Padina Pavonia Research Articles

Bioremediation of iron from polluted water using marine algae

AbstractEl-Mex Bay receives huge of toxicants and pollutants that resulted from various anthropogenic activities and different heavy metals. These pollutants adversely affect human's health and the aquatic ecosystem. In this study, iron is selected rather than other heavy metals for bioremediation as it constitutes a large part of the Bay. This work aims to the assessment of the efficiency of six marine algal species as bio-sorbents for iron, which constitutes a large part of El-Umum drain wastewater at El-Mex Bay locality. These species are Ulva linza, Ulva fasciata (Chlorophyceae), Padina pavonia, Saragassum hornschuchii (Phaeophyceae), and Pterocladia capillacea, Corallina officinalis (Rhodophyceae). Algal nanoparticles and finely powdered algae were evaluated for adsorbing iron in aqueous solutions as a function of contact time, biomass weight, different wastewater concentrations, and pH. Analyzing function groups of the biomass was also assessed. Compared to ordinary ground algal biomass, nanoparticles of dry algal biomass (ground by ball mill) is considered an efficient economic adsorbent for iron removal that occurs at high concentration levels, either dissolved or particulate. Comparing the maximum removal efficiency, it was recorded values of 95.6, 98.8, and 97.6% for Ulva linza, Sargassum hornschuchii, and Corallina officinalis, respectively, using 0.1 g nano-biomass at pH 9.4, these values were 79.60, 96.33, and 83.41%, for the same algal species using 0.5 g ground powder biomass at the same pH.

Extraction Optimization, Analysis and Biological Activity of Volatile Compounds from Padina pavonia Collected from Farasan Island’s Coasts, Jazan, Saudi Arabia

Marine brown algae are a source of a broad spectrum of active compounds with nutritional and pharmaceutical applications. This study aimed to identify the essential oil (EO) compounds and assay the antimicrobial and antioxidant activity of ethanol and acetone extracts of Padina pavonia harvested from Farasan Island’s coasts in the Red Sea, Saudi Arabia. Steam distillation was employed to extract the EO and analyze using GC-MS. Forty-one compounds were identified in the volatile fraction of P. pavonia, accounting for 89.23% of the total oil. Fatty acids were the primary class of volatile compounds (44%). A freeze-dried algal sample was used for solvent extraction. Optimized extraction with ethanol (50%) and acetone by Soxhlet extractor at 60oC for 2h yielded extracts with high antioxidant activity (IC50: 143 and 222 µg/mL), respectively. Acetone extract showed higher broad-spectrum antimicrobial activity against bacteria and fungi than ethanol 50% extract. The results of this paper present the first report on essential oils from P. pavonia in the Red Sea.

Effect of nanoparticle macroalgae in the treatment of fatty liver disease using logistic regression, and support vector machine

One of the major health issues facing people worldwide is liver fibrosis. Liver fibrosis may be brought on by long-term exposure to harmful substances, medicines, and microorganisms. The development of liver fibrosis in children was particularly worrying due to their longer life-span, which was possibly related to a great risk of developing long-term complications. Marine algae species have provided a biological variety in the research phase of novel approaches to the treatment of numerous ailments. Marine macroalgae have recently been the subject of research due to their rich bioactive chemical composition and potential for the production of various nutraceuticals. Macroalgae are potentially excellent sources of bioactive substances with particular and distinct biological activity when compared to their terrestrial equivalents. Macroalgae in diverse marine cases offer a few biologically active metabolites, comprising sterols, polyunsaturated fatty acids, carotenoids, oligosaccharides, polysaccharides, proteins, polyphenols, vitamins, and minerals. Accordingly, there is great interest in their high potential for supporting immunomodulatory, antimicrobial, antidiabetic, antitumoral, anti-inflammatory, antiangiogenic, and neuroprotective properties. Using an experimental model, the current research intends to collect data on the therapeutic value of macroalgae nanoparticles for fatty liver disease. The researchers' goal of predicting illnesses from the extensive medical datasets is quite difficult. The purpose of this research is to assess the protective effects of a seaweed, Padina pavonia (PP), on liver fibrosis caused by carbon tetrachloride (CCl4). This research presents two models of logistic regression (LR) and support vector machines (SVM) for predicting the likelihood of liver disease incidence. The performance of the model was evaluated using a dataset. PP macro-algae considerably reduce the high blood concentrations of aminotransferases, alkaline phosphatases, and lactate dehydrogenases, as well as causing a considerable (p < 0.05) decrease in serum bilirubin levels. In addition to improving kidney function (urea and creatinine), algal extracts enhance fat metabolism (triglycerides and cholesterol). With an accuracy rate of 70.2%, a sensitivity of 92.3%, a specificity of 74.7%, a type I error of 9.1%, and a type II error of 21.0%, the predictive model has demonstrated excellent performance. The model validated laboratory tests' ability to predict illness (age; direct bilirubin (DB), total proteins (TP), and albumin (ALB). These classifier methods are compared on the basis of their execution time and classification accuracy.

