Composición del fitoplancton frente a la costa ecuatoriana durante septiembre de 1995

Abstract

During the period 6th - 13th of september 1995, the National Fisheries Institute carried out an oceanographic cruise in the Gulf of Guayaquil area and at the northern ecuadorian coast from 3~'10'S and 00~' latitude to 80~'- 82~'W longitude. During the survey, 22 planktological stations were carried out. Vertical towings in the water colum of 50 m depth were also made, using a net of 55~km. A total of 109 species were identified. High concentrations of diatoms and dinoflagellates were observed along the sampling area. The most common species were Proboscia alata, Rhizosolenia styliformis, Ornithocercus steinu and Ceratium tripos. It was also determined a high fertilitty area (1,3 x 106 cel.m-3). Yet, this indicates the presence of an equatorial undercurrent which's linked to the high concentrations of nutrients and chlorophyl. The highest phytoplanktonic concentration was observed in the northern area where as the lowest concentration was observed in the south, in spite of being an upwelling area, probably due to the phytoplankton consumption by larvae.