Marine Macroalgae Research Articles

Environmental benefits of macroalgae products: A case study of agar based on life cycle assessment

Seaweed (marine macroalgae) cultivation and hydrocolloids industries can contribute significantly to sustainable development and bio-economy. However, there has been a lack of study on the environmental impacts of agar manufactured from macroalgae. This study is one of the first attempts to analyze environmental sustainability of agar extracted from Gracilaria lemaneiformis using an integrated method of life cycle assessment (LCA) and environmental profit and loss (EP&L). The “cradle-to-gate” life cycle stages are considered, namely, seaweed cultivation, transportation, agar production, and waste treatment. Two scenarios are conducted to explore the different production methods of agar. Results reveal that the carbon sequestration during the seaweed cultivation stage of agar amounts to 7.21 kgCO2eq/kg, and the net “cradle-to-gate” carbon emission of agar is −1.11 kgCO2eq/kg. The cultivation of seaweed can also benefit the marine environment through the removal of nitrogen, phosphorus, and heavy metals. In addition, the environmental impacts of agar production in China are converted into monetary values and estimated as total external costs based on EP&L. The comparative analysis elucidates a reduced environmental loss of 667 CNY in Scenario 2, while the external cost of Scenario 1 is 1020 CNY, indicating the environmental impact of Scenario 2 is reduced due to the improved process of agar production. As one of the first systematic LCA studies of seaweed cultivation and agar manufacturing, this work promotes the understanding of the environmental sustainability of seaweed hydrocolloid industry.

High nutrient availability modulates photosynthetic performance and biochemical components of the economically important marine macroalga Kappaphycus alvarezii (Rhodophyta) in response to ocean acidification

Increased atmospheric CO2 concentrations not only change the components of inorganic carbon system in seawater, resulting in ocean acidification, but also lead to decreased seawater pH, resulting in ocean acidification. Consequently, increased inorganic carbon concentrations in seawater provide a sufficient carbon source for macroalgal photosynthesis and growth. Increased domestic sewage and industrial wastewater discharge into coastal areas has led to nutrient accumulation in coastal seawaters. Combined with elevated pCO2 (1200 ppmv), increased nutrient availability always stimulates the growth of non-calcifying macroalgae, such as red economical macroalga Gracilariopsis lemaneiformis. Here, we evaluated the interactive effects of nutrients with elevated pCO2 on the economically important marine macroalga Kappaphycus alvarezii (Rhodophyta) in a factorial 21-day coupling experiment. The effects of increased nutrient availability on photosynthesis and photosynthetic pigments of K. alvarezii were greater than those of pCO2 concentration. The highest Fv/Fm values (0.660 ± 0.019 and 0.666 ± 0.030, respectively) were obtained at 2 μmol L−1 of NO3–N at two pCO2 levels. Under the elevated pCO2 condition, the Chl-a content was lowest (0.007 ± 0.004 mg g−1) at 2 μmol L−1 of NO3–N and highest (0.024 ± 0.002 mg g−1) at 50 μmol L−1 of NO3–N. The phycocyanin content was highest (0.052 ± 0.012 mg g−1) at 150 μmol L−1 of NO3–N under elevated pCO2 condition. The malondialdehyde content declined from 32.025 ± 4.558 nmol g−1 to 26.660 ± 3.124 nmol g−1 with the increased nutrients at under low pCO2. To modulate suitable adjustments, soluble biochemical components such as soluble carbohydrate, soluble protein, free amino acids, and proline were abundantly secreted and were likely to protect the integrity of cellular structures under elevated nutrient availability. Our findings can serve as a reference for cultivation and bioremediation methods under future environmental conditions.

Anatomical and phytochemical properties of Codium, a marine macroalga

Anatomical and phytochemical properties of Codium, a marine macroalga

Resolving phytosterols in microalgae using offline two-dimensional reversed phase liquid chromatography-supercritical fluid chromatography coupled with quadrupole time-of-flight mass spectrometry.

