The presence of free d-aspartate in marine macroalgae is restricted to the Sargassaceae family

The presence of d-aspartate (d-Asp), a biologically rare amino acid, was evaluated in 38 species of marine macroalgae (seaweeds). Despite the ubiquitous presence of free l-Asp, free d-Asp was detected in only 5 species belonging to the Sargassaceae family of class Phaeophyceae (brown algae) but not in any species of the phyla Chlorophyta (green algae) and Rhodophyta (red algae). All other members of Phaeophyceae, including 3 species classified into the section Teretia of Sargassaceae did not contain d-Asp. These results indicate that the presence of free d-Asp in marine macroalgae is restricted only to the Sargassaceae family, excluding the species in the section Teretia.     

烟台养马岛潮间带大型海藻分布特征及环境影响因素

2010年4月—2011年3月对烟台养马岛潮间带大型海藻进行了逐月调查.在养马岛潮间带共设置了A、B两个点,对大型海藻物种组成、生物量以及与环境变化的关系进行了研究.结果表明: 调查区域共有大型海藻35种,其中红藻24种,占总数的68.6%;绿藻6种,占总数的17.1%;褐藻5种,占总数的14.3%.夏季优势种以褐藻和绿藻为主,秋、冬、春季优势种以红藻和褐藻为主,鼠尾藻在各季节中均为优势种.大型海藻生物量呈现夏季高、冬季低的特点,生物量最高值出现在6月,A、B采样点大型海藻生物量最小值分别出现在1月和11月,具有温带海域藻类变化特点.温度、营养盐和pH对大型海藻生物量有显著影响.
     

LIGHT INDEPENDENT CARBON FIXATION BY MARINE MACROALGAE1

Several marine macroalgae representative of the Chlorophyceae, Rhodophyceae and Phaeophyceae were investigated for their potentials of photosynthesis and light independent (dark) carbon fixation. In addition, the activities of ribulose-1,5-bisphosphate carboxylase (RubP-C; EC 4.1.1.39) and of phosphoenolpyruvate carboxykinase (PEP-CK; EC 4.1.1.32) were studied. In contrast to the green and red algae investigated, all brown algae exhibited comparably high rates of dark fixation accounting for up to 20% of photosynthetic carbon uptake. These observations are confirmed by the activities of RubP-C and PEP-CK measured after extraction from different species and thallus regions. Dark fixed ¹⁴C was mainly recovered from aspartate, citrate, malate, glutamate, and alanine. Appreciable amounts of ¹⁴C were incorporated into insoluble (polymeric) constituents even after relatively short periods of dark fixation.     

Changes in the species composition of benthic macroalgal communities of the upper subtidal zone on a coral reef in Sanya Bay (Hainan Island, China) during 2009–2012

Investigations of macroalgae were carried out on a coral reef at the Luhuitou Peninsula in Sanya Bay (Hainan Island, China) in the upper subtidal zone at a depth of 0.5 to 4 m during the dry season (in April 2009 and 2012). In total, 130 species, varieties, and forms of marine macroalgae were found: 71 (54%) Rhodophyta, 33 (25%) Chlorophyta, and 26 (21%) Phaeophyceae. In terms of the number of species and the floristic composition of algae in the communities, the reef benthic flora in the subtidal zone of Sanya Bay, which is polluted by municipal waste waters and aquaculture wastes, was close to the flora of Indo-Pacific coral reefs situated in areas with low pollution. In 2009 and 2012, the algal turf communities differed both in the algal species diversity and in the composition of dominant species. These differences might be due to an annual periodicity of changes in vegetation: algal turf patches are detached from the hard substrate and a new algal community is formed at this location.     

