Phycology, Volume 5, Issue 4 (December 2025) – 39 articles

Alaska’s kelp farming industry is expanding, with Alaria marginata (ribbon kelp) emerging as a promising crop. This species is valued for its food-grade applications, yet little is known about its cultivation performance. We tested the effects of five line-spacing treatments (0.31–1.83 m) on blade phenotype and yield under farmed conditions. Wider spacings produced longer, wider, and thicker blades. Sporophytes at 1.23 m and 1.83 m spacings were most likely to exceed 200 cm in length, while most blades were half that length for treatments closely spaced. Yield per meter was lowest at 0.31 m spacing (~2 kg m⁻¹) but exceeded 3 kg m⁻¹ in all wider treatments, with 1.23 m and 1.83 m spacings showing a probability of producing 6 kg or more. Results aligned with those of other kelp studies assessing line spacing on kelp performance. This work highlights the importance of aligning cultivation practices with market demands for either biomass or blade quality. The study was limited to one site and one growing season. Nonetheless, findings provide an initial framework for optimizing A. marginata cultivation in Alaska. Full article

This study describes the results of integrative analysis of cyanobacterial communities in waterbodies of Moscow, Russia. 16S rRNA V3–V4 metabarcoding and light microscopy are implemented to investigate the diversity, abundance, and distribution of cyanobacteria, including the representatives of potentially toxigenic taxa—Anabaena, Aphanizomenon, Dolichospermum, Microcystis, and Planktothrix. High convergence is observed between microscopy and metabarcoding data for dominant genera, including Microcystis and Planktothrix. Sequence verification reveals total (100%) similarity between previously isolated toxigenic strains (e.g., Microcystis aeruginosa CBMC403m and CBMC523m) and corresponding highly abundant ASVs. In addition, current study ascertains the efficiency of metabarcoding for detection of rare cyanobacterial taxa missed by microscopy. We hereby acknowledge the limitations of V3–V4 16S rRNA-based metabarcoding approach for region species-level resolution and distinguishing potentially toxigenic taxa of cyanobacteria. At the same time, our findings validate metabarcoding as a rapid and reliable tool for monitoring of CyanoHABs in urban water ecosystems. Full article

Coastal lagoons are recent geological formations, crucial biodiversity hot-spots, and fragile ecosystems which provide several ecosystem services. These areas are strongly affected by nutrient inputs, which can lead to eutrophication and algal blooms. We identified nine Italian coastal lagoons with a surface area greater than 10 km². Most of them were previously classified in a poor ecological condition. Therefore, we used remote sensing, in particular Sentinel-2 images, to assess the trophic state of these areas over time from 2015 until 2025. Automatic products of chlorophyll-a (Chl-a), total suspended matter (TSM), and water transparency (kd_z90max) were derived. Chl-a concentrations indicated predominantly eutrophic conditions, ranging from 0.44 (Mare Piccolo) to 80.81 mg·m⁻³ (Comacchio). Comacchio and Cabras showed persistently high Chl-a values and low transparency, while Mare Piccolo was characterized by high transparency and oligotrophic conditions. Varano and Cabras showed a significant increase in Chl-a (p < 0.05) coupled with an increase in TSM (p < 0.01) and decline in transparency in Varano (p < 0.05). Most other lagoons showed no long-term trends but remained in eutrophic–hypereutrophic states. Therefore, the Italian coastal lagoons studied are vulnerable areas to environmental degradation. Many of the lagoons showed persistent eutrophic conditions and no long-term recovery trends. However, among the lagoons, there were heterogeneous ecological conditions, ranging from oligotrophic (Mare Piccolo) to chronically hypereutrophic (Comacchio, Cabras). Water clarity was mainly affected by suspended solids; however, in some cases, there was a key role in primary production (algal blooms). Sentinel-2 data proved effective for monitoring spatial and temporal variability in coastal lagoon water quality, offering a valuable tool for environmental management and early detection of degradation trends. Full article

The Gulf of Mexico is a marginal sea recognized as one of the world’s Large Marine Ecosystems. It is characterized by significant climate variability that influences phytoplankton communities. In this paper we investigated the phytoplankton assemblages in the Campeche Canyon, located in the Southern Gulf of Mexico, during a “Nortes” storm season. Additionally, we assessed the role of hydrographic conditions and circulation patterns in species distribution. The assessment was based on in situ observations collected during a multidisciplinary research cruise conducted in February 2011. High-resolution hydrographic data were gathered using a CTD sonde, and water samples were collected at various depths for phytoplankton cell analysis. The findings revealed a deep thermocline at a depth of 90 m, with a deep chlorophyll-a maximum (DCM) occurring below 75 m. The circulation pattern in the area was dominated by a dipole eddy, consisting of both cyclonic and anticyclonic movements, which created strong currents at the edges. The species composition varied by depth; a total of 77 species were identified in the surface waters, while the DCM exhibited a richness of 81 species. In the surface waters, dinoflagellates were the most abundant group, comprising 41 species, whereas diatoms were more prevalent in the DCM, with 44 species identified. In terms of abundance, dinoflagellates were more prevalent at both depths, with concentrations reaching up to 12,000 cells L⁻¹. The most abundant species identified included the ciliate Mesodinium rubrum, the cyanobacteria Trichodesmium hildebrandtii, the diatoms Asteromphalus cleveanus and Pseudo-nitzschia multistriata, the dinoflagellates Lingulaulax polyedra and Blepharocysta denticulata, and the silicoflagellate Dictyocha fibula. Analysis of the horizontal distribution patterns of phytoplankton species revealed that species tend to aggregate in areas with strong currents. These findings enhance our understanding of phytoplankton dynamics in the Campeche Canyon, particularly during climatic seasons when in situ observations are limited due to challenging navigation conditions caused by “Nortes” storms. Full article

