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This study evaluated the potential use of several Thai seaweed species for ethanol production. The high biomass of the green algae Ulva intestinalis and Rhizoclonium riparium and the red algae Gracilaria salicornia and Gracilaria tenuistipitata in an earthen pond culture led us to select these species for our study. The seaweed species were analyzed for chemical composition, resulting in ash contents of 37.62 ± 0.15 % and fiber of 11.93 ± 0.16 %, with the highest values in R. riparium. Low lipid values were found in all species, with the highest value ( p < 0.05) in G. salicornia (1.69 ± 0.07 %) and the lowest in R. riparium (0.28 ± 0.01 %) and G. tenuistipitata (0.26 ± 0.01 %). The highest carbohydrate contents were found in G. tenuistipitata (54.89 %), and the lowest were in R. riparium (29.53 %). G. tenuistipitata (8.58 ± 0.36 %) and U. intestinalis (8.24 ± 0.28 %) had higher sulfate contents compared with G. salicornia (4.69 ± 0.04 %) and R. riparium (1.97 ± 0.20 %). The monosugar algal tissue components were analyzed by HPLC; rhamnose, xylose, fucose, arabinose, mannose, glucose, and galactose were used as reference sugars. Total sugar was found to be highest in G. tenuistipitata (98.21 %). Arabinose, glucose, and galactose were the main sugar components in all species. Glucose obtained from G. tenuistipitata (6.55 %) and R. riparium (6.52 %) was higher than in G. salicornia (0.27 %) and U. intestinalis (2.78 %). G. tenuistipitata fermentation gave a higher yield of ethanol (4.17 × 10 g ethanol g sugars; 139.12 μg ethanol g glucose) than R. riparium (0.086 × 10 g ethanol g sugars; 33.84 μg ethanol g glucose), U. intestinalis (0.074 × 10 g ethanol g sugars; 9.98 μg ethanol g glucose), and G. salicornia (0.031 × 10 g ethanol g sugars; 1.43 μg ethanol g glucose). [ABSTRACT FROM AUTHOR]

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The article presents the results of a study on the bioaccumulation abilities of Polysiphonia fucoides, a red algae specific to the southern Baltic Sea, towards (of) gamma emitting isotopes. A laboratory experiment was carried out to determine changes in the activities of some isotopes-Mn, Co, Zn, Ag,Sn, Cs, Cs and Am-occurring in P. fucoides exposed to a seawater medium containing these isotopes over the course of 1 month. All analyzed isotopes showed the greatest increase of radioactive activity in plant tissue in the first 24 h of exposure. The temporary concentration factors of cesium isotopes were increasing linearly during the experiment from 114 to 274 in the case of Cs, and from 144 to 351 in the case of Cs. The level of the initial concentration factor of cesium isotopes in the plant proved to be independent of the initial concentration of the isotope in seawater and it took the lowest (125 dm kg) level among the studied isotopes. In the case of a mixture of gamma emitting isotopes, a linear relation between the individual isotope activity in P. fucoides and its initial concentration in seawater was established after the first day of exposure; the isotopes initial concentration factors ranged from 767 to 874 dm kg. Having reached the maximal concentration level, a statistically significant decline in radioactivity concentrations of the five isotopes in the plant tissue was observed. A half-life of biological removal of the isotopes from the plant tissue was established at: 3.8 days in the case of Mn, 4 days-Co, 4 days-Co, 4.2 days-Cs and Am-3.5 days. [ABSTRACT FROM AUTHOR]

Most phaeophytes (brown algae) and rhodophytes (red algae) dwell exclusively in marine habitats and play important roles in marine ecology and biodiversity. Many of these brown and red algae are also important resources for industries such as food, medicine and materials due to their unique metabolisms and metabolites. However, many fundamental questions surrounding their origins, early diversification, taxonomy, and special metabolisms remain unsolved because of poor molecular bases in brown and red algal study. As part of the 1 000 Plant Project, the marine macroalgal transcriptomes of 19 Phaeophyceae species and 21 Rhodophyta species from China's coast were sequenced, covering a total of 2 phyla, 3 classes, 11 orders, and 19 families. An average of 2 Gb per sample and a total 87.3 Gb of RNA-seq raw data were generated. Approximately 15 000 to 25 000 unigenes for each brown algal sample and 5 000 to 10 000 unigenes for each red algal sample were annotated and analyzed. The annotation results showed obvious differences in gene expression and genome characteristics between red algae and brown algae; these differences could even be seen between multicellular and unicellular red algae. The results elucidate some fundamental questions about the phylogenetic taxonomy within phaeophytes and rhodophytes, and also reveal many novel metabolic pathways. These pathways include algal CO fixation and particular carbohydrate metabolisms, and related gene/gene family characteristics and evolution in brown and red algae. These findings build on known algal genetic information and significantly improve our understanding of algal biology, biodiversity, evolution, and potential utilization of these marine algae. [ABSTRACT FROM AUTHOR]

