Corallina Elongata Research Articles

Antibacterial properties of marine algae incorporated polylactide acid membranes as an alternative to clinically applied different collagen membranes

The reconstruction of bony defects in the alveolar crest poses challenges in dental practice. Guided tissue regeneration (GTR) and guided bone regeneration (GBR) procedures utilize barriers to promote bone regeneration and prevent epithelial growth. This study focuses on evaluating the antibacterial properties of marine algae-polylactic acid (PLA) composite membranes compared to commercially available collagen membranes. Marine algae (Corallina elongata, Galaxaura oblongata, Cystoseira compressa, Saragassum vulgare, and Stypopodium schimperi) were processed into powders and blended with PLA to fabricate composite membranes. Cytocompatibility assays using human periodontal ligament fibroblasts (n = 3) were performed to evaluate biocompatibility. Antibacterial effects were assessed through colony-forming units (CFU) and scanning electron microscopy (SEM) analysis of bacterial colonization on the membranes. The cytocompatibility assays demonstrated suitable biocompatibility of all marine algae-PLA composite membranes with human periodontal ligament fibroblasts. Antibacterial assessment revealed that Sargassum vulgare-PLA membranes exhibited the highest resistance to bacterial colonization, followed by Galaxaura oblongata-PLA and Cystoseira compressa-PLA membranes. SEM analysis confirmed these findings and revealed smooth surface textures for the marine algae-PLA membranes compared to the fibrous and porous structures of collagen membranes. Marine algae-PLA composite membranes show promising antibacterial properties and cytocompatibility for guided bone and tissue regeneration applications. Sargassum vulgare-PLA membranes demonstrated the highest resistance against bacterial colonization. These findings suggest that marine algae-PLA composite membranes could serve as effective biomaterials for infection control and tissue regeneration. Further in vivo validation and investigation of biodegradation properties are necessary to explore their clinical potential.Graphical

Development of novel CaO-based catalysts from Corallina elongata alga for enhanced methylene blue photodegradation

Development of novel CaO-based catalysts from Corallina elongata alga for enhanced methylene blue photodegradation

Tissue nutrient contents of the red alga Ellisolandia elongata as a tool to assess the ecological status in NW Mediterranean coastal waters

Eutrophication is a major threat to aquatic ecosystems because excessive nutrient enrichment may result in biodiversity loss, profound functional changes and reduction of ecosystem services. Unless several water quality indexes have been developed following the implementation of the EU Water Framework Directive (WFD), there is still room for improvement. In particular, the stress-tolerant articulated red coralline alga Ellisolandia elongata (=Corallina elongata) is dominant in a wide range of environmental conditions, hampering a proper evaluation of the water quality of some of these places. Here we have checked whether E. elongata can be used as a eutrophication bioindicator by measuring the tissue phosphorus and nitrogen contents. Our results detect an increase in tissue nutrient contents in E. elongata along a gradient of nutrient enrichment and, thus, it can be used as bioindicator of water quality status. Their measurement will allow a more accurate water quality assessment in places dominated by E. elongata where WFD compliant indexes based whether on species/assemblages presence and/or abundance do not provide enough resolution.

DNA barcoding of marine macroalgae as bioindicators of heavy metal pollution

Metal pollution in the marine coastal environment is an important topical issue. In this study, the water quality in five locations along the Alexandria coast (Eastern Harbor, El-Tabia pumping station, El Mex Bay, Sidi Bishir, and Abu Talat) was assessed by measuring physicochemical parameters from water samples. Depending on the morphological classification of macroalgae, the collected morphotypes were related to Ulva fasciata, Ulva compressa, Corallina officinalis, Corallina elongata, and Petrocladia capillaceae. Corallina officinalis and Corallina elongata demonstrated a high capacity for Cd, Pb, and Ni accumulation, and the highest values of Fe, Cu, and Mn were reported in Ulva fasciata and Ulva compressa. Two standard markers were applied, and results showed that the morphological classification matched the molecular data. Moreover, the analysis of algae can only reflect the accumulation of metals. The conclusion is that Ulva compressa and Corallina officinalis are potentially suitable indicators of localized short-term heavy metal pollution.

The effect of Enteromorpha intestinalis and Corallina elongata on physiological parameters of Zea mays L.

