Species Of Red Macroalgae Research Articles

Characterization and comparative analysis of the complete organelle genomes of three red macroalgae species (Neoporphyra dentata, Neoporphyra seriata, and Neopyropia yezoensis) and development of molecular makers for their identification.

Many species of red algae belonging to the phylum Rhodophyta are consumed by humans as raw materials for nutrition and medicine. As the seaweed market grows, the importance of the laver species has increased. The classification of red algal species has changed significantly, and the accuracy of this classification has improved significantly in recent years. Here, we report the complete circular genomes of the chloroplasts (cp) and mitochondria (mt) of three laver species (Neoporphyra dentata, Neoporphyra seriata, and Neopyropia yezoensis). This study aims to assemble, annotate, and characterize the organization of the organelle genomes of three laver species, conduct comparative genomic studies, and develop molecular markers based on SNPs. We analyzed organelle genome structures, repeat sequences, sequence divergence, gene rearrangements, and phylogenetic relationships of three laver species. The chloroplast genomes of the three species contained an average of 212 protein-coding genes (PCGs), while the mitochondrial genomes contained an average of 25 PCGs. We reconstructed the phylogenetic trees based on both chloroplast and mitochondrial genomes using 201 and 23 PCGs (in cp and mt genomes, respectively) shared in the class Bangiophyceae (and five species of Florideophyceae class used as an outgroup). In addition, 12 species-specific molecular markers were developed for qRT-PCR analysis. This is the first report of Neoporphyra seriata complete organellar genomes. With the results, this study provides useful genetic information regarding taxonomic discrepancies, the reconstruction of phylogenetic trees, and the evolution of red algae. Moreover, the species-specific markers can be used as fast and easy methods to identify a target species.

Range expansion of some non-indigenous seaweeds along the coasts of Brittany – English Channel

Abstract Non-indigenous seaweed species have been introduced to the coasts of Brittany, France for decades, with an increasing arrival rate since the 1970s due to both the introduction of the Pacific oyster and increased maritime traffic. In this study, seven species of red macroalgae originating from the Pacific Ocean were found in new locations around the coasts of Brittany between 2018 and 2022. The seaweed species belong to four different orders: Ceramiales (Antithamnion hubbsii, Polysiphonia morrowii, and Symphyocladiella dendroidea), Halymeniales (including Pachymeniopsis lanceolata and Polyopes lancifolius), Rhodymeniales (Botryocladia wrightii), and Gigartinales (Solieria sp.). The dispersal mode and putative invasive potential of each species were examined, and the species were described in terms of their macroscopic and microscopic appearance and habitat. These finds result from a combination of citizen science and long-term monitoring. Used together, these two approaches can aid in the detection of these species on other European coasts and in understanding their dispersion.

Dietary red macroalgae (Halopithys incurva) improved systemic an mucosal immune and antioxidant parameters and modulated related gene expression in zebrafish (Danio rerio)

In the present study, the effects of dietary Halopithys incurva, a red macroalgae species, (0.25, 0.50, 1%) on whole-body serum and skin mucus immune system, antioxidant system and expression of various genes in zebrafish were investigated. At the end of the 8-week study, total protein, total immunoglobulin and lysozyme activities in whole-body serum and skin mucus increased in fish fed H. incurva (P < 0.05). While an increase was observed in superoxide dismutase (SOD), Catalase (CAT) and glutathione peroxidase (GPx) which are antioxidant enzyme activities in whole-body serum and skin mucus, a decrease in malondialdehyde (MDA) levels was detected (P < 0.05). All of the immune-related genes examined, such as Interleukin-1 beta (IL-1β), Tumor necrosis factor-alpha (TNF-α), Interferon-gamma (INF- γ), were upregulated by the addition of 0.5% H. incurva (P < 0.05). While SOD and GPx, which are antioxidant enzyme-related genes, were remarkably upregulated in macroalgae fed fish (P < 0.05), no change was observed in CAT gene expression (P > 0.05). Based on the results of this study, it is considered that the addition of 0.5% H. incurva to the diets of commercially farmed fish will increase their immune and antioxidant defences and may contribute to the aquaculture sector for more sustainability.

