Phycology, Volume 5, Issue 3 (September 2025) – 7 articles

Cyanobacteria (also called blue-green algae)-based dietary supplements are commonplace, but cyanobacteria-enhanced foods, such as spirulina crackers, are just appearing on New Zealand supermarket shelves. While much research has been devoted to consumer attitudes towards macro-algae-based products, little research has been devoted to micro-algae-based or cyanobacteria-enhanced consumer products. The current study, following the Capability–Opportunity–Motivation to Behaviour theory, examines likely consumer drivers of favouring or disfavouring spirulina crackers. These drivers include food neophilia, food neophobia, perception of sustainability and health-related product attributes, involvement with algae and an exploratory driver, snacking behaviour. Fully supported drivers (related to increased favour and decreased disfavour) included food neophilia and perception of sustainability and health-related product attributes. Algae involvement was only related to increased favour, and food neophobia was not supported. Surprisingly, snacking behaviour was related to increased disfavour of spirulina crackers. Both theoretical and managerial implications are offered. Full article

The demand for sustainable animal production is increasing. Microalgae such as Chlorella and Spirulina show promise as sustainable and functional ingredients in animal (poultry) feed. However, little is known about consumer perceptions regarding the use of algae in broiler diets and potential effects of algae on chicken meat. Residents of Flanders (Belgium) were surveyed to evaluate consumer knowledge, attitudes and willingness to buy chicken meat produced with algae-supplemented feed. Demographic data were collected, and both descriptive and inferential statistics were applied to assess influencing factors (n = 275 respondents who purchase chicken meat). While most respondents (69.6%) had tasted macroalgae (seaweed), only 11.4% and 24.6% indicated having tasted Chlorella and Spirulina before, respectively. Health, taste and safety were the most important drivers for consuming algae. Meat quality was the most important factor when purchasing chicken meat, while organic production was least valued. Regarding algae-fed chicken, 72.5% expressed willingness to purchase meat labeled as such, and 83.7% would buy algae-fed chicken regardless of its color. Sustainability beliefs significantly influenced willingness to accept a yellower meat color (β = 0.42 to 0.66, p < 0.001). Educational level and age also played a role, with higher-educated consumers showing greater acceptance. The influence of age was also related to the price of the meat, with consumers over 30 expressing a greater willingness to pay more than young people (under 30). Despite limited general knowledge about microalgae, the consumers surveyed are open to the idea of algae-fed chicken meat, particularly when it is framed as more sustainable. Clear ingredient labeling and consumer education may further support market acceptance. Full article

High ash content in algal biomass limits its suitability for biofuel production by reducing combustion efficiency and increasing fouling. This study presents a green deashing strategy using nitrilotriacetic acid (NTA) and deionized (DI) water to purify Scenedesmus algae, which was selected for its high ash removal potential. The optimized sequential treatment (DI, NTA chelation, and DI+NTA treatment at 90–130 °C) achieved up to 83.07% ash removal, reducing ash content from 15.2% to 3.8%. Elevated temperatures enhanced the removal of calcium, magnesium, and potassium, while heavy metals like lead and copper were reduced below detection limits. CHN analysis confirmed minimal loss of organic content, preserving biochemical integrity. Unlike traditional acid leaching, this method is eco-friendly after three cycles. The approach offers a scalable, sustainable solution to improve algal biomass quality for thermochemical conversion and supports circular bioeconomy goals. Full article

Salinity serves as a critical environmental factor influencing the physiological and morphological characteristics of Spirulina, a filamentous cyanobacterium used for food production and commercial purposes. This study examined a Spirulina strain’s responses to different salinity levels (10–45 ppt) through three independent laboratory experiments that determined growth, productivity, and size structure. Growth across salinity treatments was assessed by monitoring optical density in 24-well microplates over 20 days and estimating specific growth rates using a logistic growth model. Primary productivity under different salinity and light conditions was measured using light and dark bottle experiments to calculate gross primary productivity (GPP) and to estimate photosynthetic efficiency through linear regression of GPP against light intensity. The size structure was assessed through tube-based experiments and image analysis, with organism sizes categorized and analyzed to identify salinity-induced patterns in filament structure. The study demonstrated that the Spirulina strain achieved its greatest growth at 10 ppt yet produced the highest photosynthetic efficiency between 27 and 45 ppt because it reallocated energy during salinity stress. The morphological analysis revealed that the Spirulina strain produced medium-sized filaments between 400 and 799 µm at elevated salinity levels, and our analysis confirmed substantial variations in size structure. The Spirulina strain demonstrates both physiological and morphological plasticity when exposed to salinity changes. The cultivation of the Spirulina strain at 27 ppt provides conditions that support moderate growth, enhanced productivity, and manageable morphological shifts while using its natural salinity tolerance to improve the efficiency and scalability of production for diverse biotechnological applications. Full article