Purpose: Algae are living organisms capable of photosynthesis and live mainly in an aquatic environment (marine or freshwater), and considered as plants like those growing on the soil. It can therefore be used to enrich the soil in organic matter, and mineral elements, as for composting green waste, for example. The objective of this study was to investigate the effect of marine macroalgae Enteromorpha intestinalis (Ulvophycae) and Corallina elongata (Corallinacae) as biofertilizers on the growth of Zea mays L. Method: After rinsing, the algae were ground into a fine powder. The powder obtained from each seaweed was divided into two batches. For the first batch, the seaweed powder (AP), was used directly in the pots one week before planting. Two concentrations, 5% and 10%, were studied. The second batch was used to prepare liquid algal fertilizer (ALF). To determine the mineral composition of each seaweed, X-ray fluorescence analysis was performed. the biofertilizing potential of Enteromorpha intestinalis and Corallina elongata was studied on corn plants, evaluating the effect of these two algae at different growth stages (15, 25, 45 and 60 days) and the chlorophyll a and b content. Results: The elemental analysis of the two algae by X-ray Fluorescence shows that the main elements are water, chlorine, potassium, calcium, silicon, natrium, magnesium, iron and sulfur. The results show that E.intestinalis is richer in minerals compared to C.elongata, except for Strontium and calcium, where C.elongata is more rich. Conclusion: The results of this study showed that the macroalgae Enteromorpha intestinalis and Corallina elongata from the Atlantic coast of Morocco are valuable biofertilizers. On the other hand, the application of seaweed extract is more effective than the application of seaweed powder, and Enteromorpha intestinalis can affect the growth parameters at a low concentration (5%), unlike Corallina elongata. The different positive roles of algae in agriculture should be clarified, as our results showed that they can be used as an excellent fertilizer.

Antioxidant, antidiabetic, anti-inflammatory and anticancer potential of some seaweed extracts

This study aims to evaluate the secondary metabolites, cytotoxicity, antioxidant, antidiabetic, anti-inflammatory, and anticancer activities of four selected seaweeds Padina pavonica, Taonia atomaria, Jania rubens, and Corallina elongata. The maximum value of phenolic content (176.7 ± 6.9 mg gallic acid equivalents/g crude extract) and tannin content (26.5 ± 4.3 mg tannic acid equivalents/g crude extract), was shown in the methanol extract of J. rubens and P. pavonica, respectively. While the ethanol extract of T. atomaria recorded the highest values of total flavonoid content (374.1 ±27.4 mg quercetin equivalents/g crude extract) and total saponins content (30.2 ± 0.7 mg cholesterol equivalents/g crude extract, respectively) compared to other seaweeds. Methanol extract of J. rubens and C. elongata exhibited the greatest content of alkaloids (25.8 ± 4.4 and 22.7 ± 2.6 mg/g d wt.). The methanol extract of P. pavonica established the highest DPPH radical scavenging activity (55.7% ± 0.1) at 50 μg/mL. Among the selected seaweed extracts, the ethanol extract of T. atomaria demonstrated the maximum α-amylase inhibition capacity (66.3% ± 0.0). Methanol extract of J. rubens and P. pavonica species effectively prevented the hypotonicity-induced haemolysis in a concentration-dependent manner compared with the diclofenac potassium as a standard anti-inflammatory drug. In vitro, the reported results also supported the safety and non-toxicity of the four seaweed extracts on WI-38 cell line at lower concentrations. J. rubens and P. pavonica methanol extracts recorded the highest cell growth inhibition of the HeLa Cancer Cell Lines compared to other seaweed extracts and the standard drug Cisplatin.

