Search Results (44)

Evaluating the bathymetric distribution of phytobenthic communities is essential for understanding the factors affecting habitat heterogeneity along a depth gradient. In the present study, we investigated the composition and vertical zonation patterns of phytobenthic communities across different bottom types (rocky and sedimentary) along the Turkish Aegean coasts. Dominant habitat types were identified in 175 depths and classified into 18 categories (Posidonia oceanica, Cymodocea nodosa, Halophila stipulacea, Halopteris spp., Stypopodium schimperi, Ericaria crinita, coralligenous, coralligenous/Mesophyllum spp., Jania spp./Halopteris spp., Ulva spp., rocky, rocky-turf, sandy, sandy-Caulerpa taxifolia var. distichophylla, sandy-Gongolaria montagnei var. compressa, silt, muddy, slime). Among the study sites, P. oceanica meadows (41%) were the dominant habitat in 70 depths, followed by sandy (30%), and rocky bottoms (11%). Total coverage of P. oceanica meadows was recorded as 28%, 80%, 76%, and 56% at 5 m, 10 m, 15 m, and 20 m depths, respectively. Seagrass meadows have started to be replaced by sandy bottoms at 30 m (52%) and 40 m (72%). Considering the bathymetrical divergence in phytobenthic community composition and abundance particularly in urban sites, reflected the influence of intense anthropogenic stressors. Here, non-destructive and cost-effective visual sampling technique based on in situ observations of phytobenthic community assemblages, proved to be an effective approach for the assessment of subtidal habitats. Full article

Macroalgal species are widely distributed throughout the world’s oceans and are well recognised for their biotechnological, ecological, and pharmacological potentials, containing a wide range of diverse bioactive compounds. In many coastal habitats worldwide, excessive accumulations of algal biomass (including rapidly growing blooms and drift accumulations resulting from dislodgement from benthic habitats) are commonplace and can pose environmental and economic challenges. In this study, we report occurrences of algal blooms and drift accumulations during 2024 and 2025 involving three major macroalgal clades, Chlorophyta, Phaeophyceae, and Rhodophyta, from two distinct marine regions: the North Atlantic Ocean and the South Pacific Ocean. Species identified included Grateloupia turuturu, Polyides rotundus, Ascophyllum nodosum, Ulva spp., Sargassum spp. and Fucus spp., among others. The indicated species are known for their diverse pharmacological properties, including antimicrobial, antioxidant, and anti-inflammatory effects. Specialised bioinformatic tools were employed to assess the potential of identified macroalgae as a source of antimicrobial peptides (AMPs). For selected macroalgal species, in silico screening of publicly available databases was performed to identify previously reported and characterised AMPs associated with these species. This in silico approach presents a promising strategy for discovering novel antimicrobial agents with potential activity, especially against drug-resistant bacteria. Finally, applying proteomics methodologies for in silico evaluation of the selected algal species advances modern technologies for the sustainable use of natural resources. Full article

This study evaluated the effects of four macroalgae (Colaconema spp., Ulva intestinalis, Ceramium spp., Pylaiella litoralis) and two microalgae (Haematococcus pluvialis, Porphyridium purpureum), chosen due to their local cultivability in the southern Baltic Sea region and potential gas-reducing properties reported for their taxa, on rumen fermentation and methane production. Therefore, the in vitro ANKOM Rf gas production system was used; three trials were conducted and gas kinetics, gas composition after 48 h of incubation, and short-chain fatty acids (SCFAs) were analyzed. For Trial 1.1, the algae biomasses were added at 4% to a conventional dairy diet and incubated in buffered rumen fluid for 48 h, to evaluate their potential as a supplement. In Trial 1.2, the polysaccharide-enriched algae extracts were added at 2% to the base diet using the same procedure, to investigate the role of the polysaccharide content. For Trial 2, the macroalgae biomasses were evaluated solely to assess their fermentation potential. The addition of the red alga Colaconema spp. (Colaconema) altered the SCFA profile with a shift towards propionate (rate of change in propionate concentration, ΔC3 = 1.216; p < 0.001), without compromising total SCFA yield. The same could be assessed for Ulva intestinalis (U. intestinalis), limited to Trial 2 (ΔC3 = 0.516; p < 0.001). The addition of U. intestinalis led to reduced initial gas production (p = 0.003), reaching the maximum gas production rate at 5.8 h of incubation, 0.3–0.7 h later than the others (5.1–5.5 h). While there was no significant methane reduction at the chosen inclusion rates, the results indicate that both algae influence the SCFA profile and therefore fermentation pattern, with U. intestinalis warranting further investigation on gas production dynamics. Full article

