ABSTRACT
Climate change can be associated with variations in the frequency and intensity of extreme temperatures and precipitation events on the local and regional scales. Along coastal areas, flooding associated with increased occupation has seriously impacted products and services generated by marine life, in particular the biotechnological potential that macroalgae hold. Therefore, this paper analyzes the available information on the taxonomy, ecology and physiology of macroalgae and discusses the impacts of climate change and local stress on the biotechnological potential of Brazilian macroalgae. Based on data compiled from a series of floristic and ecological works, we note the disappearance in some Brazilian regions of major groups of biotechnological interest. In some cases, the introduction of exotic species has been documented, as well as expansion of the distribution range of economically important species. We also verify an increase in the similarities between the Brazilian phycogeographic provinces, although they still remain different. It is possible that these changes have resulted from the warming of South Atlantic water, as observed for its surface in southeastern Brazilian, mainly during the winter. However, unplanned urbanization of coastal areas can also produce similar biodiversity losses, which requires efforts to generate long-term temporal data on the composition, community structure and physiology of macroalgae.
ABSTRACT
Effects of the interaction of irradiance and nutrient levels on growth and contents of photosynthetic pigments, carotenoids and proteins in Gracilaria domingensis (Kütz.) Sonder ex Dickie (Gracilariales, Rhodophyta) were investigated experimentally. Nutrient availability provided by dilutions of the nutrient solution of von Stosch (25 and 50 percent, which corresponded to nitrate concentrations of 125 and 250 μmol, respectively) and two photon flux densities [low PFD (50±5) and high PFD (100±5) μmol photons.m-2.s-1] were tested. Growth rates of G. domingensis were stimulated by high PFD. The interaction between high nutrient availability (50 percent VSES) and high PFD stimulated the accumulation of total soluble protein. Phycobiliprotein concentrations (phycoerythrin, phycocyanin, and allophycocyanin) and carotenoid contents were influenced by irradiance levels. Phycobiliprotein concentrations were higher at low PFD and high irradiances stimulated carotenoid accumulation. These results reflect the function of these pigments in photoprotection and the acclimation of G. domingensis to changes in irradiance levels. Our results indicate that light is a limiting factor for G. domingensis growth, that variations in phycobiliprotein contents under different irradiance levels are related to photoacclimation process, and that higher carotenoid contents at high irradiances are due to a photoprotection mechanism.
ABSTRACT
The aim of this work was to study the cultivation of Gracilaria domingensis in a mussel farming urbanized area in Santa Catarina, Brazil. Relative growth rate was the parameter used to evaluate the cuttings attachment methods on the cultivation rope, cuttings density, cultivation period and cystocarpic versus unfertile thalli performance. The cultivation was feasible only when protected by net cages due to herbivory. The tie-tie attachment method presented the best results. No differences were observed when comparing the cuttings densities and reproductive phase. Future studies should evaluate the cost-effectiveness of producing the species in net cages and its potential as biofilter.
ABSTRACT
Foram coletadas amostras de algas marinhas de 19 espécies (sendo 4 pertencentes ao filo Chlorophyta, 5 ao filo Phaeophyta e 10 ao filo Rhodophyta) em dois locais do litoral catarinense. Os extratos etanólicos foram submetidos ao teste de letalidade para larvas de Artemia salina com objetivo de realizar uma triagem das espécies. Dos 26 extratos testados, 25 apresentaram toxicidade significativa em pelo menos uma das 3 concentrações testadas. O grupo de algas vermelhas (Rhodophyta) foi o que obteve maior porcentagem de extratos com resultados estatisticamente significativos pelo método do qui-quadrado e também menores valores de CL50, com destaque para Acanthophora spicifera, Hypnea musciformis e Pterocladiella capillacea. Observaram-se diferenças entre as espécies de um mesmo gênero (Codium decorticatum e Codium isthmocladium) e também a influência de fatores ambientais (Hypnea musciformis) na toxicidade dos extratos.
Samples of 19 macroalgae species (4 Chlorophyta, 5 Phaeophyta and 10 Rhodophyta) have been collected from two points of Santa Catarina's coast. The ethanolic extracts were avaluated with the brine shrimp assay in order to perform a screening for potential toxicity. A total of 25 extracts presented significant results in one or more of the tested concentrations. The phylum Rhodophyta presented more statistically significant results with the chi-square test, as well as lower values of LC50. The extracts of Acanthophora spicifera (from Canasvieiras and Ilha do Francês), Hypnea musciformis and Pterocladiella capillacea (both from Ilha do Francês) presented LC50 below 50 mg/mL. Differences between the species of same genus (Codium decorticatum and Codium isthmocladium) and the influence of environmental factors (Hypnea musciformis) were observed.
ABSTRACT
O efeito antioxidante de quatro espécies de algas marinhas do filo Chlorophyta (Codium decorticatum, Enteromorpha intestinalis, Ulva fasciata e Chaetomorpha anteninna) foi avaliado através da inibição da peroxidação do ácido linoléico em emulsão. Os extratos etéreos e metanólicos, na concentração de 0,01 por cento, foram obtidos por extração seqüencial das biomassas secas. As espécies mais efetivas sobre a peroxidação lipídica foram Enteromorpha intestinalis e Chaetomorpha anteninna, com porcentagens de inibição acima de 70 por cento. A habilidade dos extratos metanólicos para seqüestrar o peróxido de hidrogênio foi avaliada, obtendo-se valores médios para porcentagens de captura entre 1,26 por cento e 20,01 por cento...