Sterols are unsaponifiable lipids resulting from plant metabolism that exhibit interesting bioactive properties. Microalgae are a major source of specific phytosterols, most of which are still not fully characterized. The similarity in sterol structures and the existence of positional isomers make the separation of phytosterols challenging. A method was developed based on an offline two-dimensional (2D) system, reversed-phase liquid chromatography (RPLC)-supercritical fluid chromatography (SFC)/quadrupole time-of-flight (Q-ToF) mass spectrometry, for the identification of sterols in microalgae. Subsequent positive-mode MS/MS was used to confirm the identified phytosterols. The 2D chromatogram exhibited a pattern related to the positions of the double bonds, which were confirmed by standard injection, enabling structural elucidation. The analysis of the unsaponifiable fraction of two algae, namely Scenedesmus obliquus, a freshwater microalgae, and Padina pavonica, a marine macroalgae, highlighted the ability of the method to distinguish a large number of sterol isomers.

Application of Artificial Neural Network and Genetic Algorithm Modeling for In Vitro Regeneration of Seaweed Seedling Production.

Marine macro-algae, commonly known as "seaweed," are used in everyday commodity products worldwide for food, feed, and biostimulant for plants and animals and continue to be one of the conspicuous components of world aquaculture production. However, the application of ANN in seaweeds remains limited. Here, we described how to perform ANN-based machine learning modeling and GA-based optimization to enhance seedling production for implications on commercial farming. The critical steps from seaweed seedling explant preparation, selection of independent variables for laboratory culture, formulating experimental design, executing ANN Modelling, and implementing optimization algorithm are described.

НАХОДКИ ЛАМИНАРИЕВЫХ И ДРУГИХ ВОДОРОСЛЕЙ В УЛОВАХ ДОННЫМ ТРАЛОМ И ЯРУСОМ У ЗАПАДНОГО ПОБЕРЕЖЬЯ КАМЧАТКИ В 2018–2023 гг.

Data are provided on findings of marine macroalgae during bottom trawls and longline fishing on the Western Kamchatka shelf in 2018-2023. During the study period, algae were noted at 65 stations in the depth range from 20 to 350 m. Most of the algae findings were found in the Kamchatka-Kuril fishing subzone, within the South Kamchatka Nature Reserve. Among the macrophytes, representatives of the order Laminariales predominated: Agarum pertusum, A. clathratum, Alaria esculenta, Arthrothamnus bifidus, Eualaria fistulosa, Hedophyllum bongardianum, H. dentigerum, Laminaria yezoensis, Laminaria inclinatoriza and Thalassiophyllum clathrus. For southwestern Kamchatka, only 9 out of 13 species of kelp algae indicated in the literature were discovered. Brown algae Fucus distichus, Desmarestia intermedia, red algae – Ptilota asplenioides, Turnerella mertensiana and lamellar green algae – Ulva fenestrata were found sporadically. A comparative analysis of aerial photography data of coastal areas from Cape Sivuchy to Cape Lopatka in 2002 and modern satellite images did not reveal significant changes in the distribution of littoral and sublittoral algae beds. In the coastal line of capes Sivuchy, Kambalny and Maria that we studied, the kelp belt with an average width of 100-130 m reached in the summer of 2018–2023 the total coverage area is 1.92 km2. The use of accompanying data when conducting bottom surveys of commercial invertebrates and fish, longline cod fisheries, together with the analysis of satellite images, allows for an expert assessment of changes in the species composition and distribution of kelp algae, and is also a promising tool for monitoring the state of macrophyte communities in the Far Eastern seas of Russia.

Quantification of the invasiveness risk of non‐native macroalgae in the Azores to support conservation measures