This study, conducted on the Cap-Vert peninsula (Dakar, Senegal), examines the epifaunal communities associated with macroalgae, revealing significant variations depending on the species of algae. In 2023 (in situ samples), amphipods dominated most macroalgae, particularly Coralina officinalis (29.40%) (Rhodophyceae), Chlorophyceae (30.38%), and Codium sp. (29.38%) (Chlorophyceae). In 2022, copepods (76–92%) were most abundant on Sargassum spp. and Ulva spp., which had washed up on the beach. A significant link between epifaunal abundance and macroalgae species highlighted their ecological interdependence. These findings are of relevant interest for West Africa’s blue economy, where the growing exploitation of wild macroalgae could disrupt these ecosystems. Sustainable management must take into account epifaunal species, particularly those found on structurally important macroalgae (e.g., Corallina sp., Codium sp.). The study recommends including macroalgae-epifauna associations in biodiversity inventories, particularly in marine protected areas, and continuing research on influencing factors (e.g., algal morphology, environmental conditions). Mass strandings of Sargassum spp. and Ulva spp. can cause mortality in marine larvae and eggs, leading to a local reduction in recruitment. Future research integrating these conclusions could allow a more detailed analysis of the epifauna on macroalgae. Ecosystem approach is essential to strike a balance between economic development and biodiversity conservation. Full article

This study explores a multi-resource approach for extracting and characterizing l-rhamnose-rich polysaccharides from nine natural biomasses, including green macroalgae (Ulva spp.), sumac species (Rhus spp.), and agro-industrial by-products such as sea buckthorn and sesame cakes. Hot-water and alkaline extractions were performed by biomass type, and the resulting fractions were analyzed using biochemical assays, monosaccharide profiling (HPAEC/PAD and GC/MS-EI), FTIR, and antioxidant activity tests. Extraction yields ranged from <1% in sea buckthorn residues to 15.48% in Ulva spp., which showed the highest recovery. l-rhamnose enrichment varied across biomasses: the highest proportions were found in Ulva extracts and Rhus semialata galls (PRS), reaching up to 44% of total sugars by HPAEC/PAD and 58% by GC/MS-EI. Antioxidant activities also differed markedly. In DPPH assays, the most active extracts were those from sea buckthorn berry cake (PTBA), Rhus coriaria seeds (PRC), and commercial sea buckthorn powder (PPA), with IC₅₀ values of 32, 43, and 42 µg/mL, respectively. Hydroxyl-radical inhibition was also substantial, reaching 83.0% for PTBA, 79.4% for PRC, and 79.9% for Ulva lactuca at 1 g/L, compared with 97.5% for ascorbic acid. These results highlight specific biomasses as promising dual sources of l-rhamnose and natural antioxidants for valorization within a circular bioeconomy. Full article

The lack of an established seaweed aquaculture industry in the Atlantic Southeast reflects the persistent challenges in identifying macroalgal species that can consistently produce year-round under regional environmental conditions. As a result, in this study, locally abundant Charlestonian Ulva spp. were selected as sustainable algal candidates for a pilot investigation, due to their resilience to abiotic (e.g., seasonal changes in temperature and nutrients) and biotic (e.g., predation and epiphytes) factors, thus allowing for practical land-based aquaculture. Ulva spp. were analyzed for their seasonal biomass and potential bioremediation applications using the existing land-based aquaculture infrastructure of the SCDNR in Charleston, South Carolina. The biomass of tank-cultivated Ulva spp. was monitored on a biweekly basis for 16 months and was found to be highest (31.8 kg) in the spring, increasing by 22% in just two weeks as water temperatures rose. A synthetic nutrient fertilizer was incorporated into aquaculture at the latter stages of this study to observe the effects on algal biomass while simulating an anthropogenic event. Interestingly, inorganic supplementation did not induce growth but was absorbed by the algal tissue, significantly lowering the δ¹⁵N to <7‰. Additionally, Vibrio spp. bacteria proliferated following the inorganic nutrient spike, while coliform populations decreased. Biochemical composition analyses comparing tank-cultivated and wild in situ Ulva spp. revealed variations in essential trace element (e.g., potassium: tank—19,530; wild—5520 mg/kg) concentrations, yet shared similar trace metal (e.g., arsenic: tank—4.47; wild—4.52 mg/kg) and pesticide (e.g., DEET: tank—0.048; wild—0.040 mg/kg) concentrations. This is the first reported macroalgal aquaculture research in South Carolina and serves as a pilot study for future research or commercialization in the Lowcountry and the greater southeastern coastal communities of the United States. Full article

