Summer microphytoplankton characteristics during the pelagic resources cruise 0702-04

Abstract

A total of 114 samples were collected using phytoplankton net (75 μm). The plankton volumes fluctuated between 0.02 and 3.78 mL.m-3 and resulted in a general average of 0.43 mL.m-3. The greatest concentrations ranged between 4 and 5°S. The microphytoplankton was composed by central diatoms belonging to the intermediate phases succession and upwelling species (Coscinodiscus perforatus, Actinocyclus sp., Thalassiosira subtilis, Detonula pumila y Chaetoceros debilis), associated with cosmopolitan dinoflagellates. Red tides produced by Akashiwo sanguinea (Huacho) and ciliate Mesodinium rubrum (Pisco) were registered. Ceratium praelongum, Surface Subtropical Waters (SSW) indicator, and C. breve, Surface Equatorial Waters (SEW) indicator, were found off Pimentel and Huarmey, mainly out of 60 nm, with a maximum approach to coast by C. praelongum off Atico. Protoperidinium obtusum, Cold Coastal Waters (CCW) indicator, was found within the coastal area, except in Malabrigo, Callao and Pisco where its distribution reached 60 nm.