Abstract Non‐native species (NNS) might become invasive and threaten biodiversity, economy and public health. Therefore, it is essential that their invasiveness risk be quantified to support conservation measures. The Azores, located in the mid‐northern Atlantic, is the crossroad of macroalgal native distributions and also present almost three times the global ratio of macroalgae reported as NNS. Aquatic Species Invasiveness Screening Kit, a decision‐support tool consisting of 49 questions for the Basic Risk Assessment (BRA) and six for the Climate Change Assessment (CCA), was applied to the 42 marine macroalgae classified as NNS in the Azores. The results indicate that 21 species pose a medium risk of becoming invasive, and 15 present a high risk under current climate conditions (BRA scores only). The combined BRA + CCA scores show that Laurencia dendroidea poses a high risk instead of a medium risk. Thirty‐three Rhodophyta species were screened, with 10 (BRA) and 11 (BRA + CCA) classified as high risk. All four Chlorophyta species ranked as high risk. Only one of the five Ochrophyta species was classified as high risk, namely Rugulopteryx okamurae, one of the most invasive species in European waters. High‐risk species are present in all islands, likely spread by the continuous maritime traffic between islands. Six of the high‐risk species are restricted to single islands (BRA and BRA + CCA scores), and efforts should be made to contain their further expansion. Asparagopsis armata, a species introduced in Europe in the 1920s, is the only high‐risk species present in all islands. Conservation measures for prevention, monitoring and control of NNS are proposed for the different islands of the Azores, including regulation of introduction pathways, prospection of areas with high risk of invasion, risk screening, eradication and containment of NNS. The involvement of stakeholders and maritime workers is also recommended.

Floristic classification of opportunistic green macroalgae communities of the European myxomesohaline seas

Shallow-water communities of opportunistic green marine macroalgae in eutrophicated areas are currently gaining an advantage over communities dominated by other groups of macrophytes. Therefore, their classification, study of composition and observation of structural changes are of particular importance. One class (Ulvae intestinalis–Ulvetea linzae), one order (Ulvae intestinalis–Ulvetalia linzae), three alliances (Ulvae intestinalis–Ulvion linzae, Ulvae intestinalis– Ceramion virgati, Ulvae rigidae–Gelidion spinosi) and three new associations of macroalgal communities of meso- and polysaprobic sublittoral vegetation within the shelf of the Black, Azov and Baltic Seas are described for the first time, using the Braun-Blanquet approach. Principal components analysis revealed two main factors influencing the floristic composition of the investigated communities: salinity and nutrient enrichment with associated turbidity. The proposed classification of opportunistic communities of green algae should be used in assessing the dynamics of the state of vegetation during eutrophication of the aquatic environment.

Evaluation of the proximate composition, minerals, and heavy metals of brown seaweeds: Sargassum wightii and Sargassum thunbergii collected from the Mandapam coastal regions, Tamil Nadu

A vital renewable resource for the marine environment, seaweed naturally supplies nutrients and has several health benefits. The nutritional properties of seaweed compounds have yet to be well investigated; much research has been done on their chemical and biological makeup. Seaweeds provide an alternate supply of these essential nutrients, including protein, fibre, and necessary and non-essential trace elements. In the present study, two brown seaweeds-Sargassum wightii and Sargassum thunbergii,collected from the Mandapam coastal region of Tamil Nadu, were assessed for their proximate composition, minerals, and heavy metals.The findings on dry weight basis showed that carbohydrates (65.1–67.9%) predominated in the proximal analysis, followed by ash content (12.5–16.3%). On a dry weight basis, the critical trace elements found in seaweeds, such as copper (Cu), zinc (Zn), and iron (Fe), were between 8.14–12.41 ppm, 3.95–4.86 ppm, and 648.92-898.45 ppm, respectively. Both seaweeds have a very high calcium (Ca) concentration, ranging from (14,805.08-16,235.62) ppm. The seaweed species did not contain any measurable levels of dangerous heavy metals such as cadmium (Cd), beryllium (Be), lead (Pb), or mercury (Hg). The results demonstrated how seaweed or marine macroalgae may be helpful for essential nutrient supply.

Supplementation of Kappaphycus alvarezii Solid Waste (Bioethanol Production) in Fish Feed for Barbonymus schwanenfeldii Growth