Valorization of red macroalgae biomass via hydrothermal liquefaction using homogeneous catalysts

Hydrothermal liquefaction of red macroalgae species, Kappaphycus alvarezii (KA) and Eucheuma denticulatum (ED), was performed at 350 °C in the presence of 5 wt% neutral and alkali catalysts like Na2CO3, K2CO3, CaCO3, Na2SO4, NaOH, and KOH. The maximum bio-crude yield of 26.7 wt% and 18.5 wt%, on a dry ash-free basis, was obtained from Na2CO3 treatment of KA and KOH treatment of ED, respectively. The bio-crude from both feedstocks mainly consisted of cyclic oxygenates, whose selectivities were maximum in K2CO3 and CaCO3 treatments. The calorific value of the bio-crude was 38.5 MJ/kg from KA and 30.8 MJ/kg from ED, while that of biochars was 20–24 MJ/kg. A high degree of deoxygenation (64.2%) was observed in bio-crude produced from Na2SO4 treatment of KA biomass. Salts of Cl–, SO42– and K+ constituted the major inorganic portion of the aqueous phase. Maximum energy recovery (99%) was observed from the Na2CO3 treatment of ED.

Extraction, Isolation and Characterization of Mycosporine-like Amino Acids from Four Species of Red Macroalgae.

Marine macroalgae is known to be a good source of mycosporine-like amino acids (MAAs), especially red macroalgae. As a new type of active substance with commercial development prospects, the current progress in the extraction, isolation and characterization of MAAs is far from sufficient in terms of effectiveness in application. To determine the extraction processes of MAAs from four species of red macroalgae (Bangia fusco-purpurea, Gelidium amansii, Gracilaria confervoides, and Gracilaria sp.), a series of single-factor and orthogonal experiments were carried out in which the effects of solvents, the solid–liquid ratio, the time of extraction, the extraction degree and the temperature, on the yields of MAA extracts, were analyzed. Further, the isolation and identification of MAAs from Bangia fusco-purpurea and Gracilaria sp. were investigated. The results showed that the solid–liquid ratio, the time of extraction, the extraction degree and the temperature were 1:20 g/mL, 2 h, three times and 40 °C, respectively, when 25% methanol or 25% ethanol were used as the extraction solvent; these values were found to be suitable for the extraction of MAAs from four species of red macroalgae. Silica gel thin-layer chromatography was successfully used, for the first time, for the detection MAAs in this work, and it could be clearly seen that Bangia fusco-purpurea had the highest contents of MAAs among the four species of red macroalgae. MAA extracts from Bangia fusco-purpurea (or Gracilaria sp.) were isolated by silica gel column chromatography to obtain one fraction (or two fractions). The compositions and proportions of the MAAs in these fractions were determined via HPLC-ESI-MS spectra and by comparison with existing studies. Shinorine, palythine and porphyra-334 were found in 95.4% of the T1 fraction, and palythenic acid was found in 4.6% of this fraction, while shinorine, palythine and porphyra-334 were found in 96.3% of the J1 fraction, palythenic acid was found in 3.7% of the J2 fraction, and palythine was found in 100% of the J2 fraction, taken from the MAA extracts found in Bangia fusco-purpurea and Gracilaria sp., respectively. In addition, the relevant compositions and proportions of the MAA extracts taken from Gelidium amansii and Gracilaria confervoides were identified. This was the first study to report on the extraction process, isolation and identification of MAAs from Bangia fusco-purpurea, Gelidium amansii, Gracilaria confervoides, and Gracilaria sp.

Evaluating the potential bioextractive capacity of South Florida native macroalgae Agardhiella subulata for use in integrated multi-trophic aquaculture (IMTA)

With the expansion of marine aquaculture throughout the world comes a need for solutions to improve the economic viability and environmental sustainability of farming operations. Integrated multi-trophic aquaculture (IMTA) has been identified as a promising method of farming that typically combines multiple cultured species in connected systems in an effort to decrease the concentration of nutrients expelled as waste products from intensive finfish culture while also increasing commercial profits via subsequent extractive biomass production. This study examined the effectiveness of South Florida native red macroalgal species Agardhiella subulata for use as a productive, nutrient-extracting species for IMTA in the Atlantic, Gulf of Mexico, and Caribbean regions. When cultured in a pilot-scale, land-based IMTA system for replicated 15 day trials with American red snapper, Lutjanus campechanus, A. subulata grew up to 14.4% d−1 and significantly decreased the concentration of all measured dissolved inorganic nutrients in the effluent water. The average percent (% ± SE) removal of nutrients were: 68.8 ± 4.8 ammonia, 94.5 ± 1.3 nitrate, 96.6 ± 2.0 nitrite, and 93.2 ± 3.1 phosphate from primary culture effluents. Further evidence of A. subulata fitness for commercial IMTA practices is shown through significantly high bulk nitrogen tissue concentration of experimental (nutrient-enriched) compared to control (un-enriched) groups. Results of this study demonstrate the efficient growth and nutrient removal capabilities of A. subulata when used in IMTA applications with marine finfish production in warm water environments, as may be encountered in marine aquaculture projects in the Atlantic, Gulf of Mexico and Caribbean regions.

