Spyridia Filamentosa Research Articles

Screening on the Presence of Plant Growth Regulators in High Biomass Forming Seaweeds from the Ionian Sea (Mediterranean Sea)

The use of seaweed as plant biostimulants is a solution for sustainable agriculture. The present study aims to quantify and compare the presence of plant growth regulators (PGRs) in four genetically labeled macroalgae growing in the Ionian Sea. Species were selected because they produce abundant biomass, disturbing ecological equilibrium and anthropic activities. We measured the content of gibberellic acid (GA3), kinetin (KN), indoleacetic acid (IAA), abscisic acid (ABA) and indole butyric acid (IBA). The method applied was modified from the literature to obtain simultaneously different PGRs from seaweed biomass in a shorter period of time. Among results, it is notable that Hypnea corona Huisman et Petrocelli (Rhodophyta) showed higher GA3 concentration, while in Spyridia filamentosa (Wulfen) Harvey (Rhodophyta), higher KN, IBA, IAA and ABA contents were recorded. The latter species displayed an interesting profile of PGRs, with an IAA value comparable with that reported in Ascophyllum nodosum (Linnaeus) Le Jolis (Ochrophyta), which is currently used as a source of plant biostimulants in agriculture. Macroalgae thrive abundantly in nutrient-rich environments, such as anthropized coastal areas affecting human economic activities. Consequently, environmental agencies are forced to dredge algal thalli and discard them as waste. Any use of unwanted biomass as an economic product is highly desirable in the perspective of ecosustainable development.

Normal, The Blob, and El Niño conditions: Effects on macroalgal blooms in a subtropical zone of the Gulf of California

The different oceanographic conditions influence marine ecosystems, particularly on macroalgae communities. For this reason, this study explored the effect of oceanographic events such as Normal Conditions, The Blob, and El Niño in the Southwest Gulf of California, in terms of species richness and biomass of macroalgal blooms. Temperatures in 2013 (Normal condition) were lower than in 2014–2015. The high temperatures recorded in 2014 (22.8 °C–32 °C) are associated with a warming phenomenon known as The Blob, whereas 2015 was an El Niño year. The anomalies in these two years ranged from 0.1 to 2.8 and from 0.3 to 1.7, respectively, relative to the average for 2002–2021. It was evident that the co-occurrence of The Blob and El Niño modified the patterns of species richness and abundance in the macroalgal blooms recorded in Bahía de La Paz, compared to a year under the Normal condition. The lowest species richness was observed in 2014. Regarding seasonal variability, in 2014 the highest species richness was recorded in spring and the maximum biomass in summer, contrary to what is generally the case in the bay. Species of tropical affinity such as Spyridia filamentosa, Padina durvillei, and Caulerpa sertularioides significantly increased their biomass in the El Niño year.

Environmental assessment of three different sites in shallow environments of La Paz Bay (Gulf of California) using the TRIX index and macroalgae biomass. Part I

Coastal areas are of particular ecological and economic importance as they provide direct and indirect goods and services to society, both biological indicators and water quality assessment are of importance when monitoring these environments. Hydrographical parameters, nutrients, chlorophyll-a, and macroalgae biomass were measured, and the TRIX index was obtained, at three sites of La Paz Bay subjected to different types of anthropogenic influence: San Juan de la Costa (SJC), Casa del Marino (CM), and El Tecolote (TE), during two months of 2017 and four months of 2018. Also, macroalgae blooms at these sites were monitored by sampling the biomass of key species. Temperature showed the typical seasonal variation, from 21 °C in winter to 28 °C in summer, while salinity showed little variation (35–37 psu). Chlorophyll-a varied in parallel with changes in water temperature (0.3–2.4 μg L−1), while nutrients varied depending on the season and site. The TRIX index showed significant differences between seasons, with the highest values in the warmer months (6.0) and the lowest in November (2.7); the sites studied ranged from mesotrophic to oligotrophic. Four macroalgae species accounted for over 60% of the biomass during the sampling period: Ulva ohnoi (16.1 kg), Spyridia filamentosa (6.5 kg), Acanthophora spicifera (4.2 kg), and Ulva sp. 1 (2.7 kg). Ulva, Gracilaria, and Hypnea species showed a positive significant correlation with nutrients and the TRIX index. A high macroalgae biomass may be related to a mesotrophic state, showing its value for determining the health status of coastal ecosystems and issuing proper management recommendations.

