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Massive accumulations of invasive brown algae Rugulopteryx okamurae are exacerbating environmental and socio-economic issues on the Mediterranean and potentially Atlantic coasts. These golden tides, likely intensified by global change processes such as changes in wind direction and intensity and rising temperatures, pose increasing challenges to coastal management. This study employs the Normalized Difference Vegetation Index (NDVI), with values above 0.08 from Level-2 Sentinel-2 imagery, to effectively monitor these strandings along the coastline of Los Lances beach (Tarifa, Spain) in the Strait of Gibraltar Natural Park from 2018 to 2022. Los Lances beach is one of the most affected by the R. okamurae bioinvasion in Spain. The analysis reveals that wind direction determines the spatial distribution of biomass accumulated on the shore. The highest average NDVI values in the western patch were observed with south-easterly winds, while in the eastern patch, higher average NDVI values were recorded with south-westerly, westerly and north-westerly winds. The maximum coverage correlates with elevated temperatures and minimal rainfall, peaking between July and October. Leveraging these insights, we propose a replicable methodology for the early detection and strategic pre-shore collection of biomass, which could facilitate efficient coastal cleanup strategies and enhance biomass utility for biotechnological applications. This approach promises cost-effective adaptability across different geographic areas impacted by golden tides. [ABSTRACT FROM AUTHOR]

Field studies are a useful tool to understanding how seaweeds develop protective mechanisms against environmental variation and acclimate to them. These mechanisms can include morphological changes, inhibition of electron transportation rate, pigments and UV-absorbing compounds production. The present paper evaluates the daily cycle of photosynthesis and biochemistry of Plocamium cartilagineum from Spain under varying radiation and temperature conditions. For this purpose, four sites were chosen at La Herradura beach, Spain. Photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) were measured in situ at the sites, and ETRin situ (electron transport rate) as an estimator of photosynthetic capacity was determined. Algal thalli from each site were sampled throughout the day at 09:30, 11:00, 13:00, 15:30, 17:00, 19:30 h, to quantify photosynthetic pigments, UV-photoprotective compounds (i.e. mycosporine-like amino acids, MAAs), and antioxidant capacity. Higher irradiance and temperature at two sites directly influenced ETRin situ. Algae from the site with highest PAR and UV radiation had dynamic photoinhibition when compared to algae from a more shaded site during certain periods of the day. Lower pigment concentrations were observed in algae that received higher irradiances, suggesting photoacclimation. Samples found at the site exposed to the highest ultraviolet-A radiation had the highest concentrations of mycosporine-like amino acids between 15:30 h and 19:30 h. MAAs proportion varied among the sites and during the day. We conclude that environmental conditions in the short-term influenced photosynthetic parameters and the accumulation of pigments and MAAs in P. cartilagineum showing its high physiological plasticity. [ABSTRACT FROM AUTHOR]

Porphyra sensu lato is one of the most economically significant and widely cultured and consumed algae in the world. Porphyra species present excellent nutraceutic properties due to their bioactive compounds (BACs). This research aimed to find the most efficient aqueous extraction method for BACs by examining alkaline and enzymatic hydrolysis. Alkaline hydrolysis with 2.5% sodium carbonate (SC) and at 80 °C proved optimal for extracting all BACs (phycobiliproteins, soluble proteins, polyphenols, and carbohydrates) except mycosporine-like amino acids (MAAs), which were best extracted with water only, and at 80 °C. Enzymatic hydrolysis, particularly with the 'Miura' enzymatic cocktail (cellulase, xylanase, glycoside hydrolase, and β-glucanase), showed superior results in extracting phycoerythrin (PE), phycocyanin (PC), soluble proteins, and carbohydrates, with increases of approximately 195%, 510%, 890%, and 65%, respectively, compared to the best alkaline hydrolysis extraction (2.5% SC and 80 °C). Phenolic content analysis showed no significant difference between the 'Miura' cocktail and 2.5% SC treatments. Antioxidant activity was higher in samples from alkaline hydrolysis, while extraction of MAAs showed no significant difference between water-only and 'Miura' treatments. The study concludes that enzymatic hydrolysis improves the efficiency of BACs extraction in P. linearis, highlighting its potential for the nutraceutical industry, and especially with respect to MAAs for topical and oral UV-photoprotectors. [ABSTRACT FROM AUTHOR]

The potential of seaweed extracts in cosmetic applications have increased with novel development and market. Beneficial biological properties include the ability to struggle aging and anticancer agents. This research aimed to evaluate antioxidant, photoprotective and cytotoxic properties of extracts from beach-cast seaweed species from the Brazilian coast in order to propose an appropriate use of this sustainable resource. Analysis of antioxidant capacity, UV/VIS absorption, quantification of UV photoprotectors, total content of C, N and S, development of cosmetic creams and evaluation of the cytotoxicity activity against tumoral cells lines were performed. The highest antioxidant capacity was found in extracts of brown seaweeds, followed by red seaweeds, with the lowest activity detected in the green seaweed. Same pattern was observed for phenolic compounds. The extracts did not show cytotoxicity activity against healthy human cells. Other forms of extraction and incorporation of the extract into the base creams should be evaluated, the isolation and purification of substances could increase the efficiency of the photoprotective capacity. The species were highly promising and proved to be natural sources of antioxidants and substances with cytotoxicity activity against tumoral cells; therefore, they could be exploited as functional ingredients with specific applications for different types of industries. The application of seaweed extracts in combination with other natural ingredients can help in the design of new cosmetics against the negative effects of UV radiation, in addition to having the great advantage of not presenting toxicity to health or the environment because they are biodegradable. [ABSTRACT FROM AUTHOR]