Kappaphycus alvarezii is a renewable resource rich in dietary sources such as vitamins, proteins, carbohydrates and trace minerals. The solid waste of this marine macroalgae produced from bioethanol production was used to produce fish feed. This study aims to evaluate the efficacy of K. alvarezii fish feed in Barbonymus schwanenfeldii fish growth. The proximate analysis, micro and macronutrient and mycotoxin in the K. alvarezii fish feed were determined using a standard protocol. For the fish culture design, fish were randomly divided into two groups: group I – feed with commercial fish feed (control); group II – feed with K. alvarezii fish feed (experimental group). The initial body weight of the fish was recorded, and thereafter weekly for 12 weeks. Proximate analysis indicated that the dried K. alvarezii fish feed is high in nitrogen (46.30+0.1%) and low in moisture (6.40+0.1%), ash (4.50+0.1%) and fiber (4.75+0.1%) contents, while rich in macro and micronutrients. There was no mycotoxin found in the K. alvarezii fish feed. For the 12 weeks of the feeding of commercial and K. alvarezii fish feed, our results did not show any significant difference (P > 0.05) in the B. schwanenfeldii specific growth rate between the groups, 0.36+0.03% in the control group and 0.34+0.02% in the experimental group, respectively. Proximate analysis of the B. schwanenfeldii fish, indicated a moisture content of 19.20+0.1%, crude extract protein of 74.70+0.1% and crude lipid of 3.50+0.1% in the control group, which are significantly higher (P < 0.05) than in the experimental group [moisture content (15.60+0.1%), crude extract protein (70.00+0.1%) and crude lipid (2.60+0.1%)]. Although the proximate analysis in the control group is significantly higher than the experimental group, the use of K. alvarezii as fish feed supplement is still a good option as it utilizes the waste of K. alvarezii and can support towards the UN Sustainable Development Goal 12, Responsible Consumption and Production.

Antibacterial Activity of Some Selected Marine Macro-algae from Rameswaram Coastal Region, India

Marine algae are known as source of bioactive secondary metabolites. Twenty macroalgae were collected from Mandapam cost, Gulf of Mannar, Rameswaram were tested against two-gram negative bacteria’s using agar well diffusion method. The following species were used in the current study include seven species in Chlorophyta (Caulerpa peltata, Ulva lactuca, Halimeda gracilis , Chaetomorpha aerea, Cladophora vagabunda, Enteromorpha flexuosa, Halimida macroloba), seven in Phaeophyta (Sargassum cinereum, Padina boergesenii, Sargassum cristaefolium, Turbinaria decurrens, Turbinaria conoides, Hydroclathrus clathratus, Lobophora variegate) and six in Rhodophyta (Hypnea spicefera, Solieria robusta, Porphyra indica, Ceramium rubrum, Gelidiella acerosa Gracilaria edulis). They were air-dried thoroughly and powdered using a grinder. Powdered algae were extracted using solvents such as water, ethanol and methanol. In the present study ethanol extract was found to be excellent antibacterial activity from macroalgae. Among the selected Twenty different macroalgae the red algae (Rhodophyta) showed the higher antibacterial activity followed by brown (Phaeophyta) and green (Chlorophyta) against the tested two selective negative bacteria (Pseudomonas aeruginosa and Klebsiella pneumoniae). This finding supports the view that algal extracts are a reliable source of bioactive compounds for upcoming medication development.

Immunomodulation by extracellular vesicle-like nanoparticles from marine macroalgae Sargassum fusiforme: Enhancing Type 1 T helper and cytotoxic T lymphocyte-mediated immune responses

This study investigated the immunological features and therapeutic potential of extracellular vesicle-like nanoparticles isolated from the marine macroalgae Sargassum fusiforme (SF-NPs). SF-NPs were approximately 266.4 nm in size, and comprehensive metabolomic analysis revealed 38 metabolites. SF-NPs can upregulate dendritic cell (DC) maturation markers, increase pro-inflammatory cytokine production, and enhance antigen presentation capacity. DC maturation is regulated by the mitogen-activated protein kinase and nuclear factor-kappa B pathways. Notably, SF-NPs-primed DCs orchestrated robust CD4+ and CD8+ T-cell proliferation, fostering potent Type 1 T-helper(Th1) responses and cytotoxic T lymphocyte (CTL) activity. In a cyclophosphamide-induced immunosuppression mouse model, SF-NPs restored and activated immune cell populations, including DCs, natural killer, CD4+ T, and CD8+ T cells. SF-NPs reversed cyclophosphamide-induced Type 2 T-helperand regulatory T cell-biased responses, favoring Th1 and CTL responses, including multifunctional T cell responses. This study highlighted the potential of SF-NPs as therapeutic candidates for diseases requiring Th1 and CTL responses.