(1) Background: The increasing soil and water pollution in agriculture is mainly due to the uncontrolled use of synthetic fertilizers. As the responsibility to adopt sustainable agricultural practices grows, biofertilizers may offer a solution to reduce the use of chemical inputs and improve crop productivity. This study focused on evaluating the physiological effects of Trichoderma asperellum, Bacillus sp., and seaweed extracts (Ulva lactuca and Solieria spp.) on the cultivation of serrano pepper plants. (2) Methods: Five treatments were carried out: control (T1), T. asperellum (T2), Bacillus sp. (T3), seaweed extract (T4), and their combination (T5). The microbial inoculants were applied to the root zone, while the seaweed extracts were applied to the foliage. Leaf samples were collected at the end of the vegetative phase to evaluate physiological and agronomic traits. (3) Results: The application of T3 significantly increased leaf area (12.34%), biomass (11.91%), and yield (10.7%) while decreasing the SPAD, chlorophyll, and carotenoid contents. T4 resulted in the highest nitrate reductase activity, while T5 resulted in the peak total chlorophyll content. No significant differences were observed in nitrate reductase activity between T4 and the control or in the carotenoid content between T1, T2, T4, and T5. (4) Conclusions: Bacillus sp. demonstrated agronomic benefits despite a decrease in pigments, supporting its application in the sustainable production of peppers. Full article

Anthropogenic warming of the world’s oceans is not just an environmental crisis, but may result in a significant threat to human health. The combination of a warming ocean and increased human activity in coastal waters sets the stage for increased pathogenic Vibrio–human interaction. Warming patterns due to climate change have already been related to the emergence of Vibrio outbreaks in temperate and cold regions. Seafoods, including seaweeds, are uniquely poised to contribute to global food and nutrition security. In recent years there has been a resurgence of interest in seaweeds due to their many uses, high nutritional value, and ability to provide ecosystem services such as habitat provision, carbon and nutrient uptake, and coastal protection. However, some seaweed species can be a reservoir for harbouring pathogenic Vibrio, and illnesses like gastroenteritis have recently been associated with foods prepared with seaweeds. In this study, we investigated the impact of elevated water temperatures on abundances of the major human pathogens Vibrio parahaemolyticus, Vibrio alginolyticus, and Vibrio vulnificus/cholerae on seaweed and in coastal waters. Three seaweed species, Fucus serratus, Palmaria palmata, and Ulva spp., were exposed to temperature treatments (16 °C and 20 °C) to assess the effects of mean-temperature rise on Vibrio parahaemolyticus, Vibrio alginolyticus, and Vibrio vulnificus/cholerae colonisation. Colony-forming units (CFUs) on seaweed surfaces and in surrounding water were counted. F. serratus and P. palmata showed significantly higher Vibrio abundances at higher temperatures compared with Ulva spp.; however, temperature did not significantly affect abundances of tested Vibrio species in surrounding waters. These results indicate that certain seaweed species may serve as major hotspots for human pathogenic bacteria in warmer conditions, with implications for human health. Full article

This review examines sustainable cascading biorefinery strategies for the green alga Ulva, which is globally prevalent in eutrophic marine waters and often forms extensive “green tides.” These blooms cause substantial environmental and economic damage to coastal communities. The primary target products within an Ulva biorefinery typically encompass salts, lipids, proteins, cellulose, and ulvan. Each of these components possesses unique properties and diverse applications, contributing to the economic robustness of the biorefinery. Salts can be repurposed for agricultural or even human consumption. Lipids offer high-value applications in nutraceuticals and animal feed. Proteins present significant potential as plant-based nutritional supplements. Cellulose can be transformed into various advanced materials. Finally, ulvan, a polyanionic oligosaccharide unique to Ulva, holds promise due to its distinct properties, particularly in the biomedical field. Furthermore, state-of-the-art chemical modifications of ulvan are presented with the aim of tailoring its properties and broadening its potential applications. Future research should prioritize optimizing these integrated extraction and fractionation processes. Furthermore, a multi-product biorefining approach, integrated with robust Life Cycle Assessment studies, is vital for transforming this environmental challenge into a significant opportunity for sustainable resource valorization and economic growth. Full article

