Biodiversity of microphytoplankton off Callao (12°S)

Abstract

Diatoms and dinoflagellates are considered as the most abundant and diverse groups of phytoplankton microalgae. This research reveals the relative composition of microphytoplankton within the 20 nm of the coastal zone of Callao, from April 1993 to November 2010, collected by means of superficial trawls with net (75 μm mesh size). The material was analyzed with light microscopes. A total of 241 species were determined: 124 diatoms, 114 dinoflagellates, and 3 silicoflagellates. Chaetoceros (25 species), Protoperidinium (28 species), and Tripos (32 species) presented greater richness. Inter-annual, seasonal, and temporal variation of species richness is described, including information on biological indicators of water masses, El Niño/La Niña events, and their distribution. The species richness in Callao is considered high since it is one of the main upwelling areas with a similar richness to other areas of the Peruvian sea. Five species corresponded to new records: Entomoneis alata Ehrenberg, Amylax triacantha Sournia, Dinofurcula cf. ventralis Kofoid & Skogsberg, Protoperidinium venustum Balech, and Glenodinium cf. cinctum Ehrenberg.