Notas sobre las algas marinas de la Reserva Internacional de la Biosfera Seaflower, Caribe Colombiano VIII: nuevos registros de algas rojas (Rhodophyta) de San Andrés, Providencia y Santa Catalina, Colombia

Antecedentes y Objetivos: En la última década, la investigación ficológica en la Reserva Internacional de Biosfera Seaflower ha revelado una diversidad en su flora marina que no había sido previamente apreciada. Este trabajo tiene como objetivo contribuir al conocimiento de la biodiversidad macroalgal del Archipiélago de San Andrés, Providencia y Santa Catalina en el Caribe Colombiano, adicionando 11 nuevos registros de algas rojas. Métodos: Las algas fueron recolectadas alrededor de las islas en 10 puntos, cubriendo diferentes ecosistemas, por medio de buceo SCUBA a profundidades entre 0 y 37 m. El muestreo se realizó entre agosto y noviembre de 2009, diciembre de 2012 y septiembre de 2019 durante la Expedición Científica Seaflower. Las algas recolectadas se conservaron en una solución de formalina/agua de mar al 4%. La identificación se realizó mediante microscopio óptico y literatura especializada. Todos los especímenes fueron depositados en el herbario JIW del Departamento de Biología de la Universidad Nacional de Colombia, en Bogotá, Colombia. Resultados clave: Se presentan 11 nuevos registros de especies de macroalgas rojas para la Reserva Internacional de la Biosfera Seaflower en el Mar Caribe. Seis taxa fueron previamente citados para el Caribe colombiano: Botryocladia spinulifera, Champia taironensis, Dasya caraibica, Pterocladiella bartlettii, Seirospora occidentalis y Spyridia aculeata subsp. complanata. Las restantes cinco especies son nuevos registros para el país: Botryocladia cf. bahamensis, Botryocladia cf. bermudana, Ceramium brevizonatum var. caraibicum, Gloioderma iyoense y Wrightiella tumanowiczii. Con estos resultados la Reserva Internacional de Biosfera Seaflower presenta un total de 153 especies de rodófitas, pertenecientes a 12 órdenes, 27 familias y 73 géneros. Conclusiones: Con las investigaciones realizadas en los últimos 10 años, el número de taxones registrados ha aumentado de 202 a 325, lo que representa un aumento de 62% en el conocimiento de la diversidad macroalgal y ubica al Archipiélago en la segunda región más diversa del Caribe colombiano.

Sterols in red macroalgae from antarctica: extraction and quantification by Gas Chromatography–Mass spectrometry

Antarctica is considered a major reservoir of microorganisms and macroorganisms, including seaweed, which can biosynthesize secondary metabolites with unique structures and specific biological activities. Macroalgae are considered an interesting source of steroids, a class of metabolites involved in the control of membrane fluidity and permeability. This study reports the extraction and quantification of sterols in four red macroalgal species from Antarctica: Palmaria decipiens, Plocamium cartilagineum, Iridaea cordata, and Pyropia endiviifolia. The extraction of sterols involved alkaline hydrolysis from algal biomass. The quantification of cholesterol, brassicasterol, campesterol, stigmasterol, β-sitosterol, and fucosterol were performed by gas chromatography hyphenated with mass spectrometry (GC–MS). In general, cholesterol was the most abundant compound (216.32 to 3195.69 mg kg−1), followed by β-sitosterol (131.42 to 654.18 mg kg−1), stigmasterol (68.35 to 393.20 mg kg−1), brassicasterol (68.56 to 337.43 mg kg−1), campesterol (64.95 to 277.78 mg kg−1), and fucosterol (57.67 to 286.18 mg kg−1). Brassicasterol was not found in I. cordata, but it was identified in the other three samples. This work enriches the knowledge about the profile of steroids biosynthesized by Antarctic macroalgae and supports research to discover bioactive compounds with nutraceutical and pharmaceutical applications.