Comparative assessment of antioxidant activity and biochemical composition of four seaweeds, Rocky Bay of Abu Qir in Alexandria, Egypt

The current study estimated the antioxidant activity and biochemical composition of four seaweeds; Toania atomaria (Phaeophyta), Padina pavonia (Phaeophyta), Jania rubens (Rhodophyta) and Corallina elongate (Rhodophyta). The highest total antioxidant activity was observed with ethanol extract of T. atomaria (44.6 ± 1.6 mg ascorbic acid equivalents/g crude extract). Among the four seaweeds, ethanol extract of T. atomaria has recorded the highest value in ferric reducing antioxidant power (FRAP) assay (32.3 ± 0.0 mg ascorbic acid equivalents/g crude extract). The uppermost level of carbohydrates was (20.4% ± 0.4 and 19.5% ± 0.7 dry wt.) in P. pavonia and T. atomaria. Proteins were maximum (10.5% ± 0.6 and 8.0% ± 0.0 dry wt.) in P. pavonia and T. atomaria. The results detected that T. atomaria had the largest amounts of lipids (5.92% ± 0.09 dry wt.). The polyunsaturated ω6 essential fatty acids were recorded in T.atomaria, P. pavonia, and J. rubens (11.39%, 8.09%, and 6.28%), and ω3 essential fatty acids were recorded in T. atomaria and P. pavonia (0.65% and 0.97%). The seaweeds are interesting candidates for medicinal, pharmaceutical, and nutritional applications owing to their antioxidant activities, biochemical composition; they are not widespread in the coastal waters of Egypt and has few studies, especially T. atomaria.

Consumption of Terpenoids-Rich Padina pavonia Extract Attenuates Hyperglycemia, Insulin Resistance and Oxidative Stress, and Upregulates PPARγ in a Rat Model of Type 2 Diabetes.

Seaweeds are rich in structurally diverse bioactive compounds with promising therapeutic effects. This study aimed to isolate and identify terpenes from the brown alga Padina pavonia and to investigate its antidiabetic activity, pointing to the possible involvement of peroxisome proliferator-activated receptor (PPAR)γ. Type 2 diabetes was induced by feeding rats a high fat diet (HFD) for 4 weeks followed by injection of 35 mg/kg streptozotocin (STZ). The diabetic rats received P. pavonia extract (PPE; 50, 100 and 200 mg/kg) for 4 weeks and samples were collected for analyses. HFD/STZ-induced rats showed hyperglycemia, dyslipidemia, impaired glucose tolerance, decreased insulin, and increased HbA1c and HOMA-IR. PPE ameliorated hyperglycemia and dyslipidemia, and improved glucose tolerance and insulin sensitivity in diabetic rats. Treatment with PPE increased hepatic hexokinase activity and glycogen, suppressed glucose-6-phosphatase, fructose-1,6-biphosphatase, and glycogen phosphorylase, and attenuated oxidative stress, inflammation, and liver injury and lipid infiltration in HFD/STZ-induced rats. In addition, PPE boosted antioxidants and upregulated PPARγ gene and protein expression in the liver of diabetic rats. Phytochemical investigation resulted in the isolation of six terpenes from PPE and in silico analysis revealed their binding affinity toward PPARγ. In conclusion, P. pavonia-derived terpenes attenuated hyperglycemia, dyslipidemia, oxidative stress, and inflammation, and improved insulin sensitivity and carbohydrate metabolism in type 2 diabetic rats. These beneficial effects are mediated via PPARγ activation. However, further studies to explore the exact mechanisms underlying the antidiabetic effect of PPE are recommended.