Temperature effects on photosynthesis and respiration were investigated in the green macroalga, Ulva conglobata, collected from low rocky coast of Nanao Island, Shantou, China. Thalli were cultured at 15 and 25°C and at low nitrogen (LN) and high nitrogen (HN) availability. Dark respiration and light-saturating photosynthesis were measured as oxygen exchange; the characteristics of chlorophyll fluorescence were also assayed. The maximal photochemical yield (Fv/Fm) and maximum relative electron transport rates (rETRmax) remained stable with moderate fluctuations of temperature (15-30°C) in the short term. However, the values of Fv/Fm and rETRma. declined with the high temperature (≧ 35°C), and such a decline was more accentuated in 15°C- than 25°C-grown algae. Both the rates of photosynthesis and respiration were sensitive to measurement temperature, with the Q10 values being higher in 25°C- grown algae (HN) than 15°C-grown algae. It appeared that 25°C-grown algae displayed an optimum temperature (Topt) of 30°C for photosynthesis, while 15°C-grown algae exhibited the Topt of a range of 20-30°C. When measured at their respective growth temperature, the rates of photosynthesis were significant higher in 25°C- than 15°C-grown algae, while the rates of respiration were identical between 25°C- and 15°C-grown algae. Our results demonstrated that respiration displayed full acclimation; whereas, photosynthesis exhibited partial acclimation to changing growth temperatures in U. conglobata. Consequently, the balance between respiration and gross photosynthesis was re-established by changing growth temperature, with the ratio being lowered with warmer growth temperature. The results also showed that HN availability in culture significantly increased pigments and soluble protein contents and enhanced photosynthesis and respiration. We suggested that the acclimation potential of metabolisms in U. conglobata favored carbon acquisition and net carbon balance with the increasing seawater temperature resulting from climate change and/or increasing N loading from coastal eutrophication. [ABSTRACT FROM AUTHOR]

Marine macroalgal biomass provides polysaccharides that could result in the valuable transformation of waste into an economic resource. Crude extracts, or polysaccharides, from Chaetomorpha aerea (Chlorophyta) and Agardhiella subulata and Hypnea cornuta (Rhodophyta), collected from the coastal brackish Lake Ganzirri (Italy), were evaluated for their effects on the adhesion and biofilm formation of Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 29213, as model organisms. Without exerting any antibacterial activity, each crude extract showed dose-dependent inhibitory effect on biofilm formation, differing each other and also on the strain tested. The highest concentration (400 μg mL−1) of C. aerea extract, a sulfated polysaccharide mainly composed by glucuronic acid, strongly acted on the initial attachment of P. aeruginosa (54% of biofilm reduction), whereas H. cornuta extract greatly acted on that of S. aureus (59%). The addition of A. subulata and C. aerea extracts reduced the biofilm growth of S. aureus , but did not its mature biofilm. Conversely, A. subulata extract, a κ-carrageenan was also able to reduce the developed biofilm of P. aeruginosa. As resulted by surface-coating and the bacterial affinity to hydrocarbons assays, extracts from C. aerea and H. cornuta were able to inhibit the adhesion to polystyrene of P. aeruginosa and S. aureus, and modify their cell-surface properties and hydrophobicity. Furthermore, all the extracts formed stable emulsions. No in vitro cytotoxicity effects were observed for H. cornuta extract, while they were moderate for C. aerea and high for A. subulata. However, all the extracts did not show any potential toxicity in vivo fish-embryo Danio rerio assay. These extracts could be used to prevent or remove the bacterial biofilms in several medical and non-medical applications. • Seaweed biomass provides polysaccharides able to hinder bacterial biofilm formation. • C. aerea and H. cornuta extracts strongly acted on the initial bacterial attachment. • A. subulata extract was able to reduce the developed biofilm of P. aeruginosa. • No in vivo toxicity effects of crude polysaccharides were observed in D. rerio assay. [ABSTRACT FROM AUTHOR]

Three marine macroalgae, i.e., Grateloupia filicina, Ulva pertusa and Sargassum qingdaoense, were selected as the deputies of Rhodophyta, Chlorophyta and Ochrophyta for comparative analysis of the molecular structures and biological activities of sulfated polysaccharides (SP). The ratio of water-soluble polysaccharides, the monosaccharide composition and the sulfated contents of three extracted SPs were determined, and their structures were characterized by Fourier transformation infrared spectroscopy. In addition, biological activity analysis showed that all three SPs had immune-modulatory activity both in vitro and in vivo, and SPs from S. qingdaoense had the best effect. Further bioassays showed that three SPs could not only enhance the immunity level stimulated by inactivated avian influenza virus (AIV) in vivo but also significantly inhibited the activity of activated AIV (H9N2 subtype) in vitro. G. filicina SP exhibited the strongest anti-AIV activity. These results revealed the variations in structural features and bioactivities among three SPs and indicated the potential adjuvants for immune-enhancement and anti-AIV.

Highlights: [•] Presentation of a laboratory experiment for analysis of reflectance spectra of marine macroalgae. [•] At the higher taxonomic group level, spectral mixture of macroalgae is linear. [•] Inner-group spectral similarity is high; therefore unmixing can hardly be performed. [•] Sub-pixel analysis of macroalgae is feasible to a limited extend. [Copyright &y& Elsevier]

Antifouling biocides are found in the marine ecosystem were they can affect non-target organisms. In this study the effects of five antifouling biocides on the settlement and growth of Ulva lactuca zoospores were investigated. The biocides investigated were copper (Cu), 4,5-dichloro-2- n-octyl-3(2H)-isothiazolone (DCOIT), triphenylborane pyridine (TPBP), tolylfluanid and medetomidine. Full concentration-response curves where determined for each compound. EC values were determined for copper, DCOIT, TPBP and tolylfluanid, all of which inhibited settlement and growth in a concentration dependent manner with the following toxicity ranking; tolylfluanid (EC 80 nmol L) ~ DCOIT (EC 83 nmol L) > TPBP (EC 400 nmol L) > Cu (EC 2,000 nmol L). Medetomidine inhibited settlement and growth only at the extreme concentration of 100,000 nmol L (93 % effect). The low toxicity is possibly a consequence of a lack of receptors that medetomidine can bind to in the U. lactuca zoospores. [ABSTRACT FROM AUTHOR]

