Phytoplankton in the Peruvian sea in late spring 2008. Pelagic resource assessment, Cruise 0811-12

Abstract

76 samples were collected using a network of phytoplankton and 33 were collected with Niskin bottles. Plankton volumes ranged between 0.08 and 10.7 mL.m-3, with a mean of 1.02 mLm-3. Phytoplankton was restricted to 30 nm from Pimentel to Atico and 200 nm off Pacasmayo. It was formed by diatoms of early and intermediate stages of ecological succession. The highest mean value was latitudinally located between 6 and 7°S and within 30 nm, while other important values were located between 30 and 60 nm. In terms of quantity, the highest concentration was in Chimbote (16.390 x103 cel.L-1) and the lowest in Paita (33 x103 cel.L-1) with important representation of nanoplankton. The two-way ANOVA showed significant differences between plankton volumes based on coastal distances (P<0.002; F=8.53). The distribution of biological indicators evidenced the unusual displacement of Ceratium breve var. schmidtii (SEW) off Punta La Negra. Protoperidinium obtusum (CCW) was limited to the coastal strip (20 nm) and its distribution increased off Salaverry and Pacasmayo, while Ceratium praelongum was coastal off Paita and it was associated with SEW beyond 60 nm at Punta La Negra and off San Juan, outside 90 nm.