Antarctic intertidal macroalgae under predicted increased temperatures mediated by global climate change: Would they cope?

The Antarctic Peninsula is one of the regions to be most affected by increase in sea surface temperatures (SSTs) mediated by Global Climate Change; indeed, most negative predictions imply an up to 6 °C increment by the end of the XXI century. Temperature is one of the most important factors mediating diversity and distribution of macroalgae, although there is still no consensus as to the likely effects of higher SSTs, especially for polar seaweeds. Some available information suggests that potential strategies to withstand future increases in SSTs will be founded upon the glutathione-ascorbate cycle and the induction of chaperone-functioning heat shock proteins (HSPs); however, their eventual role, even for general stress responses, is unclear. The intertidal green, brown and red macroalgae species Monostroma hariotii, Adenocystis utricularis and Pyropia endiviifolia, respectively, from King George Island, Antarctic Peninsula, were exposed to 2 °C (control) and 8 °C (climate change scenario) for up to 5 days (d). Photosynthetic activity (αETR and ETRmax, and EkETR), photoinhibition (Fv/Fm) and photoprotection processes (αNPQ, NPQmax, and EkNPQ) provided no evidence of negative ecophysiological effects. There were moderate increases in H2O2 production and levels of lipid peroxidation with temperature, results supported by stable levels of total glutathione and ascorbate pools, with mostly higher levels of reduced ascorbate and glutathione than oxidized forms in all species. Transcripts of P. endiviifolia indicated a general upregulation of all antioxidant enzymes and HSPs genes studied under warmer temperature, although with different levels of activation with time. This pioneering investigation exploring different levels of biological organization, suggested that Antarctic intertidal macroalgae may be able to withstand future rise in SSTs, probably slightly altering their latitudinal distribution and/or range of thermal tolerance, by exhibiting robust glutathione-ascorbate production and recycling, as well as the induction of associated antioxidant enzymatic machinery and the syntheses of HSPs.

Preliminary Characterization of Crude Lectins Fractions of Red Macroalgae Species Collected from the Southern Coast of Gunungkidul Indonesia

Lectins or hemagglutininsare specific sugar-binding proteins (glycoproteins) of non-immune origins that typically agglutinate certain cells and/or precipitate glycoconjugates. This study aimed to evaluate the activity of hemagglutination, protein comtent, and initial characterization (the stability towards pH, temperature, divalent cation and inhibition of hemagglutination activity by sugars and/or glycoproteins) crude lectins fractions of red macroalgae from the coast of Gunungkidul Beach, Yogyakarta. The findings showed that hemagglutination activity using trypsin treated rabbit erythrocytes of crude fractions of red algae lectins Nitophylium punctatum species, Helminthora divaricata, and Acanthophora spicifera were 26, 26, and 213, respectively. The protein contents were 8,123.47 μg / ml; 9,545.65 μg / ml; and 7,368.45 μg / ml. Although the three red macroalgae species tend to maintain a relatively stable pH, their temperature tolerance was unstable, and were unaffected by divalent cations. The carbohydrate-binding specificities assay of the red macroalgae species showed the occcurence of inhibition in certain glycoproteins and not simple sugars.

Description of two new Caribbean species from the Hypnea musciformis complex (Cystocloniaceae, Rhodophyta)

Hypnea musciformis is a red macroalgal species with economic importance as a source for production of carrageenan. Recent phylogeographic studies revealed a hidden diversity of cryptic species, putting in check its cosmopolitan distribution. The DNA barcode marker COI-5P and plastid rbcL, in addition to morphological studies, were used to investigate the species in this complex and to compare them with specimens from other countries including the type locality in Italy. The divergences between sequences within the H. musciformis complex were significantly high for both markers. Based on these analyses two new species are described, Hypnea caraibica Nauer, Cassano &amp; M.C. Oliveira sp. nov. and Hypnea schneideri Nauer, Cassano &amp; M.C. Oliveira sp. nov. Hypnea caraibica seems to be a common, widespread species in the Gulf of Mexico and the Caribbean and was recently introduced into Hawaii. This species was unnoticed due to lack of phylogeographic studies in the region. Hypnea schneideri seems to be more geographically restricted, but further surveys are needed to understand the distribution of this species. Because the identification of Hypnea species is complicated by their relatively simple and plastic morphology, DNA barcoding surveys and other molecular studies are essential to uncover hidden biodiversity in the genus and to supplement traditional studies based on morphology.