Preliminary observations on the benthic marine algae of the Gorringe seabank (northeast Atlantic Ocean)

Examination of marine samples collected in 2006 from the Gettysburg and Ormonde seamounts on the Gorringe seabank southwest of Portugal has revealed 29 benthic Chlorophyta, Phaeophyceae (Ochrophyta), and Rhodophyta that were identified provisionally to genus and to species. Combining lists for the present and a previous expedition brings the total of algae thus far recorded to 48. The brown alga Zonaria tournefourtii and the red alga Cryptopleura ramosa were the most abundant species in the present collections. The kelp Laminaria ochroleuca was present only in the Gettysburg samples while Saccorhiza polyschides was observed only on the Ormonde seamount. Comparisons with the benthic marine algae recorded on seamounts in the mid-Atlantic Azores archipelago show features in common, notably kelp forests of L. ochroleuca at depths below 30 m and Z. tournefortii dominance in shallower waters.     

Antimicrobial activity of some macroalgae of the Veracruzano Reef System (SAV), Mexico

The study of macroalgae antimicrobial agents is limited to Mexico and scarce in the Veracruzano Reef System (SAV). It is necessary to devote efforts towards this field of applied phycology. The aim was to evaluate the antimicrobial activity of some phyla of Rhodophyta, Chlorophyta and Ochrophyta from SAV. Methanolic extracts from 23 marine macroalgae species (7 Chlorophyta, 4 Phaeophyta and 12 Rhodophyta) from the Veracruzano Reef System (SAV) (Mexico) were evaluated for antimicrobial activity. Antibacterial and antifungal activity were assessed by agar diffusion and agar dilution methods. The differences between mean values obtained for experimental groups was done by analysis of variance (ANOVA multifactorial model), p-values of 0.001 or less were considered statistically significant. Two new records are recognized for SAV (Laurencia gracilis and Sebdenia flabellata) and Compsothamnion thuioides for the Gulf of Mexico coasts. 16 species showed antibacterial activity, of which Caulerpa sertularioides, Ulva lactuca and Laurencia obtuse had significant activity on Gram-positive bacteria. 43.7% belong to the phyla Chlorophyta (7 species), 50% Rhodophyta (8 species) and 6.25% Ochrophyta (1 species). This indicates that the extracts of the algae of the Rhodophyta and Chlorophyta are the ones that showed the greatest activity. Regarding the yeasts, 16.6% of the total algae collected were active in the different yeast strains. 43.7% belongs to Chlorophyta species and for Rhodophyta were 60%. The macroalgae with the highest antifungal activity were: Cymopolia barbata, Ulva lactuca and Laurencia gracilis. The macroalgae of the Veracruzano Reef System present antimicrobial activity. This study is the first investigation of macroalgae's bioactive components from SAV, where they could be sources for future medical applications.     

New records of marine benthic algae from the Lagon Sud-Ouest of New Caledonia, South Pacific

As part of an ongoing project to substantially increase knowledge of the marine algal flora of the French Pacific territory of New Caledonia, a survey of the Nouméa region was conducted that has resulted in the discovery of 41 previously unrecorded species of macroalgae, including 1 Chlorophyta, 1 Phaeophyceae (Heterokontophyta) and 39 Rhodophyta. Among the biogeographically interesting new records are the green macroalga Rhipilia penicilloides N’Yeurt et Keats (previously endemic to the islands of Fiji some 1000 km east of new Caledonia) and the brown alga Cutleria mollis Allender et Kraft (originally described from Lord Howe Island some 1000 km to the south). The red alga Gloiophloea articulata Weber‐van Bosse, known only from its initial discovery in 1928 from the Mascarene Islands in the western Indian Ocean, is now recorded in the deep‐water channels of the Nouméa region of New Caledonia. The widely distributed Indian Ocean species Corynomorpha prismatica (J. Agardh) J. Agardh has its easternmost distribution record from this area, and Dotyella hawaiiensis (Doty et Wainwright) Womersley et Shepley is recorded for the first time outside its central‐Pacific distribution. These new discoveries represent a 12% increase in the total number of species (377) that are reliably known from New Caledonia.     

