Eurico C. Oliveira

PHYLOGENY AND SYSTEMATICS OF THE MARINE ALGAL FAMILY GRACILARIACEAE (GRACILARIALES, RHODOPHYTA) BASED ON SMALL SUBUNIT rDNA AND ITS SEQUENCES OF ATLANTIC AND PACIFIC SPECIES1

We sequenced the small subunit rDNA and internal transcribed spacer region of Gracilariaceae from the tropical Atlantic and Pacific, with emphasis on flattened or compressed species. Sequence comparisons confirmed three main lineages of Gracilariaceae: Curdiea/Melanthalia, Gracilariopsis/Gracilariophila, and Gracilaria. The Curdiea/Melanthalia diverged early in the family. Gracilariopsis was paraphyletic, because at least one Gracilariophila species evolved from it. The Atlantic Gracilariopsis were monophyletic and separated from the Pacific lineages. The Gracilaria included all species referable to its own species and to Hydropuntia, which was paraphyletic, formed by distantly related lineages. The new combination Gracilaria pauciramosa (N. Rodríguez Ríos) Bellorin, M. C. Oliveira et E. C. Oliveira is proposed for Polycavernosa pauciramosa N. Rodríguez Ríos. Recognition of subgenera within Gracilaria, based on spermatangial arrangement, was not supported. Instead, infrageneric groups were delineated by geographic origins and combinations of reproductive characters. Most Pacific species with either “textorii” or “verrucosa” type spermatangia were deeply separated from Atlantic species. Within the Atlantic Gracilaria, a lineage encompassing mostly tropical cylindrical species with “henriquesiana” type spermatangia and distinctive cystocarp anatomy was recognized. A lineage was also retrieved for cold water stringy species with verrucosa type spermatangia. Several species from the western Atlantic are closely related to Gracilaria tikvahiae McLachlan with nearly identical morphology. On the other hand, most flattened species from the tropical Atlantic were closely related despite their diverse morphologies. The interpretation of our data in addition to the literature indicates that more populations from the Indo‐Pacific must be studied before a general picture of Gracilariaceae evolution can be framed.

Gracilaria vermiculophylla: A western Pacific species of Gracilariaceae (Rhodophyta) first recorded from the eastern Pacific

We report Gracilaria vermiculophylla (Ohmi) Papenfuss from the Pacific coast of North America based on a morphoanatomical revision and comparison of sequences of the nuclear gene coding for the small subunit of ribosomal RNA and the internal transcribed spacers of populations from Baja California, Mexico and Hiroshima, Japan. It is the first convincing report of this species out of its center of distribution in western north Pacific, where it has been considered as a synonym of former ‘G. verrucosa’ records. G. vermiculophylla also occurs in central California as indicated by internal transcribed spacer sequences of a previously unknown Gracilaria Greville material. In the northeastern Pacific G. vermiculophylla is characterized by a robust somewhat vermiform, well‐branched cylindrical thallus, with gradual cell size transition from cortex to medulla, deep spermatangial conceptacles, regular chains of carposporangia and carposporangial initials, downwardly oriented tubular nutritive cells, but rarely with upwardly oriented tubular nutritive cells. In some features of its cystocarp anatomy G. vermiculophylla is related to Gracilariopsis E. Y. Dawson or Hydropuntia Montagne and it is a relevant species for discussions about Gracilariaceae genera.

Fungal community associated with marine macroalgae from Antarctica

Filamentous fungi and yeasts associated with the marine algae Adenocystis utricularis, Desmarestia anceps, and Palmaria decipiens from Antarctica were studied. A total of 75 fungal isolates, represented by 27 filamentous fungi and 48 yeasts, were isolated from the three algal species and identified by morphological, physiological, and sequence analyses of the internal transcribed spacer region and D1/D2 variable domains of the large-subunit rRNA gene. The filamentous fungi and yeasts obtained were identified as belonging to the genera Geomyces, Antarctomyces, Oidiodendron, Penicillium, Phaeosphaeria, Aureobasidium, Cryptococcus, Leucosporidium, Metschnikowia, and Rhodotorula. The prevalent species were the filamentous fungus Geomyces pannorum and the yeast Metschnikowia australis. Two fungal species isolated in our study, Antarctomyces psychrotrophicus and M. australis, are endemic to Antarctica. This work is the first study of fungi associated with Antarctic marine macroalgae, and contributes to the taxonomy and ecology of the marine fungi living in polar environments. These fungal species may have an important role in the ecosystem and in organic matter recycling.