The life cycle of plants entails an alternation of generations, the diploid sporophyte and haploid gametophyte stages. There is little information about the characteristics of gene expression during each phase of marine macroalgae. Promoter analysis is a useful method for understanding transcriptional regulation; however, there is no report of promoter analyses in marine macroalgae. In this study, with the aim of elucidating the differences in the transcriptional regulatory mechanisms between the gametophyte and sporophyte stages in the marine red alga Porphyra yezoensis, we isolated the promoter from the sporophyte preferentially expressed gene PyKPA1, which encodes a sodium pump, and analyzed its promoter using a transient gene expression system with a synthetic β-glucuronidase (PyGUS) reporter. The deletion of −1432 to −768 relative to the transcription start site resulted in decreased GUS activity in sporophytes. In contrast, deletion from −767 to −527 increased GUS activity in gametophytes. Gain-of-function analyses showed that the −1432 to −760 region enhanced the GUS activity of a heterologous promoter in sporophytes, whereas the −767 to −510 region repressed it in gametophytes. Further mutation and gain-of-function analyses of the −767 to −510 region revealed that a 20-bp GC-rich sequence (−633 to −614) is responsible for the gametophyte-specific repressed expression. These results showed that the sporophyte-specific positive regulatory region and gametophyte-specific negative regulatory sequence play a crucial role in the preferential expression of PyKPA1 in P. yezoensis sporophytes. [ABSTRACT FROM AUTHOR]

Sargassum fluitans y Sargassum natans are holopelagic brown macroalgae that can aggregate to form extensive floating mats on the surface of North Atlantic (Sargasso Sea). The present paper describes the occurrence of an excessive drift of Sargassum fluitans in the East coast of Cienfuegos province, central-southern region of Cuba, in May of 2012. Most impact of the drift by mechanic effect on the coast was reported in the touristic sector. Atypical meteorological conditions were observed during the Sargassum drift. [ABSTRACT FROM AUTHOR]

Five species of macroalgae (rhodophytes) are newly added to Cuban marine flora, all collected in the coast of Cienfuegos province: Dasya ocellata (Gratel.) Harv. in Hook., Griffithsia schousboei Mont. in Webb var. anastomosans E.C. Oliveira, Gelidium torulosum Kützing, Halymenia pseudofloresii Collins & M. Howe and Champia vieillardii Kützing. Griffithsia schousboei var. anastomosans and Gelidium torulosum represent new records for the Caribbean region; these taxa were previously known only from Brazil. Comments about taxonomy, ecology and biogeography of the involved taxa are also discussed offered in this paper. It is noteworthy that Halymenia pseudofloresii showed a great variability in size and branches diameter, as in its type locality (Bermuda). [ABSTRACT FROM AUTHOR]

The responses of respiration and photosynthesis to temperature fluctuations in marine macroalgae have the potential to significantly affect coastal carbon fluxes and sequestration. In this study, the marine red macroalga Gracilaria lemaneiformis was cultured at three different temperatures (12, 19, and 26°C) and at high- and low-nitrogen (N) availability, to investigate the acclimation potential of respiration and photosynthesis to temperature change. Measurements of respiratory and photosynthetic rates were made at five temperatures (7°C-33°C). An instantaneous change in temperature resulted in a change in the rates of respiration and photosynthesis, and the temperature sensitivities (i.e., the Q10 value) for both the metabolic processes were lower in 26°C-grown algae than 12°C- or 19°C-grown algae. Both respiration and photosynthesis acclimated to long-term changes in temperature, irrespective of the N availability under which the algae were grown; respiration displayed strong acclimation, whereas photosynthesis only exhibited a partial acclimation response to changing growth temperatures. The ratio of respiration to gross photosynthesis was higher in 12°C-grown algae, but displayed little difference between the algae grown at 19°C and 26°C. We propose that it is unlikely that respiration in G. lemaneiformis would increase significantly with global warming, although photosynthesis would increase at moderately elevated temperatures. [ABSTRACT FROM AUTHOR]

Abstract: In this investigation, Enteromorpha compressa algal oil with high free fatty acids (FFA) used as a feedstock for biodiesel production. Two step process was developed and kinetic study executed to obtain reaction rate constant for the transesterification reaction. The acid esterification was carried out to reduce FFA from 6.3% to 0.34% with optimized parameters of 1.5% H2SO4, 12:1 methanol–oil ratio, 400rpm at 60°C and 90min of reaction time. The maximum biodiesel yield 90.6% was achieved from base transesterification through optimum conditions of 1% NaOH, 9:1 methanol–oil ratio, 600rpm and 60°C temperature for 70min. The algal biodiesel was characterized by GC–MS, HPLC and NIR. This transesterification follows first order reaction kinetics and the activation energy was determined as 73,154.89J/mol. The biodiesel properties were analyzed and found to be within the limits of American standards. Hence, E. compressa serves as a valuable renewable raw-material for biodiesel production. [Copyright &y& Elsevier]

Allelopathy is an important non-resource interaction in terrestrial plant communities that may affect invasions by non-indigenous plants. The 'novel weapons hypothesis' ( NWH) predicts that non-indigenous plants will become invasive if they have allelopathic compounds that assemblages in the new range are not adapted to. Recently, the non-indigenous, chemically rich macroalga Bonnemaisonia hamifera (Hariot) has become one of the most abundant filamentous red algae in Scandinavian waters., We used B. hamifera to specifically test the aspect of the NWH that concerns invasion success based on novel allelochemicals in the invaded range. Allelopathic interactions were tested through effects on the growth rate of adult native macroalgae in co-cultures with B. hamifera and through the settlement success of native macroalgal propagules and microalgae on surfaces coated with 1,1,3,3-tetrabromo-2-heptanone. We also investigated whether 1,1,3,3-tetrabromo-2-heptanone can be transferred from B. hamifera to its native host algae, as a means of pre-emptive competition., The settlement of native macroalgal propagules and microalgae was strongly inhibited on surfaces coated with 1,1,3,3-tetrabromo-2-heptanone at ecologically relevant concentrations, but there were no effects of adult B. hamifera on growth rates of adults of the six native naturally co-occurring species. The compound was shown to be transferred from B. hamifera to the surface of its native host algae at inhibitory concentrations in both laboratory and field experiments., By inhibiting the settlement of propagules on its thallus and on surrounding surfaces, B. hamifera achieves a competitive advantage over native macroalgae, a finding that parallels previous reports on soil- and litter-mediated allelopathic interactions among vascular plants. Because competition for available substrata in marine benthic systems is intense, the ability to reserve space may be vital for B. hamifera's successful invasion. This is the first example of an allelopathic compound that can be transferred by direct contact from an exotic to a native species, with an active and unaltered function., Synthesis. Our results clearly show that the main secondary metabolite of the invasive red alga B. hamifera has strong allelopathic effects towards native competitors, suggesting that its novel chemical weapon is important for the highly successful invasion of new ranges. [ABSTRACT FROM AUTHOR]