Novel insights into crystal violet dye adsorption onto various macroalgae: Comparative study, recyclability and overview of chromium (VI) removal

In this study, effective biomaterials were prepared from marine macroalgae, namely Fucus spiralis (F.S), Ulva intestinalis (U.I), and Corallina officinalis (C.O). The ability to adsorb the hazardous organic dye crystal violet (CV) was examined, revealing different adsorptive properties for the three algae. The removal of CV dye occurred onto only a homogeneous monolayer for F.S, and both a homogeneous monolayer and a heterogeneous multilayer for U.I and C.O algae. The predicted monolayer capacities at 25 °C were approximately 53 mg/g, 55 mg/g, and 97 mg/g for F.S, C.O, and U.I, respectively. The adsorption of CV dye on all the algae was found to follow a pseudo-second-order rate. Ulva intestinalis algae, as a potential adsorbent of CV dye, were also tested in the adsorption of inorganic substances and demonstrated significant efficiency in the removal of chromium (VI). The findings highlight various adsorption properties and the relevance of macroalgae for wastewater treatment applications.

Biotechnological Potential of Macroalgae during Seasonal Blooms for Sustainable Production of UV-Absorbing Compounds.

Marine macroalgae (seaweeds) are important primary global producers, with a wide distribution in oceans around the world from polar to tropical regions. Most of these species are exposed to variable environmental conditions, such as abiotic (e.g., light irradiance, temperature variations, nutrient availability, salinity levels) and biotic factors (e.g., grazing and pathogen exposure). As a result, macroalgae developed numerous important strategies to increase their adaptability, including synthesizing secondary metabolites, which have promising biotechnological applications, such as UV-absorbing Mycosporine-Like Amino Acid (MAAs). MAAs are small, water-soluble, UV-absorbing compounds that are commonly found in many marine organisms and are characterized by promising antioxidative, anti-inflammatory and photoprotective properties. However, the widespread use of MAAs by humans is often restricted by their limited bioavailability, limited success in heterologous expression systems, and low quantities recovered from the natural environment. In contrast, bloom-forming macroalgal species from all three major macroalgal clades (Chlorophyta, Phaeophyceae, and Rhodophyta) occasionally form algal blooms, resulting in a rapid increase in algal abundance and high biomass production. This review focuses on the bloom-forming species capable of producing pharmacologically important compounds, including MAAs, and the application of proteomics in facilitating macroalgal use in overcoming current environmental and biotechnological challenges.

Structural characterization of marine macroalgae derived silver nanoparticles and their colorimetric sensing of hydrogen peroxide

The present study investigates the algae-mediated synthesis, characterization, and H2O2 sensing ability of silver nanoparticles using Sargassum spp. extract. The synthesized nanoparticles were spherical agglomerates and exhibited an absorbance peak at 418 nm, as analyzed by FE-SEM and UV–vis spectrophotometric analysis. TEM-SAED analysis interpreted the size between 2 and 35 nm and crystallinity corresponding to face-centered cubic (FCC) silver structure. This was further supported from XRD findings, which ascertained the presence of (111), (200), (220), and (311) lattice planes. FT-IR analysis confirmed the capping of algal phenolics as corresponding functional groups, which was further confirmed by XPS studies. The nanoparticles were observed to be highly stable in aqueous suspensions, due to the zeta potential value (−22.6 mV). On incubation of synthesized nanoparticles, with H2O2 solutions, decolorization of nanoparticle solution was observed along with the reduction of absorbance peak at 418 nm. This color change could be utilized for H2O2 detection in contaminated samples. Therefore, this study reveals the potential of sustainable Sargassum spp. biomass in synthesizing beneficial silver nanoparticles which could be exploited for environmental detection applications.