Fatty acid contents and profiles of 16 macroalgae collected from the Irish Coast at two seasons

Due to the established health benefits of omega-3 long-chain polyunsaturated fatty acids (LC-PUFA), there is a globally increasing demand for alternative natural resources with appropriate fatty acid profiles. To assess the suitability of macroalgae as a source, 16 species (nine Phaeophyceae, five Rhodophyta and two Chlorophyta) were collected at two seasons (June and November) from the Irish west Coast, and total fatty acid contents and specific profiles were determined. Total fatty acid contents, expressed per percentage of dry weight, ranged from 6.4 %?±?0.3 (Pelvetia canaliculata, Phaeophyceae) to 0.8 %?±?0.2 (Porphyra dioica, Rhodophyta). Most common fatty acids were palmitic (16:0), oleic (OLE, 18:1 n-9), α-linolenic (ALA, 18:3 n-3), arachidonic (ARA, 20:4 n-6) and eicosapentaenoic (EPA, 20:5 n-3) acids. Fatty acid profiles were highly variable between and within algal groups; red and brown seaweeds were generally richer in LC-PUFA (e.g. 20:4 n-6 and 20:5 n-3), while high levels of saturated fatty acids such as palmitic acid (16:0) were observed in green species. Most omega-3 PUFA-rich species investigated had a omega-6/omega-3 fatty acid ratio close to 1, which is favourable for human health. The two seasonal sampling times revealed significant differences in total fatty acid and 20:5 n-3 (EPA) contents, with changes depending on species, thus implying varying suitability as potential target species for EPA production. At both times of the year, Palmaria palmata was identified as most promising species as a source of 20:5 n-3 (EPA) amongst all species investigated, with levels ranging from 0.44 to 0.58 % of dry weight in June and November, respectively.     

The eco-evolutionary importance of reproductive system variation in the macroalgae: Freshwater reds as a case study

The relative frequency of sexual versus asexual reproduction governs the distribution of genetic diversity within and among populations. Most studies on the consequences of reproductive variation focus on the mating system (i.e., selfing vs. outcrossing) of diploid-dominant taxa (e.g., angiosperms), often ignoring asexual reproduction. Although reproductive systems are hypothesized to be correlated with life-cycle types, variation in the relative rates of sexual and asexual reproduction remains poorly characterized across eukaryotes. This is particularly true among the three major lineages of macroalgae (green, brown, and red). The Rhodophyta are particularly interesting, as many taxa have complex haploid–diploid life cycles that influence genetic structure. Though most marine reds have separate sexes, we show that freshwater red macroalgae exhibit patterns of switching between monoicy and dioicy in sister taxa that rival those recently shown in brown macroalgae and in angiosperms. We advocate for the investigation of reproductive system evolution using freshwater reds, as this will expand the life-cycle types for which these data exist, enabling comparative analyses broadly across eukaryotes. Unlike their marine cousins, species in the Batrachospermales have macroscopic gametophytes attached to filamentous, often microscopic sporophytes. While asexual reproduction through monospores may occur in all freshwater reds, the Compsopogonales are thought to be exclusively asexual. Understanding the evolutionary consequences of selfing and asexual reproduction will aid in our understanding of the evolutionary ecology of all algae and of eukaryotic evolution generally.     

Seaweeds in cold seas: evolution and carbon acquisition

Much evidence suggests that life originated in hydrothermal habitats, and for much of the time since the origin of cyanobacteria (at least 2.5 Ga ago) and of eukaryotic algae (at least 2.1 Ga ago) the average sea surface and land surface temperatures were higher than they are today. However, there have been at least four significant glacial episodes prior to the Pleistocene glaciations. Two of these (approx. 2.1 and 0.7 Ga ago) may have involved a 'Snowball Earth' with a very great impact on the algae (sensu lato) of the time (cyanobacteria, Chlorophyta and Rhodophyta) and especially those that were adapted to warm habitats. By contrast, it is possible that heterokont, dinophyte and haptophyte phototrophs only evolved after the Carboniferous-Permian ice age (approx. 250 Ma ago) and so did not encounter low (相似文献   

New records of Malaysian marine algae

Checklists of the marine algae of Malaysia have been published. The last checklist included the marine algae of Singapore. The checklist recorded 212 taxa for the region. This paper lists an additional 7 taxa of Chlorophyta, 18 taxa of Rhodophyta and 5 taxa of Phaeophyta, which had been left out of the last checklist. These include marine algae from Pulau Pinang, Pulau Redang and Pulau Sibu. In addition, new records of Cyanophyta (2 species), Chlorophyta (4 species), Rhodophyta (10 species) and Phaeophyta (3 species) are reported.     