The ulvans are sulfated heteropolysaccharides that can stimulate the immune response in vitro. Using a human cell model, this study aimed to characterize and evaluate the immunostimulatory properties of crude ulvans extracted from Ulva spp., collected in Algarrobo, Chile. The crude ulvans, characterized by spectrophotometric methods, are composed of 47.6% total sugars, 14.3% uronic acids, and 8.9% sulfates, with an average molecular weight of 40.000 kDa. The FTIR spectrum showed bands related to uronic acids, rhamnose, and sulfate groups. GCMS analysis confirmed the presence of rhamnose, xylose, glucose, and galactose, with a predominance of the disaccharides U3s and B3s. HL60 cells differentiated into macrophages were cultured with three concentrations of crude ulvans (25, 50, and 100 μg/mL), with cell viability remaining above 90% at the lower concentrations. The crude ulvan activated CD86 co-stimulatory molecules and promoted the release of IL-6, IL-10, IL-4, and nitric oxide cytokines. The results suggest that ulvan is non-toxic and can activate inflammatory pathways, making it a potential candidate for studies as a vaccine adjuvant. Full article

This study investigates the health benefits of supplementing Asian seabass diets with hot water crude extract from the sea lettuce Ulva rigida (Ur-HWCE). The extract’s proximate composition consists of 57.63% carbohydrates, 6.75% protein, 31.96% ash, and 6.01% sulfate polysaccharides, as confirmed by FTIR spectrum analysis. It also exhibits significant antioxidant properties, including total antioxidants, ABTS, DPPH, and reducing power. The study involved four groups fed Ur-HWCE at 0.5, 1.0, and 5 g/kg compared to a control group, with feed prepared daily and given twice at 5% of body weight for 4 weeks. Ur-HWCE supplementation did not negatively impact growth performance. It significantly upregulated insulin-like growth factor 1 (igf1) in the brain and liver, enhancing growth processes. Ur-HWCE reduced oxidative stress markers, such as malondialdehyde (MDA). Enhanced immune responses were observed, including increased bactericidal activity, serum IgM levels, and the upregulation of immune-related genes (dcs, c3, ighm, lyz, il8, il10). Gut microbiota analyses showed increased beneficial aerobic and natural probiotic Bacillus spp., particularly Bacillus amyloliquefaciens, enhancing gut health by reducing pathogenic bacteria. Blood biochemical parameters remained stable, and no histopathological alterations were found in the liver and intestine tissues, confirming the supplement’s safety. Fish fed with Ur-HWCE showed significantly higher survival rates and relative percent survival (RPS) against Vibrio vulnificus AAHM-VV2312 compared to the control group, demonstrating improved disease resistance. The study concludes that Ur-HWCE is a promising dietary supplement for enhancing the health, growth, and disease resistance of Asian seabass, supporting its potential in sustainable aquaculture practices. Full article

The green tide is the biggest ecological disaster in Yellow Sea in recent decades, and the species composition has varied from year to year. The ITS (internal transcribed spacer) sequence combined with 5S rDNA spacer are the mainstream molecular markers for green macroalgae. The former can perfectly distinguish the majority of Ulva spp. except the LPP (Ulva linza–procera–prolifera) complex, and the latter is used to distinguish U. linza and U. prolifera exactly based on the former. However, in practice, 5S rDNA spacer is difficult to amplify perfectly with universal primers, and this ultimately affects the experimental process. For this reason, we developed a stable mitochondrial marker for the distinction between U. linza and U. prolifera. The phylogenetic tree based on the mitochondrial rps2 (ribosomal protein S2) gene fragment can distinguish the LPP complex into two clades: U. linza and U. prolifera. Therefore, we concluded that the mitochondrial marker can be a great substitute for 5S primers to distinguish U. linza and U. prolifera. Full article