The overview of charophytes in Bosnia and Herzegovina has been updated after 35 years through a revision of existing specimens in the BEOU Charophyte Collection, verification and listing of known vouchers in other herbarium collections, and a detailed review of the available literature covering the period from 1848 to 2024. According to all available data, 18 species and three genera of charophytes are found in 122 sites in Bosnia and Herzegovina. Chara papillosa Kütz. and C. subspinosa Rupr. are newly reported species in Bosnia and Herzegovina. Chara vulgaris L., C. contraria A. Braun ex Kütz., C. globularis Thuill., C. gymnophylla (A. Braun) A. Braun, and C. squamosa Desf. are the most frequently recorded. The Dinaric Mountains mixed forests are the most representative and species-rich ecoregion. Most charophytes were recorded before 1930 and after 1980, with a clear discrepancy between the sites documented in these periods. Bosnia and Herzegovina has the lowest charophyte species richness compared to neighbouring countries. We strongly encourage further revision of available collections and continued systematic field research, which will enable the preparation of the Red List and the formal protection of species and habitats. Full article

Conventional petroleum-based protective coatings release high levels of volatile organic compounds (VOCs) and contribute to resource depletion, urging the development of environmentally responsible alternatives. Among the bio-based candidates, microalgae and Cyanobacteriophyta have recently gained attention for their ability to produce diverse biopolymers and pigments with intrinsic protective functionalities. However, existing literature has focused mainly on algal biofuels and general biopolymers, leaving a major gap in understanding their application as sustainable coating materials. This review addresses that gap by providing the first integrated assessment of algae-based protective coatings. It begins by defining abiotic and biotic surface degradation mechanisms, including microbiologically influenced corrosion, to establish performance benchmarks. The review then synthesizes recent findings on key algal components, including alginate, extracellular polymeric substances (EPS), and phycocyanin, linking biochemical composition to functional performance, techno-economic feasibility, and industrial scalability. It evaluates their roles in adhesion strength, UV stability, corrosion resistance, and antifouling activity. Reported performance metrics include adhesion strengths of 2.5–3.8 MPa, UV retention above 85% after 2000 h, and corrosion rate reductions of up to 40% compared with polyurethane systems. Furthermore, this study introduces the concept of carbon-negative, multifunctional coatings that simultaneously protect infrastructure and mitigate environmental impacts through CO₂ sequestration and pollutant degradation. Challenges involving biomass variability, processing costs (>USD 500/ton), and regulatory barriers are critically discussed, with proposed solutions through hybrid cultivation and biorefinery integration. By bridging materials science, environmental engineering, and sustainability frameworks, this review establishes a foundation for transforming algae-based coatings from laboratory research to scalable, industrially viable technologies. Full article

Non-geniculate crustose coralline algae (NCA) are important in algal reef ecosystems, yet their physiological responses to turbidity and sediment burial remain insufficiently understood. We examined how six turbidity levels (0–300 mg L⁻¹) and four sediment deposition depths (0–3 cm) affected two dominant species, Sporolithon sp. and Phymatolithon sp. Under turbidity treatments, for Sporolithon sp., Fv/Fm was lowest at 0 mg L⁻¹ (0.43 ± 0.01) and highest at 250 mg L⁻¹ (0.62 ± 0.01). ETRmax increased markedly under 150 mg L⁻¹ (17.94 ± 0.27) but declined under 300 mg L⁻¹ (5.33 ± 0.19). In Phymatolithon sp., turbidity levels of 150–250 mg L⁻¹ produced consistently higher Fv/Fm values (0.58–0.60) and the lowest ETRmax occurred at 300 mg L⁻¹ (5.71 ± 0.34). Sediment burial caused strong early reductions in photosynthetic performance. In Sporolithon sp., all burial depths except 0 cm caused significant Fv/Fm declines within five days (decrease to 0.46). After 45 days, ETRmax ranged from 9.28 ± 0.38 at 0 cm to 4.02 ± 0.11 at 3 cm, with intermediate values at 1 and 2 cm. Phymatolithon sp. showed rapid declines in Fv/Fm at all depths (1 to 3 cm) before partial recovery after 15–20 days. Overall, moderate turbidity (150–250 mg L⁻¹) provided protective light attenuation, whereas sediment deposition imposed strong early physiological stress. The contrasting responses of the two species highlight different adaptive strategies for surviving low-light and sediment-rich environments. Full article