Neurotrophic factors are vital not only to support neuronal development but also to protect mature neurons from atrophy in neurodegenerative diseases. As an effort to explore natural sources that possess neurotrophic activity, we screened common marine algae for their neuritogenic activity in the developing rat hippocampal neurons in culture. Of the 22 seaweed species examined, ethanol extracts of Gelidium amansii (GAE) exhibited potent neuritogenic activity, followed by Undaria pinnatifida and Sargassum fulvellum extracts. The effects of GAE were dose dependent with an optimum concentration of 15 µg/mL. The GAE significantly promoted the initial neuronal differentiation from the stage I into the stage II and increased the indices of axonal and dendritic development such as the length, the numbers of primary processes, and branching frequencies by a minimum of twofold compared with the vehicle control. These results show that marine algae are promising candidates for neurotrophic potentials. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Analysis of coastal marine algae communities enables us to adequately estimate the state of coastal marine environments and provides evidence for environmental changes. Hyperspectral remote sensing provides a tool for mapping macroalgal habitats if the algal communities are spectrally resolvable. We compared the performance of three classification approaches to determine the distribution of macroalgae communities in the rocky intertidal zone of Heligoland, Germany, using airborne hyperspectral (AISAeagle) data. The classification results of two supervised approaches (maximum likelihood classifier and spectral angle mapping) are compared with an approach combining k-Means classification of derivative measures. We identified regions of different slopes between main pigment absorption features of macroalgae and classified the resulting slope bands. The maximum likelihood classifier gained the best results (Cohan's kappa = 0.81), but the new approach turned out as a time-effective possibility to identify the dominating macroalgae species with sufficient accuracy (Cohan's kappa = 0.77), even in the heterogeneous and patchy coverage of the study area. [ABSTRACT FROM AUTHOR]

Seaweeds are ecologically important primary producers, competitors, and ecosystem engineers that play a central role in coastal habitats ranging from kelp forests to coral reefs. Although seaweeds are known to be vulnerable to physical and chemical changes in the marine environment, the impacts of ongoing and future anthropogenic climate change in seaweed-dominated ecosystems remain poorly understood. In this review, we describe the ways in which changes in the environment directly affect seaweeds in terms of their physiology, growth, reproduction, and survival. We consider the extent to which seaweed species may be able to respond to these changes via adaptation or migration. We also examine the extensive reshuffling of communities that is occurring as the ecological balance between competing species changes, and as top-down control by herbivores becomes stronger or weaker. Finally, we delve into some of the ecosystem-level responses to these changes, including changes in primary productivity, diversity, and resilience. Although there are several key areas in which ecological insight is lacking, we suggest that reasonable climate-related hypotheses can be developed and tested based on current information. By strategically prioritizing research in the areas of complex environmental variation, multiple stressor effects, evolutionary adaptation, and population, community, and ecosystem-level responses, we can rapidly build upon our current understanding of seaweed biology and climate change ecology to more effectively conserve and manage coastal ecosystems. [ABSTRACT FROM AUTHOR]

As mammals are unable to synthesize essential polyunsaturated fatty acids (PUFA), these compounds need to be taken in through diet. Nowadays, obtaining essential PUFA in diet is becoming increasingly difficult; therefore this work investigated the suitability of using macroalgae as novel dietary sources of PUFA. Hence, 17 macroalgal species from three different phyla (Chlorophyta, Phaeophyta and Rhodophyta) were analyzed and their fatty acid methyl esters (FAME) profile was assessed. Each phylum presented a characteristic fatty acid signature as evidenced by clustering of PUFA profiles of algae belonging to the same phylum in a Principal Components Analysis. The major PUFA detected in all phyla were C18 and C20, namely linoleic, arachidonic and eicosapentaenoic acids. The obtained data showed that rhodophytes and phaeophytes have higher concentrations of PUFA, particularly from the n-3 series, thereby being a better source of these compounds. Moreover, rhodophytes and phaeophytes presented ?healthier? Σn-6/Σn-3 and PUFA/saturated fatty acid ratios than chlorophytes. Ulva was an exception within the Chlorophyta, as it presented high concentrations of n-3 PUFA, α-linolenic acid in particular. In conclusion, macroalgae can be considered as a potential source for large-scale production of essential PUFA with wide applications in the nutraceutical and pharmacological industries. [ABSTRACT FROM AUTHOR]