Evaluation of Antimicrobial Effects of Four Selected Marine Macroalgae from Iskenderun Bay

In the present study, the seaweeds belong to Phaeophyaceae (Cystoseira elegans Sauvageau 1912, Cystoseira amentacea (C.Agardh) Bory 1832, Padina crassa Yamada 1931) and Florideophyceae (Corallina elongata J.Ellis & Solander 1786) collected from nearby Iskenderun-Turkey of Mediterranean Sea were detected for their antimicrobial activities against seven bacterial strains (Escherichia coli ATCC 35218, Bacillus cereus NRRL B-371, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC 13883, Salmonella typhimurium ATCC 14028, Proteus vulgaris RSKK 96029). The antimicrobial activities were expressed as minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs). According to the results obtained from MICs and MBCs values of the extracts on pathogenic microorganisms were between 0.78 to 50 mg/mL. The lowest MICs and MBCs values were recorded for C. elegans extract against B. cereus with a MIC value of 0.78 mg/mL. These results suggest that secondary metabolites of brown and red algae are important sources that could be used as broad spectrum of biological and pharmaceutical activities.

A New Biofertilizer Formulation with Enriched Nutrients Content from Wasted Algal Biomass Extracts Incorporated in Biogenic Powders

Raw algae waste naturally thrown on shores could pose serious threats for landfilling and its reuse for composting or further processing as added-value by-products require knowledge-based decisions and management for the sustainable development of local ecosystems. Raw marine waste containing salt (halite) and heavy metals that eventually accumulate in algae hamper their safe applicability in soil fertilization or in other exploitations. Here, the suitability of algal biomass for use as an environmentally safe fertilizer was investigated, thereby supporting sustainable coastal management. The simple extraction of the dry algal biomass of three abundant Mediterranean species, Enteromorpha intestinalis, Corallina elongata, and Gelidium pulchellum, in water containing sodium carbonate resulted in a greenish extract containing a reduced heavy metals content, and nutrients such as K+, PO43−, SO42−, NO3−, Ca2+, and Mg2+. UV-Vis and Raman techniques, including surface-enhanced Raman scattering (SERS), were employed for the fast evidencing of polyphenols, carotenoids, and chlorophylls in the extracts content, while E. intestinalis extract additionally exhibited polysaccharide signals. Heavy metals analysis showed that the major metals in the extracts were Fe, Ni, Zn, and Cu; however, their levels were an order of magnitude lower than in the dry biomass. The extracts also showed a mild antibacterial effect. The combination option of aqueous extracts with powdered crustacean shells to obtain a novel, eco-friendly, solid biofertilizer complex was further shown, which could be pelleted for convenient use. The immersion of solid biofertilizer pellets in water is accompanied by re-solubilization of the compounds originating from algae extracts, presenting the opportunity for dry storage and easier handling and land applicability. In summary, aqueous extracts of marine algae waste present an environmentally safe and attractive way to recycle excessive algal biomass and to formulate a new, eco-friendly biofertilizer complex.

Chemical Composition and Nutritional Value of Different Seaweeds from the West Algerian Coast

ABSTRACTAnalysis of proximate composition, lipid fraction (fatty acids and lipid classes), macroelements, and trace elements was carried out on brown (Cystoseira stricta; Cystoseira compressa), red (Corallina elongata), and green (Enteromorpha compressa; Ulva lactuca) seaweeds collected from the west Algerian coast to assess their nutritional value. Protein, lipid, carbohydrate, and ash content (g kg−1 dry alga) was in the ranges 58.5–141.4, 6.4–27.1, 134.0–461.1, and 246.1–764.2, respectively. The lowest caloric value was obtained for C. elongata (827.6 kcal kg−1 dry alga); the remaining values being in the range 2,106–2,479 kcal kg−1 dry alga. C. elongata and C. stricta provided the highest polyunsaturated fatty acid content, while a valuable n-6/n-3 ratio of between 0.95 and 4.20 was obtained for all species. α-Tocopherol was present in all seaweeds; the highest level was obtained in U. lactuca. Macroelements K and Na were predominant in C. compressa and C. stricta; while Mg and Ca were most abundant in E. compressa and C. elongata, respectively. In all cases, a healthy Na/K value < 0.7 was observed, and a profitable ion quotient ratio was observed in all cases, except for C. elongata. Estimated daily intake of most minerals from the algae studied is lower than the corresponding recommended daily intake.