Component Analysis and Antifungal Activity of the Compounds Extracted from Four Brown Seaweeds with Different Solvents at Different Seasons

The polar and nonpolar extracts of Colpomenia sinuosa, Padina pavonia, Cystoseira barbata and Sargassum vulgare collected during spring, summer and autumn were evaluated for their antifungal activities. The phytochemicals of unexplored seaweeds were analyzed by gas chromatography and mass spectrometric (GC/MS). The algal extracts were tested for their antifungal activities against Aspergillus niger, A. flavus, Penicillium parasiticus, Candida utilis and Fusarium solani. Phytochemicals were extracted from the four seaweeds with various solvents including methanol, ethanol, acetone, chloroform and dimethyl ether. Among the various extracts, methanolic extract showed the highest inhibition activity on all fungal species. Seasonal variation in antifungal activity was studied, while methanol extracts showed the best antifungal activity in spring. Cystoseira barbata was the most effective seaweed, having antifungal activity throughout the whole year. The UV-Vis phytochemical procedure and GC-MS analysis of the methanol extracts from tested species indicated the existence of different constituents. In conclusions, the compounds with antifungal activity were identified as indoles, terpenes, acetogenins, phenols, and volatile halogenated hydrocarbons.

Biosynthesis of silver nanoparticles by using of the marine brown alga Padina pavonia and their characterization.

Silver nanoparticles (AgNPs) are gaining considerable importance due to their attractive physicochemical properties for many applications. In the present study, (Ag NPs) were synthesized by the reduction of aqueous solutions of silver nitrate (AgNO3) with powder and solvent extracts of Padina pavonia (brown algae). The obtained nanoparticles exhibited high stability, rapid formation of the biogenic process (2 min -3 h), small size (49.58–86.37 nm) (the diameter of formed nanoparticles was measured by TEM and DLS) and variable shapes (spherical, triangular, rectangle, polyhedral and hexagonal). Preliminary characterization of nanoparticles was monitored by using UV–visible spectroscopy (UV–vis), Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS) and finally by Fourier Transform Infrared spectroscopy (FTIR). The ratios of converted Ag NPs were recorded as 88.5; 86.2 and 90.5% in case of P. pavonia powder. extract and chloroform extract, respectively.

Pesticide residues in muscles of some marine fish species and seaweeds of Iskenderun Bay (Northeastern Mediterranean), Turkey.

Pesticide residues in muscles of nine marine fish and four seaweed species of Iskenderun Bay (Northeastern Mediterranean) have been investigated. In sampled fish species, two herbicides, three insecticides, two fungicides, and one synergist were identified and quantified. Metribuzin DADK, propamocarb HCl, and piperonyl butoxide (PBO) were detected in all the muscles of sampled fish species. Metribuzin DADK was the most abundant pesticide residue in fish muscles and the highest metribuzin DADK concentration was found in sardine (311.20μg/kg). Propamocarb HCl concentrations varied greatly among species; from 0.530 ± 0.020μg/kg in striped sea bream to 34.170μg/kg in sea bass. The level of PBO ranged from 0.001μg/kg for fourlined terapon to 0.013μg/kg for sardine. No measurable oxamyl residue was found in any of the muscles of sampled fish species (except sardine). In seaweeds, two herbicides and two insecticides were identified and quantified. Metribuzin DADK was the most abundant and found in Cystoseira corniculata (5.01mg/kg), Corallina elongata (0.703mg/kg), and Jania rubens (3.85mg/kg). Molinate was a minor contaminant and only found in Corallina elongata (0.002mg/kg). Pyrethrin I was determined only in Padina pavonia to be 0.567mg/kg. Pyrethrine II was found in Padina pavonia and Corallina elongate to be 1.214 and 0.229mg/kg, respectively. The most hazardous pesticide residues of organochlorines and organophosphorus were not detected in both sampled fish muscles and seaweeds. There are no clear maximum residue limits for the detected eight pesticide residues declared for fish muscle by European Union MRL (2017). In conclusion, it can be considered that observed concentrations of pesticides in sampled nine marine fish species do not have a potential health risk for consumers. Some of the detected pesticide residues can be toxic for algae and aquatic life and regular monitoring studies are therefore essential to control the pesticide concentrations of aquatic biota in the region.

