Zonal and depth patterns in the trophic and community structure of hyperiid amphipods in the Southeast Pacific

Espinosa-Leal, Liliana; Bode, Antonio; Escribano, Ruben

Abstract

The structure of the pelagic food web is a key issue to understand the variability in C and N fluxes in the ocean. The trophic structure of the hyperiid amphipods and its spatial variation in the subtropical area of the Southeast Pacific was studied based on C and N isotope composition. Zooplankton were collected off northern and Central-southern Chile during September-November 2016 at the coastal zone and in oceanic areas. Measurements of delta N-15 and delta C-13 of individual hyperiids were used to estimate the trophic position for each species, and to assess the community isotopic niche for 3 pre-defined areas: the coastal upwelling (eutrophic) zone, the coastal transition (mesotrophic) zone and the oceanic (oligotrophic) zone, as well as three depth layers. Our results showed different assemblages of species among the 3 zones, but also a large overlap between the isotopic niche for all zones and depth layers. In the mesotrophic zone there was a noticeable increase in the trophic position of individual species. The trophic diversity of hyperiids over the study region was relatively high, including primary consumers, omnivores and carnivorous feeders, and was associated with the changes in productivity across zones. However, carnivory was more prevalent in the mesotrophic zone and in the mesopelagic (500-1000 m) layer. We suggest that such variations reflect both the biogeochemical processes controlling the productivity in each zone, and the life-traits of individual species.

Más información

Título según WOS: Zonal and depth patterns in the trophic and community structure of hyperiid amphipods in the Southeast Pacific
Título de la Revista: DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS
Volumen: 165
Editorial: PERGAMON-ELSEVIER SCIENCE LTD
Fecha de publicación: 2020
DOI:

10.1016/j.dsr.2020.103402

Notas: ISI