Abstract: The Water Framework Directive (WFD) requires European Member States to assess the Ecological Quality Status (EQS) of their water bodies based on Biological Quality Elements (BQEs). A tool called MarMAT (Marine Macroalgae Assessment Tool) was developed to implement the WFD in Portugal, which assesses the EQS of Portugal''s coastal intertidal rocky shores. MarMAT is a multimetric method that is compliant with the European WFD requirement. It is based on the composition (Chlorophyta, Phaeophyceae and Rhodophyta) and abundance (coverage of opportunists) of marine macroalgae. This study focused on the demands of the WFD to have the assessment methodologies legally accepted by the European Commission. The following factors were examined: (a) the response of MarMAT against anthropogenic pressures; (b) the ability of MarMAT to report all of the five quality classes (bad, poor, moderate, good and high); and (c) the performance of MarMAT, specifically in comparing the RSL (Reduced Species List) methodology with the utility of including the abundance (coverage of opportunists) metric and the necessity of locally adapted reference conditions and boundaries. MarMAT was high inversely correlated (p <0.001) with anthropogenic pressure. MarMAT also successfully reported all of the quality classes (bad to high) and captured the community changes more accurately when using the coverage of opportunists metric. Because MarMAT satisfactorily covered all of the issues examined, MarMAT may be accepted as a compliant assessment methodology in the scope of the WFD requirements. [Copyright &y& Elsevier]

We report the occurrence of four red macroalgae new to Europe. Two species were unambiguously determined to the species level with a DNA barcoding approach, while the remaining two species could only be assigned to a genus. Gelidium vagum was found in the Oosterschelde estuary (the Netherlands). Gracilariopsis chorda, Chondracanthus sp. and Solieria sp. were found in the Gulf of Morbihan in Brittany (France); Solieria sp. was also subsequently observed in the Thau Lagoon (France). Gelidium vagum and Gracilariopsis chorda are species originating from the north-western Pacific, around the Japanese archipelago. Phylogenetic analyses also show a likely Pacific origin for Chondracanthus sp. and Solieria sp. Three of these species are likely to have been introduced after 2008, indicating some active transport pathways between the Pacific and the north-eastern Atlantic. These findings also underline the importance of consistent and continuous local expertise (versus rapid assessment) in early warning systems. [ABSTRACT FROM AUTHOR]

Burgeoning global demand for products derived from seaweeds is driving the increased removal of wild coastal seaweed biomass, an emerging low trophic level industry. These products are marketed as organic and 'sustainable.' Brown macroalgae, such as kelps (Laminariales) and rockweeds (Fucales), are foundational species that form underwater forests and thus support a diverse vertebrate, invertebrate, and algal community-including important commercial species-and deliver organic matter to coastal ecosystems. The measure of sustainability used by the rockweed ( Ascophyllum nodosum (L.) LeJolis) industry, maximum sustainable yield, accounts for neither rockweed's role as habitat for 150+ species, including species of commercial or conservation significance, nor its role in coastal and estuarine ecosystems. To determine whether rockweed cutting is 'sustainable' will require data on the long-term and ecosystem-wide impacts of cutting rockweed. Once a sustainable level of cutting is determined, strict regulation by resource managers will be required to protect rockweed habitat. Until sustainable levels of cutting and appropriate regulations are identified, commercial-scale rockweed cutting presents a risk to coastal ecosystems and the human communities that depend on those ecosystems. [ABSTRACT FROM AUTHOR]

Sulfated polysaccharides and their lower molecular weight oligosaccharide derivatives from marine macroalgae have been shown to possess a variety of biological activities. The present paper will review the recent progress in research on the structural chemistry and the bioactivities of these marine algal biomaterials. In particular, it will provide an update on the structural chemistry of the major sulfated polysaccharides synthesized by seaweeds including the galactans (e.g., agarans and carrageenans), ulvans, and fucans. It will then review the recent findings on the anticoagulant/antithrombotic, antiviral, immuno-inflammatory, antilipidemic and antioxidant activities of sulfated polysaccharides and their potential for therapeutic application. [ABSTRACT FROM AUTHOR]

The photosynthetic oxygen evolution characteristics were examined in both vegetative (blade) and sexual reproductive (receptacle) tissues of Sargassum henslowianum (Fucales, Phaeophyta) from the Shenao bay of Nanao Island, China, to establish the mechanism of photosynthetic acquisition of inorganic carbon (Ci) in this species. In natural seawater (pH 8.1, ca. 2.2 mM Ci), irradiance-saturated net photosynthetic rate (NPR) was greater by 25.3% in blade than receptacle, whereas dark respiratory rate (DR) was 2-fold higher in receptacle than blade. NPR at pH 8.1 was nearly saturated with the 2.2 mM Ci for both blade and receptacle. However, the values of the half-saturation constant for Ci were sharply increased at pH 9.0. NPR was significantly affected, but DR was remained unchanged, with the variation of the pH values in seawater. The data from the final pH value derived from the pH-drift experiments and the comparison between the measured and theoretically estimated photosynthetic rates suggested that both blade and receptacle were capable of acquiring HCO in seawater. The inhibitors experiments showed that a HCO dehydration mechanism mediated by external carbonic anhydrase activity occurred in both the blade and receptacle tissues of S. henslowianum. The proton buffer TRIS had no inhibitory effect on NPR at normal pH value in natural seawater (pH 8.1), but it significantly depressed NPR at pH 9.0. This suggested that proton transport occurred at the outside of the plasma membrane facilitated the operation of the carbon acquisition at pH 9.0. It was proposed that the strategy of photosynthetic carbon acquisition at higher pH would prevent the alga from the damage of over-excitation and photoinhibition in case of sunshine and calm water. We concluded that the blade and receptacle tissues of S. henslowianum have similar mechanism of acquisition of exogenous Ci from seawater to drive photosynthesis; yet they are differentiated more or less with the photosynthetic properties. [ABSTRACT FROM AUTHOR]