Brown seaweeds protect against azoxymethane-induced hepatic repercussions through up-regulation of peroxisome proliferator-activated receptor gamma and attenuation of oxidative stress

Context: Seaweeds of the genera Turbinaria and Padina have long been used as food and in traditional medicine for treating several diseases.Objective: The current study determines the protective efficacy of the brown seaweeds Turbinaria ornata (Turner) J. Agardh (Sargassaceae) and Padina pavonia (Linnaeus) J.V. Lamouroux (Dictyotaceae) against liver injury induced by azoxymethane (AOM).Materials and methods: Male Swiss mice received 10 mg/kg AOM once a week for two consecutive weeks and then 100 mg/kg daily dose of either T. ornata or P. pavonia ethanolic extract. Thirteen weeks after the first AOM administration and 24 h after the last treatment, overnight fasted mice were sacrificed and samples collected.Results: Compared with the AOM group, both T. ornata and P. pavonia significantly decreased the activity of aminotransferases and the concentration of bilirubin while increased albumin levels in the serum. The antioxidative effect of both extracts was observed from the increased activity of superoxide dismutase and glutathione peroxidase activities in the liver, both of which were decreased by AOM. Moreover, the levels of malondialdehyde and nitric oxide were reduced, and histological findings also confirmed the antihepatotoxic activity. In addition, treatment with T. ornata and P. pavonia significantly increased PPARγ and decreased NF-κB expression in the liver of AOM-administered mice.Discussion and conclusion: Our findings indicate that the protective function of T. ornata and P. pavonia on AOM-induced liver injury may be possibly exerted by multiple pathways including abolishment of inflammation and oxidative damage, and activation of PPARγ.

Antimicrobial activity of some seaweeds species from Red sea, against multidrug resistant bacteria

This study evaluates the antibacterial activity of diethyl ether, methanol, ethanol and chloroform extracts of red algae Ceramium rubrum (Rhodophyta), Sargassum vulgare, Sargassum fusiforme and Padina pavonia (Phaeophyta) collected from Red sea, Egypt. The algal extracts were tested for their antibacterial activity against ten multidrug resistant clinical isolates of Gram positive and Gram negative bacteria. The highest inhibition activity among all extracts was obtained with 100μl diethyl ether extract S. fusiforme against Staphylococcus aureus 2 and 50μl ethanol extract of S. vulgare against Klebsiella pneumoniae. The algal extract of S. fusiforme and S. vulgare was characterized by Gas chromatography–mass spectrometry (GC–MS). The compounds with antimicrobial activity were identified, such as phenols, terpenes, acetogenins, indoles, fatty acids and volatile halogenated hydrocarbons. Transmission electron microscopy was applied for determining the morphological changes in S. aureus 2 and K. pneumonia treated with 100μl diethyl ether extract of S. fusiforme and 50μl ethanol extract of S. vulgare, respectively. Perforation of cell wall, leakage of cytoplasmic contents, severe distortion of outer cell shape, inner chromatin mild scattered cytoplasmic vacuolation, rupture of cell wall, and decreased cell size for both bacterial isolates treated with 100μl diethyl ether of S. fusiforme extract and 50μl S. vulgare ethanolic extract were recorded.

Evaluation of sulphated polysaccharide-protein complexes isolated from marine algae on colon carcinoma by MTT

Cold and hot extraction methods (CEM and HEM) were used for polysaccharides from Dictyopetris membraceae, Padina pavonia, Colpomenia sinusa, Ulva fasciata, Enteromorpha intestinalis, Corallina officinalis, Petrocladia capillraceae, Jania rubes and Spirulina platensis. These polysaccharides were tested against a colon carcinoma cell line (HCT115) at various concentrations (100 – 6.26 µg/mL) using the MTT assay.

Anti - Diabetic Effects of Padina Pavonia in Fructose - Induced Diabetic Rats

Anti - Diabetic Effects of Padina Pavonia in Fructose - Induced Diabetic Rats

Protective Effects of Turbinaria ornata and Padina pavonia against Azoxymethane-Induced Colon Carcinogenesis through Modulation of PPAR Gamma, NF-κB and Oxidative Stress.

