José Marcos de Castro Nunes

Coastal urbanization leads to remarkable seaweed species loss and community shifts along the SW Atlantic

Coastal urbanization is rapidly expanding worldwide while its impacts on seaweed communities remain poorly understood. We assessed the impact of urbanization along an extensive latitudinal gradient encompassing three phycogeographical regions in the SW Atlantic. Human population density, number of dwellings, and terrestrial vegetation cover were determined for each survey area and correlated with diversity indices calculated from seaweed percent cover data. Urban areas had significantly lower calcareous algal cover (-38%), and there was significantly less carbonate in the sediment off urban areas than off reference areas. Seaweed richness averaged 26% less in urban areas than in areas with higher vegetation cover. We observed a remarkable decline in Phaeophyceae and a substantial increase of Chlorophyta in urban areas across a wide latitudinal gradient. Our data show that coastal urbanization is causing substantial loss of seaweed biodiversity in the SW Atlantic, and is considerably changing seaweed assemblages.

The impact of coastal urbanization on the structure of phytobenthic communities in southern Brazil

The anthropogenic pressures on coastal areas represent important factors affecting local, regional, and even global patterns of distribution and abundance of benthic organisms. This report undertakes a comparative analysis of the community structure of rocky shore intertidal phytobenthos in both pristine like environments (PLE) and urbanized environments (UBE) in southern Brazil, characterizing variations on different spatial scales. Multivariate analysis of variance indicated that the PLE is characterized by a larger number of taxa and an increased occurrence of Rhodophyta species in relation to UBE. In contrast, UBE were dominated by opportunistic algae, such as Cladophora and Ulva spp. Significance tests further indicated higher species richness and Shannon-Wiener diversity on the PLE in relation to UBE. Here we provide data showing the magnitude of seaweed biodiversity loss and discuss direct and indirect consequences of unplanned urbanization on these communities.

Phylogeny of Gracilariaceae (Rhodophyta): evidence from plastid and mitochondrial nucleotide sequences.

Gracilariaceae are mostly pantropical red algae and include ~230 species in seven genera. Infrafamilial classification of the group has long been based on reproductive characters, but previous phylogenies have shown that traditionally circumscribed groups are not monophyletic. We performed phylogenetic analyses using two plastid (universal plastid amplicon and rbcL) and one mitochondrial (cox1) loci from a greatly expanded number of taxa to better assess generic relationships and understand patterns of character distributions. Our analyses produce the most well‐supported phylogeny of the family to date, and indicate that key characteristics of spermatangia and cystocarp type do not delineate genera as commonly suggested. Our results further indicate that Hydropuntia is not monophyletic. Given their morphological overlap with closely related members of Gracilaria, we propose that Hydropuntia be synonymized with the former. Our results additionally expand the known ranges of several Gracilariaceae species to include Brazil. Lastly, we demonstrate that the recently described Gracilaria yoneshigueana should be synonymized as G. domingensis based on morphological and molecular characters. These results demonstrate the utility of DNA barcoding for understanding poorly known and fragmentary materials of cryptic red algae.

BENTHIC MARINE ALGAE OF THE CORAL REEFS OF BRAZIL: A LITERATURE REVIEW

In Brazil, algae in coral reef environments can be found from Maranhao to Bahia State and there are today around 700 taxa, of which 78% are found on reef formations. The Rhodophyta are among the most common taxa found. Corallinales are the least studied group, in spite of their role in the formation and maintenance of Brazilian coral reefs. The species richness of algae on coral reefs is low in comparison with other coastal habitats, but there is an abundance of turf and fleshy macroalgae on certain parts of the coastal reefs. Halimeda spp., Dictyota spp., Dictyopteris spp., Hypnea spp., Gracilaria spp., Gelidium spp. and Sargassum spp. are some of the most conspicuous algae, while Caulerpa and Udotea and seagrasses are frequently found on unconsolidated sandy bottoms. Benthic marine algae are important components of shallow coral-reef communities in the Atlantic and they can be regarded as major competitors to corals. Over the last two decades, numerous cases of phase shifts from coral to algal predominance over coral reefs were reported worldwide. These reports coincide with the increasing concern with reef degradation, mainly attributed to anthropogenic nutrient enrichment and overfishing. In Brazil the effects of nutrification over coral reef dynamics are only recently being assessed, and crucial basic information is still lacking. The exploitation of marine algae, mainly of Gracilaria, is also recent in Brazil. Macroalgae growth in some disturbed Brazilian reefs were associated with grazing reduction caused by overfishing or nutrification. Rapid assessments of coral reef flora are needed in order to generate reliable information for environmental