Evaluation of several macroalgae species on methane emission and antioxidant activity based on in vitro rumen fermentation characteristics

Marine macroalgae are the prospective and promising Indonesian natural resources containing bioactive compounds. This study aimed at evaluating various seaweed species with optimal biological activity to mitigate in vitro rumen methane emission and to confirm their antioxidant properties. In addition, relationships among several phenolic fractions and methane (CH4) production of seaweeds were elucidated by Pearson Correlation to screen seaweeds for their capacity to reduce CH4 formation. For in vitro batch cultures experiment, the diets were 500 mg of a substrate of seaweed. They were incubated with 50 ml of buffered rumen fluid (1:2 ratio of rumen fluid to buffer media) in a 100 ml serum vial at 39°C for 72 hours incubation time. A randomized block design was carried out with 14 dried seaweed treatments and 5 different cattle rumen fluid groups as a block. For total phenol, flavonoid, and antioxidant activity, a completely randomized design with 14 treatments and 3 replications was carried out. Data were analyzed by Analysis of Variance (ANOVA) and Duncan analysis. The results showed that the lowest methane production (ml/g DM incubated) significantly (P<0.05) was reduced by Halymenia sp. (0.24) and Caulerpa racemosa (0.41). Caulerpa racemosa showed high flavonoid content (1.5 mg Quercetin/g) and Ulva lactuca had the highest phenol content (0.55 mg Gallic Acid/g). Gracilaria coronopifolia had strong antioxidant activity DPPH radical scavenging activity (77.5% inhibition). It was concluded that Halymenia sp., Caulerpa racemosa and Gracilaria coronopifolia could be used as methane inhibitors and antioxidants for ruminants.

Macroalgae as a Source of Functional Foods in the Prevention of Cardiovascular Diseases

Noncommunicable diseases (NCD), such as cardiovascular diseases (CVD), are responsible for the majority of annual deaths worldwide. Dyslipidemia, hypertension, diabetes, and obesity, among others, can enhance the onset of metabolic syndrome (MetS). The integration of natural products in the diet, such as marine macroalgae or hydrocolloids extracted from them, has been extensively studied. The application of these substances in the prevention of pathologies is expanding due to the high content of bioactive compounds and as dietary fiber, constituting an excellent source of organic components to produce functional foods. The objective of this review will be to compile the effectiveness of algal polysaccharides, specifically agar, alginates and carrageenan, in the prevention of CVD, focusing on its action on the pathophysiology underlying this group of diseases, as well as exploring the various human and animal studies available. Additionally, we emphasize the benefits of dietary fiber consumption and the mechanisms of its action throughout the gastrointestinal tract. The present work will also present information about the benefits of consuming macroalgae in regulating intestinal health and its general relationship with CVD.

Characterization of Three Brown Algae Bifurcaria Bifurcata, Cystoseira Gibraltarica and Fucus Spiralis

In recent years, scientists have become interested in marine macroalgae, which represent a rich source of bioactive substances. These molecules are characterized by a multitude of forms and structures and have several biological activities. The present study aims to characterize the three brown algae Bifurcaria bifurcata, Cystoseira gibraltarica and Fucus spiralis. These were collected in the region of Cap Ghir north of Agadir. The results obtained show that the mineral analyses of the extracts of F. spiralis, B. bifurcata and C. gibraltarica highlighted the richness of these brown algae in macroelements (Ca, K, P, Na, N). Concerning the total sugar content of C. gibraltarica shows a significant difference with the other two algae B. bifurcata and F. spiralis and has the highest content. For the protein content, no significant difference was recorded between the three algal extracts. Indeed, the aqueous extract of C. gibraltarica has a protein content of 48.44 mg/g DM, the aqueous extract of F. spiralis showed an average protein content of 45.55 mg/g DM, and that of the aqueous extract of B. bifurcata is 44.03 mg/g DM. The three brown algae C. gibraltarica, B. bifurcata and F. spiralis have consistent levels of organic matter. F. spiralis and C. gibraltarica have significantly equivalent organic matter contents (73.74 and 73.44 g/100g DM, respectively). In this study, the analysis of total phenols shows that F. spiralis presents a significant difference with the two other algae and has the highest content (7.2 µg/mg dry matter). In general and whatever the method of flavonoid determination, the flavonoid content of the three algae is significantly different. The methanolic extract of F. spiralis shows the highest flavonoid content, followed by B. bifurcata. While the lowest content is presented with the methanolic extract of C. gibraltarica. The results of the antioxidant potential using DPPH reveal a significant difference between the three algae. Indeed, the extracts of the analyzed algae present an antioxidant activity varying between 33.61 and 88.3%, with a high antioxidant potential (88.3%) for F. spiralis and thus an important capacity to trap the DPPH radical. These three studied brown algae represent a promising source of biologically active molecules that can be used in several fields such as organic agriculture.

