Meiofauna spatial distribution in Rio Formoso estuary, Pernambuco, Brazil

Abstract

Estuarine environments are favorable habitats for the development of meiofauna that has a proeminent role within the food web, nutrient regeneration and as pollution indicator. This study aims to describe the meiofauna community structure along the Rio Formoso estuarine gradient. Samples were collected on eight stations (#1 o 8) at midlittoral (M) and sublitoral habitats (S). The community structure was correlated o the following variables: salinity, temperature, organic matter, chlorophyll-a, phaeopigments and sediment size classes. Meiofauna samples were fixed with 4% formaldehyde and animals were separated from the sediment washing the samples through a 1,0mm sieve mesh size o exclude macrofauna and a 0,04mm sieve mesh size to retain the meiofauna. Fourteen major taxa were identified. Nematoda was the dominant group, with 58% of total abundance, followed by Copepoda with 24% of the animals. Density values varied from 1,461 to 12,353 ind.10cm-2 at stations #8-I and #2-I respectively, with an average value of 5,003 ind.10cm-2 over the estuary. Phaeopigments, sediment granulometric characteristics and vegetation presence were the most important factors structuring he meiofauna community.