Organic matter sources for fish larvae and juveniles in a marine-estuarine interface (Mar Chiquita lagoon, Argentina)

DANIEL BRUNO; LUCIANA RICCIARDELLI; FLORENCIA BOTTO; MARCELO ACHA

ENVIRONMENTAL BIOLOGY OF FISHES

SPRINGER

Lugar: Berlin; Año: 2017 vol. 100 p. 1609 - 1622

0378-1909

The aim of this study was to analyze the organic matter (OM) origin in the nearshoreand the surf zones adjacent to Mar Chiquita lagoon, in order to determine theimportance of allochthonous estuarine detritus and in situ marine phytoplankton ascarbon (C) sources for young fishes prior to entering the lagoon. Water samples fromboth, the nearshore and the surf zones were collected for estimation of Chlorophyll αconcentration, and δ¹³C and δ¹⁵N values of the particulate organic matter (POM).Isotopic composition of the zooplankton and fish larvae from both zones and fishjuveniles from the surf zone were also estimated. The contribution of potential OMsources was quantified by Bayesian stable isotope mixing models (SIAR). SIARmodels revealed that the POM composition in the coastal area close to Mar Chiquitalagoon comprised a mix of primary producers (terrestrial and marine). The cordgrassSpartina densiflora that develops in the saltmarshes bounding the lagoon, contributedmost to the POM of the surf zone, being important as a C source for zooplankton fromthe same zone. Towards deeper waters (10 - 12 m, ~2.5 km offshore) with higherchlorophyll α concentrations, phytoplankton contributed most to the POM. Spartinadensiflora was not relevant as a C source for larval and juvenile fishes. However, it wasof importance to the group of primary consumers, which apparently sustain otherzooplankton organisms that fish fed on. In this sense, the OM derived from S densifloraand exported to the coastal area contributes to sustaining the prey for young fishesoutside Mar Chiquita.