The diffusive availability of CO₂ for photosynthesis is orders of magnitude lower in water than in air. This, and the low affinity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) for CO₂, implies that most marine photoautotrophs (cyanobacteria, microalgae, macroalgae and marine angiosperms or seagrasses) would be severely restricted were they to rely only on dissolved CO₂ for their photosynthetic performance. On the other hand, the ~120 times higher concentration of bicarbonate (HCO₃⁻) makes this inorganic carbon (Ci) form more available for utilisation by marine photosynthesisers. The most common way in marine macrophytes to utilise HCO₃⁻ is to convert it to CO₂ within acidic micro-zones of diffusion boundary layers (DBLs), including the cell walls, as catalysed by an outwardly acting carbonic anhydrase (CA). This would then generate an intra-chloroplastic (or for cyanobacteria intra-carboxysomal) CO₂-concentrating mechanism (CCM). Some algae (e.g., the common macroalgae Ulva spp.) and most cyanobacteria and microalgae feature direct HCO₃⁻ uptake as the most efficient CCM, while others (e.g., some red algae growing under low-light conditions) may rely on CO₂ diffusion only. We will in this contribution summarise our current understanding of photosynthetic carbon assimilation of submerged marine photoautotrophs, and in particular how their ‘biophysical’ CCMs differ from the ‘biochemical’ CCMs of terrestrial C₄ and Crassulacean Acid Metabolism (CAM) plants (for which there is very limited evidence in cyanobacteria, algae and seagrasses). Full article

Seaweed biomass is globally underutilized as a source of proteins despite its nutritional potential, with much of its use focused on hydrocolloid extraction. This study evaluated the nutritional quality and digestibility of protein and amino acids from two brown seaweeds (Durvillaea spp. and Macrocystis pyrifera), one green seaweed (Ulva spp.), and a novel mycoprotein derived from Durvillaea spp. through fungal fermentation. Using an in vitro gastrointestinal digestion Megazyme assay kit, protein digestibility-corrected amino acid scores (PDCAASs) and digestible indispensable amino acid scores (DIASSs) were determined. Compared with seaweeds, seaweed-derived mycoprotein presented significantly greater protein contents (~33%) and amino acid profiles (2.2 times greater than those of Durvillaea spp. and M. pyrifera), with greater digestibility (~100%) than seaweeds (<60%). The PDCAAS values were 0.37, 0.41, 0.53, and 0.89 for Ulva spp., Macrocystis pyrifera, Durvillaea spp., and mycoproteins, respectively. The DIASSs highlighted the superior nutritional quality of the mycoprotein, particularly for lysine (0.59) and histidine (0.67). SDS-PAGE revealed soluble peptides (<25 kDa) in Durvillaea spp., Macrocystis pyrifera, and mycoproteins, whereas Ulva spp. proteins exhibited limited solubility due to structural aggregation. These findings highlight the need to characterize the nutritional properties of edible seaweeds in Chile further and emphasize the importance of optimized processing techniques, such as fermentation or bioconversion, to improve the nutritional potential of seaweeds and develop high-quality food ingredients for diverse applications. Full article

The impact of macroalgae species on rumen function remains largely unexplored. This present study aimed to identify the biocompounds of the three types of marine macroalgae described: Macrocystis pyrifera (Brown), Ulva spp. (Lettuce), Mazzaella spp. (Red) and their effect on species-specific modulations of the rumen microbiome. The macroalgae were characterized using GC-MS. Twelve Rambouillet lambs were randomly assigned to one of four experimental diets (n = 3 per treatment): (a) control diet (CD); (b) CD + 5 g of Red algae; (c) CD + 5 g of Brown algae; and (d) CD + 5 g of Lettuce algae. After the lambs ended their fattening phase, they donated ruminal fluid for DNA extraction and 16S rRNA gene V3 amplicon sequencing. Results: The tagged 16S rRNA amplicon sequencing and statistical analysis revealed that the dominant ruminal bacteria shared by all four sample groups belonged to phyla Firmicutes and Bacteroidota. However, the relative abundance of these bacterial groups was markedly affected by diet composition. In animals fed with macroalgae, the fibrinolytic and cellulolytic bacteria Selenomonas was found in the highest abundance. The diversity in chemical composition among macroalgae species introduces a range of bioactive compounds, particularly VOCs like anethole, beta-himachalene, and 4-ethylphenol, which demonstrate antimicrobial and fermentation-modulating properties. Full article