Variación estacional de las características químicas de las aguas ecuatoriales subsuperficiales al oeste de las Islas Galápagos en el área de ocurrencia de la corriente de Cromwell (1988-2002)

Abstract

Este estudio se lo realizó al oeste de las Islas Galápagos de los diferentes cruceros oceanográficos realizados desde 1988 hasta el 2002, con el propósitoo de conocer las características hidroquímicas de las Aguas Ecuatoriales Subsuperficiales (AESS), las cuales se estima mantienen relación con el flujo y aporte de la Corriente de Cromwell que tiene su mayor incidencia en esta área y su comportamiento estacional frente a los cambios climáticos en época húmeda (Marzo-Mayo) y seca (Agosto-Septiembre).

This information is based on the cruises accomplished in the oceanographic R/V Orion western Galapagos Islands since 1988 until 2002 at the section 92°W between latitude 1°N and 4°S. The research includes hydrochemical determinations (dissolved oxygen, nitrate, phosphate and silicate on Equatorial Subsurface water (ESSW). Furthermore on the basis of the thermohalines conditions (diagrams T/S), the bevaviour of the water mass into the water column (until 300 m) and the mean rates of the parameters during the cold events such as La Niño and normal periods is studied. Averages of 2.45ml/(-dissolved oxygen, 19.93 ugat/(-nitrate, 1.66 ugat/(-phosphate and 17.41 ugat/(-silicate, in the AESS in La Niña event (rainy season) is located (march-may) between 75 and 250 meters were determined. The ESSW in the normal period was located between 100 and 250 meters (in which averages of 2.14m(/(dissolved oxygen, 18.74ugat/(-nitrate, 1.46ugat/(-phosphate and 14.01ugat/(-silicate were determined).Whereas in the dry season (august-september) between 20 and 200 meters (in which, averages of 2.46m((-dissolved oxygen, 2o.60ugat/(-nitrate, 1.73ugat/(-phosphate and 20.79 ugat7-silicate were determined). In normal period the ESSW was located between 75 and 250 meters (in which, averages of 1.94m(/(-dissolved oxygen, 17.98ugat/(-nitrate, 1.59ugat/(-phosphate and 17.88 ugat/(-silicate were determined). Instead El Niño was located deeper between 150 and 300m (in which aversges of 1.37m(/(-dissolved oxygen, 24.68ugat/(-nitrate, 2.65ugat/(phosphate and 9.21 ugat/(-silicate were determined).