Photo-protective compounds in red macroalgae from Brittany: Considerable diversity in mycosporine-like amino acids (MAAs)

To cope with the biotic and abiotic stresses experienced within their environment, marine macroalgae have developed certain defence mechanisms including the synthesis of photo-protective molecules against light and particularly harmful UV radiation. The aim of this study was to screen selected red algae, a highly diverse phylogenetic group, for the production of photo-protective molecules. The pigment content and composition (i.e. chlorophyll-a, phycobiliproteins and carotenoids) and the composition of mycosporine-like amino acids (MAAs) were studied in 40 species of red macroalgae collected in Brittany (France), at two distinct periods (i.e. February and July 2017). A high inter-specific variability was demonstrated in terms of pigment content and MAA composition. Twenty-three potential MAAs were detected by HPLC, and six were identified by LC-MS (i.e. shinorine, palythine, asterina-330, porphyra-334, usurijene and palythene). This is the first study to report on the composition of pigments and MAAs in a diverse group of red seaweeds from Brittany, including some species for which the MAA composition has never been studied before. Nevertheless, the results suggested that some species of red algae are more likely to cope with high levels of light radiation since those species such as Bostrychia scorpioides, Porphyra dioica, Gracilaria vermiculophylla and Vertebrata lanosa are living in environments exposed to higher levels of irradiation, and had various MAAs in addition to their photo-protective pigments.

Carotenoid Pigments of Red, Green and Brown Macroalgae Species as Potential Active Pharmaceutical Ingredients

Active Pharmaceutical Ingredient (API) is a substance used in a finished pharmaceutical product, intended to furnish pharmacological activity or contribute direct effect in the diagnosis, cure, mitigation, treatment or prevention of disease. It also provides a direct effect in restoring, correcting or modifying physiological functions in human beings. Macroalgae, also known as seaweed, are plant-like organisms that can be found in a marine habitat. Macroalgae has been given huge concern because of its high nutritional value and short-term growth, which is only 45 days per cycle. Therefore, three red macroalgae species of Eucheuma denticulatum, Gracilaria tikvahiae and Kappaphycus striatum), as well as green and brown macroalgae species of Caulerpa lentillifera and Padina pavonica were selected to determine their carotenoids content and composition by using UV-Vis spectrophotometer and HPLC analysis. The main carotenoids identified in red, green and brown macroalgae species were zeaxanthin, lutein, ?-carotene and violaxanthin. Marked differences were observed between red, green and brown macroalgae carotenoids content and composition. Zeaxanthin and ?-carotene were detected in all red, green and brown macroalgae ranged from 3.61 to 21.30 ?g/g DW and 2.44 to 10.70 ?g/g DW respectively. Violaxanthin was found only in green macroalgae (8.93 ?g/g DW) whereas lutein was found only in red macroalgae (9.57 to 38.60 ?g/g DW). In terms of total carotenoid content, green macroalgae contained the highest amount of carotenoid (100.89 ± 14.71 ?g/g DW). The significant outcome of the research will be new natural carotenoid pigment sources as potential active pharmaceutical ingredients which can be beneficial to halal health-promoting products industry.

Effect of supplementing sheep diets with macroalgae species on in vivo nutrient digestibility, rumen fermentation and blood amino acid profile

In this study, a brown macroalgae species, Saccharina latissima, processed to increase its protein concentration, and a red macroalgae species, Porphyra spp., were used to evaluate their in vivo digestibility, rumen fermentation and blood amino acid concentrations. Four castrated rams were used, whose diets were supplemented with a protein-rich fraction of S. latissima, a commercial Porphyra spp. and soybean meal (SBM). Our results show that the protein digestibility of a diet with S. latissima extract was lower (0.55) than those with Porphyra spp. (0.64) and SBM (0.66). In spite of the higher nitrogen (N) intake of diets containing Porphyra spp. and SBM (20.9 and 19.8 g N/day, respectively) than that with S. latissima (18.6 g N/day), the ratio of N excreted in faeces to total N intake was significantly higher in the diet with S. latissima than those with Porphyra spp. and SBM. This reflects that the utilization of protein in S. latissima was impaired, possibly due to reduced microbial activity. The latter statement is corroborated by lower volatile fatty acid composition (25.6, 54.8 and 100 mmol/l for S. latissima, Porphyra spp. and SBM, respectively) and a non-significant tendency for lower ammonia concentration observed in diets with S. latissima and Porphyra spp. compared to SBM. It is important to note that the S. latissima used in this trial was rinsed during processing to remove salt. This process potentially also removes other water-soluble compounds, such as free amino acids, and may have increased the relative fraction of protein resistant to rumen degradation and intestinal absorption. Furthermore, the phlorotannins present in macroalgae may have formed complexes with protein and fibre, further limiting their degradability in rumen and absorption in small intestines. We recommend that further studies explore the extent to which processing of macroalgae affects its nutritive properties and rumen degradability, in addition to studies to measure the intestinal absorption of these macroalgae species.