Macrophytes in the anthropic constructions of the Venice littorals and their ecological assessment by an integration of the “CARLIT” index

A check-list of the macroalgae which colonize the artificial structures “dykes” formed by limestone blocks, placed between the northern Adriatic Sea and the Venice Lagoon to protect the wide sea inlets of Lido and Malamocco, the stone breakwaters and the submerged reefs parallel and perpendicular to the sea coastline of the Lido island “Murazzi” is presented. Macroalgae have been sampled monthly during one-year period (February 2007–January 2008) both in the lagoon inlets and along the marine coast. Flora was represented by 213 taxa: 61 Chlorophyta, 114 Rhodophyta, 38 Ochrophyta (37 Phaeophyceae, 1 Xanthophyceae), with the richest and luxuriant vegetation in the lagoon inlet areas. The application of the Rhodophyta/Chlorophyta (R/C) index and the Expert-Macrophyte Quality Index (E-MaQI) highlighted the “High” ecological status (EQR > 0.9) of the lagoon inlet areas.As E-MaQI is not applicable in marine areas, an adaptation of CARLIT to the anthropic structures of the north-western coasts of the northern Adriatic Sea and its integration with the dominant taxa is proposed.The application of the revised index to the Lido dykes and breakwaters placed along the marine littorals shows “Moderate” conditions.     

A practical perspective on ulvan extracted from green algae

Researchers have many times turned their attention to nature and biological processes to develop novel technologies and materials. In a medical perspective, nature-based products are believed to be a strategic alternative approach to the use of fully synthetic materials, particularly in the design of medical devices. In the past decades, marine organisms have become the focus of considerable attention as potential sources of valuable materials. The sustainable exploitation and valorisation of natural marine resources constitutes a highly attractive and strategic platform for the development of novel biomaterials, with both economic and environmental benefits. In this context, algae are known to synthesise large quantities of polysaccharides and are well established sources of these particularly interesting molecules, many of which are known for their applicability in the design of biomaterials. Agar, carrageenan and alginates are some of the most known examples, and their uses can range from food to biomedical applications. However, few of the world’s available seaweed species are used commercially. Among the three main divisions of macroalgae (Chlorophyta, Phaeophyta and Rhodophyta), the green algae remain largely unexploited in this biomedical arena. While the demand for novel materials and technologies increases, so does the research of unexploited marine green algae including its unique polysaccharide ulvan.     

Marine macroalgae as foods for fishes: an evaluation of potential food quality

Synopsis A revitalized view of feeding by herbivorous marine fishes is sought through two questions. First, What characteristics of major taxa of algae identify them as predictably high or low quality foods? Second, are marine algae valuable foods for fishes which do not mechanically disrupt cell walls and do not harbor specialized enzymes or microbes capable of lysing cell walls? Energy, ash and nutrient content of 16 species of marine algae were employed to assess food quality of fleshy red, green, brown and calcareous red algae. On the basis of ash, calories, total protein and total lipid content, fleshy algae should be superior to calcareous algae as foods for fishes; in addition, green algae should be superior to brown algae and brown algae superior to red algae. When the probable digestibility of storage and extracellular carbohydrates is considered, green and red algae are predicted superior to brown algae as food. Two species of damselfishes (Pomacentridae) from the Gulf of California,Eupomacentrus rectifraenum andMicrospathodon dorsalis, eat red and green algae and ignore brown and calcareous algae. They feed, therefore, in a fashion consistent with predictions based only on algal chemistry. These fishes absorb at least 20–24% of the biomass, 57–67% of the protein, 46–56% of the lipid and 37–44% of the carbohydrate contained in algae eaten in the wild. Since these damselfishes do not masticate their food, it appears that herbivorous fishes can digest major fractions of algal nutrients without mechanical destruction of algal cells.     