Study of the macroalgae and application of ecological evaluation index (EEI-c) in the coastal waters of Algeria

The diversity of macroalgae and evaluation of the Algerian coastal waters using EEI-c index were studied. Macroalgae were sampled at seven stations in summer 2019. Coverage data for the macroalgae at each site were analysed at species level. Eleven species have been identified and the results showed the prevalence of Cystoseira compressa and Ulva sp .. The least abundant species were Cladophora sp. and Corallina elongata . Classification of sites based on the cluster analysis shewed an agreement with the water degradation information. Based on the results, the EEI-c values were quite homogeneous over all the studied sites, and generally correspond to undisturbed states except for one site.

Characterisation of carrageenan extracted from fresh and defatted red algae along the Pamban coast, Tamilnadu, India

Studies carried out to breakdown the yield and Fourier-Transform Infrared (FTIR) spectral properties of polysaccharide from Corallina elongata (J.Ellis & Solander), Liagora mannarensis (V.Krishnamurthy & Sundararajan) and Portieria hornemannii (Lyngbye). Carrageenan yield in the range of 16.4 to 24.2% in fresh algae than 14.2 to 23.8% defatted algae was recorded. Spent biomass in the range of 62.0 to 72.0% in fresh algae than 61.2–70.4% defatted algae was recorded. Total sugar, reducing sugar and sulphate were maximum in P. hornemannii (Lyngbye) and minimum in C. elongata (J.Ellis & Solander) having fresh algae carrageenan compared to the defatted algae carrageenan. FTIR spectroscopy study shows that the carrageenan extracted from fresh and defatted C. elongata (J.Ellis & Solander) have both kappa and iota type carrageenan. Fresh and defatted carrageenan from L. mannarensis (V.Krishnamurthy & Sundararajan) and P. hornemannii (Lyngbye) have kappa, lamda and iota type carrageenan.

Evaluation of the energetic valorization of the lagoon and Mediterranean algae (Caulerpa prolifera &amp; Corallina elongata) by anaerobic digestion

Abstract Morocco is characterized in the North-East by two aquatic ecosystems (the Mediterranean Sea and the Nador Lagoon).The latter is a reservoir of algal proliferation that worsens with the installation of localized pollution in the last decades. In this work, we have evaluated and compared the energy recovery of the two important algae (Caulerpa prolifera, Corallina elongata) that are abundant in these two ecosystems. Thus, we found that Caulerpa prolifera produces more biogas than Corallina elongata. Caulerpa prolifera shows a significant influence of mechanical pretreatment on anaerobic digestion, which is reflected in a decrease in biogas production from 30.4 ml/gTS to 12 ml/gTS. On the other hand, Corallina elongata has a low dependence on pretreatment which varies between 4.42 and 6.63 ml/g TS. Additionally, the digestion of this red alga leads to the disappearance of the bacterial arsenal in the digester so it reacts negatively on the efficiency of this process. Therefore, the energy recovery of Corallina elongata shows a significant influence of its chemical composition on the anaerobic digestion that is not in favor of this process. Based on the obtained results, the mixing test of these two algae in the same digester shows that it is not beneficial for a common valuation. The anaerobic digestion of Caulerpa prolifera with a particle size of 0.12 mm makes it possible to obtain a large production of biogas which allows a good valorization of this natural resource.

Fatty acid and lipophilic vitamin composition of seaweeds from Antalya and Çanakkale (Turkey)

The lipophilic vitamin and fatty acid profiles were determined in five edible seaweeds: Corallina elongata J. Ellis &amp; Solander, 1786; Cystoseira barbata (Stackhouse) C. Agardh, 1820; Jania rubens (Linnaeus) J.V. Lamouroux, 1816; Laurencia obtusa (Hudson) J.V. Lamouroux, 1813 and Sargassum vulgare C. Agardh, 1820. Saturated fatty acids (SFAs) were the major fatty acid group, and16:0 formed the highest SFA content (34–40%). 16:0 was higher in the brown seaweeds (C. barbata, 40.55%; S. vulgare, 37.11%) than in the red seaweeds (C. elongata, 36.5%; L. obtusa, 34.57%; J. rubens, 34.22%). The other major fatty acids in the seaweeds were 18:1n-9 and 16:1n-7 from MUFA in the analyzed species. In addition, EPA was found in significant levels in the red seaweeds, whereas DHA was not detected in the analyzed species. The findings showed that difference among species were not statistically significant (p = 0.09–0.11), yet differences between two families (Sargassaceae and Corallinaceae) were significant (p = 0.006) in the fatty acid profile (p &lt; 0.01). Also, differences between the Corallinaceae and Rhomomelaceae families were partially significant (p = 0.011–0.013) (p &lt; 0.01). K1 and K2 vitamins as well as δ-tocopherol, α-tocopherol and retinol acetate were determined to be present in the seaweed extracts. Finally, ergosterol, stigmasterol and ß-sitosterol were found in all samples in differing ratios per species.