Abstract: Macroalgae build biogenic habitats which give shelter and provide a suitable physical environment for a great variety of organisms. Structural complexity of algal substrates may influence the composition of their attached epifauna. The aim of this study is to test whether the taxonomic relatedness of the algal hosts and the functional groups to which they belong influence the species richness and composition of their epifaunal bryozoans. We analysed 36 algal genera from the Atlantic coast of South America between 42°S and Cape Horn. Changes in bryozoan species richness (number of species) among different algal functional groups (filamentous algae, foliose algae, corticated foliose algae, corticated macrophytes) were non-significant. The composition of the epifaunal assemblages differed significantly only between filamentous and foliose algae. Sheet-like bryozoans (i.e. encrusting, pluriserial colonies) were more frequent on foliose than on filamentous algae, while runner-like species (i.e. uniserial stolons) were characteristic epibionts on filamentous thallii. Similarity of bryozoan assemblages increased with increasing taxonomic relatedness of their hosts. As most filamentous seaweeds analysed in this study are members of the Order Ceramiales, the influence of algal taxonomic relatedness and functional groups on the composition of their bryozoan assemblages can be viewed as two different aspects of the same phenomenon. [ABSTRACT FROM AUTHOR]

Dark respiration (non-photorespiratory mitochondrial respiration), which occurs both in the light and in darkness, is vital for growth and survival of algae and plays a critical role in modulating the carbon balance of them. In the present study, we have investigated dark respiration in the light ( R) and in darkness ( R) in three marine macroalgal species, Hizikia fusiformis (phaeophyta), Gracilaria lemaneiformis (Rhodophyta) and Ulva lactuca (Chlorophyta), cultured at 20 °C using aeration with two CO conditions: current ambient (CO concentration about 380 µl/L) and elevated CO (approximately 720 µl/L) air. R was estimated by using the Kok method, whereas R was determined as the rate of O influx at zero light. The results showed that both R and R were unchanged for the elevated CO-grown algae relative to ambient CO concentration for all the algal species tested. However, R was significantly lower than R across all the algal species and growth CO treatments, demonstrating that daytime respiration was partly depressed by the light. The percentage of inhibition of respiration by light was similar between ambient and elevated CO-grown algae. The ratio of respiration to photosynthesis, which tended to decrease when estimated using R instead of R, was not altered for the elevated relative to ambient CO concentration. The results suggest that R, rather than R, is a more accurate estimate of nonphotorespiratory carbon loss in marine macroalgae during the daytime. It would not be anticipated that elevated atmospheric CO would exert a substantial influence on respiratory flux either in the light or in darkness in these particular marine macroalgal species. [ABSTRACT FROM AUTHOR]

Hizikia fusiformis thalli experience dynamic incident light conditions during the period of growth. The present study was designed to examine how changing photon irradiance affects the photosynthesis both in the short and long terms by culturing H. fusiformis under three different light levels: 35 μmol photons m-2 s-1 (low light, LL), 85 μmol photons m-2 s-1 (intermediate light, IL), and 165 μmol photons m-2 s-1 (high light, HL). A similar relative growth rate was observed between IL- and HL-grown algae, but the growth rate was significantly reduced in LL-grown algae. The photosynthetic rates ( Pn) measured at their respective growth light levels were found to be lowest in the thalli grown at LL and highest at HL. However, LL-grown algae exhibited much higher Pn in comparison with IL- and the HL-grown thalli at the same measuring photosynthetic photon flux density, indicating the photosynthetic acclimation to low growth light in H. fusiformis. The photosynthesis–light curves showed that LL-grown algae had a highest light-saturating maximum Pn ( Pmax) in comparison with IL- or HL-grown algae when the photosynthetic rates were expressed on the biomass basis. However, Pmax was highest in HL-grown algae compared to IL- or LL-grown algae when the rates were normalized to chlorophyll a. The photosynthesis–inorganic carbon (Ci) response curves were also significantly affected by the growth light conditions. The highest value of apparent photosynthetic conductance occurred in LL-grown algae while the lowest value in HL-grown algae. Additionally, the activity of external carbonic anhydrase (CA) tended to increase while the total CA activity inclined to decrease in H. fusiformis thalli when the growth light level altered from 35 to 165 μmol photons per square meter per second. The external CA inhibitors showed a higher inhibition in HL-grown algae compared with LL-grown algae. It was proposed that photosynthetic acclimation to low light condition in H. fusiformis was achieved through an increase in the number of reaction centers and increased capacities of electron transport and of Ci transport within cells. The ability of photosynthetic acclimation to low light confers H. fusiformis thalli to overcome the environmental low light condition as a result of the attenuation of seawater or self-shading through enhancing its photosynthetic performance and carbon assimilation necessary for growth. [ABSTRACT FROM AUTHOR]

Abstract: A two-dimensional biomarker approach, using stable isotopes (δ13C, δ15N) and fatty acids, was used to evaluate differences both amongst and within benthic primary producer types (seagrass, fleshy red algae, calcareous red algae, brown algae, and seagrass periphyton) that are typical of the nearshore, temperate Australian region. The primary source of variance (as examined by permutational ANOVA) for all biomarkers examined was amongst primary producer types, as opposed to amongst species within type. δ13C showed a clear separation (Monte Carlo p <0.05) between seagrass (range of means=−10.1 to −14.0‰) and macroalgae (−14.6 to −25.2‰), but could not differentiate amongst the algal types examined. Similarly, distinct δ15N signatures (p <0.05) were found only for seagrass (range of means=3.6–4.1‰) versus calcareous red algae (4.6–5.5‰), with all other types overlapping in their mean δ15N values. In contrast, multivariate analysis of fatty acid data (using Canonical Analysis of Principal coordinates; CAP) distinguished not only between seagrass and macroalgae, but also between red and brown algae (and to a limited extent between the calcareous and fleshy red algal types). The principal unsaturated fatty acids in the samples were C20 polyunsaturates (found primarily in the macroalgae and periphyton), and C18 mono- and polyunsaturates, with high proportions of 18:2n-6 and 18:3n-3 typical of the seagrasses. The C18 monounsaturate 18:1n-7 was one of the most diagnostic compounds for the red algae examined, being present in very low amounts in seagrass and virtually absent in the brown algae. Conversely, brown algae were high in 18:4n-3, with 20:4n-3 particularly diagnostic of the kelp Ecklonia radiata. In contrast to stable isotopes, fatty acids helped distinguish different algal groups, thereby providing support that a two-dimensional approach using stable isotopes and fatty acids is likely to provide the most useful tool to distinguish primary producers in food web structure. [Copyright &y& Elsevier]