Enriching marine macroalgae with eicosatetraenoic (arachidonic) and eicosapentaenoic acids by chilling

Summary Twelve macroalgae belonging to the Chlorophyta, Phaeophyta and Rhodophyta were collected from the Arabian Gulf. Field samples and samples that were first incubated at 5° C and 24° C in the light for 1 week were analysed for lipids and fatty acids. The lipid contents varied according to the macroalga and, within the Chlorophyta and Phaeophyta, some representatives accumulated more lipids at 5° C and others at 24° C. All samples of algae had similar lipid composition with only quantitative differences. The temperature did not have a common effect on the lipid composition of representative algae, although changes in the relative concentration of specific classes were recorded. The Phaeophyta and Rhodophyta were as a rule richer than the Chlorophyta in eicosatetranoic (20:4) and eicosapentaenoic (20:5) but poorer in linolenic (18:3) acids. In most of the algae, incubation at 5° C was associated with lowering the proportion of palmitic acid (16:0) in the total lipids, and, but only in the Phaeophyta and Rhodophyta, increasing the concentration of 20:4 and 20:5. These polyunsaturated fatty acids occurred in high levels in monogalactosyldiacylglycerols (MGDG) and digalactosyldiacylglycerols (DGDG) of the Phaeophyta and Rhodophyta but not the Chlorophyta, the MGDG and DGDG of which were rich in 18:3 and hexadecatrienoic acid (16:3). Offprint requests to: R. H. Al-Hasan     

Epibiotic macroalgae on the scallop <Emphasis Type="Italic">Mizuhopecten yessoensis</Emphasis> in Peter the Great Bay,Sea of Japan

The composition and structure of the epibiotic flora of the Japanese scallop Mizuhopecten yessoensis were studied on the basis of data from long-term (1979 to 2007) observations on the scallop beds in Peter the Great Bay (Sea of Japan). In all, 52 species of macroalgae belonging to three phyla were found on the scallop shells; 3 species were new records for the benthic flora of the area studied. Red algae constituted the bulk of the species richness of algal epibionts; brown algae were represented by the lowest number of species. Species of Chlorophyta predominated in terms of biomass; species of Rhodophyta were found in lower numbers. The main form of the thallus of epibiotic algae was bushy or filamentous. The ratio of common to rare species was 30 : 70. As compared to the benthic flora, the epibiotic flora on the scallop shells was characterized by a greater number of warm-water species.     

Seasonal and interannual variation of sterols in macrophytes from the Pacific coast of Baja California Peninsula (Mexico)

The seasonal and interannual proximate and sterol composition were assessed in two red (Gelidium robustum, Gelidiaceae and Gracilariopsis sjoestedtii, Gracilariaceae), two brown (Ecklonia arborea, Lessoniaceae and Macrocystis pyrifera, Laminariaceae), and two green (Ulva lactuca and Ulva clathrata, Ulvaceae) macroalgae species and the seagrass Phyllospadix torreyi (Zosteraceae) sampled over 3 years in a subtropical climate in Baja California Sur, Mexico. Each macroalga had a particular sterol composition that was typical of their taxonomic group. The red algae had cholesterol as the major sterol; 92% on average in G. robustum and 90% in G. sjoestedtii, followed by t‐dehydrosterol and brassicasterol. In the brown algae the major sterol was fucosterol, which accounted for approx. 90% and 92% of total sterols for M. pyrifera and E. arborea, respectively, followed by campesterol (7% and 5%) and isofucosterol (1.5% and 1.3%). The green algae had isofucosterol as the major sterol, with 92% on average for U. lactuca and 87% for U. clathrata, followed by cholesterol, fucosterol, and brassicasterol or norcholesterol. The seagrass P. torreyi had β‐sitosterol as the major sterol (39 to 89%, depending on the season), followed by campesterol (4 to 7%), stigmasterol (3 to 6%), and isofucosterol (1.7 to 3.5%). Four (cholesterol, campesterol, fucosterol, and isofucosterol) of the 14 sterols identified in macroalgae and the seagrass could be used to differentiate between classes (Florideophyceae – red, Phaeophyceae – brown, Ulvophyceae – green, and Monocots – seagrass) both seasonally and interannually. The seasonal and interannual sterol composition of macroalgae and seagrass was quite stable, with the exception of red G. sjoestedtii sampled in August and green macroalga U. lactuca and seagrass P. torreyi both sampled in May 2002. Seasonal and interannual variations of proximate and sterol composition are discussed in relation to their reproductive state and environmental parameters.     

