Distribution and seasonal spread of zooplankton in Iraqi waters

A summary of zooplankton research done in Peruvian marine waters is presented. We first provide a brief overview of the evolution of zooplankton studies off Peru before reviewing zooplankton biodiversity, regional distribution, seasonal and interannual fluctuation, trophodynamics, secondary production, and modeling are some of these topics. We evaluate research on various meroplankton, macroplankton, mesoplankton, and microplankton groups and provide a list of species from both published and unpublished sources. Three regional zooplankton groups have been identified:

·         A shelf group on the continental shelf dominated by Acartia tonsa and Centropages brachiatus;

·         A slope group on the continental shelf with siphonophores, bivalves, foraminifera, and radiolaria

·         An oceanic group with adiversity of species.

Where the continental shelves are thin, between 4-6°S and 14-16°S, the largest zooplankton abundances and biomasses were frequently seen.

The diversity of species varies according to distance from the shore.

As a result of advection, peaks in larval production, trophic interactions, and community succession, species composition and biomass also change significantly over short time intervals.

Based on the detrimental consequences of weak summer upwelling intensity or exceptionally high and persistent winter upwelling on zooplankton abundance off Peru, an intermediate upwelling hypothesis is put forth. This concept states that a window of optimal environmental conditions for zooplankton groups is produced by intermediate upwelling. Finally, we identify significant knowledge gaps that demand future attention.