Trophic flexibility and prey selection of the wild long-snouted seahorse Hippocampus guttulatus Cuvier, 1829 in three coastal habitats

The present study examined the dietary composition of long-snouted seahorse H. guttulatus Cuvier, 1829 in Mar Piccolo of Taranto (Apulia, Italy) using a non-destructive flushing method. To assess differences in the selection of prey among different habitats, adult specimens were collected from both highly complex (Cladophora prolifera and Corallina elongata) and low complex (unvegetated Sandy bottom) habitats. Additionally, samples of benthic fauna were collected from the same habitats and were used to investigate the local availability of potential preys. Results showed significant differences in the diet composition among three studied habitats. Consistently with the results of faunal analysis, gut contents of specimens sampled on C. elongata had higher prey abundance and diversity compared to the other two habitats. Dietary composition of seahorses found in the vegetated habitats was similar, and it was mainly based on Amphipoda and Copepoda. However, small prey (<1 mm) was more consumed on C. elongata than on C. prolifera. On the sandy bottom, H. guttulatus preyed mainly on small crustaceans, but actively selected larger prey (i.e. Galathoidea and Paguroidea). Nematodes were also highly preyed in all habitats, although the high consumption could be possibly attributed to the high abundance and availability of these organisms at the investigated site. H. guttulatus showed a great ability to exploit available resources in the best possible manner among different habitats, acting as a specialist predator. With an aim to understand the use of food resources that are available in the environment, the results of this study could help to propose initiatives directed to the seahorse conservation.Since prey availability does not seem to be a limiting factor in the understanding of variability and consistency of H. guttulatus populations, further studies on other environmental and biological aspects could be useful in the assessment of the conservation status of long-snouted seahorses.

Characterization of the Corallina Elongata Alga and Study of its Biosorption Properties for Methylene Blue

Biosorbents can be an alternative to activated carbon. They are derived from agricultural by-products or aquatic biomass. They are low cost and they may have comparable performances to those of activated carbon. The present study focuses on the characterization of the Corallina Elongata (CE) alga and its adsorption performance for Methylene Blue (MB), this alga is found in abundance at the Mediterranean coast of the city of Jijel in eastern Algeria. The dried alga was characterized using various characterization techniques such as DTA, TG, FTIR, XRD, SEM and EDX, which showed that the material consists essentially of a calcite containing magnesium. Batch adsorption studies were carried out and the effect of experimental parameters Such as pH, initial dye concentration, temperature, adsorbent dose and contact time, on the adsorption of MB was studied. The kinetic experimental data were found to conform to the pseudo-second-order model with good correlation and equilibrium data were best fitted to The Langmuir model, with a maximum adsorption capacity of 34.4 mg/g. The adsorption isotherms at various temperatures allowed the determination of certain thermodynamic parameters (ΔG, ΔH and ΔS). Finally, the adsorption results showed a good affinity between CE and MB with a high adsorption capacity.

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.

The Phenolic Contents and Antimicrobial Activities of Some Marine Algae from the Mediterranean Sea (Algeria)

In this study, three marine algae collected from western coast of algerian mediteranean sea (Ulva lactuca, Dictyota dichotoma, and Corallina elongata) were tested using the agar-well diffusion method for their production of antibacterial and antifungal agents on various organisms that cause diseases of humans and plants (Eschirichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Salmonella sp, Candida albicans, and Penicillium sp.). The total phenol content and antimicrobial activity were determined using different crude seaweeds extracts (methanol, diethylether, and chloroform). The results show that the chloroform extracts of (Ulva lactuca and Corallina elongata) had the highest activity against E. coli and Salmonella sp. The methanol extract obtained from (Ulva lactuca, Dictyota dichotoma, and Corallina elongata) showed antifungal activity for Candida albicans. The results of the study revealed that the seaweeds from Algeria appear to have immense potential as a source of antibacterial and antifungal compounds; they can be used in treating diseases caused by these organisms.

