Diel vertical distribution of the larvacean Oikopleura dioica in a North Patagonian tidal frontal system (42°–45°S) of the SW Atlantic Ocean

Publicado en Marine Biology Research, v. 11(6):633-634
Autores

Spinelli, M., Derisio, C., Martos, P., Pájaro, M., Esnal, G., Mianzan, H. and Capitanio, F.

Año de publicación 2015
DOI https://doi.org/10.1080/17451000.2014.978338
Afiliaciones
  • Instituto de Biodiversidad y Biología Experimental y Aplicada, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
  • Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
  • Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), Mar del Plata, Argentina
  • Facultad de Ciencias Exactas y Naturales, Instituto de Investigaciones Marinas y Costeras (IIMyC), Universidad Nacional de Mar del Plata, Consejo Nacional de Investigaciones Científicas y Técnicas, Mar del Plata, Argentina
  • Departamento de Ciencias Marinas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, UNM, Mar del Plata, Argentina

 

Programa

CRN3

Proyecto CRN3070
Keywords

Abstract

In frontal systems, larvaceans generally comprise a significant fraction of the mesozooplankton. Given the low mobility of these organisms, their vertical distribution is directly influenced by the physical conditions of the water column. The main goal of this study was to investigate the day and night vertical distribution of the larvaceans Oikopleura dioica in the different sectors of the Península Valdés tidal front (42°&ndash45°S SW Atlantic Ocean), focusing on possible causes such as oceanographic conditions (well-mixed, frontal and stratified), feeding activities, reproductive behaviour and predation risks. Day and night samples were collected with a MultiNet of 67 µm and 300 µm mesh size, from two depth layers. Conductivity-temperature-depth (CTD) profiles were also recorded. In the well-mixed waters, the size structure of O. dioica was similar in the upper and lower layers both in the day and night samples, probably due to the continuous vertical movement caused by the turbulent mixing of waters. In the frontal and stratified areas, mature animals were found in the upper layers during the night, possibly due to their aggregation in surface waters for synchronized spawning. In these areas, a high percentage of well-fed larvaceans was also found. Principal component analysis showed that, at night, the abundance of potential predators such as chaetognaths, ctenophores and anchovy larvae was correlated with the parameter of stability of the water column (Simpson parameter), and that these were more abundant in the upper layers of the stratified area containing larvaceans. Our results suggest that the degree of stratification of the water column was the main factor affecting the vertical distribution of O. dioica.