Evaluation of the Antimicrobial and Antioxidant Activity of Two Chlorophyceae and Two Rhodophyceae Seaweeds from Porbandar Coast

Seaweeds are significant marine sources of bioactive compounds with prospective use inefficient foods and nutraceutical products. Four marine macroalgae species from the western coasts of Gujarat were evaluated for their antimicrobial and antioxidant activity. The antimicrobial activity of extracts of red seaweed Hypnea valentiae and Spyridia filamentosa and green seaweed Enteromorpha compressa and Caulerpa racemosa using cold percolation extraction in an in-vitro method and testing against six pathogenic bacteria and one fungi. Results showed effective inhibition zone. The antioxidant activity of the seaweeds methanol extracts was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay for measuring potential scavenger of free radical. Both activities were shown promising result of all four seaweeds. This study suggested that seaweeds could have shown a potential role in the future remedy and nutrition which can be used as drug or food additive.

Utilization of marine seaweed Spyridia filamentosa for silver nanoparticles synthesis and its clinical applications

The present study describes an environment-friendly biosynthesis of silver nanoparticles from marine red algae Spyridia filamentosa through the bio-reduction process. S. filamentosa have significantly high amounts of phytochemicals and secondary metabolites responsible for the formation of AgNPs. UV–Vis spectra results showed corresponding AgNPs peak at 420 nm. Transmission electron micrographs showed well dispersed spherical particles with the 20–30 nm in size. FT-IR and XRD results revealed the characteristics of AgNPs. Further, the AgNPs displayed potential antibacterial activity against Staphylococcus sp. (KC688883) and Klebsiella sp.(KC899845), and anticancer activity against MCF-7 cells.

Biosynthesis of Gold Nanoparticles using Scytosiphon lomentaria (Brown algae) and Spyridia filamentosa (Red algae) from Kyrenia Region and Evaluation of their Antimicrobial and Antioxidant Activity

This study was carried out for biosynthesis of gold nanoparticles using Scytosiphon lomentaria (brown algae) and Spyridia filamentosa (red algae) and compared. Synthesized gold nanoparticles were characterized using the UV-Vis spectroscopy (UV-Vis), Fourier transform infrared (FTIR) and Master Sizer analysis. Antioxidant and antimicrobial activity of the synthesized nanoparticles were tested against E. coli and S. typhi. Macro algae involvement in the stabilization of the gold nanoparticles was confirmed by the presence of UV-Vis peak at 540 nm and is an indication of the presence of the gold nanoparticles (AuNPs). Stretching in peaks of the FTIR showed that the biomolecules present in the seaweed extract reduced the gold ions. Master sizer results for AuNPs were within the range of 15-55 nm. Antioxidant activity carried out using DPPH free radical scavenging activity revealed significant activity for both AuNPs. Biosynthesized AuNPs also showed antimicrobial activity against Salmonella typhii and Escherichia coli. The S. lomentaria gold nanoparticles exhibited great inhibition against Escherichia coli, whereas S. filamentosa gold nanoparticles showed great antibacterial activity against S .typhi. Synthesized AuNPs using S. lomentaria and S. filamentosa as stabilizing agents showed convincing antioxidant and antimicrobial activity against gram negative and gram positive bacteria.

Gross chemical composition, fatty acids, sterols, and pigments in tropical seaweed species off Sinaloa, Mexico

