Quetognatos: ¿Indicadores de eventos climáticos anómalos en el Océano Pacífico Colombiano?

Abstract

This principal aim of this work was to establish the value of chaetognaths as indicators of El Nino and La Nina events in the Colombian Pacific Ocean. The studied periods were 23.Jun-12.Jul.01, 27.Ago15.Sep.01, 03-22.Sep.02 and 01-21.Sep.03, including abiotic and biotic information, comparing the results with historical data. The moderate 2002 El Nino was not evidenced, because there were analyzed only temperature; salinity and chlorophyll a at surface and the depth of the termocline was not considered. The highest abundances of chaetognaths in the period 03-22.Sep.02 suggested better general conditions for those organisms, despite of the reigning El Nino. The global analysis of the studies on chaetognaths realized until now in the CPO showed that these organisms are not useful as indicators of anomalous episodes in that area, since they appear indistinctly in normal periods, as during El Nino and La Nina, in very variable densities and distribution; Sagitta minima could be the exception as indicator of cold events. The high density and permanent wide distribution of S. enflata and S. hexaptera demonstrate that these species are the only euritypical ones at the CPO, while the presence of the mesozooplanktonic S. hexaptera, S. serratodentata and K. subtilis, just as the euribatial S. zetesios at the surface evidence upwelling processes in the study area.