Estudo do crescimento, eficiência de biofiltração e cinética de absorção de nutrientes (N-NH, N-NO e P-PO4³) da macroalga Gracilaria cervicornis (Turner) J. Agardh

The objective of this study was to examine the growth of Gracilaria cervicornis cultured in a shrimp (Litopenaeus vannamei) pond and to determine the absorption efficiency and the kinetics parameters (Vmax, Ks e Vmax:Ks) of this macroalgae for the nutrients N-NO3-, N-NH4+ and P-PO4-3, aiming at its use as bioremediatory of eutrophicated environments. For this study, two experiments (field and laboratory) were developed. In the field study, the seaweed was examined in relation to the growth and the biomass. In the laboratory experiment, the absorption efficiency of G. cervicornis was measured through the monitoring of the concentration of the three nutrients (N-NO3-, N-NH4+ e P-PO4-3) during 5 hours and the kinetic parameters were determined through the formula of Michaelis-Menten. The results obtained in this study demonstrated that G. cervicornis benefited from the available nutrients in the pond, increasing 52.4% of its biomass value after 30 days of culture. It was evidenced that the variability of the biomass could be explained through the salinity, availability of light (transparency and solid particle in suspension) and concentration of N-NO3- in the environment. In the laboratory experiment, the highest absorption efficiency was found in the treatments with low concentration (5 µmol.L-1), being evidenced a reduction of up to 85,3%, 97,5% and 81,2% of N-NH4+, N-NO3- and P-PO43-, respectively. Regarding the kinetic parameters, G. cervicornis presented better ability in absorbing N-NH4+ in high concentrations (Vmax = 158,5 µmol g-1 dry wt h-1) and P-PO43- in low concentrations (Ks = 5 µmol.L-1 e Vmax:Ks = 10,3). The results of this study show that G. cervicornis could be cultivated in shrimp ponds, presents a good capacity of absorption for the tested nutrients and is a promising candidate for biorremediation in shrimp pond effluent

Extracción, identificación y prueba microbiológica del agar extraído de Gracilaria fortissima dawson (rhodophyta, gigartinales, gracilariaceae) (ING)

The red seaweed Gracilaria fortissima colected in the caribean coast of Costa Rica, was studied for the extraction, identification and microbiological performance of the agar contend of this plant, as well as the mineral contend. The research was done focused on the agar quality included pH, % extraction, geling point, fusion point and gel strength, as well as infrared analysis and the performance as a microbiological culture of bacteria and fungus and compared with commercial agar from BDH chemicals.

Seaweed industry in India

The seaweed industry in India is mainly a cottage industry and is based only on the natural stock of agar yielding red seaweeds, such as Gelidiella acerosa and Gracilaria eduli and algin yielding brown seaweed species such as Sargassum and Turbinaria. India produces 110-132 t of dry agar annually utilizing about 880-1100 t of dry agarophytes, and 360-540 t of algin from 3600-5400 t of dry alginophytes.

A taxonomic study of some red algae commonly growing on the coast of Karachi

Eighteen commonly occurring species of marine benthic red algae, i.e., Asparagopsis taxiformis (Delile) Trevisan, Bangia atropurpurea (Roth) C. Agardh, Centroceras clavulatum (C. Agardh) Montagne, Calliblepharis fimbriata (Greville) Kiitzing, Coelarthrum muelleri (Sonder) B¢rgesen, Cottoniella filamentosa (Howe) B¢rgesen, Gracilariafoliifera (Forsskai) B¢rgesen, Halymenia porphyraeformis (B¢rgesen) Parkinson, Hypnea muscifor:mis (Wulfen) Lamouroux, Hypnea valentiae (Turner) Montagne, Laurencia obtusa (Hudson) Lamouroux, Me!anothamnus somalensis Bomet et Falkenberg, Porphyra vietnamensis Tanaka et Pham-hoang H6, Sarconema filiforme (Sonder) Kylin, Sebdenia flabellata (J. Agardh) Parkinson, Scinaia fascicularis (B¢rgesen) Huisman, Scinaia hatei B¢rgesen, and Solieria robusta (Greville) Kylin were collected from coastal areas near Karachi (Pakistan) and taxonomically investigated. All the investigated seaweeds are taxonomically known species. During this study, Melanothamnus somalensis is reported for the first time from northern Arabian Sea and Asparagopsis taxiformis, Bangia atropurpurea, Cottoniella filamentosa, Gracilaria foliifera, Halymenia porphyraeformis, Melanothamnus somalensis, Sarconema filiforme, Sebdenia flabellata, Scinaia fascicularis, and Solieria robusta are taxonomically described for the first time from the coast of Pakistan.

