Adilma de Lourdes Montenegro Cocentino

Ceramium nitens (Ceramiaceae, Rhodophyta), an uncommon species from Brazil

Morphological studies on Ceramium nitens (C. Agardh) J. Agardh, a completely corticated species, were carried out based on specimens rediscovered in Brazil fifty years after its first record. Its occurrence in Brazil was considered doubtful since it had been collected only once since 1945. Ceramium nitens can be recognized by having axial cells entirely covered by cortical cells, except for the cells near the apex, obscuring the nodal and internodal banding thalli, characteristic of most Ceramium species. In this paper the occurrence of Ceramium nitens in Brazil is confirmed and its vegetative and tetrasporangial structures are described in detail and their implications for the taxonomy of the genera Ceramium, Centroceras and Corallophila are discussed. Brief comments on the geographic distribution of C. nitens are also included.

Antioxidant activity of three seaweeds from tropical reefs of Brazil: potential sources for bioprospecting

We report the first screening for antioxidant activity (AOX) of three dominant seaweeds from low intertidal reefs of Brazil. Sargassum furcatum, Bryothamnion triquetrum, and Osmundaria obtusiloba were extracted with dichloromethane and methanol (2:1), and AOX was measured by five UV-vis microplate spectrophotometric methods: DPPH (2,2-diphenyl-1-picryhydrazyl) and ABTS (2,2-azinobis (3-ethylbenzthiazoline-6-sulfonic acid)) free radical scavenging, metal chelating capacity, total phenolic compounds using reducing power by Folin-Ciocalteu and FRAP (ferric reducing antioxidant power). All studied species showed high AOX, even at very low extract concentrations. We can attribute these results to the stressful environment in which these seaweeds live, high hydrodynamics, air exposure during low spring tides, intense solar radiation, and other factors that may contribute to oxidative stress, featuring O. obtusiloba as a new source of natural antioxidants.

Macroalgal responses to coastal urbanization: relative abundance of indicator species

This study aimed to evaluate and compare the intertidal macroalgae community from reef structures subject to different urbanization degrees. Samplings were made in 11 beaches from the Pernambuco coast, northeastern Brazil. The sites were classified according to the level of urbanization into three classes of increasing urbanization pressure: non urbanized (NU), in urbanization process (UP), and consolidated urbanization (UC). Macroalgae were identified in situ non-destructively. A total of 53 taxa were identified, 41 of these were macroalgae. Significant differences were observed in the composition of macroalgae according to the urbanization levels, with Palisada perforata, Gelidiella acerosa, and Caulerpa spp. dominating NU and UP sites, whereas Chondracanthus acicularis, Bryopsis sp., and Ulva spp. dominated UC sites. This work shows that urbanization can have a strong effect on the structure of rocky intertidal macroalgal assemblages and highlights some macroalgae species that can be used as bioindicators for assessing the impact of urbanization on coastal shores.

FENOLOGIA DE Amansia multifida E Vidalia obtusiloba (CERAMIALES, RHODOPHYTA) EM RECIFE DE UMA PRAIA DO NORDESTE ORIENTAL DO BRASIL

As rodoficeas Amansia multifida e Vidalia obtusiloba ocorrem principalmente nos recifes costeiros das regioes tropicais. As especies sao produtoras de substâncias farmaceuticas, como analgesicas, antibioticas e antioxidantes, com expressivo potencial biotecnologico. Em vista disso, os aspectos fenologicos das populacoes de A. multifida e V. obtusiloba que ocorrem nos recifes da Praia de Boa Viagem, em Recife, foram analisados visando auxiliar o manejo e conservacao destes recursos marinhos. Aleatoriamente, 15 especimes de cada taxon foram coletados mensalmente de dezembro/2013 a novembro/2014, para analisar as fases reprodutivas e padroes de crescimento. Os resultados sugerem que a fase tetrasporofitica predomina sobre a gametofitica em ambos os taxons. Em relacao a Amansia multifida, apenas a fase tetrasporofitica e os especimes nao ferteis foram encontrados. Em Vidalia obtusiloba foram registradas as fases gametofiticas, cistocarpica, tetrasporofitica e nao fertil. Quantitativamente foi analisado um total de 180 especimes durante o periodo estudado, dos quais 14 especimes sao da fase gametofitica masculina e cinco sao da fase feminina com cistocarpo. A preponderância da fase tetrasporofitica sobre as demais fases e um evento observado em outras especies de Rhodophyta.