Primary production in the marine environment southeast Pacific, Peru, 1960-2000

Abstract

The results of research on primary production, within the interdisciplinary scope of the marine environment off the Peruvian coast, include national, foreign and joint research contained by different international projects (1960-2000). Circulation in the Peruvian coast is dominated by a stream towards Ecuador in a layer 20 to 50 m. The structure of feathers upwelling occurs in each area and could be the key to the development of short supply chains: phytoplankton - cupleids fish. Nutrients distribution follows temperatures feather, with higher values in the coast and offshore low; chlorophyll shows minimum values near the sea (10 nm) that increases with distance. Phytoplankton growth in Peruvian waters varies from 0.5 to 0.8 d/d. In newly upwelled water growth is limited by lack of “biological conditioning” and organic compounds (15°S). These types of water can be related to the “ blue water “ high nutrient and phytoplankton poor with small cells (chlorophyll <2 mg/L ) and “ brown water “ with dense phytoplankton (chlorophyll >5 ug/L ) greater diversity and cell diameter >5 microns. The average primary production was 3 gC/m2 /d (1960-1985), comparable to most studies in which varies between 3 and 4 gC/m2 /d in the coastal band, the last value is highly variable in space with peaks within 10 km. Values greater than 12 gC/m2 /d found in upwelling of Chimbote. El Niño, La Niña and ENSO phases, affecting primary production. Low temperatures cause changes in the chemical composition of phytoplankton and reduce productivity index mgC/mgclor-a/d which is also attributed to limitations of light.