Due to the scarcity of sustainable inputs for photosynthetic microorganisms’ biotechnology, the search for natural substrates such as coconut water has gained prominence. This by-product is a substrate rich in macro- and micronutrients, as well as endogenous phytohormones that support microbial growth. In this context, this study aimed to use it as an alternative cultivation medium for Limnospira platensis (Gomont), formerly known as Arthrospira platensis, a high-value cyanobacterium. We evaluated growth parameters, phycocyanin concentration, purity, and biomass yield cultivated in coconut water and in SAG_1x medium, a modified Zarrouk medium. Over 35 days of cultivation, both media efficiently supported cyanobacterial growth. In coconut water, the specific growth rate was 0.305 d⁻¹, the maximum growth rate was 0.629 d⁻¹, and the productivity was 0.256 g L⁻¹ d⁻¹. In SAG_1x medium, the values obtained were 0.240 d⁻¹, 0.676 d⁻¹, and 0.218 g L⁻¹ d⁻¹, respectively. Phycocyanin obtained from cultivation in SAG_1x medium presented food-grade purity (OD620/OD280 ratio > 0.7), while in coconut water, it was 0.6. The pigment concentration and yield in SAG_1x (19.1 mg/L and 34.3%, respectively) also slightly exceeded those obtained with coconut water (14.3 mg/L and 25.5%, respectively). Despite this, the data reinforce the potential of coconut water as a viable and economically competitive alternative to conventional media for L. platensis production. Full article

The agro-industrial sector in Indonesia produces significant amounts of nutrient-rich waste and wastewater, which pose environmental risks but also present opportunities for valorization within a circular bioeconomy. Microalgae provide a promising solution for transforming these wastewaters into valuable products such as biomass for bioenergy, biofertilizers, or pigments, all while helping to remediate pollutants. This review synthesizes current knowledge on the use of major Indonesian agro-industrial effluents, specifically palm oil mill effluent (POME), byproducts from cassava and sugarcane, and soybean residues, as substrates for microalgal biomass production and cultivation. Furthermore, various cultivation strategies are summarized, including autotrophic, heterotrophic, and mixotrophic methods, as well as the use of open ponds, photobioreactors, and hybrid systems. These cultivation processes influence biomass yield, metabolite production, and nutrient removal. Reported studies indicate high removal efficiencies for organic loads, nitrogen, and phosphorus, along with considerable production of lipids, proteins, pigments, and biofuels. Yet, effluent pretreatment, concerns about heavy metal and pathogen contamination, high downstream processing costs, and biosafety issues remains as challenges. Nonetheless, the application of microalgal cultivation into Indonesia’s agro-industrial wastes treatment can provide the dual benefits of waste mitigation and resource recovery, helping to advance climate goals and promote rural development. Full article

Marine algal polysaccharides (MAPs) are multifunctional biopolymers with significant potential in biomedical applications. Derived from brown, red, and green algae, key examples include alginate, agar, carrageenan, fucoidan, ulvan, and laminarin. Their structural diversity underlies a broad range of biological activities, particularly among sulfated polysaccharides, which exhibit antiviral, anticancer, anticoagulant, immunomodulatory, and antioxidant effects. Owing to their biocompatibility and tunable physicochemical properties, MAPs are also valuable in wound healing, tissue regeneration, and drug delivery. Advances in ultrasound-, microwave-, and enzyme-assisted extraction methods have enhanced yield and functionality. This review combines structural, extraction, and biomedical views on MAPs, with a focus on how molecular characteristics relate to their potential as drugs. Future work should focus on scalable green extraction, molecular-level characterization, and clinical validation to develop MAPs-based biomaterials for next-generation drug delivery, wound healing, and tissue engineering. Full article

Massive strandings of holopelagic Sargassum cause major ecological and economic problems, but its conversion into bioproducts offers a sustainable alternative. This study assessed the potential of holopelagic Sargassum (S. fluitans and S. natans) collected in the Caribbean as ecofriendly insecticides against the whitefly Bemisia tabaci, a major pest of tomato crops. Extracts were produced using green methods: ultrasound-assisted extraction (UAE) and ultrasound-assisted enzymatic hydrolysis (UAEH) with enzymes cocktails. Biochemical analyses revealed high mineral and polysaccharide contents, varying with the extraction technique. Extracts were tested at 1–6% (w/v) using clip-cage (adults) and leaf-dip (eggs) methods. All extracts reduced adult survival, with UAE and UAEH-P/C extracts achieving over 50% mortality at ≥4% concentration after 48 h (LD₅₀: 3.9–4.5%). Egg mortality was significant only with UAE and UAEH-P extracts at 6% (LD₅₀: 1.9–2.8%). These results suggest insecticidal activity through both ingestion and cuticle/embryo disruption. Although enzymatic extraction did not markedly enhance biochemical yields, extracts showed, for the first time, promising biocidal and ovicidal properties. This research highlights holopelagic Sargassum as a renewable source of natural insecticidal compounds, supporting sustainable management of both invasive algal biomass and agricultural pests. Full article