Novas referências de rodofíceas marinhas bentônicas para o litoral brasileiro

Seven taxa of benthic marine rodophytes are reported for the first time from the Brazil littoral: Acrochaetium corymbiferum (Thur. in Le Jolis) Batters, A. liagorae Borgesen, Aglaothamnion herveyi (M. Howe) Aponte, D.L. Ballant. & J.N. Norris, Crouanophycus latiaxis (L.A. Abbott) Athanas., Grallatoria reptans M. Howe and Gelidiella sanctarum Feldmann & Hamel. Gelidiopsis repens (Kutz.) Weber Bosse this is the new reference to the Atlantic Ocean. The material collected on mediolittoral and infralittoral was deposited in the Herbarium Alexandre Leal Costa (ALCB) at the Universidade Federal da Bahia. Reference to the original description, basionym, morphological description, geographical distribution and taxonomical comments are presented for each taxon studied.

Species delimitation and phylogenetic analyses of some cosmopolitan species of Hypnea (Rhodophyta) reveal synonyms and misapplied names to H. cervicornis, including a new species from brazil

Hypnea has an intricate nomenclatural history due to a wide pantropical distribution and considerable morphological variation. Recent molecular studies have provided further clarification on the systematics of the genus; however, species of uncertain affinities remain due to flawed taxonomic identification. Detailed analyses coupled with literature review indicated a strong relationship among H. aspera, H. cervicornis, H. flexicaulis, and H. tenuis, suggesting a need for further taxonomic studies. Here, we analyzed sequences from two molecular markers (COI‐5P and rbcL) and performed several DNA‐based delimitation methods (mBGD, ABGD, SPN, PTP and GMYC). These molecular approaches were contrasted with morphological and phylogenetic evidence from type specimens and/or topotype collections of related species under a conservative approach. Our results demonstrate that H. aspera and H. flexicaulis represent heterotypic synonyms of H. cervicornis and indicate the existence of a misidentified Hypnea species, widely distributed on the Brazilian coast, described here as a new species: H. brasiliensis. Finally, inconsistencies observed among our results based on six different species delimitation methods evidence the need for adequate sampling and marker choice for different methods.

Coleção de microalgas de ambientes dulciaquícolas naturais da Bahia, Brasil, como potencial fonte para a produção de biocombustíveis: uma abordagem taxonômica

O presente trabalho envolveu a identificacao taxonomica de especies nativas de microalgas (isoladas de ecossistemas dulciaquicolas localizados nos arredores de Salvador, Bahia) integrantes da Colecao de Microalgas dulciaquicolas do LABIOMAR/IB/UFBA, visando estudos taxonomicos mais aprofundados (ultraestruturais e moleculares) e experimentos que possam avaliar sua capacidade para suprir cadeias produtivas de biocombustiveis. As coletas foram realizadas nos arredores de Salvador, Bahia, Brasil. A identificacao das especies foi efetuada com base em caracteres morfologicos. Foram identificados 19 taxons, 12 em nivel de especie e nove em nivel de genero, sendo 14 Chlorophyceae (Chlamydomonas sp1, Chlamydomonas sp2, Chlamydomonas sp3, Chlamydocapsa bacillus (Teiling) Fott, Chlorococcum sp1, Chlorococcum sp2), Coelastrum indicum Turn.. Coelastrum microporum Nageli, Desmodesmus brasiliensis (Bohl.) Hegew, Scenedesmum obliquus (Turpin) Kutz, Ankistrodesmus falcatus (Corda) Ralfs, Ankistrodesmus fusiformis Corda, Kirchneriella lunaris (Kirchner.) Mobius, Pseudokirchneriella subcapitata (Korshikov) F. Hindak), tres Trebouxiophyceae (Botryococcus braunii Kutz., Botryococcus terribilis Komarek et Marvan e Chlorella vulgaris Beijerinck), uma Bacillariophyceae (Nitzschia sp.) e uma Cyanobacteria (Synechocystis sp.).