Biochemical composition was assessed in green (Ulva expansa, Caulerpa sertularioides, Rhizoclonium riparium, Codium isabelae), red (Spyridia filamentosa, Gracilaria vermiculophylla), and brown (Padina durvillaei) seaweeds collected from different tropical lagoons on the Pacific coast of Sinaloa, Mexico. Protein content was higher in C. sertularioides, S. filamentosa, and G. vermiculophylla (10–12%), followed by R. riparium, P. durvillaei, and U. expansa (8%, 6%, and 4%, respectively). Lipid content was in the range of 0.3–1.5%, with the highest value found in R. riparium. The highest content of nitrogen-free extract (i.e., carbohydrates) (69%) and the lowest ash value (25%) were assessed in P. durvillaei. Polyunsaturated fatty acid content was in the range of 5–45%, with higher values in R. riparium (45%), C. sertularioides (39%), and P. durvillaei (23%). Red seaweeds showed the highest value of cholesterol+dehydrocholesterol (>90%), while green seaweeds showed the highest contents of β-sitosterol (71–77%), except for U. expansa, for which fucosterol+isofucosterol (79%) was highest. Pigment composition was different among seaweeds but coincided with previous reports. The biochemical components used as biomarkers were assessed by principal component analysis to discriminate among assessed variables and to cluster seaweed species according to the common variability of their biochemical composition. Results showed that composition was similar within seaweed divisions but particularly different in U. expansa and P. durvillaei. Biochemical compounds that contributed to total variability were β-sitosterol, 20:4n-6, 20:5n-3, chlorophyll a and b, and β-carotene, and to a lesser extent fucosterol+isofocusterol and 22:6n-3. Results showed that the analyzed seaweed species may be useful for animal nutrition and appropriate for human consumption.

JENIS-JENIS MAKROALGA EPIFIT PADA BUDIDAYA (Kappaphycus alvarezii) DI PERAIRAN TELUK GERUPUK LOMBOK TENGAH

Abstract:Epiphytes are organisms that attach to other organisms to support their growth and development. One type of epiphytes that has a negative impact on the host is algae (macroalgae). This algae is a competing organism for cultivation algae (Kappaphycus alvarezii). This research was conducted From May to October 2017 in Gerupuk Bay, Central Lombok. The aim of the research is to find out the types of macroalgae epiphytes on macroalgae kappaphycus alvarezii. This research was conducted using exploratory methods by taking seaweed samples overgrown with epiphytes, the research data obtained were descriptive analisys. As supporting data, environmental parameters are measured including temperature, pH, salinity, DO, phosphate, and NH4. Based on the results of exploration found 13 species of epiphytic algae in kappaphycus alvarezi cultivation, namely: Chaetomorpha linum, Chaetomorpha linum, Cladophora dalmatica, Acanthophora spicifer, Batrachospermum sp, Callithamnion sp., Caulachantus ustulatus, Ceramium sp, Hypnea spinnosa, Hypnea spinella, Hypnea sp, Polysiphonia brodiaei , Spyridia filamentosa. The type of epiphytes found that grows in both cultivation methods and some others are found only in one method. Meanwhile, data on environmental parameters are in the optimal range for macroalgae growth.This data is expected to be used as a consideration for the cultivateddevelopment in the Gerupuk Bay cultivation center. Keywords : Macroalgae, Epiphytes, Aquaculture, Kappaphycus alvarezii

Tratamiento subcrónico en ratones diabéticos con Caulerpa sertularioides (Chlorophyta) y Spyridia filamentosa (Rhodophyta)

Background. Algae are a potential source of natural compounds with diverse biological activities. It has been reported that algae may contain hypoglycemic and hypolipidemic compounds, and are an alternative to diabetes mellitus controls, a disease with very high rates of prevalence and mortality in Mexico. Goals. The objective of this research was to determine the hypoglycemic and hypolipidemic effects of extracts from two algal species (Caulerpa sertularioides and Spyridia filamentosa) through a sub-chronic study in a murine model of experimental diabetes. Methods. The algal extracts were administrated by gavage during 30 days to diabetic mice (50 mg/kg/day), using saline isotonic solution and glibenclamide (5 mg/kg/day) as controls. At the end of the experiment glucose, total cholesterol, triglycerides and liver transaminases (aspartate aminotransferase and alanine aminotransferase) were measured. Results. It was observed that these two algal species have significant hypoglycemic effect, causing alterations in the lipid levels. The extracts did not show changes in transaminases nor other signs of toxicity. Conclusions. Both species represent an alternative as a source of new agents for controlling diabetes mellitus.