A DNA mini‐barcode for marine macrophytes

Studies focusing on marine macrophyte metabarcoding from environmental samples are scarce, due to the lack of a universal barcode for these taxa, and to their poor representation in DNA databases. Here, we searched for a short barcode able to identify marine macrophytes from tissue samples; then, we created a DNA reference library which was used to identify macrophytes in eDNA from coastal sediments. Barcoding of seagrasses, mangroves and marine macroalgae (Chlorophyta, Rhodophyta and Phaeophyceae) was tested using 18 primer pairs from six barcoding genes: the plant barcodes rbcL, matK and trnL, plus the genes ITS2, COI and 18S. The 18S gene showed the highest universality among marine macrophytes, amplifying 95%–100% of samples; amplification performance of the other barcodes was limited. Taxonomy was assigned using a phylogeny‐based approach to create an 18S DNA reference library. Macrophyte tissue sequences were accurately identified within their phyla (88%), order (76%), genus (71%) and species (23%). Nevertheless, out of 86 macrophytes tested, only 48% and 15% had a reference sequence at genus and at species level, respectively. Identification at these levels can be improved by more inclusive reference libraries. Using the 18S mini‐barcode and the reference library, we recovered eDNA from 21 marine macrophytes in sediments, demonstrating the barcode's ability to trace primary producers that contribute to blue carbon. We expect this barcode to also be useful for other ecological questions, such as tracing macro primary producers in marine food webs.     

Distribution of carbonic anhydrase in British marine macroalgae

Summary Thirty-four species of marine macroalgae from around St. Andrews, Scotland, have been assayed for their external activity and thirty-three species for their total activity of carbonic anhydrase. Activity was detected in all the Rhodophyta tested apart from Chondrus crispus, but was absent in Codium fragile, Enteromorpha sp. and Monostroma fuscum (Chlorophyta), and Alaria esculenta, Laminaria digitata, L. saccharina and L. hyperborea (Phaeophyta). Total activity of carbonic anhydrase per unit fresh weight tended to be higher in the Rhodophyta than in the Chlorophyta or Phaeophyta. External activity was present in two of the six Chlorophyta, four of the twelve Phaeophyta and four of the sixteen Rhodophyta tested. On average, when present, external carbonic anhydrase activity represented 2.7% of the total activity. A relationship was found between total carbonic anhydrase activity and habitat. Species from the high intertidal and the low-light subtidal habitats had significantly higher activity than species from the mid and low intertidal, rockpools, or high-light region of the subtidal. External carbonic anhydrase activity did not vary significantly with habitat. There appeared to be no strong relationship between carbonic anhydrase activity and the ability of a species to use HCO _- ³ in photosynthesis under water.     

New records of marine benthic algae from New South Wales, eastern Australia

Twenty‐four species of marine macroalgae are recorded from the mainland coast of New South Wales for the first time. One species, Laurencia platyclada Boergesen, represents a new record for Australia and the Pacific Ocean. Included in these new records is the introduced, invasive and cold‐tolerant strain of the green alga Caulerpa taxifolia, which was formerly known only as native, non‐invasive populations from Lord Howe Island. Based on published accounts, the composition of the marine benthic algae for the state of New South Wales now stands at 131 green, 140 brown and 449 red macroalgae. This baseline information adds significantly to our knowledge of the overall marine biodiversity of the state, as well as to the phycogeography of the southwestern Pacific region.