&amp;lt;i&amp;gt;Kappaphycus alvarezii&amp;lt;/i&amp;gt; (Rhodophyta): New Record of an Exotic Species for the Caribbean Coast of Costa Rica

Kappaphycus alvarezii, a red macroalgal species native to South-East Asia, has been introduced for commercial purposes to more than 20 tropical countries. In 2000, Panama became the first Central American country to develop its cultivation following a pilot-commercial approach. Twelve years after his introduction to Panama, the species was found to the south Caribbean coast. In the present study, we report the first record of K. alvarezii collected in Costa Rican waters. Genetic identification of the sample was performed with the mitochondrial marker cox2-cox3 intergenic spacer, and phylogenetic analyses showed that the sample collected grouped into a monophyletic clade with GenBank sequences from Vietnam, Indonesia, the Philippines, Brazil and Venezuela. Here we provide further description of its position with respect to other strains of K. alvarezii collected globally. Its possible route of entry to the Caribbean coast of Costa Rica is discussed. To date, it is possible to locate K. alvarezii in different areas away from the production fields which show its dispersion, and that the species is expanding; but more studies are needed to know the phase of colonization in which it is located because it is a combination of natural factors and human exploitation that determines the invasive potential of the species.

Carotenoid and Chlorophyll Profiles in Five Species of Malaysian Seaweed as Potential Halal Active Pharmaceutical Ingredient (API)

Seaweed, also known as macroalgae, consist of various species that have been gaining the interest of researchers due to the presence of functional bioactive compounds that can be extracted from their biomass. This research aimed to study the chlorophyll and carotenoid content from five species of Malaysian seaweed as potential Active Pharmaceutical Ingredient (API). Three species of red macroalgae, (Eucheuma denticulatum, Gracilaria tikvahiae, and Kappaphycus striatum), green macroalgae (Caulerpa lentillifera ) and one brown macroalga (Padina pavonica) were selected and their chlorophyll and carotenoid contents were determined by using UV-Vis spectrophotometer and HPLC. Their antioxidant and antimicrobial activities were investigated using DPPH Radical Scavenging activity and Disc Diffusion methods, respectively. In terms of carotenoid content, P. pavonica contained the highest amount of carotenoid (100.9 ± 14.7 ug/g DW) and chlorophyll content (7.5 ±1.5 ug/g DW). Meanwhile, based on individual carotenoid content, K. striatum had the highest lutein content (38.6 ug/g DW). Zeaxanthin, beta-carotene, and violaxanthin were significantly higher in C. lentillifera at 21.3 ug/g DW, 10.7 ug/g DW, and 8.9 ug/g DW respectively. Besides that, the antioxidant test showed that P. pavonica presented the strongest DPPH activity with the percentage of inhibition (I %) of (61.0 % ± 0.9). Finally, for the antimicrobial test, strong antimicrobial activities were shown by all the seaweed samples toward E. coli and P. aerugenosa. Overall results of the antifungal test demonstrated moderate antifungal action by all seaweed samples towards M. gypseum and Fusarium sp.

Culture of Chondracanthus teedei and Gracilariopsis longissima in a traditional salina from southern Spain

The cultivation of two red macroalgal species, Chondracanthus teedei (Martens ex Roth) and Gracilariopsis longissima (S.G. Gmelin) Steentoft M, L.M. Irvine & W.F. Farnham, was assessed in a traditional salina, a system of earthen ponds used for marine salt extraction taking advantages of solar evaporation and tidal cycle. Vegetative thalli of both species were cultivated in rafts holding polypropylene ropes, from January to June 2015, when lock-gates were opened during the period of no salt production. The effects of three factors in the net growth rate were analysed: seedling density, water motion and seasonality. Water motion and seasonality showed a significant effect in the growth of both species. Seedling density only showed a significant effect in the growth of Gp. longissima, where the growth rates improved at high seedling densities. Values of tissue N were generally lower than critical quotas, suggesting that maximum growth was limited by the concentrations of dissolved nutrients. In addition, the high salinity and temperatures in late spring seemed to condition the values of net growth rate. The study suggested that macroalgal cultivation of these two valuable species could be a promising complementary activity in the integrated management of the salina during winter and early spring, when salinity is lower than 40 PSU, if nutrients in the water are increased with the semi-intensive fish cultivation and the hydrodynamic conditions along the rafts are enhanced.