Mariculture of the Agar-Producing Gracilarioid Red Algae

ABSTRACT The gracilarioid red algae (Gracilaria, Gracilariopsis, and Polycavernosa) are the basis of a worldwide, multimillion-dollar industry, mainly associated with the production of agar, a commercially useful polysaccharide. Much of the current production comes from mariculture, and there have been numerous advances in research and cultivation in recent years. This review summarizes recent advances in the cultivation of gracilarioid algae in tanks, ponds, and in the sea (bottom planting and suspended cultivation) and compares those techniques. The main constraints to cultivation are discussed, including nutrient supply, epiphytes, grazers, and diseases. Further advances are predicted to depend on effective domestication of the wild plants, strain selection, and the commercialization of integrated cultivation with animals.

Mass cultivation of the agar-producing alga Gracilaria chilensis (Rhodophyta) from spores

Abstract Gracilaria chilensis has been extensively cultivated in Chile by means of vegetative propagation. This method consists of outplanting pieces of thalli, which are anchored by several methods to muddy or sandy substrata at densities of about 1 kg (wet weight) m −2 . Here we describe a new technique for mass cultivation of Gracilaria on ropes inoculated with spores. The paper describes: (i) induction of sporulation and fixation on polypropylene ropes; (ii) evaluation of spore settlement on the ropes; (iii) incubation of the germlings in tanks with agricultural fertilizers and (iv) outplanting of the ropes with plantlets to a pilot stand of about 5000 m 2 in an estuary in Central Chile. The technique will allow the establishment of a commercial farm using the stock of spores contained in 30–40 kg cystocarpic Gracilaria chilensis ha −1 , compared with the 10000 kg of seaweed necessary for planting 1 ha using the traditional methodology.

Chemical screening of Brazilian marine algae producing carrageenans

The yield, IR spectra, 3,6-anhydro-d-galactose and sulfate content are given for several species of putative carrageenophytes from different sites on the Brazilian coast. Kappa carrageenan was found in Hypnea musciformis and Gigartina spp. ; all the other species tested yield an iota type. The lowest carrageenan yield was found in Cryptonemia crenulata (5%), and the highest in Gigartina sp. (72%); 3,6-anhydrogalactose content was highest in Hypnea musciformis and Gigartina spp., whereas sulfate was lowest in H. musciformis. Slight variations in the yield of carrageenans were found during the period of observation (March 1988 to May 1989), but no clear pattern could be recognized. No significant variation was observed in plants from different collection sites.

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.

The seaweed flora of Admiralty Bay, King George Island, Antarctic

Admiralty Bay is located on the western side of King George Island. Although several research teams of different nationalities have carried out surveys in the region for decades, there are only two publications dealing with the seaweed flora of the bay. Here, we report on a taxonomic survey of the seaweeds we collected during the 25th Brazilian Antarctic Expedition (December 2006/November 2007). We discovered 42 species (21 Rhodophyta, 14 Phaeophyceae, and 7 Chlorophyta), corresponding to an increase of about 31% in the seaweed biodiversity hitherto known for the region. Considering that the Antarctic Peninsula, adjacent to King George Island seems to be one of the most rapidly warming spots on the planet, this kind of survey may provide a valuable tool for detecting eventual changes in seaweed biodiversity.

Temperature responses of economically important red algae and their potential for mariculture in Brazilian waters

Data are presented on temperature responses, based onin vitro growth performance, of eight species of colloid-producing red algae; these include the five most important commercial species of agarophytes in South America. The temperature optima do not conform strictly to geographic distribution, and intolerance to high temperature is not the factor that controls the spreading of temperate species ofGracilaria to warmer areas. WithinPterocladia capillacea (Gmelin) Bornet et Thuret, populations from two distinct localities had different responses to temperature optima. Data suggest that the disjunct distribution of this species in the American Atlantic is due to its poor performance at temperatures above 26 °C. The fastest maximum growth rate was observed inHypnea cornuta (Lamouroux) J. Agardh (doubling time 2.8 d), and the slowest inP. capillacea from Cabo Frio (doubling time 50.0 d). All the species studied, including the valuable Chilean and Argentinean species ofGracilaria, could tolerate the temperature regimes of the Brazilian waters.