Farming seaweeds at SEAFDEC/AQD

The article presents the practices that have been developed or documented by SEAFDEC Aquaculture Department for farming seaweeds. These practices are: the cage culture of Kappaphycus, and the ‘rice planting’ method for cultivating Gracilaria. The seaweed gathering practices in coastal communities in western Visayas is also presented.

Village level processing techniques

The agar-bearing seaweeds Gracilaria and Gelidium grow abundantly in the Asia-Pacific region. Production and post-harvest techniques and methods for processing Gracilaria to produce agar suitable for local market is necessary to increase the meager income of coastal dwellers. A flow diagram of a village level agar production is provided. A guide is also given for the quality of dried seaweeds, which are divided into 3 classes.

Farming techniques for seaweeds

Details are given of farming methods developed by the SEAFDEC Aquaculture Department for 3 different seaweeds: 1) Bottom line culture method for Kappaphycus; 2) Pond culture of Gracilaria; and, 3) Gracilariopsis bailinae, the new seaweed on the block.

The Philippine seaweed industry

A brief outline is given of the Philippine seaweed industry, which involves mainly the red seaweed Kappaphycus alvarezii, produced as a source of the semi-refined or Philippine natural grade (PNG) carrageenan. Other species cultured and marketed include: Gracilaria changii, G. firma, G. heteroclada, G. manilaensis and G. tenuistipitata. The Philippines has the largest carrageenan refinery in Asia. However, production of seaweeds is rather erratic, which is attributed to the following factors: 1) indiscriminate harvesting, seasonal abundance of different species in different areas and lack of proper management; 2) shortage and deteriorating quality of seedlings, especially for Kappaphycus; and 3) natural calamities.

湖南省小型甲壳动物新种和新记录

本文记述了湖南省首次记录的63种小型甲壳动物。其中包括一新亚种密纹尖额溞Alona verrucosa lineolata和6个中国新记录种和亚种.将国内学者以前记载的钩足平直溞Pleuroxus hamulatus移入锐额溞属,即钩足锐额溞Alonella hamulatus。

粗疣类钱袋苔[Apomarsupellaverrucosa(Nichols.)Vana]及其新异名

对产自中国云南缺萼苔科(Gymnomitriaceae)粗疣类钱袋苔(Apomarsupella verrucosa(Nichols.)Vana)和产自尼泊尔(Gymnomitrion papillosumKitag.&S.Hatt.)的模式标本进行了对比研究,发现Gymnomitrion papillosum和粗疣类钱袋苔特征相一致,将其处理为粗疣类钱袋苔的异名。

Transforming kelp into a marine bioreactor

The past decade has seen the genetic engineering of various types of seaweed. To date, genetic transformation studies have been carried out in several seaweeds, including the red seaweeds Porphyra, Gracilaria, Grateloupia, Kappaphyclus and Ceramium and the green seaweed Ulva. A genetic transformation model system has been established in the most commonly cultivated seaweed, the brown seaweed Laminaria japonica (kelp), based on the transfer of technology used in land plant transformation and also by modulating the seaweed life cycle. This model showed the potential for application of transgenic kelp to the production of valuable products and an indoor cultivation system for transgenic kelp was proposed, taking into account necessary factors for bio-safety. In this review, the establishment at use of the kelp transformation model is introduced, highlighting the potential for transforming kelp into a marine bioreactor.

Solving the coastal eutrophication problem by large scale seaweed cultivation

Eutrophication is becoming a serious problem in coastal waters in many parts of the world. It induces the phytoplankton blooms including 'Red Tides', followed by heavy economic losses to extensive aquaculture area. Some cultivated seaweeds have very high productivity and could absorb large quantities of N, P, CO2, produce large amount of O-2 and have excellent effect on decreasing eutrophication. The author believes that seaweed cultivation in large scale should be a good solution to the eutrophication problem in coastal waters. To put this idea into practice, four conditions should be fulfilled: (a) Large-scale cultivation could be conducted within the region experiencing eutrophication. (b) Fundamental scientific and technological problems for cultivation should have been solved. (c) Cultivation should not impose any harmful ecological effects. (d) Cultivation must be economically feasible and profitable. In northern China, large-scale cultivation of Laminaria japonica Aresch. has been encouraged for years to balance the negative effects from scallop cultivation. Preliminary research in recent years has shown that Gracilaria lemaneiformis (Bory) Daws. and Porphyra haitanensis Chang et Zheng are the two best candidates for this purpose along the Chinese southeast to southern coast from Fujian to Guangdong, Guangxi and Hong Kong. Gracilaria tenuistipitata var. liui Chang et Xia is promising for use in pond culture condition with shrimps and fish.