Antioxidant, antimutagenic and antiproliferative activities in selected seaweed species from Sinaloa, Mexico

Context Seaweeds from the Mexican Pacific Ocean have not been evaluated as a source of chemoprotectants.Objective The objective of this study is to evaluate chemopreventive activities of the seaweeds Phaephyceae – Padina durvillaei (Dictyotaceae) – Rodhophyceae – Spyridia filamentosa (Spyridiaceae), Gracilaria vermiculophylla (Gracilariaceae) – and Chlorophyceae – Ulva expansa (Ulvaceae), Codium isabelae (Codiaceae), Rhizoclonium riparium (Cladophoraceae) and Caulerpa sertularioides (Caulerpaceae).Materials and methods Methanol, acetone and hexane seaweed extracts were assessed at 30 and 3 mg/mL on antioxidant capacity (DPPH and ABTS assays), 0.003–3.0 mg/plate on antimutagenic activity against AFB1 using Salmonella typhimurium TA98 and TA100 tester strains in Ames test, and 12.5 to 100 μg/mL on antiproliferative activity on Murine B-cell lymphoma. Phenols, flavonoids and pigments content were also assessed as antioxidant compounds.Results Extraction yield was higher in methanol than in acetone and hexane extracts (6.4, 2.7 and 1.4% dw). Antioxidant capacity was higher in brown and green than in red seaweed species, particularly in P. durvillaei extracted in acetone (EC50 value= 16.9 and 1.56 mg/mL for DPPH and ABTS). Flavonoids and chlorophylls were identified as mainly antioxidant components; particularly in hexane extracts, which were correlated with the antioxidant capacity. Highest mutagenesis inhibition (> 40%) occurred in R. riparium at the lowest concentration assayed (0.003 mg/plate), while highest antiproliferative inhibition (37 and 72% for 12.5 and 25 μg/mL) occurred in C. sertularioides.Discussion and conclusion Flavonoids and chlorophylls explained the chemopreventive activities assessed in S. filamentosa, R. riparium and C. sertularioides. These seaweeds have a high potential as a source of novel chemoprotectants.

Biosorption for lead (II) ions from aqueous solutions by the biomass of Spyridia filamentosa algal species found in Indian Ocean

Biosorption of heavy metals is an efficient cost effective method for removal of heavy metal ions from industrial wastewater. Studies have shown that algal species biomasses have high uptake of heavy metal ions. In this research, an adsorption property of Spyridia filamentosa algal species was studied on the basis of equilibrium isotherms and kinetics from batch experiments. It was found that biosorption capacities were pH dependent. The maximum adsorption capacity was found to be at 0.86 mmol/g at pH of 5. It was observed that biosorption kinetics was first within the first 30 minutes before equilibrium was obtained. The effect of light metal ions was found not to significantly affect uptake of lead (II) ions. It was as well found that Spyridia filamentosa biomass could purify 2.1, 1.1, 0.7 and 0.5 liters when the feed concentrations were 0.5, 1.0, 2.0 and 4.0 mM, respectively of lead (II) before breakthrough was reached. This study illustrated that that biomass of Spyridia filamentosa is a good biosorbent for treatment of lead (II) contained in industrial wastewater.

Winter Nutrient Pulse and Seagrass Epiphyte Bloom: Evidence of Anthropogenic Enrichment or Natural Fluctuations in the Lower Florida Keys?

Nutrient enrichment continues to disrupt marine ecosystem function worldwide. Assessing eutrophication in seagrass ecosystems such as the Great White Heron National Wildlife Refuge (GWHNWR), Florida Keys is critical for protecting the diverse community that depends on the intertidal and subtidal seagrass beds. We quantified water column nutrients, chlorophyll a, tissue nutrients in macroalgae and Thalassia testudinum, and epiphyte percent cover on seagrasses on tidal flats seasonally over 1 year at three sites: Howe Key, Water Keys, and Upper Harbor Key. Water column nutrients (total nitrogen, total phosphorus, nitrate–nitrite, ammonium, dissolved inorganic nitrogen, dissolved organic nitrogen, soluble reactive phosphorus, dissolved organic phosphorus) increased from fall to winter at Water Keys. These increased nutrients coincided with a bloom of the epiphyte Spyridia filamentosa on seagrasses that exceeded 40 % cover at Water Keys and Upper Harbor Key in two consecutive seasons. Seagrasses at all sites had chronic percent cover of small epiphytes exceeding 60 %. Additionally, low δ13C in T. testudinum tissues at Upper Harbor Key compared to the other sites suggested variations in carbon sources across the study area. Spatial patterns in macrophyte nitrogen-to-phosphorus (N:P) ratios point to sources of nutrients from the inhabited islands of the Keys and from the Gulf of Mexico. Water column total nitrogen and total phosphorus concentrations exceeded the numeric nutrient criteria for the study area suggesting that the area should be monitored closely.