The aim of this study was to investigate the antiproliferative and protective effects of the brown seaweeds, Turbinaria ornata and Padina pavonia, against azoxymethane (AOM)-induced colon carcinogenesis in mice. Both algal extracts showed anti-proliferative effects on the human carcinoma cell line HCT-116 in vitro, with T. ornata demonstrating a more potent effect. Male albino Swiss mice received intraperitoneal injections of AOM (10 mg/kg) once a week for two consecutive weeks and 100 mg/kg of either T. ornata or P. pavonia extracts. AOM-induced mice exhibited alterations in the histological structure of the colon, elevated lipid peroxidation and nitric oxide, declined glutathione content and reduced activity of superoxide dismutase and glutathione peroxidase. In addition, AOM induced downregulation of peroxisome proliferator activated receptor gamma (PPARγ) and p53 mRNA expression, with concomitant upregulation of nuclear factor-kappa B (NF-κB) in colon tissue. Administration of either algal extract markedly alleviated the recorded alterations. In conclusion, the current study suggests that T. ornata and P. pavonia, through their antioxidant and anti-inflammatory effects, are able to attenuate colon inflammation by downregulating NF-κB expression. Furthermore, the protective effects of both algae against AOM-initiated carcinogenesis were attributed, at least in part, to their ability to upregulate colonic PPARγ and p53 expression.

Biochemical evaluation of antioxidant activity and polysaccharides fractions in seaweeds

In the present study ethanol and water extracts of 15 seaweeds, Dictyota dichotoma var. velutricata, Dictyota indica, Iyengaria stellata, Padina pavonia, Sargassum swartzii, Sargassum variegatum, Stoechospermum marginatum, Stokeyia indica, Jolyna laminarioides, Caulerpa taxifolia, Halimeda tuna, Ulva fasciata, Ulva lactuca, Solieria robusta, and Melanothamnus afaqhusainii, were evaluated for their antioxidant potential by ABTS or 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), superoxide and total antioxidant capacity (TAC) assays. The activity was concentration dependent and the variation in antioxidant potential was also observed by different assays in both extracts. Ethanol extract of D. dichotoma var. velutricata, D. indica and S. marginatum demonstrated highest activity by TAC assay. The antioxidant potential in organic solvent fractions of seaweeds namely P. pavonia, S. swartzii, S. marginatum and M. afaqhusainii was also determined and chloroform fraction of all the four seaweeds showed highest activity by superoxide assay. Antioxidant activity of extracted fractions of polysaccharides from S. indica, C. taxifolia and D. dichotoma var. velutricata was also evaluated by superoxide method. Polysaccharide fractions of S. indica obtained from HCl (at 700C and room temperature) and water extract demonstrated highest activity respectively. All the polysaccharide fractions of C. taxifolia showed excellent activity except CaClF70°C. Polysaccharide fractions of D. dichotoma var. velutricata also exhibited very good activity.

Biosorption of Uranium Ions by Marine Macroalga Padina pavonia

The bioremoval potential of brown marine macroalga Padina pavonia for the uranium ions from aqueous solutions was studied under different experimental conditions with respect to the influences of pH, initial uranyl concentration, contact time, biomass dosage, and temperature of solution. Langmuir, Freundlich, Dubinin–Radushkevich, Flory–Huggins, and Brunauer–Emmett–Teller models were applied to describe the biosorption isotherm of uranium ions by P. pavonia biomass. Thermodynamic parameters such as biosorption enthalpy, entropy and free energy transition have been calculated. Biosorption from simulated artificial wastewater by P. pavonia was also investigated. Bioremoval efficiency and distribution coefficient of biomass, under the optimum biosorption conditions were calculated as 98 ± 1% and 5257 ± 312 mL/g, respectively. The Dubinin–Radushkevich isotherm model better fits the biosorption data and the experimental biosorption capacity was found to be 162 mg .

Screening of the Antibacterial Activity of Some Marine Algae Against Fish and Human Pathogens

This study aims to investigate the effect of some algal extracts as antibacterial agents against some pathogenic bacteria. Thus the ethyl acetate and methanolic extracts of the marine algae Ulva lactuca, Enteromorpha compressa, Ulva fasciata, Pterocladia capillacea, Corallina mediterranea, Hypnea musciformis and Padina pavonia, collected from the coast of Alexandria (Egypt), were tested as antibacterial agents against fish and human pathogenic bacteria; Aeromonas hydrophila, Vibrio anguillarum, Pseudomonas fluorescens, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhimurium. The best activities were shown by the methanolic-L extract of P. capillacea against P. fluorescens, V. anguillarum and P. aeruginosa. The methanolic-L extract of U. lactuca showed high activity towards A. hydrophila, V. anguillarum, P. fluorescens and S. aureus. Cluster analysis was used to study the action of the crude algal extracts.

Cytotoxic xenicane diterpenes from the brown alga Padina pavonia (L.) Gaill.

