Seasonal dynamics of zooplankton in a northern Chile bay exposed to upwelling conditions

Abstract

Due to the ever-increasing use of the coastline for industrial purposes, particularly by those activities that take up great amounts of sea water, it is fundamental to understand the composition of the planktonic fauna and its natural spatial and temporal variability in relation to hydrographic variables, in order to understand the potential impact of such undertakings. Totoralillo Norte (~30°S) is an embayment located within a well-known area of recurring upwelling events, as well as a zone with projection for industrial development. Here we performed seasonal surveys (several days sampling within each season) during 2013 and 2014 recognizing an abundant zooplanktonic community with a good representation of the main taxa comprised by at least 166 species. In terms of numbers, copepods dominated the holoplankton (91.7%), whereas meroplankton was mainly composed of larval stages of barnacles, mollusks, decapods, bryozoans and fish. In spite this being a coastal zone normally affected by upwelling events, zooplankton abundance was high throughout the year, even during periods dominated by weak winds and downwelling conditions. Studies such as this can help unveil relevant ecological patterns and their related processes; vital information that must be considered during an environmental impact assessments.