Seasonal proximate and fatty acid variations of some seaweeds from the northeastern Mediterranean coast

The seasonal nutritional value of red (Jania rubens, Laurencia papillosa, Spyridia filamentosa and Dasya rigidula) and brown macroalgae (Padina pavonia and Stypopodium schimperi) was evaluated as a dietary supplement for human and animal nutrition based on proximate and fatty acid profiles. The protein content varied from 0.80% (L. papillosa) to 3.41% (J. rubens) of wet weight with the highest values in winter. The highest lipid levels were recorded in S. schimperi (2.03% in spring, 2.16% in summer), the lowest in S. filamentosa (0.08% in spring). The ash content of J. rubens (46.11–51.63%) was significantly higher than that of the other species (2.28–16.57%). Analysis of the fatty acid composition showed that these seaweed species are very rich in n-3 fatty acids.

Molecular and morphological variation of the red alga Spyridia filamentosa (Ceramiales, Rhodophyta) in the Hawaiian Archipelago

Conklin K.Y. and Sherwood A.R. 2012. Molecular and morphological variation of the red alga Spyridia filamentosa (Ceramiales, Rhodophyta) in the Hawaiian Archipelago. Phycologia 51: 347–357. DOI: 10.2216/10-26.1Genetic information is proving to be important in conservation and management efforts that involve cryptic species and their role in native ecosystem restoration. Previous molecular studies have demonstrated that the red alga Spyridia filamentosa consists of several cryptic species. Spyridia filamentosa is considered to be a native species in Hawai‘i and was recently used in preliminary seagrass meadow restoration efforts in Maunalua Bay, O‘ahu. It became necessary to understand the genetic diversity of this species in the Islands and determine if there are relationships between any molecular clades of S. filamentosa and anatomical characters that might be useful (e.g. sediment capture) in habitat remediation. Both molecular and morphological (determinate branch cell dimensions) analyses revealed the presence of multiple S. filamentosa clades in Hawai‘i. Nuclear [partial LSU (large subunit)] sequence and determinate branch cell data recovered two broad lineages (I and II), which are known worldwide. The mitochondrial sequence (cox2-3 spacer) data further separated samples into five distinct clades and indicated that S. filamentosa arrived in Hawai‘i on at least six occasions. These results aided decisions made concerning preliminary experiments involved in seagrass habitat remediation and emphasized the importance of genetically evaluating cryptic species that are being considered for use in native ecosystem restoration or conservation.

Cyanobacteria and macroalgae from an arid environment mangrove on the east coast of the Baja California Peninsula

Abstract We describe the assemblage of cyanobacteria and macroalgae on Avicennia germinans pneumatophores, Rhizophora mangle aerial roots, and within the tidal channel of a mangrove located in a lagoon bordering the east coast of the Baja California Peninsula, from samples collected every 2 months from May 2005 to May 2006. A total of 68 species were found: 21 cyanobacteria, 1 Xanthophyta, 25 Chlorophyta, 1 Ochrophyta-Phaeophyceae, 19 Rhodophyta, and 1 Anthophyta. Species richness varied between habitats; pneumatophores supported 29 species of algae, aerial roots supported 20 species of algae, and the channel bottom supported 46 species. Taxa common to the three habitats were Lyngbya sp., Vaucheria sp., Boodleopsis pusilla, Rhizoclonium riparium, and Bostrychia radicans. Mean wet weight algal biomasses on aerial roots and in the channel were 494 g root-1and 12,924 g m-2, respectively. The dominant species on aerial roots and on the channel bottom were Caulerpa sertularioides, Gracilariopsis lemaneiformis, and Spyridia filamentosa. The channel bottom also had Vaucheria sp. and two cyanobacteria (Oscillatoria sp. and Lyngbya sp.). Morphotypes of two cyanobacteria (Heteroleibleinia sp. and Johanesbaptistia sp.) are recorded in this habitat for the first time.