Comparison of in vitro antioxidant activity of some selected seaweeds from Algerian West Coast

In vitro antioxidant activity of methanolic (ME) and ethanolic (ET) extracts of six species of seaweeds (Cystoseira stricta, Cystoseira compressa, Corallina elongata, Porphyra umbilicalis, Enteromorpha compressa and Ulva lactuca) collected from Algerian West Coast was evaluated, using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assay and reducing power assay. They were tested for total phenolic content. The highest phenolic content was observed in C. compressa [10.24 ± 0.09 mg gallic acid equivalent (GAE) g-1 dry weight (DW) in ME extract and 15.70 ± 0.72 mg GAE g-1 DW in ET extract]. In general, the ET seaweed extracts were the most effective fractions. In addition, C. compressa and C. stricta extracts showed the highest antioxidant activity in all assays and better than vitamin E. However, these extracts present lower DPPH radical scavenging activity and reducing power than butylhydroxytoluene (BHT), except at concentration of 1 mg mL-1, in which it was similar. Therefore, C. compressa and C. stricta had a potential to be used as a natural antioxidant agent. Key words: Algerian, antioxidant activity, 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging, reducing power, seaweed.

Ostreopsis cf. ovata dynamics in the NW Mediterranean Sea in relation to biotic and abiotic factors

An expansion of the distribution of Ostreopsis cf. ovata, a dinoflagellate which produces palytoxin-like compounds, has been reported in recent years. Economical and social interests are affected by blooms, as they are responsible for respiratory and skin problems in humans and may cause damage to marine organisms. In order to identify the most influential environmental factors that trigger proliferations of O. cf. ovata in the area of the adjacent shallow rocky coast of the Ebro Delta (NW Mediterranean Sea) a three-year survey was performed on the metaphytic microalgae community growing on the macrophytes Jania rubens and Corallina elongata. Small-size diatoms were more abundant than dinoflagellates; O. cf. ovata was identified as the only species present from the genus. Seawater temperature was the primary driver defining the ecological niche of O. cf. ovata. Freshwater and groundwater fluxes were more pronounced in southern than in northern sites, which may have resulted in a distinct O. cf. ovata spatial distribution, with the highest records of abundance and more frequent blooms in the north. In consequence, negative correlations between the abundance of O. cf. ovata and nitrate concentrations and significant positive correlation with salinity were observed. The temporal pattern of O. cf. ovata dynamics from mid-July to early-November is probably due to the fact that this species is observed only above a certain threshold temperature of seawater. Metaphytic cells of O. cf. ovata were smaller in the northern site than in the south, possibly as a result of an increase in cell division, coinciding with higher abundance, and this could be an indicator of favorable conditions. Toxicity in planktonic cells was negatively correlated with cell abundance in the water column, achieving maximum concentrations of 25pg. PLTX eqcell−1.

Seasonal dynamics of upper sublittoral assemblages on Mediterranean rocky shores along a eutrophication gradient

Changes in the seasonal dynamics of Mediterranean macroalgal-dominated assemblages from the upper sublittoral zone are described along a gradient of sewage pollution. Algal coverage and composition were measured for more than one year at approximately monthly intervals. Nutrients concentrations (nitrites, nitrates, ammonia and phosphates) showed different seasonal patterns depending on the distance to the pollution focus. Ulva-dominated assemblages appearing close to the sewage outfall showed maximal coverage during early spring and started to decrease in May. Corallina-dominated assemblages - replacing ulvacean algae at intermediate levels of pollution - followed the same pattern, peaking in March and decreasing in May. In contrast, Cystoseira-dominated assemblages, present at sites with low or no influence of sewage, increased coverage in May and continued with high coverage until the end of summer. Neither ephemeral algae (Ulva spp.), nor stress-tolerant algae (Corallina elongata), nor canopy-forming algae (Cystoseira spp.) have a seasonal growth cycle governed by eutrophication. Results demonstrate also that the period from May to July is the best time of the year for Water Framework Directive (WFD) monitoring purposes as less variability is observed within the assemblages.