Zooplankton trophic transfer in the Humboldt Archipelago

Hydrographic conditions were assessed through vertical profiles of temperature, salinity, dissolved oxygen, and fluorescence collected at the sampling site (29.0462°S; 71.5491°W) within the Humboldt Archipelago, northern Chile. The profiles were achieved using an RBRmaestro3: multichannel logger (hereafter CTD) equipped with Coda (dissolved oxygen) and Turner Cyclops (fluorescence) sensors. The performance of the sensors was validated against discrete, higher-accuracy measurements. Discrete oceanographic samples were collected at depths of 10, 30, and 60 m with a Niskin bottle to provide samples for dissolved oxygen, chlorophyll a (Chla) and particulate organic carbon (POC) analyses. The concentration of Chla at each discrete depth was measured in triplicate filters , and clorophyll was extracted with acetone and measured using a fluorometer. Zooplankton samples were collected by means of a WP2 plankton net. The net was towed vertically, with discrete samples collected at specific strata. The samples were filtered to remove the water and then they were then dried. Dried weight was converted to carbon units.