and between Simpson's index for copepods (λc) and for holoplankton (λh), while considerable discrepancies were found between these two indices and Margalef's index (d). Variations in diversity are partly related to zooplankton dynamics, party to the degree of exchange of water masses. Both deep and surface inflows of coastal water as well as increasing estaurine conditions tend to decrease diversity. Diversity decreased also very significantly with increasing latitude of the fjords, but this gradient seemed to be more related to specific characteristics of the fjords, especially the rate of water exchange, than to factors associated with latitude.