The levels of Cd, Cu, Pb, and Zn were determined in the commonest species of green, red, and brown algae collected from five coastal sites in south-western Sardinia (Italy), an area with a long history of mining and smelting. The usefulness of employing Enteromorpha sp. and Padina pavonica (L.) Thivy to monitor metal pollution was evaluated, while diffusive gradients in thin films (DGT) devices were used to measure dissolved metals in seawater. Levels of Cd and Pb were high enough to be of environmental concern in the whole study area. A significant relationship was found between the content of Pb in P. pavonica and DGT-labile Pb in seawater, suggesting that gross elemental concentrations of nonessential metals such as Pb in algal tissues are apparently controlled by the abundance of dissolved metal species in the ambient seawater. The results pointed out the usefulness of using both DGT and algal methods for a better understanding of trace metal availability in coastal waters. [ABSTRACT FROM AUTHOR]

The marine environment is an untapped source of bioactive compounds. Specifically, marine macroalgae (seaweeds) are rich in polysaccharides that could potentially be exploited as prebiotic functional ingredients for both human and animal health applications. Prebiotics are non-digestible, selectively fermented compounds that stimulate the growth and/or activity of beneficial gut microbiota which, in turn, confer health benefits on the host. This review will introduce the concept and potential applications of prebiotics, followed by an outline of the chemistry of seaweed polysaccharides. Their potential for use as prebiotics for both humans and animals will be highlighted by reviewing data from both in vitro and in vivo studies conducted to date. [ABSTRACT FROM AUTHOR]

Eighteen species of marine macroalgae belonging to Chlorophyta, Phaeophyta and Rhodophyta were surveyed, collected from Okha coast, Gulf of Kutch, India and compared for their biochemical composition. The macroalgae showed varied quantities of biochemical constituents like total carbohydrate, total protein, amino acid, phenol and total lipid. The concentration of carbohydrate was higher in most of the species of Chlorophyta followed by Phaeophyta and Rhodophyta, while high amount of amino acid was found in the species belonged to Rhodophyta as compared to Phaeophyta and Chlorophyta. The protein content was rich in the sequence of members belonged to Rhodophyta> Chlorophyta> Phaeophyta, in contrast, lipid content was observed in the sequence of members belonged to Phaeophyta> Chlorophyta> Rhodophyta. However, phenol concentration was in inverse to carbohydrate in studied marine macroalgae. The carbohydrate, amino acid, protein, lipid and phenol content were determined in the range of 16-45%, 9-20%, 10-35%, 0.4-14% and 8- 34% of the fresh weight, respectively. In addition, significant individual differences of the biochemical parameters were recorded in all tested marine alga and the results were also substantiated with the findings of earlier reports. [ABSTRACT FROM AUTHOR]

Marine algae are one of the most important marine living resources for food, feed and medicine since ancient times in the West. However, due to lack of awareness among the people especially in India, their multifunctional properties have not yet been exploited. This paper deals with the pigment composition and its significant variation found in eighteen different species of marine macroalgae belonging to Chlorophyta, Phaeophyta and Rhodophyta, collected from the coast of Okha, Gulf of Kutch, Gujarat, India. Chlorophyll and carotenoids extraction was done with 80% acetone as solvent while phycoerythri pigment was extracted using 50mM phosphate buffer (pH 7.0). The highest chlorophyll content was registered in Cladophora fascicularis while carotenoid content was found to be the highest in Sargassum polycustum. Similarly phycoerythrin content was recorded greater in Scinaia farcellata followed by Porphyra necnamessis and Acanthophora delilei Lamour respectively. In terms of chlorophyll content, the maximum chlorophyll a, b as well as total chlorophyll was registered in most of the species of Chlorophyta followed by Phaeophyta and ultimately Rhodophyta. However, carotenoids were registered to be the highest in most of the species of Phaeophyta group. The group wise distribution of carotenoid showed an order: Phaeophyta>Rhodophyta>Chlorophyta. Chl b/Chl a, Car/Chl a and Car/Chl b ratios were also calculated and high ratios were recorded in Liagora erecta, S.polycustum and Padina gymnospora, respectively. Besides, phycoerythrin content showed the following trend in the species of: Rhodophyta>Phaeophyta>Chlorophyta. Emphasis was made to know the variation of different pigments of all eighteen species of marine macroalgae in this paper. [ABSTRACT FROM AUTHOR]

Although a broad variety of classes of bioactive compounds have already been isolated from seaweeds of the genus Dictyota, most different species are still chemically and biologically unexplored. Dictyota species are well-known brown seaweeds belonging to the Dictyotaceae (Phaeophyta). The phytochemical composition within the genus Dictyota has recently received considerable interest, and a vast array of components, including diterpenes, sesquiterepenes, sterols, amino acids, as well as saturated and polyunsaturated fatty acids, have been characterized. The contribution of these valued metabolites to the biological potential, which includes anti-proliferative, anti-microbial, antiviral, antioxidant, anti-inflammatory, and anti-hyperpigmentation activities, of the genus Dictyota has also been explored. Therefore, this is the most comprehensive review, focusing on the published literature relevant to the chemically and pharmacologically diverse biopharmaceuticals isolated from different species of the genus Dictyota during the period from 1976 to now. [ABSTRACT FROM AUTHOR]

The article discusses the study which explores the variety of marine macroalgae to test the soundness of the functional-form model and to test the hypothesis of physiological rates with surface that connects functional-form and power-scaling. The study tested the grouping species into functional-form groups with surface area to volume ratio for forecasted production of marine macroalgae from intertidal zones adjacent to metabolic rates of surface area to biomass ratio. The functional-form model and the power-scaling approach were transformed to numerical model through metabolic rates into morphological groups production and macroalgal functions groups of coastal ecosystems.