Column chromatography of the hexane fraction of a methanol extract of Padina pavonia (L.) Gaill. collected from the Red Sea at Hurghada, Egypt yielded 18,19-epoxyxenic-19-methoxy-18-hydroxy-4-acetoxy-6,9,13-triene (1) and 18,19-epoxyxenic-18,19-dimethoxy-4-hydroxy-6,9,13-triene (2). The isolated compounds have various antitumor activities against lung carcinoma (H460) and liver carcinoma (HepG2) human cell lines (in vitro).

Comparative efficacy of brown, green and red seaweeds in the control of root infecting fungi and okra

The effect of soil amendment by brown, green and red seaweeds was studied in controlling the root rot infecting fungi of okra seedlings in the greenhouse. The soil amendment with seaweeds Stokeyia indica, Padina pavonia (brown), Solieria robusta (red), at 1% w/w reduced Macrophomina phaseolina, Rhizoctonia solani and Fusarium solani infection on okra roots. Codium iyengarii (green) at 0.5 % w/w was effective against F. solani, while at 1% w/w was found phytotoxic. S.robusta showed better control of F. solani infection when used with Pseudomonas aeruginosa than either used alone. S. robusta produced better plant height and fresh weight of shoot than P. aeruginosa. Results of the present study suggest that the use of brown seaweeds S. indica and P. pavonia alone and S. robusta alone or in combination with P. aeruginosa have great potential to control root-infecting fungi of okra with enhancement of plant growth. These seaweeds alone or in combination with P. aeruginosa may be utilized as biological control of root infecting fungi of okra.

Marine macroalgae as biosorbents for cadmium and nickel in water.

Experimental studies showed that brown marine algae, Sargassum vulgaris and Padina pavonia, can be used to develop an efficient biosorbent for heavy metal removal from aqueous solutions. Sargassum vulgaris exhibited high uptake capacities for cadmium (0.9 to 1.1 mmol Cd/gr) and nickel (0.85 to 1 mmol Ni/gr) that are higher than those of other types of biomass and powdered activated carbon, while P. pavonia showed a broader range of nickel and cadmium uptake capacities (0.7 to 1 mmol Ni/gr and 0.8 to 1.1 mmol Cd/gr). The metal adsorption and desorption processes were rapid, with 70% of the sorption and desorption completed within 10 minutes. The equilibrium data for both algae fit well to Langmuir and Freundlich isotherm models. More than 90% desorption of adsorbed metals from the algae was achieved by hydrochloric acid and ethylenediaminetetraacetic acid (1:1 molar ratio). After eight to nine adsorption and desorption cycles, S. vulgaris showed a 15 to 35% decrease in metal uptake capacities; P. pavonia showed a higher decrease of 50 to 60%.

Seasonal and vertical distribution of marine epiphytic algae in the Evoikos Gulf (Aegean Sea, Greece)

The subtidal epiphytic communities of both macroalgae and microalgae of the Aegean Sea have been inadequately investigated. In this paper epiphytic algal assemblages thriving on different hosts [i.e. the phaeophyte Padina pavonia (L.) LAMOUROUX, the chlorophyte Halimeda tuna (ELLIS et SOLANDER) LAMOUROUX and the seagrass Posidonia oceanica (L.) DELILE], were studied in a typical oligotrophic site of the Aegean Sea (Dikastika, Attica Peninsula) during the course of one year (June 1997-May 1998). A total of 47 taxa of epiphytic macroalgae were identified, with Hypnophyceae and Ephemerophyceae being the dominant life forms. The major algal groups (rhodophytes, phaeophytes, chlorophytes) showed a distinct seasonality, with rhodophytes predominating on all hosts. The majority of epiphytes favoured a certain position on the host thallus or blade. A distinct vertical zonation pattern was found, with epiphytes covering only certain host areas (upper-, middle-, lower parts of the plant), and further differentiated between the frond edge and blade's lamina. A total of 175 taxa of diatoms were identified and the diatom assemblages bear great resemblance to typical epiphytic floras, with dominant genera Mastogloia, Amphora, Nitzschia, Diploneis, Navicula and Cocconeis. Mass development of epiphytic diatoms on certain hosts implies host preference, but no host-specificity could be ascertained. The total epiphytic species composition seems to be affected by the seasonal alteration of abiotic factors. Epiphytic macroalgal species abundance and diversity was the highest during spring, having a possible competitive influence on the epiphytic diatom growth, whereas higher species abundance of diatoms during summer might furthermore be attributed to the surface increase of macroalgae.