Effects of environmental parameters on macroalgae Gracilaria domingensis: acclimation and photoprotection strategy on specie

Em seu habitat natural as algas estão sujeitas a ação simultânea de vários fatores, como radiação (fotossinteticamente ativa e ultravioleta), temperatura, salinidade e disponibilidade de nutrientes, entre outros. A variação desses fatores no ambiente natural ocorre de forma coletiva e uma rápida resposta do organismo é determinante pra sua sobrevivência. Neste trabalho foram conduzidos experimentos relacionados aos efeitos da variação nos parâmetros ambientais sobre a macroalga Gracilaria domingensis. Três linhagens cromáticas dessa espécie foram cultivadas no mar, em diferentes épocas do ano (estações chuvosa e seca). Os dados fotossintéticos e bioquímicos foram acessados em uma escala de tempo referente às variações observadas durante o período de luz do dia e em uma escala referente às variações observadas em semanas. Os resultados obtidos a partir de análises dos parâmetros fotossintéticos, conteúdo pigmentar, concentração de glutationa, concentração de aminoácidos tipo micosporina, conteúdo tecidual de carbono, nitrogênio e fósforo, teor de lipídeos e ácidos graxos e rendimento do ágar mostraram alterações no perfil bioquímico e fisiológico da macroalga. Essas alterações foram correlacionadas com os fatores abióticos e sugerem alterações no metabolismo como uma das estratégias de aclimatação da espécie.In their natural habitat algae are exposed to simultaneous action of various factors, as radiation (photosynthetically active radiation and ultraviolet), temperature, salinity, nutrient availability and others. The variation in these factors in the natural environment occurs collectively and the algae capability for quick response is determinant for survival. In this work, studies related to the effects of environmental variation on the macroalgae Gracilaria domingensis were performed. Three chromatic strains were cultivated in the sea, at different times of the year (dry and rainy seasons). Biochemical and photosynthetic responses were accessed on a daylight time scale and on a week time scale. The reached results for photosynthetic parameters, pigment content, glutathione concentrations, mycosporine-like amino acids concentrations, carbon, nitrogen and phosphorus tissue content, lipids and fatty acids levels and agar yield, revealed the altered biochemical and physiological profile of macroalgae. These changes were environment related and suggest metabolism changes as a strategy used by this organism to acclimate

Seasonal changes in the pigment composition of natural population of Gracilaria domingensis (Gracilariales, Rhodophyta)

The concentrations of phycobiliproteins (phycoerythrin and phycocyanin), chlorophyll-a and total soluble proteins were determined monthly in three strains (red, green and brown) of Gracilaria domingensis (Kützing) Sonder ex Dickie, collected from natural populations on the coast of Rio Grande do Norte, Brazil. In all the strains, pigment and protein concentrations were higher in the months of less sunlight and greater nitrogen availability and decreased gradually with increased sunlight and decreased nutrient concentration. The red strain showed higher concentrations of phycoerythrin and total soluble proteins. The difference in the concentration of biochemical components over the course of the year indicates species acclimation to different environmental conditions

Cultivation of three color strains of Gracilaria domingensis in an integrated organic system

Abstract Species of the genus Gracilaria are widely distributed around the world, and many are wild harvested and cultivated for phycocolloid production (agar) and human food. This study investigated the growth performance of three color strains of Gracilaria domingensis in an integrated organic system. The three chromatic variants (red, green, and brown) were cultured in a shrimp farm at two depths (surface and 20 cm). The highest relative growth rates were obtained in the first week of cultivation for all three strains studied. Although the growth rates and biomass were slightly higher at a depth of 20 cm, significant differences were not observed at different depths (p < 0.05). The growth of the three strains varied significantly over time (p < 0.001). The maximal growth values obtained were 11.25 ± 1.50% day−1 (red), 12.76 ± 3.96% day−1 (green), and 7.86 ± 1.75% day−1 (brown). The mean growth rates for the whole period were 4.63 ± 6.97, 3.38 ± 9.09, and 2.16 ± 6.61% day−1 for the red, green, and brown strains, respectively. The pigment content (chlorophyll a, phycocyanin, and phycoerythrin) of the three strains studied was higher at a depth of 20 cm, while the maximum electron transport rate (ETRmax) and photosynthetic efficiency were higher at the surface. The high growth rates obtained in this study demonstrate the great potential of this species for integrated organic farming. Moreover, the ecological success shown by the red strain suggests that this strain is the most suitable for integrated cultivation