Change in the meiofauna community structure of sandy beaches of the Nuevo Gulf (Chubut, Argentina)

Carlos A Harguinteguy,Catalina T Pastor De Ward,M Noelia Cofré

doi:10.1590/s0031-10492012021400001

Abstract

The composition and distribution of the benthic meiofauna assemblages of the Nuevo Gulf (Chubut, Argentina) are described in relation to abiotic variables. The meiofauna and sediment samples were collected in the intertidal zone of four sandy beaches with different anthropic disturbances in June 2005. The samples were obtained at 20 sampling sites using a 2.5 cm diameter core tube at a depth of 10 cm. A total of 13 meiofauna taxa were identified, with the meiofauna being primarily represented by nematodes, gastrotrichs, ciliates and polychaetes and the meiofauna abundances ranging from 1.5 × 10³ to 6.5 × 10³ ind. 10 cm‑2. Univariate (one-way ANOVA test) and multivariate (ANOSIM/MDS test) analyses showed clear dissimilarities in community structures between sites with anthropic effects and those in pristine condition, revealed by the significant differences were found between beaches near to and far way from a city with port activity. The meiofaunal assemblage varied in abundance and diversity, and these changes in the community structure may have been related to environmental gradients on the shore. The BIO‑ENV analysis showed that the redox potential discontinuity depth might be the main factor in the spatial distribution of organisms.

Highlights

The interest of the benthic biologist in meiofauna increases started in the early 1980s
The main obstacles of benthic meiofauna are its small size, together with difficulties in isolating the meiofauna from the sediments and the identification of species belonging to different taxa (Austen et al, 1994)
The objective of this work was to evaluate the meiofaunal community structure and their relation with measuring the abiotic variables, in order to determine if the number of taxa and abundances of meiofauna change along of different beaches with anthropic effects

Summary

Introduction

The interest of the benthic biologist in meiofauna increases started in the early 1980s. Meiofaunal organisms play an important ecological role in the aquatic ecosystem and are well suited for environmental impact assessment studies. They have short generation times, continuous reproduction, and in situ direct development and, their potential for rapid response to environmental change is high (Giere, 1993; Fraschetti et al, 2006; GyeduAbabio & Baird, 2006). 1. Instituto Multidisciplinario de Biología Vegetal (IMBIV) – Facultad de Ciencias Exactas, Físicas y Naturales (FCEFyN) – Universidad Nacional de Córdoba (UNC), Avda.

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