In July–August 2024, a severe dystrophic process occurred in the Orbetello lagoon (Italy). This study reports the following: (1) the macroalgal biomass and the sediment labile organic matter (LOM) between 2018 and 2024; (2) the water temperature and dissolved oxygen values between June and September 2024 and the T-mean, T-max, and T-min in July and August between 2013 and 2024; (3) the list of microphyte taxa that occurred during the dystrophy; (4) satellite images documenting the evolution of the dystrophic process. The results suggest that the dystrophy was caused by the decay of a large macroalgal mass and high accumulations of LOM in the sediment, which triggered anaerobic processes, particularly intense sulphate-reductive activity. This virulent process was facilitated by a record increase in temperatures (with T-min and T-max higher than those of the previous years), in a context of poor hydrodynamics, typical of non-tidal lagoons. Microphyte blooms, which occurred during the dystrophy, were at the basis of the evolution of the phenomenon, allowing for the most critical phase to be overcome through intense oxygen production. Microphytic blooms, with intense water colouring, although constituting an evident sign of a eutrophic/hypertrophic state of the lagoon, could lead to a rapid evolution of the dystrophy and mitigate the environmental conditions. Full article

Many cyanobacteria synthesize cyanophycin, a nitrogen-rich amino acid polymer with metabolic engineering and biomanufacturing potential. In non-diazotrophic cyanobacteria, cyanophycin serves as a source of nitrogen under nitrogen stress conditions. However, the role of these storage granules in diazotrophic cyanobacteria, which fix nitrogen on demand, is yet to be understood. The enzyme cyanophycin synthetase, encoded by cphA, synthesizes cyanophycin from the amino acids aspartate and arginine. We probed the consequences of the inability to synthesize cyanophycin on the physiology of a nitrogen-fixing unicellular cyanobacterium, Cyanothece sp. ATCC 51142, by generating a markerless cphA deletion strain (∆cphA) using CRISPR/Cpf1. Under continuous high light and N₂-fixing conditions, the ∆cphA strain exhibited a growth defect and phycobilisome degradation, implying nitrogen starvation. Interestingly, under low light conditions, the nitrogen starvation phenotype was not observed. This suggests a critical role for the nitrogen storage bodies in maintaining an optimal cellular carbon/nitrogen balance, especially when the cellular nitrogen fixing machinery cannot match high levels of carbon fixation. Thus, when photosynthetic efficiency is high, the cyanophycin storage granules act as a readily available nitrogen source that ensures optimal metabolism and growth. This study illustrates the essential role of cyanophycin when engineering unicellular nitrogen-fixing cyanobacteria for use as production chassis. Full article

A growing body of evidence indicates that freshwater bodies, particularly eutrophic systems, are significant sources of the greenhouse gases (GHGs) carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). Unlike marine environments, freshwater systems are generally shallower and more directly influenced by terrestrial inputs, including nutrient enrichment, organic matter deposition, and steep redox gradients in both the water column and sediments. These conditions promote intense phytoplankton growth, including massive harmful cyanobacterial blooms (HCBs), and stimulate microbial processes that drive GHG production and release. This opinion article examines the biogeochemical mechanisms underlying these emissions and evaluates the potential of mitigation treatments to both enhance carbon sequestration and reduce CH₄ and N₂O emissions. We argue that effective control of HCBs, whether through nutrient load reduction or direct mitigation protocols, would not only provide communities with toxin-free water but also significantly lower GHG emissions from eutrophic waterbodies. As this is an opinion paper rather than a comprehensive review, we intentionally avoided citing widely accepted concepts, since doing full justice to the many excellent contributions across all relevant subfields would not be possible within the scope of this work. Full article

Chlorella is a valuable object of biotechnology with high productivity of biomass and metabolites. The use of Chlorella for CO₂ binding in autotrophic metabolism is also discussed. Various types of stress are used to increase the yield of valuable metabolites. One of the effective approaches may be dark stress. However, there is insufficient data to fully understand the effect of dark stress on productivity, biochemical parameters, the antioxidant system, and the rate of CO₂ fixation by Chlorella during the transfer from autotrophic culture to aphotic conditions. To study these processes, we used two-step cultivation. In the second step, the biomass was grown for 96 h on a BBM medium under standard lighting and in aphotic conditions. According to the results of the study, the metabolic systems of the studied strain of Chlorella sp. CAMU G–145 specifically react to cultivation under aphotic conditions. The greatest response was found in lipid–protein metabolism and the antioxidant defense system, which determines an increase in the overall antioxidant status of cells. At the same time, productivity, CO₂ absorption characteristics, and pigment composition of the photosynthetic system did not change after 96 h of darkening. In general, this approach is a promising strategy for increasing biotechnological productions efficiency. Full article