Conservation units (CUs) play a fundamental role in maintaining and conserving biodiversity, and are important in preserving streams, reducing impacts from human activities and increasing water availability beyond the boundaries of the reserves. However, knowledge about the phytoplankton biodiversity of ecosystems in CUs is scarce. This study evaluated how environmental integrity alters microphytoplankton communities in extractive CUs and their surroundings in the southwestern Brazilian Amazon. Our results demonstrated that the streams exhibited distinct physicochemical and hydrological characteristics, representing spatially heterogeneous environments. Differences in habitat integrity values altered species composition in streams within and outside conservation units. Local beta diversity (LCBD) was negatively influenced by habitat integrity, indicating that sites with greater habitat integrity did not always present a greater number of unique species. The species Trachelomonas hispida, Gyrosigma scalproides and Spirogyra sp. were the ones that contributed the most to beta diversity. However, the phytoplankton species that contributed most to beta diversity were not always associated with streams with greater integrity, indicating that even environments that are less intact play a relevant role in maintaining species richness and beta diversity of microphytoplankton. Factors such as habitat integrity, pH, temperature and dissolved oxygen were the main influencers of microphytoplankton in the streams. Thus, the streams of both CUs and their surroundings, despite their physical–chemical and hydrological differences, effectively contribute to the high richness and beta diversity of regional microphytoplankton. Full article

The nutrient-rich composition of seaweeds and lichens makes them well-suited for agricultural applications. Their use as alternatives to synthetic fertilizers contributes to sustainable agricultural production, enabling farmers to adopt ecological practices while maintaining or increasing crop productivity. This review aims to highlight the status and trends of research, along with a literature analysis on the application of these biomasses in sustainable agriculture. A bibliometric analysis was performed based on two databases (Scopus and Web of Science) to overview the main research topics regarding the use of biomasses studied in agriculture, thus providing useful information for future research. The biochemical composition and agricultural applications of these biomasses have been highlighted. The analysis shows that these biomasses are rich of nutrient compounds, revealing their roles and mechanisms of action on the chemical, nutritional properties, and soil microbial activities and their effect on plant growth, using various extraction and application methods. It also highlighted the potential of seaweeds for protection against biotic and abiotic stresses. In light of all the data presented in this review, it is possible to stimulate farmers’ interest in using seaweeds and lichens as natural fertilizers, with a focus on sustainable and ecological agriculture mainly in developing countries. Full article

Bangiales are photosynthetic organisms that grow in the intertidal zone, a region characterized by fluctuating environmental conditions. The order comprises genera exhibiting two different morphological variations, filamentous and foliose. It was recently demonstrated that the filamentous alga ‘Bangia’ sp. ESS1 possesses the intrinsic ability to “memorize” an experience of prior heat stress to enhance its survival under subsequent, normally lethal, high-temperature conditions via the acquisition of heat stress tolerance. Here, we investigated whether foliose red algae can similarly memorize heat stress to acquire thermotolerance. When Pyropia yezoensis thalli were primed with non-lethal, high-temperature treatments (22 and 25 °C) for 7 days, vegetative cells subsequently triggered with a normally lethal temperature of 30 °C showed dramatically increased survival rates, indicating that P. yezoensis can acquire heat stress tolerance via exposure to non-lethal high temperatures. In addition, when 22 °C-primed thalli were incubated at 15 °C for recovery, vegetative cells survived subsequent incubation at 30 °C; their survival rates varied depending on the duration of recovery. These findings indicate that, like filamentous red algae, the foliose species P. yezoensis memorizes heat stress to acquire tolerance to recurrent thermostress. The identification of heat stress memory in foliose Bangiales lays a foundation for improving the heat stress tolerance of these important algae, supporting the sustainability of the nori mariculture industry. Full article