Effects of micro and macroalgal diet supplementations on growth and immunity of greenlip abalone, Haliotis laevigata

Algae contain nutrients and bioactive compounds, which can have effects on the growth and immunity of aquatic organisms. This study examines the effect of macroalgae Ulva lactuca and Spyridia filamentosa, cyanobacteria Arthrospira maxima, and microalgae Dunaliella salina on the growth and immunity of Haliotis laevigata, in comparison to a commercially formulated pellet. Over 12 weeks, U. lactuca or S. filamentosa produced the lowest growth rate, indicating lack of nutrients for abalone growth in a single macroalgae diet. Pellets supplemented with 10% A. maxima or D. salina resulted in increased abalone shell length (13.3 and 30.7%, respectively) and body weight (19.9 and 33.4%) over the pellet control diet. The impact of algal supplementation on hemolymph immunity was mainly represented by a drop in total hemocyte counts (THC) and some diet specific effects on superoxide anion and antibacterial activity against Vibrio anguillarum. No effect of diet was observed on phagocytosis, phenoloxidase, or antiviral activity against herpes simplex virus type 1. It is conceived that the humoral antimicrobial factors in abalone hemolymph are innately biosynthesized rather than dietary derived compounds. Nevertheless, concomitant with strong antiviral activity against HSV-1 in a lipophilic extract of U. lactuca and S. filamentosa, higher antiviral activity was detected in the digestive lipid extract of abalone fed U. lactuca (64.2% at 650 μg ml −1) or S. filamentosa (69.51%) compared to abalone fed pellets (47.42%) or pellets supplemented with A. maxima (46.3%) or D. salina (46%). This suggests that abalone may also derive some protection against oral pathogens by algal derived bioactive compounds. These results indicate that abalone growth rate could be optimized by A. maxima and D. salina supplementations, whereas U. lactuca and S. filamentosa could be useful supplements for abalone aquaculture, especially in areas with high risk of herpesvirus infection.

A Floristic Comparison of Seaweeds from James Bay and Three Contiguous Northeastern Canadian Arctic Sites

The seaweed flora from James Bay, Canada is compared with three contiguous northeastern Canadian Arctic areas (Hudson Bay, Hudson Strait, and the Ellesmere-Baffin Islands area extending northward to the Arctic Ocean). A conspicuous reduction pattern was evident with 131 taxa recorded for the Ellesmere-Baffin Islands area, 106 for Hudson Strait, 81 from Hudson Bay, and 44 in James Bay. The Ellesmere-Baffin Islands area has a more rocky open coastal environment and higher salinities than James Bay, which is more highly sedimented and impacted by hydroelectric development and freshwater discharge. The Ellesmere-Baffin Islands area (∼32–30.5‰) has a higher mean number of shared taxa (90.0 ± 18.4 SE) than James Bay (37.6 ± 2.7 SE), while Hudson Strait and Hudson Bay have intermediate values of 78 ± 14.1 SE and 64 ± 9.2 SE, respectively. The combined flora from the four areas consists of 164 taxa, including 49 red, 65 brown, 1 chrysophyte, and 49 green algae. Fifty of these total taxa (31%) were only found in one area, with 25 occurring between Ellesmere Island and Baffin Island, 13 within the Strait proper, and 6 in both Hudson and James Bays. Strong habitat and salinity gradients, as well as the great distances between collection sites and the haphazard nature of collections may have contributed to these restrictive patterns. Cheney's (1977) floristic ratio documents that all four geographies (including their composite flora) have cold water floras. Four new distributional records are documented from James Bay: Chaetomorpha minima, Elachista fucicola, Phyllophora pseudoceranoides, and Spyridia filamentosa. The cryptogenic taxon Spyridia, which has unclear origins, is a warm-water disjunct in the northwestern Atlantic previously known only from one site in Nova Scotia and a few locations in southern Maine/New Hampshire but mostly south of Cape Cod, Massachusetts. A single introduced species (Dumontia contorta from Europe) is recorded from James Bay and the Ellesmere-Baffin Islands area, while none are documented from the other areas.