Reduced macrofauna diversity and abundance in response to red macroalgal detritus

Macrophyte detritus from exogenous sources can play an important role in structuring benthic communities. Macrofaunal responses to seagrass wrack, mangrove leaf litter, and detritus from brown and green macroalgae have previously been examined through enrichment experiments. Yet effects from red macroalgal detritus, which is a major component of algal drift in many regions, are not well understood. In this study, enrichment experiments were performed on a shallow subtidal sandflat in Puget Sound, Washington, USA with detritus from three species of red macroalgae to assess: (1) whether macrofaunal assemblages were affected by two different “dosages” of red macroalgal enrichment (100 ml vs 500 ml per 0.079 m3 of sediment); (2) whether macrofaunal response differed between one-time and repeated (weekly) additions of red macroalgae; and (3) whether responses to red macroalgal enrichment changed over time. There appeared to be little or no effect on macrofauna from one-time enrichment regardless of the amount/dosage of algae added. However, weekly additions of red macroalgae led to negative responses across macrofaunal taxa. These responses occurred rapidly, within the first 3 weeks, and were largely unchanged after 7 weeks, intensifying for only 2 of the 10 most common taxa. No opportunistic responses to weekly additions were observed. Frequent influx of some types of red macroalgae may degrade the quality of sedimentary habitats by leaching chemically defensive compounds or through other mechanisms, which should be investigated in future studies. Although weekly enrichment treatments were informed by previous estimates of detrital delivery rates near hard-bottom habitats in the same locality, further research is needed to assess detrital influx frequency and community response in other regions where red macroalgal detritus is common, and to understand the broader implications of exogenous detritus from red macroalgae on benthic ecosystems.

Phylogeography of the Red Algal Laurencia Complex in the Macaronesia Region and Nearby Coastal Areas: Recent Advances and Future Perspectives

Abstract: Since the conception of the genus Laurencia by Lamouroux in 1813, several red macroalgal species have been included in it. In recent decades, the development of modern molecular tools has resulted in multiple taxonomic modifications, and presently, eight related genera are recognized in the so-called Laurencia complex. In the Macaronesian Region (Central East Atlantic Ocean), species from the Laurencia complex are keystone elements of the benthic communities, especially in the intertidal zone. In this review, we consolidate the existing knowledge about the Laurencia complex within the Macaronesian archipelagos and nearby areas. Morphological descriptions and phylogeographic remarks of the 16 currently accepted species—whose records were molecular or morphologically confirmed—are included together with an identification key for the Macaronesian Region. The phylogeographic data allowed us to re-visit the role of the Macaronesian archipelagos as a bridge area for the marine flora of the Mediterranean and Caribbean Seas (remnants of the former Thetyan Sea) or contemplate their marine flora as the result of successive processes of recolonization after the Quaternary glaciations from those donor areas. Finally, some comments about the frontiers of the research in the Laurencia complex in the Macaronesian Region and nearby coastal areas are included.

Notes on marine algae in the International Biosphere Reserve Seaflower, Caribbean Colombia, VII: Additions to the benthic flora of San Andrés Island

Se presentan diez nuevos reportes de especies de macroalgas rojas para la Reserva Internacional de la Biosfera Seaflower en el Mar Caribe. Cuatro taxones fueron previamente citados para el Caribe colombiano: Dohrniella antillarum, Halydictyon mirabile, Taenioma nanum y Aglaothamnion cordatum. Las restantes seis especies son nuevos registros para el país: Callithamniella tingitana, Frikkiella searlesii, Lejolisia exposita, Melanothamnus gorgoniae, Monosporus indicus y Wrangelia gordoniae. Todas las algas fueron colectadas en hábitat de arrecife coralino (9–17 m de profundidad), y todas las especies menos una son algas de tamaño diminuto, creciendo principalmente sobre coral muerto o como epifitas de algas más grandes. Se discuten las características morfológicas y reproductivas de cada especie, así como las novedades de su distribución.