Biohydrogen is considered to be one of the fuels of the future, so there is a justified need to find efficient and cost-effective technologies for its production. This study evaluated the efficiency of two biohydrogen production pathways, specifically biophotolysis and dark fermentation, using Tetraselmis subcordiformis biomass. Microalgae production was performed in three variants, where the separation criterion was the type of culture medium: a control sample (synthetic medium; V1–PCR), agricultural wastewater from hydroponic tomato cultivation (V2–SL-WW), and effluent from a microbial fuel cell (V3–MFC-WW). The highest increase in biomass of T. subcordiformis was obtained in V2–SL-WW—2730 ± 212 mg VS/L, which was also associated with the maximum chlorophyll a content (65.0 ± 5.1 mg Chl-a/L). In biophotolysis, the highest specific hydrogen yields were obtained in V1–PCR (55.3 ± 4.3 mL/g VS) and V2 (54.3 ± 3.7 mL/g VS). The total hydrogen production in these variants was 166 ± 13 mL (V1–PCR) and 163 ± 11 mL (V2–SL-WW), respectively. The average H₂ production rate reached 4.70 ± 0.33 mL/h in V2–SL-WW, and the rate constant (k) was 0.030–0.031 h⁻¹. In anaerobic fermentation, the highest total and specific H₂ production was obtained in V1–PCR, 453 ± 31 mL and 45.3 ± 3.1 mL/g VS, respectively. The qualitative composition of the biogas confirmed a high hydrogen content: 61.4% (biophotolysis, V1) and 41.1% (dark fermentation, V2–SL-WW). The results obtained confirm that T. subcordiformis can be effectively cultivated on waste media and that the biohydrogen production maintains a high technological efficiency through both photolytic and fermentative mechanisms. The medium from hydroponic tomato cultivation (V2–SL-WW) proved to be particularly promising, as it combines high biomass productivity with a satisfactory biohydrogen production profile. Full article

Postharvest operations are cost intensive in microalgae production, and when electrocoagulation–electroflotation (EC/EF) with aluminum anodes is used, aluminum can remain associated with biomass and wash streams; hence, a selective postwash process is needed. Accordingly, this study defined an operational window for aluminum desorption that preserves the energetic advantage of EC/EF. A response-surface design (I-optimal/CCD) was used to evaluate the effects of the EDTA concentration (1–100 mM), contact time (5–20 min), mixing speed (100–300 rpm), and pH (6–10) on EC/EF-harvested Chlorella sp. biomass, with ANOVA and model diagnostics supporting adequacy. EDTA concentration and mixing emerged as significant factors, whereas time and pH acted mainly through interactions; moreover, quadratic terms for EDTA and mixing indicated diminishing returns at high levels. Consequently, the surface predicted an optimum near EDTA ≈ 65 mM, time ≈ 20 min, pH 10, and 100 rpm, corresponding to ~97% aluminum removal. Importantly, a confirmation run under these conditions across eight chlorophyte strains consistently achieved >95% removal, revealing narrow dispersion yet statistically distinguishable means. Taken together, coupling EC/EF with an EDTA postwash operation in the identified window effectively limits aluminum carry-over in microalgal biomass and, therefore, provides a reproducible basis for downstream conditioning and potential recirculation within biorefinery schemes. Full article

This study assesses the ecological conditions of the Colentina urban river system by investigating phytoplankton community traits, with a focus on resource use efficiency (RUE) as a functional indicator. Using phytoplankton biomass, taxonomic composition, and RUE, we assessed the ecological effects of anthropogenic pressures. Our results showed that total phosphorus values indicated chronic eutrophication conditions but supported increased phytoplankton biomass, especially in spring and summer. RUE varied independently of biomass, with maximum values recorded in autumn, suggesting a functional recovery phase, characterized by higher RUE under nutrient decline. The analysis at the phytoplankton group level highlighted distinct ecological strategies: cyanobacteria presented a high RUE in autumn, diatoms increased their efficiency during nutrient limitation periods, and green algae showed a functional flexibility throughout the study period. In contrast, spatial analyses indicated a decoupling between biomass and RUE, reflecting the influence of local environmental conditions on ecosystem functioning. RUE was significantly influenced by total phosphorus, nitrogen forms, temperature and light availability. Our results strengthen the combined approach of structural (biomass) and functional (RUE) indicators for the assessment of communities and anthropogenic impacts in urban and peri-urban aquatic ecosystems. Full article