Assessment of in vitro antitumoral and antimicrobial activities of marine algae harvested from the eastern Mediterranean sea

Antitumoral activities of five algal extracts obtained from the marine algae Scytosiphon lomentaria, Padina pavonica, Cystoseira mediterranea (Phaeophyceae), Hypnea musciformis and Spyridia filamentosa (Rhodophyta) were assessed against the human breast adenocarcinoma cell line MCF‐7 and the human prostate carcinoma epithelium like cell lines DU 145, LNCaP, PC3 using the cytotoxic assay, in vitro. The crude extract of S. filamentosa showed strong cytotoxic activity against the DU-145 cell line, and it showed less than 10% cell viability after treatment. Antimicrobial activities of the crude extracts of algae (with the exception of H. musciformis) were also tested by disc diffusion assay against three Gram positive and five Gram negative bacterial strains and against the yeast pathogen Candida albicans. Among the extraxts, S. lomentaria extract (prepared with methanol) inhibited highly Gram negative bacterium Salmonella typhimurium growth while C. albicans growth was only inhibited by C. mediterrranea extract.

The effects of nitrogen and phosphorus enrichment on algal community development: Artificial mini-reefs on the Belize Barrier Reef sedimentary lagoon

The experiments to compare DIN and SRP enrichment effects on algal community development were conducted within a lagoonal rubble/sand reef apron west of the back reef flat at Carrie Bow Cay, Belize. Macroalgae dominate (23 taxa, 57% cover), ambient dissolved inorganic nutrient concentrations are above the levels documented for release of macroalgal growth (means of 2.06 μM DIN = dissolved inorganic nitrogen and 0.12 μM SRP = soluble reactive phosphorus) and grazing is negligible (1.7% Acanthophora spicifera consumed 6 h −1). Mini-reef diffusers containing slow-release fertilizers significantly ( P < 0.05) increased DIN in the experimental DIN and SRP + DIN treatments by 2- and 3-fold (means of 4.64 and 6.41 μM), respectively; while SRP was increased significantly ( P < 0.05) in the SRP and SRP + DIN treatments by 5- and 8-fold to means of 0.69 and 0.94 μM, relative to the control treatments. SRP and SRP + DIN treatments favored colonization by Cyanobacteria such as Spirulina sp. on the mini-reef/diffusers, with an opposite detrimental effect on reef-building crustose coralline algae. The Cyanobacteria bloom further inhibited the long-term settlement and colonization of crustose coralline algae. Conversely, the DIN and control mini-reef treatments showed low Cyanobacteria cover and became colonized by abundant reef-building coralline algae, consisting mostly of Hydrolithon boergesenii and crust stages of Amphiroa fragilissima. After 1 year, the competitively overgrowing macrophytes A. spicifera, Palisada papillosa, Padina sanctae-crucis and Spyridia filamentosa conspicuously dominated all of the treatment- and control-replicates, in accordance with the nutrient-replete ambient waters and negligible herbivory within this habitat. As predicted, nutrient additions to the mini-reef diffusers resulted in significant elevations of tissue nutrients in the most-abundant colonizer and habitat dominant, A. spicifera. Although, the resultant decreases of both the C:N and C:P molar ratios corresponded to the elevated DIN and SRP treatments, this uptake was entirely superfluous, since control population colonization and growth matched that of the experimental nutrient treatments.

Macroalgae blooms and δ15N in subtropical coastal lagoons from the Southeastern Gulf of California: Discrimination among agricultural, shrimp farm and sewage effluents

Macroalgae blooms of Gracilaria vermiculophylla, Hypnea spinella and Spyridia filamentosa have been found in coastal lagoons in the SE Gulf of California. Agriculture, livestock, shrimp and poultry farms and sewage contribute anthropogenic nitrogen to the systems. The δ15N of these sources, water column and macroalgae were studied in order to identify the N supply for macroalgae blooms. δ15N of three species of macroalgae (4.3–13.6‰) were enriched compared to the water column (δ15N–NO3- 3.7–6.8‰), probably because of fractioning from the macroalgae. δ15N of POM (1.4–10.3‰) was similar to the water column but the relationship was unclear. Depending on the site, macroalgae showed different δ15N values since some sites receive more or less influence from one given source of the associated watershed, which is reflected in the different δ15N values of the macroalgae of the same system and in the relative contributions of the sources.