RESUMO
Given the ecological and biogeochemical importance of rhodolith beds, it is necessary to investigate how future environmental conditions will affect these organisms. We investigated the impacts of increased nutrient concentrations, acidification, and marine heatwaves on the performance of the rhodolith-forming species Lithothamnion crispatum in a short-term experiment, including the recovery of individuals after stressor removal. Furthermore, we developed an ecological niche model to establish which environmental conditions determine its current distribution along the Brazilian coast and to project responses to future climate scenarios. Although L. crispatum suffered a reduction in photosynthetic performance when exposed to stressors, they returned to pre-experiment values following the return of individuals to control conditions. The model showed that the most important variables in explaining the current distribution of L. crispatum on the Brazilian coast were maximum nitrate and temperature. In future ocean conditions, the model predicted a range expansion of habitat suitability for this species of approximately 58.5% under RCP 8.5. Physiological responses to experimental future environmental conditions corroborated model predictions of the expansion of this species' habitat suitability in the future. This study, therefore, demonstrates the benefits of applying combined approaches to examine potential species responses to climate-change drivers from multiple angles.
Assuntos
Ecossistema , Rodófitas , Brasil , Mudança Climática , Humanos , TemperaturaRESUMO
Absorption spectra are indicative of biological sample chemical composition and can be used as a basis for the construction of descriptive and predictive models for biotechnological screening or assays. In marine algae, chemical composition can vary due to species-specific differences in biochemistry, as well as intra-specific responses to unique environmental variables. Different indices (UVCi, UVB+Ai and PARi) were proposed and calculated to evaluate how photoprotective compounds vary in 18 species of Phaeophyceae. In addition, they were correlated to abiotic factors. Through this technique, seven main peaks were detected in the absorbing spectra of marine brown algal extracts. The highest photoprotective indices values were found in species collected in tropical areas, where higher solar radiation is observed compared to the southern Brazilian coast. Considering additional abiotic factors, water temperature and nitrate concentration were negatively correlated with UV indices. PARi's indices were positively affected by nitrate. All species collected on the Brazilian coast have absorption peaks in the region of phenolic compounds and carotenoids, suggesting that tropical marine brown macroalgae may have developed an effective antioxidant defense system, suggesting adaptation to environments characterized by high solar radiation. UVR/PAR indices congregated essential information to possible future biotechnological screening, facilitating selection of high priority species or sites, fostering actions to enhance alternative sustainable management strategies of coastal environments.
Assuntos
Absorção de Radiação , Phaeophyceae/química , Protetores contra Radiação/química , Alga Marinha/química , Raios Ultravioleta , BrasilRESUMO
Analysis of the marine red algal species Mastocarpus papillatus (C. Agardh) Kützing using paired-end 36 bp Illumina sequences resulted in the assembly of its complete mitochondrial and plastid genomes. The mitogenome is 25,906 bp in length and contains 50 genes, and the plastid genome is 184,382 bp with 234 genes. The mitochondrial and plastid genomes show high gene synteny with published Florideophyceae.