Journal of the Marine Biological Association of the United Kingdom



Research Article

Macrobenthic animal assemblages of the continental margin off Chile (22° to 42°S)


Maritza  Palma a1a2c1, Eduardo  Quiroga a3, Victor A.  Gallardo a2, Wolf  Arntz a4, Dieter  Gerdes a4, Wolfgang  Schneider a2 and Dierk  Hebbeln a5
a1 Programa de Doctorado en Ciencias Biológicas, Departamento de Zoología, Universidad de Concepción, Casilla 160-C, Concepción, Chile
a2 Centro de Investigación Oceanográfica en el Pacífico Sur-Oriental (COPAS), Departamento de Oceanografía, Universidad de Concepción, Casilla 160-C, Concepción, Chile
a3 Programa Doctorado Oceanografía, Universidad de Concepción, Casilla 160-C, Concepción, Chile
a4 Alfred-Wegener Institute for Polar and Marine Research, Columbusstrasse D-27568, Bremerhaven, Germany
a5 Geowissenschaften, Universitat Bremen, Postfach 330440, D-28334 Bremen, Germany

Article author query
palma m   [PubMed][Google Scholar] 
quiroga e   [PubMed][Google Scholar] 
gallardo va   [PubMed][Google Scholar] 
arntz w   [PubMed][Google Scholar] 
gerdes d   [PubMed][Google Scholar] 
schneider w   [PubMed][Google Scholar] 
hebbeln d   [PubMed][Google Scholar] 

Abstract

A quantitative study of macrobenthos was carried out on three transects on the shelf and continental slope off Chile (22° to 42°S; from 100 to 2000 m water depth) within and beneath the oxygen minimum zone (OMZ). Macrobenthos mean densities ranged from 104 to 13 808 ind m−2, with highest values off Concepción ([similar]36°S), where highest chloroplastic pigment equivalents were also measured. Polychaetes were the numerically dominant group in all transects and depths, followed by peracarid crustaceans. Species richness and diversity correlated with observed changes in bottom-water oxygen concentrations and sediment-bound pigments. Our results show that the shelf macrobenthic communities were negatively affected by low oxygen. The non-metric multidimensional scaling (nMDS) analysis evidenced depth-related station groups which may be related to the different environments provided by the water masses involved. Indeed, the depth ranges of stations groups with their specific species inventories coincide quite well with the boundaries of the three important water masses in the region, the Equatorial Subsurface Water ([similar]50 m to [similar]400 m depth), the Antarctic Intermediate Water ([similar]400 to [similar]1200 m depth), and the Pacific Deep Water (>1200 m depth).

(Received March 30 2004)
(Accepted February 23 2005)


Correspondence:
c1 e-mail: mpalma@udec.cl