Benthic macrofauna structure in the northeast area of Todos os Santos Bay, Bahia State, Brazil: patterns of spatial and seasonal distribution

Abstract

A B S T R A C TStructure of intertidal and subtidal benthic macrofauna in the northeastern region of Todos os Santos Bay (TSB), northeast Brazil, was investigated during a period of two years. Relationships with environmental parameters were studied through uni-and multivariate statistical analyses, and the main distributional patterns shown to be especially related to sediment type and content of organic fractions (Carbon, Nitrogen, Phosphorus), on both temporal and spatial scales. Polychaete annelids accounted for more than 70% of the total fauna and showed low densities, species richness and diversity, except for the area situated on the reef banks. These banks constitute a peculiar environment in relation to the rest of the region by having coarse sediments poor in organic matter and rich in biodetritic carbonates besides an abundant and diverse fauna. The intertidal region and the shallower area nearer to the oil refinery RLAM, with sediments composed mainly of fine sand, seem to constitute an unstable system with few highly dominant species, such as Armandia polyophthalma and Laeonereis acuta. In the other regions of TSB, where muddy bottoms predominated, densities and diversity were low, especially in the stations near the refinery. Here the lowest values of the biological indicators occurred together with the highest organic compound content. In addition, the nearest sites (stations 4 and 7) were sometimes azoic. The adjacent Caboto, considered as a control area at first, presented low density but intermediate values of species diversity, which indicates a less disturbed environment in relation to the pelitic infralittoral in front of the refinery. The results of the ordination analyses evidenced five homogeneous groups of stations (intertidal; reef banks; pelitic infralittoral; mixed sediments; Caboto) with different specific patterns, a fact which seems to be mainly related to granulometry and chemical sediment characteristics. R E S U M OA estrutura da macrofauna bêntica das regiões entre marés e infralitoral raso na porção nordeste da Baia de Todos os Santos (BTS), nordeste do Brasil, foi investigada durante um período de dois anos. Sua relação com os parâmetros ambientais mensurados foi estudada através de análises estatísticas uni -e multivariadas, sendo os principais padrões de distribuição espacial e temporal relacionados principalmente ao tipo de sedimento e ao conteúdo de três indicadores da matéria orgânica sedimentar (Carbono, Nitrogênio e Fósforo). A macrofauna, composta majoritariamente por anelídeos poliqueta (cerca de 70% do total), apresentou baixa densidade, riqueza de espécies e diversidade, exceto nas estações amostradas nos bancos recifais. Estes se destacam como ambiente peculiar, formado por sedimentos grosseiros, pobres em matéria orgânica e ricos em carbonatos, apresentando fauna abundante e diversificada. A região entre marés e os locais rasos adjacentes à refinaria RLAM são formados por sedimentos compostos principalmente por areia fina e baixo conteúdo orgânico e constituem am...

Revision of Sternaspis Otto, 1821 (Polychaeta, Sternaspidae)

“…was the most abundant species along the southwestern coast of India (Joydas and Damodaran 2009), in 30–50 m and in sandy, muddy or mixed bottoms, there were up to 1335 specimens per square metre. Likewise, in shallow water muddy bottoms in Bahia, Brazil an apparently undescribed species was the most abundant benthic species (Pires-Vanin et al 2011); a different species, identified as Sternaspis scutata , was the most abundant in Jiaozhou Bay, China (Wang et al 2006), and a similar condition was recorded for southern Chile (Rozbaczylo et al 2006). The study of these materials can help improve our knowledge about species variation and to facilitate their recognition as distinct species.…”

Zonação de recifes emersos da Área de Proteção Ambiental Costa dos Corais, Nordeste do Brasil

“…Neste contexto, metodologias que envolvam o monitoramento de fatores naturais, juntamente com os fatores antropogênicos, são essenciais para o manejo adequado dos recursos (Pires-Vanin et al, 2011). Assim, estudos de zonação nestas regiões podem contribuir para avaliar o impacto decorrente destas atividades e para subsidiar futuros planos de manejo.…”

Spatial and temporal variability in distribution, diversity, and structure of the polychaete assemblages from Dakhla Bay (Atlantic coast of South Morocco)

“…The most abundant species in Terra Nova Bay were Tharyx cincinnatus (Ehlers 1908) and Spiophanes tcherniai Fauvel 1950 (Gambi et al 1997). In Chile Bay, M. sarsi and T. cincinnatus were the dominant species (Gallardo et al 1988), while in Todos os Santos Bay (Brazil), the most abundant species was Armandia polyophthalma Kükenthal, 1887(Pires-Vanin et al 2011.…”