| Resumo: |
During april 1995 hydrochemical research in a vertical column on the east side of the Galápagos Islands (Cruise T95/04/01) onboard of the INP R/V Tohallí indicated that concentrations of ammonium, nitrate, phosphate and chlorophyll-a were found stratified from the surface to deeper layers, on the other hand the maximum levels of nitrite and silicate were detected 70 m below the thermocline. The apparent oxygen use (AOU) varied from 1 to over 3 below the thermocline, this would indicate an oxidating environment due to the high levels of nitrate, phosphate, silicate and low concentrations of dissolved Oxygen (ca. 90-134[µM]) and ammonium (<0,1[µM]). According to the high salinity average (35,0 ups), nutritive elements (nitrate 15,6 [µM], silicate 13,1 [µM]), phosphate 1,3 [µM]) and low average of chlorophyll-a 0,15 mg.m³, and in addition the general gradient of these parameters would suggest the presence of an upwelling event, whose nucleus presented low biological activity.
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