Water pollution is a growing concern for aquatic ecosystems worldwide, with threats like plastic waste, nutrient pollution, and oil spills harming biodiversity and impacting human health, fisheries, and local economies. Traditional methods of monitoring water quality, such as ground sampling, are often limited in how frequently and widely they can collect data. Satellite imagery is a potent tool in offering broader and more consistent coverage. This review explores how Multispectral Imagery (MSI) and Synthetic Aperture Radar (SAR), including polarimetric SAR (PolSAR), are utilised to monitor harmful algal blooms (HABs) and other types of aquatic pollution. It looks at recent advancements in satellite sensor technologies, highlights the value of combining different data sources (like MSI and SAR), and discusses the growing use of artificial intelligence for analysing satellite data. Real-world examples from places like Lake Erie, Vembanad Lake in India, and Korea’s coastal waters show how satellite tools such as the Geostationary Ocean Colour Imager (GOCI) and Environmental Sample Processor (ESP) are being used to track seasonal changes in water quality and support early warning systems. While satellite monitoring still faces challenges like interference from clouds or water turbidity, continued progress in sensor design, data fusion, and policy support is helping make remote sensing a key part of managing water health. Full article

The Yamuna River, among India’s most polluted waterways, is burdened by industrial, agricultural, and domestic discharges containing complex organic and inorganic contaminants. This study introduces a novel, integrated approach combining comprehensive pollutant profiling by liquid chromatography–mass spectrometry (LC-MS) with bioremediation using laboratory-validated native algal consortia. Water samples from a severely polluted Delhi stretch revealed alarming levels of heavy metals (e.g., lead: 47.33 mg/L) and over 550 organic pollutants, including polychlorinated biphenyls, dioxins, carcinogens, and neurotoxins. Two consortia, each assembled from indigenous algal strains, were evaluated under controlled conditions against both pollutant-rich water and non-polluted controls. Consortium 1 (Scenedesmus, Chlorococcum, Oocystis) outperformed Consortium 2 (Chlorella, Klebsormidium, Monoraphidium), achieving up to 87.07% reduction in lead and >95% removal of nitrate and phosphate, alongside substantial decreases in chemical and biological oxygen demand. By integrating high-resolution chemical analytics with native microbial remediation, this work provides the first demonstration of simultaneous removal of diverse pollutant classes in Yamuna water. The findings establish native algal consortia as cost-effective, sustainable bioremediation tools and underscore LC-MS as a critical method for holistic aquatic pollution assessment. Full article

Macroalgae have low nutrient bioavailability, often requiring pretreatments—physical, chemical, or biological—typically using low-solid loading hydrolysis, which produces separate liquid and solid phases. In contrast, high-solid loading hydrolysis offers a single-phase alternative, though it remains underexplored for macroalgae. This study evaluated the effectiveness of high-solid loading hydrolysis for breaking polysaccharides and increasing the availability of nutrients and antioxidant compounds in Codium tomentosum. Treatments using mixtures containing 25% dry biomass and 75% water or 0.5N and 1N NaOH, autoclaved for 30 or 60 min, were performed. Among the tested treatments, high-solid loading alkaline autoclaved treatment (1N NaOH, 60 min) was most effective in reducing neutral detergent fiber and enhancing the availability of bioactive compounds, particularly soluble proteins and phenols. Based on these results, a sequential enzymatic hydrolysis with Natugrain^® at 0.2 and 0.4% was also applied to pre-treated C. tomentosum with water or 1N NaOH. Enzymatic hydrolysis after autoclaving had no major effect on fiber, soluble protein, or ash, but increased phenol levels. In conclusion, high-solid loading alkaline treatment (1N NaOH) followed by enzymatic hydrolysis with Natugrain^® enzyme reduced fiber content and enhanced soluble protein and phenolic compounds, thereby improving the nutritional and functional potential of C. tomentosum for inclusion in animal feeds. Full article

The study focuses on the phylogeny and systematics of the order Mastogloiales sensu Cox. Results of a two-gene (18S rRNA and rbcL) molecular analysis on the order demonstrate that genera Aneumastus, Decussiphycus, Mastogloia, and Stigmagloia form a closely related phylogenetic group, while Achnanthes and Craspedostauros belong to a different evolutionary lineage. Heterogeneity is also expressed in the difference in morphological features, including the structure of pore occlusions. Combining molecular and morphological data, we hereby amend the description of the order Mastogloiales and describe new types of pore occlusions, typical for the order. Using our material from freshwater and saline waterbodies in China, Indonesia, Mongolia and Vietnam, we illustrate the diversity and ultrastucture of pore occlusions. As a part of morphological analysis, Mastogloia recta is studied with SEM and TEM for the first time. In addition, our study reveals a new species of the genus Aneumastus from Mongolia—Aneumastus khovsgolensis sp. nov.—which was subjected to molecular and morphological investigations using light and scanning electron microscopy. This new species is compared to similar taxa of the Aneumastus tusculus-group. Full article