Molecular biotechnology of marine algae in China

Molecular biotechnology of marine algae is referred to as the biotechnology on the identification, modification, production and utilization of marine algal molecules. It involves not only the manipulation of macromolecules such as DNA, RNA and proteins, but also deals with low molecular weight compounds such as secondary metabolites. In the last decade, molecular systematic researches to investigate the relationship and to examine the evolutionary divergence among Chinese marine algae have been carried out by Chinese scientists. For example, RAPD has been widely used in several laboratories to elucidate genetic variations of the reds, such as Porphyra, Gracilaria, Grateloupia and the greens such as Ulva and Enteromorpha. Some important data have been obtained. The study on molecular genetic markers for strain improvement is now in progress. In 1990s, genetic engineering of economic seaweeds such as Laminaria, Undaria, Porphyra, Gracilaria and Grateloupia has been studied in China. For Laminaria japonica, the successfully cultivated kelp in China, a model transformation system has been set up based on the application of plant genetic techniques and knowledge of the algal life history. Progress has been made recently in incorporating a vaccine gene into kelp genome. Evidence has been provided showing the expression of gene products as detectable vaccines. In the present paper, the progress of molecular biotechnological studies of marine algae in China, especially researches on elucidating and manipulating nucleic acids of marine algae, are reviewed.

Algal biotechnology industries and research activities in China

In old China there were very few people engaged in the study of the algae, but in new China, freshwater and marine algae are studied by over one hundred old and new phycologists. There is now an algal biotechnology industry consisting of an aquaculture industry, producing large amounts of the seaweeds Laminaria, Porphyra, Undaria, Gracilaria, eucheumoids, and the microalgae Dunaliella and Spirulina. There is also a phycocolloid industry, producing algin, agar and carrageenan; an industry producing chemicals and drugs, such as iodine, mannitol, phycocyanin, beta -carotene, PSS (propylene glycol alginate sulfate) and FPS (fucose-containing sulfated polysaccharides) and an industry producing food, feed and fertilizer. The Laminaria cultivation industry produces about 900,000 t dry Laminaria, probably the largest producer in the world and 13,000 t algin, undoubtedly one of the largest algin producer in the world.

Dynamic changes of total bacteria and Vibrio in an integrated seaweed-abalone culture system

Polyculture of seaweeds alongside fed animal aquaculture is an environmentally friendly means of avoiding eutrophication problem both in land-based and sea-based monoculture systems. Many aspects of such polyculture systems have been described, but little attention has been given to the impact of live seaweeds on the microbiological properties of the water that connects the algae and animals. In this investigation, the Pacific red alga Gracilaria textorii was cultured in a recirculated dual tank system (150 L) with the juvenile abalone Haliotis discus hannai. Dynamic changes of total bacteria (TB) and total Vibrio (TV) in the water of polyculture and monoculture systems were evaluated. Results revealed that (1) level of TB in the polyculture was constantly higher than in the monoculture over a 6.5-day period. While levels of TV in the polyculture was detected to be constantly lower than in the monoculture, (2) integration of G. textorii in the abalone culture changed the Vibrio compositions in the water as judged by the changes of bacteria colony types; (3) application of artificial diet led to dramatic increase of the levels in TB and TV in both systems at 12 h after application in the 24-h test and resulted in selective propagation of Vibrio in the water in the monoculture system; (4) polyculture of G. textorii with juvenile abalone in combination with feeding with live algal diet helped to maintain low levels of TV and the balance of the Vibrio composition; (5) living biomass of G. textorii was effective in preventing propagation of two purified Vibrio strains (V alginolaticus and V logei) in the water. These results provide a general basis of the dynamic changes of levels in TB and TV in a seaweed-abalone polyculture system with or without artificial diet in tanks. (c) 2005 Elsevier B.V All rights reserved.