Biosynthesis of Copper Nanoparticles From Seaweed Ulva lactuca and Their In Vitro Antioxidative Potential.

Marine macroalgae is consumed by individuals in several regions, including Scandinavia, Great Britain, Ireland, China, and Japan; in Japan, it is commonly referred to as aosa. Copper nanoparticles are primarily composed of copper and exhibit a size distribution ranging from 1 to 100 nm. Copper nanoparticles can be synthesized using chemical or natural means, similar to other nanoparticle variants. The nanoparticles in question have garnered significant attention owing to their historical utilization as coloring agents, as well as their contemporary applicability in medicine and antibacterial treatments. The objective of this study was to investigate the biosynthesis of copper nanoparticles derived from Ulva lactuca seaweed and explore their in vitro antioxidative potential. Seaweed samples (10 g) were mixed with 50 ml of distilled water and placed in a shaker for two days. Copper sulfate (10 mM) was mixed with 100 ml of distilled water to obtain a copper (Cu) solution. Cu nanoparticles were then synthesized by adding the aqueous extract to 100 ml of the Cu solution and mixing it in an orbital shaker at 180 rpm for 24 hours. They were observed both visually and via ultraviolet(UV) spectrophotometry to confirm their nanoparticle synthesis. The initial reading was performed using a UV-visible spectrometer at 300-800 nm. The sample was centrifuged at approximately 8000 rpm for 15 minutes, the pellet was removed, and the pellet was dried in a hot-air oven. The synthesized Cu nanoparticles were then investigated using in vitro antioxidant assays. The seaweed-derived copper nanoparticles exhibited a 1.2 peak absorbance at 580 nm. Various concentrations of copper nanoparticles (25, 50, 75, and 100 µg/ml) were tested for free radical scavenging. As the copper nanoparticle concentration increased, the scavenging ability on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radicals assay showed that the free radical scavenging activity increased in a dose-dependent manner. Similar to the DPPH assay, the total antioxidant and hydrogen peroxide (H2O2)assays showed increased free radical scavenging with increasing concentration. The application of Cu nanoparticles in the synthesis process has the potential to enhance the antioxidant activity of Ulva lactuca as evidenced by the observed increase in antioxidant capacity and defense against reactive oxygen species.

The north-south divide? Macroalgal functional trait diversity and redundancy varies with intertidal aspect.

Marine macroalgae ('seaweeds') are critical to coastal ecosystem structure and function, but also vulnerable to the many environmental changes associated with anthropogenic climate change (ACC). The local habitat conditions underpinning observed and predicted ACC-driven changes in intertidal macroalgal communities are complex and probably site-specific and operate in addition to more commonly reported regional factors such as sea surface temperatures. We examined how the composition and functional trait expression of macroalgal communities in SW England varied with aspect (i.e. north-south orientation) at four sites with opposing Equator- (EF) and Pole-facing (PF) surfaces. Previous work at these sites had established that average annual (low tide) temperatures vary by 1.6 °C and that EF-surfaces experience six-fold more frequent extremes (i.e. >30 °C). PF macroalgal communities were consistently more taxon rich; 11 taxa were unique to PF habitats, with only one restricted to EF. Likewise, functional richness and dispersion were greater on PF-surfaces (dominated by algae with traits linked to rapid resource capture and utilization, but low desiccation tolerance), although differences in both taxon and functional richness were probably driven by the fact that less diverse EF-surfaces were dominated by desiccation-tolerant fucoids. Although we cannot disentangle the influence of temperature variation on algal ecophysiology from the indirect effects of aspect on species interactions (niche pre-emption, competition, grazing, etc.), our study system provides an excellent model for understanding how environmental variation at local scales affects community composition and functioning. By virtue of enhanced taxonomic diversity, PF-aspects supported higher functional diversity and, consequently, greater effective functional redundancy. These differences may imbue PF-aspects with resilience against environmental perturbation, but if predicted increases in global temperatures are realized, some PF-sites may shift to a depauperate, desiccation-tolerant seaweed community with a concomitant loss of functional diversity and redundancy.