Herbaria, originally books of medicinal plants, became collections of dried plants after 1500, later extending to seaweeds and supporting taxonomy and systematics. Digitalization has made herbaria accessible, and advances in DNA sequencing have transformed them into valuable resources for genetic research. Label data, which include place and date of collection, make exsiccata essential tools for biogeographic studies and conservation strategies, helping map biodiversity and protect endangered species. The historical Pierpaoli herbarium (MBMP) houses 584 seaweed specimens collected from the Ionian and Adriatic seas between 1920 and 1965. It has been digitized within the NPRR Project ITINERIS and the DiSSCo infrastructure. Floristic changes in the Mar Piccolo over three periods (1920–2024) and the Mar Grande (1920–1992) were compared using herbarium specimens, papers, and recent data. Mar Piccolo’s flora over a century revealed significant changes. Many historical species disappeared, while new ones appeared, including 14 non-indigenous species. The biogeographical composition also shifted, with Cosmopolitan and Indo-Pacific elements increasing. In the Mar Grande, less than half the species were found again in 1992. Evidently, phytobenthic communities underwent noticeable changes over a century, highlighting the impact of environmental shifts. This confirms that Natural Science Collections are invaluable resources for understanding our planet’s biodiversity and history. Full article

Codium tomentosum is a native green seaweed of high ecological and commercial interest along the Atlantic coast of Portugal. Although recently introduced into aquaculture via vegetative propagation, its cultivation remains limited. Production still relies primarily on wild-harvested biomass, including the supply of starting material for aquaculture. Understanding the species’ reproductive biology, particularly the timing of sexual reproduction, is important to support sustainable biomass production and reduce pressure on wild populations. In this context, the present study aimed to assess the seasonal reproductive pattern of a natural C. tomentosum population from the Aguçadoura shore (Northern Portugal). The reproductive status of C. tomentosum was assessed monthly between September 2020 and August 2022. Gametogenesis was initiated in summer, with gametangia persisting through autumn and winter, followed by a marked reduction or complete absence in spring, coinciding with thallus regression observed in the field. Male and female gametangia differed significantly in length (247.34 ± 36.22 µm and 288.70 ± 28.39 µm, respectively). Fertile individuals, yielding viable gametes, were identified between August and March across the years. Male gametes measured 4.32 ± 0.46 µm in length, and female gametes were significantly larger (19.42 ± 0.40 µm). This study confirms that C. tomentosum exhibits a well-defined reproductive period on the Northern Portuguese coast, extending from late summer to early spring. These findings are expected to contribute to the responsible management of natural populations and guide strategies for the collection of starting material, ultimately ensuring the long-term sustainable production of this species. Full article

An unknown species of the diatom genus Ulnaria was identified during the study of freshwater environments in Mongolia. Monoclonal strains of the unknown species were obtained and subjected to molecular analysis. The strains were investigated through light and scanning electron microscopy, coupled with molecular analysis of SSU rRNA and rbcL gene sequences. The features of sexual reproduction of the cultured specimens were studied, and traits previously unknown to representatives of Ulnaria were demonstrated. Based on the results of morphological comparison against similar species from the Ulnaria ulna species complex and data from the two-gene molecular analysis, a description of Ulnaria williamsii sp. nov. was provided. Analysis of the features of sexual reproduction—gametogenesis, the mating system, and gamete movement—allowed us to discuss the species dispersion and evolution within the genus Ulnaria. Full article

Mycosporine-like amino acids (MAAs) are multifunctional, UV-absorbing and antioxidant metabolites produced by marine algae, offering promising applications in biotechnology and dermocosmetic sciences. In this study, MAAs were sustainably extracted from nori seaweed (Porphyra spp.) using an ultrasound-assisted aqueous method, an eco-friendly approach that ensures efficiency and industrial scalability. Chromatographic enrichment followed by MALDI-TOF mass spectrometry confirmed the presence of bioactive compounds, including porphyra-334, palythine, and myc-ornithine. The enriched fraction exhibited potent antioxidant activity (low IC₅₀ in DPPH and ABTS assays) and significant anti-elastase effects, highlighting its potential as a natural anti-aging agent. To optimize delivery, MAAs were incorporated into a stable water-in-oil nanoemulsion, which maintained droplet sizes below 400 nm and a low polydispersity index (PDI < 0.2) for up to four months. A randomized, double-blind clinical study in 20 volunteers further demonstrated that the MAA-based nanoemulsion significantly improved skin hydration (+53.6%) and reduced transepidermal water loss (TEWL), confirming its humectant and barrier-strengthening efficacy. These findings position Porphyra spp. as a sustainable marine resource for producing MAAs, and demonstrate their practical potential as natural, multifunctional ingredients in eco-conscious cosmetic and pharmaceutical formulations. Full article

