Research papers Macrofauna associated with the brown algae Dictyota spp. (Phaeophyceae, Dictyotaceae) in the Sebastião Gomes Reef and Abrolhos Archipelago, Bahia, Brazil Tauana Junqueira Cunha n , Arthur Ziggiatti Güth, Sandra Bromberg, Paulo Yukio Gomes Sumida Universidade de São Paulo, Instituto Oceanográfico, Room 139. Praça do Oceanográfico,191, Cidade Universitária, CEP 05508-120, São Paulo, SP, Brazil article info Available online 12 September 2013 Keywords: Abrolhos Brazil Dictyota Phytal macrofauna Spatial distribution Temporal distribution abstract The taxonomic richness and distributional patterns of the macrofauna associated with the algae genus Dictyota from the Abrolhos Bank (Eastern Brazilian coast) are analyzed. Macrofauna comprised a total of 9586 specimens; a complete faunal list of the most abundant taxa (Crustacea, Polychaeta and Mollusca, accounting for 95.6%) resulted in 64 families and 120 species. Forty six species are registered for the first time for the Abrolhos Bank, of which 3 are also new for the Brazilian coast. The most abundant families were Ampithoidae amphipods (with Ampithoe ramondi as the main faunal component), Janiridae isopods, Rissoellidae gastropods and Syllidae polychaetes. Comparisons were made between summer and winter periods and among sites from Sebastião Gomes Reef, near the coast, and from Siriba Island, in the Abrolhos Archipelago, away from the mainland. Algae size was lower in the summer, when faunal density was higher, suggesting a possible effect of grazing. Macrofaunal communities were significantly different among sites and periods. Coastal and external communities were markedly different and winter had the greatest effects on the fauna. Environmental conditions related to sediment type and origin and turbidity appear to be a good scenario for our macrofauna distribution results. & 2013 Elsevier Ltd. All rights reserved. 1. Introduction The Abrolhos Bank shelters the largest and most diverse reefal complex of the South Atlantic (Leão, 1982; Dutra et al., 2005) presenting high levels of coral endemism (Leão and Dominguez, 2000). Due to the high biodiversity and the uniqueness of its biological assemblages and reef formations, the first National Marine Park of Brazil was established in Abrolhos in 1983 (Dutra et al., 2005). Most studies on the biodiversity of this area have focused primarily on conspicuous taxa such as corals, fishes, birds and whales. None- theless, broadening research spectra in the area is a matter of high interest to scientists as well as to decision-makers given its biological importance and the current concern on the impact generated by climate change and human activities (Moura et al., 2013). During the last decades, a rise in the economic activities has been witnessed in this marine region and its continental border, including tourism, mariculture, marine transportation, dredging activities, deforestation and monoculture practices (Leão and Dominguez, 2000). In addition, future actions may also include oil exploitation. These activities have led to increased sedimenta- tion rates (Silva et al., 2013), overfishing and other impacts on marine communities, such as breakage of coral heads and dis- turbance of sea grass beds, especially on shallow water reefs (Leão et al., 1993). One of the major concerns for the long-term maintenance of the mosaic of marine and coastal ecosystems of the Abrolhos Bank is the insufficient representation of key habitats in the existing network of Marine Protected Areas (Dutra et al., 2005). This scenario makes Abrolhos a priority area for scientific studies, especially for biodiversity, that provide background information for conservation and manage- ment programs (Leão et al., 1993; Moura et al., 2013). Benthic studies play a key role since information on the present diversity and standing stock is urgently needed as baseline data for the evaluation of upcoming changes (Jackson et al., 2001; Montiel et al., 2011). Seaweeds constitute one of the most abundant elements of the Abrolhos' shallow reefs, particularly over inter-reefal bottoms (Leão, 2002). Brown macroalgae may cover more than 90% of coastal reefs (Amado-Filho et al., 1997) and Phaeophyceae richness in the region is disproportionately high compared to other Brazilian sites (Paula et al., 2003; Torrano-Silva and Oliveira, 2013). Dictyotaceae is one of the most diverse families of seaweeds in Abrolhos (Figueiredo, 2005) and species of the genus Dictyota are recognized among the most abundant, varying from approximately 18% (August 1995) to 15% (April 1996) of the total biomass of macroalgae found between Siriba Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/csr Continental Shelf Research 0278-4343/$ - see front matter & 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.csr.2013.09.001 Abbreviations: Sebastião Gomes Reef, SG n Corresponding author. Tel.: þ1 617 4965308. E-mail addresses: tauanacunha@fas.harvard.edu (T.J. Cunha), azguth@gmail.com (A.Z. Güth), bromberg@usp.br (S. Bromberg), psumida@usp.br (P.Y.G. Sumida). Continental Shelf Research 70 (2013) 140–149