Aportación al conocimiento fenológico de las rodofíceas marinas de la playa de Guarajuba (Camaçari, Bahia) Brasil

LUCIO, A. M. & NUNES, J. M. DE C. 2002. Aportacion al conocimiento fenologico de las rodoficeas marinas de la playa de Guarajuba (Camacari, Bahia) Brasil. Bot. Complutensis 26: 17-34. En el estudio de las rodoficeas marinas bentonicas de la playa de Guarajuba fueron identificadas 41 especies. Para el presente trabajo fueron realizados analisis fenologicos, de habitat, frecuencia, estacionalidad y de epifitismo. La region frontal del arrecife y la plataforma arrecifal fueron las regiones de mayor riqueza en especies, con 35 y 30 especies, respectivamente. El genero mejor representado fue Gracilaria, con 6 especies. De las especies estudiadas, un 70% presentaron estructuras reprodutivas, y las algas tetrasporicas fueron las mas frecuentes. En general, Guarajuba presento mas ejemplares fertiles que la orla oceanica de Salvador. Gelidium torulosum Kutzing constituye en nueva cita para el Estado de Bahia y Petroglossum undulatum C.W. Schneider para el litoral del nordeste de Brasil.

Morphology and phylogeny of Prorocentrum caipirignum sp. nov. (Dinophyceae), a new tropical toxic benthic dinoflagellate

A new species of toxic benthic dinoflagellate is described based on laboratory cultures isolated from two locations from Brazil, Rio de Janeiro and Bahia. The morphology was studied with SEM and LM. Cells are elliptical in right thecal view and flat. They are 37-44μm long and 29-36μm wide. The right thecal plate has a V shaped indentation where six platelets can be identified. The thecal surface of both thecal plates is smooth and has round or kidney shaped and uniformly distributed pores except in the central area of the cell, and a line of marginal pores. Some cells present an elongated depression on the central area of the apical part of the right thecal plate. Prorocentrum caipirignum is similar to Prorocentrum lima in its morphology, but can be differentiated by the general cell shape, being elliptical while P. lima is ovoid. In the phylogenetic trees based on ITS and LSU rDNA sequences, the P. caipirignum clade appears close to the clades of P. lima and Prorocentrum hoffmannianum. The Brazilian strains of P. caipirignum formed a clade with strains from Cuba, Hainan Island and Malaysia and it is therefore likely that this new species has a broad tropical distribution. Prorocentrum caipirignum is a toxic species that produces okadaic acid and the fast acting toxin prorocentrolide.

Delimitating cryptic species in the Gracilaria domingensis complex (Gracilariaceae, Rhodophyta) using molecular and morphological data.

Species in the genus Gracilaria that display conspicuously flattened vegetative morphologies are a taxonomically challenging group of marine benthic red algae. This is a result of their species richness, morphological similarity, and broad phenotypic plasticity. Within this group, the Gracilaria domingensis complex is one of the most common, conspicuous, and morphologically variable species along the tropical western Atlantic Ocean. Previous research has identified that members of this complex belong to two distantly related clades. However, despite this increased phylogentic resolution, species delimitations within each of these clades remain unclear. Our study assessed the species diversity within this difficult complex using morphological and molecular data from three genetic markers (cox1, UPA, and rbcL). We additionally applied six single‐marker species delimitation methods (SDM: ABGD, GMYCs, GMYCm, SPN, bPTP, and PTP) to rbcL, which were largely in agreement regarding species delimitation. These results, combined with our analysis of morphology, indicate that the G. domingensis complex includes seven distinct species, each of which are not all most closely related: G. cervicornis; a ressurected G. ferox; G. apiculata subsp. apiculata; a new species, Gracilaria baiana sp. nov.; G. intermedia subsp. intermedia; G. venezuelensis; and G. domingensis sensu stricto, which includes the later heterotypic synonym, G. yoneshigueana. Our study demonstrates the value of multipronged strategies, including the use of both molecular and morphological approaches, to decipher cryptic species of red algae.