Metazoan meiofauna within the oxygen-minimum zone off chile: results of the 2001-puck expedition

Abstract

A quantitative study of metazoan meiofauna was carried out at continental shelf and slope stations affected by the oxygen-minimum zone in the eastern South Pacific off Chile. Densities of meiobenthos at the investigated stations off Antofagasta (22 degrees S), Concepcion (36 degrees S), and Chiloe (42 degrees S) ranged from 1282.1 to 8847.8 ind 10 cm(-2). Oxygen deficiency led only to average abundances, despite higher food availability and freshness at the corresponding sites. Sediment organic carbon, chlorophyll-a, and phaeopigment contents were used as measures of the input from water-column primary production, which accumulated at the oxygen-minimum zone stations. The highest abundances were found at a station with an oxygen content of 0.79 mL L(-1), which was slightly elevated from what is defined as oxygen minimum (0.5 mL L(-1)). The most oxygenated site yielded the lowest densities. Meiofauna assemblages became more diverse with increasing bottom-water oxygenation, whereas nematodes were the most abundant taxon at every station, followed by annelids, copepods, and nauplii. (C) 2008 Elsevier Ltd. All rights reserved.