The red alga Solieria chordalis was used as a model to investigate the effects of salt and light stress on the release of volatile halogenated organic compounds (VHOCs). We used a purge and trap technique coupled with a gas chromatograph equipped with an electron capture detector. S. chordalis was exposed to hyposaline (22 psu), hypersaline (50 psu) and normal salinity (34 psu) media in combination with light stress (48 h in the dark followed by 24 h under continuous light). The releases of 9 VHOCs (i.e., CH3I, CH3CH2I, CH2ClI, CH2Br2, CHBrCl2, CHBr2Cl, CH2BrI, CHBr3, CH2I2) were measured after 0, 24, 48 and 72 h on algal sub-samples. In algae unstressed by salt, VHOC production rate decreased under dark conditions but increased with light exposure. However, long periods of light also resulted in higher production of di-halogenated compounds (as compared to tri-halogenated or mono-halogenated compounds). The results from salt-stressed samples indicate that hypoosmotic conditions strongly enhanced whole VHOC production rate, whereas hyper-osmotic conditions slightly reduced their production. An exception was mono-halogen production, which was higher under hyper-osmotic condition (especially during dark periods). Furthermore, long exposure to light and hyper-osmotic conditions led to a decrease in the production of di-halogenated compounds (this did not occur in thalli unstressed by salt). As halogen productions derive from different metabolic pathways, including an enzymatic mechanism, it is possible that the activity of these enzymes may be affected by exposure to various salinity conditions. [ABSTRACT FROM AUTHOR]

Abstract: This work reports the results of the study for cadmium binding by the dead red macroalga Mastocarpus stellatus. Kinetics sorption experiments demonstrated the high rate of metal biosorption: the system attained over 50% of the total biomass cadmium uptake within 2min of contact and over 90% in the first 9min. The kinetic data were successfully described by a pseudo-second order model with rate constants ranging from 1.06 to 10gmmol−1 min−1, as a function of initial metal concentration and temperature. The equilibrium binding was accurately represented in terms of Langmuir and Langmuir–Freundlich models. The sorption isotherms at constant pH showed uptake values as 0.49mmolg−1 (at pH 2.4), 0.56mmolg−1 (at pH 4) and 0.59mmolg−1 (at pH 6), while the affinity constant values were between 0.6 and 5mmol−1 L (Langmuir fit). The acid–base properties of the alga were also studied, obtaining the total number of acid groups, 2.5mmolg−1, and their apparent pK value, 1.56, using the Katchalsky model. Desorption studies were conducted employing different HNO3 concentrations and desorption times. [Copyright &y& Elsevier]

Axenic plantlets derived from three species of marine macroalgae, the temperate green alga Acrosiphonia coalita, the temperate red alga Porphyra yezoensis, and the tropical red alga Portieria hornemannii, all possessed a similar metabolic route to remove the explosive compound 2,4,6-trinitrotolune (TNT) from seawater. At a biomass density of 1.2gl−1 and initial TNT concentrations of 10mgl−1 or less, TNT removal from seawater was 100% within 72h for P. hornemannii and P. yezoensis. Specific rate constants for TNT uptake were 0.016–0.018lg−1 FWh−1 for A. coalita filaments, 0.047–0.062lg−1 FWh−1 for P. yezoensis blades, and 0.037–0.049lg−1 FWh−1 for P. hornemannii microplantlets. Only trace amounts of TNT were found within the biomass. All species reduced TNT to 2-amino-4,6-dinitrotoluene and 4-amino-2,6-dintrotoluene, but these products never accounted for more than 20% of the initial TNT. [Copyright &y& Elsevier]

Skeletonella nelsoniae gen. et sp. nov. is described from sublittoral habitats at Three Kings Islands (34°09′S, 172°10′E) off the northern cape of New Zealand. Plants are diminutive, reaching a height of only 2.5 mm. and consist of erect alternately branched, monosiphonous, uniseriate axes that bear two mostly simple, equal and opposite, distichously arranged determinate lateral branches from each axial ceil. Laterals are cut off from axial cells by a pronounced concavo-convex septum. Typical protrusions that precede cell division are absent, and the newly formed lateral branch initial sits nearly entirely within the original contour of the axial cell. Procarps are borne on the basal cell of a two-celled determinate lateral and consist of a four-celled carpogonial branch. The determinate lateral opposite the two-celled lateral, which bears the carpogonium, is suppressed and is never more than one cell long. After fertilization, the auxiliary cell is cut off from the supporting cell and then divides once into a foot cell and a gonimoblast initial. At this stage involucral branchlets are produced de novo from the hypogenous cell to enclose the maturing carposporophyte. Spermatangial heads are transformed from the distal cells of determinate laterals and each fertile axial cell divides longitudinally to form a whorl of four periaxial cells, which in turn, divide twice to form two spermatangial mother cells each bearing one to two spermatangia. This combination of features is shown to be unique in the family Ceramiaceae, and thus the new tribe Skeletonelleae is proposed. [ABSTRACT FROM AUTHOR]