Microcystis aeruginosa, a kind of cyanobacterium, can lead to water blooms under specific conditions and it is harmful to human and ecological security due to the toxins produced by certain strains. Artemisinin, which is derived from Artemisia annua Linn, has a strong allelopathic effect on algae. Artesunate is a water-soluble derivative of artemisinin. We investigated the effect of artesunate on M. aeruginosa, including growth and key photosynthetic parameters (Fv/Fm, φPSII). Our findings demonstrate that artesunate inhibits the growth of M. aeruginosa by damaging the photosynthetic center of photosystem II (PS II), and this inhibitory effect is enhanced with increasing concentration. At the concentration of 200 mol/L, the maximum inhibition rate was 41.62% for FACHB-315 and 43.19% for FACHB-927 after 96 h. After 24 h of exposure, the φPSII of the two strains decreased significantly (p < 0.01). These results could inform further studies on the use of artesunate to control cyanobacterial growth in water bodies and provide theoretical support for the application of artemisinin derivatives in treating water blooms. Full article

The growing demand for sustainable bioprocesses highlights microalgae as a promising source of renewable feedstock. However, high energy use for artificial lighting limits the commercial viability of photobioreactor systems. This study proposes an energy-optimized framework for cultivating Mychonastes homosphaera using LED illumination. The optimization was performed using Response Surface Methodology (RSM) with a Face-Centered Central Composite Design (FCCCD) to assess the interactive effects of light intensity, duration, airflow rate, and nitrogen concentration on biomass and lipid productivity. The performance of LED wavelengths was compared for biomass, lipid productivity, and energy consumption. RSM models were statistically significant (p < 0.01), and ANOVA had a high coefficient of determination (R²) for all LEDs. Maximum biomass productivity was 512.0 ± 12.23 mg L⁻¹ day⁻¹ with cool-white, followed by pink (401.33 ± 10.48), blue (342.66 ± 3.53), and red (189.6 ± 1.36). Cool-white consumed the least energy (228.6 Wh day⁻¹) to produce the maximum biomass, compared to blue (235.05 Wh day⁻¹), pink (240.0 Wh day⁻¹), and red (240.0 Wh day⁻¹). Lipid content was highest under red (22.84%), followed by pink (17.39%), blue (15.82%), and cool-white (8.96%). However, lipid productivity was highest under pink (69.8 mg L⁻¹ day⁻¹), followed by blue (54.2 mg L⁻¹ day⁻¹), cool-white (45.86 mg L⁻¹ day⁻¹), and red (43.3 mg L⁻¹ day⁻¹). Full article

Clay minerals and other flocculants are used to mitigate the effects of some species that produce harmful algal blooms due to their physical and chemical characteristics. In this study, we applied calcium bentonite clay (Bca) and zeolite (Ze) to flocculate and remove cells of the dinoflagellate Gymnodinium catenatum (Graham), a producer of paralyzing toxins. The flocculants were characterized by scanning electron microscopy (SEM) in combination with an energy-dispersive X-ray spectroscopy (EDS) microanalysis system. During experiments, Bca and Ze were suspended in distilled water, deionized water, and seawater at concentrations of 0.25, 0.5, 1.0, 1.5, 2.0, 2.5, and 4.0 gL⁻¹. The percentage of removal efficiency (RE%) of biomass indicators of G. catenatum was calculated. The cell number and concentration of chlorophyll a and peridinin were analyzed using high-performance liquid chromatography (HPLC-UV and HPLC-DAD). The external effects on cells of G. catenatum were recorded. As a result, the maximum RE% of Bca was 79% with respect to the total number of cells, chlorophyll a was 69% and peridinin of 73%. The RE% of Ze was less than 40%. In the matrix of sedimented Bca, malformation of cells was observed, inhibiting their swimming, as well as death and rupture of cells with temporary cyst formation after 72 h. We conclude that Bca, suspended in deionized and distilled water, was more efficient in flocculating cells of G. catenatum. Full article

The beneficial effects of algae on plant growth are widely known, so the combination of coconut fiber with algae waste from a species such as Caulerpa prolifera, which is an invasive species in the Mar Menor, could become an ideal substrate for leafy vegetable cultivation. The aim of this study was to evaluate the effect of an “algae waste + coconut fiber” combination in different proportions on the cultivation of iceberg lettuce. The proportions studied consisted of 0% algae waste + 100% coconut fiber (0% AW), 50% algae waste + 50% coconut fiber (50% AW), 75% algae waste + 25% coconut fiber (75% AW), and 100% algae waste + 0% coconut fiber (100% AW). Physiological parameters were evaluated. The results obtained showed that the mixture of algae waste and coconut fiber is a great alternative in the production of iceberg lettuce, since the proportion of 50% AW considerably improved the size of the lettuce (54.4%), the total phenol concentration (24.8%), the antioxidant activity (28.2%), the total sugars (14.1%) and reduced its nitrate concentration (24.6%), with respect to the 0% AW plants. These findings support the feasibility of reusing Caulerpa prolifera as a bio-enriched substrate for high-quality lettuce production. Full article