Digital library

  • PROCEEDINGS OF THE REGIONAL WORKSHOP ON SEAWEED CULTURE AND MARKETING

    Eucheuma seaweed culture was initiated and developed in the Philippines in the late 1960's by Dr.Maxwell Doty's team. Today, Eucheuma industry has become one of the most important fishery export industries of the Philippines. Contrary to the Philippines where seaweed farming is widespread and well developed, the Pacific island countries have experienced great difficulties, both of social and economic nature in establishing the cultivation of carrageenophytes. However, the great potential of seaweed farming in rural development has motivated Pacific countries to look at the seaweed industry very seriously.

    The first trial of Eucheuma culture in the South Pacific was carried out in Fiji in the mid 1970's with imported seedstock from the Philippines though this trial was not successful. In 1977 another trial of Eucheuma culture was carried out by Dr. M. Doty at Christmas Island, Kiribati. The seedstock of Eucheuma was brought from Hawaii, originally having come from the Philippines. The seed was afterward introduced to Tarawa from Christmas Island in 1981. Then, to Tonga from Tarawa in 1982, to Fiji from Tonga in 1984 and to Solomon Islands from Fiji in 1987. The first commercial shipment of 2 mt dried Eucheuma from the region was made in 1984 from Tarawa. In the region Eucheuma is currently exported from Fiji, Kiribati and Federated States of Micronesia. Culture trials are being or have been undertaken in Solomon Islands, Tonga, Tuvalu and French Polynesia.

    In 1986, Fiji became the major Eucheuma growing country in the region, with 200 mt of dried Eucheuma exported in 1986 and 277 mt in 1987. However, in 1988, Eucheuma culture was totally deteriorated because of the political change that happened in the country and the sudden withdrawal of the sole Eucheuma buyer from New Zealand.

    In order to overcome the marketing crisis in Fiji, most of Eucheuma buyers were contacted world-wide through the FAO network. As a result, the FMC Corporation Marine Colloids Division visited Fiji in the late 1988 and showed interest in trading the Fiji Eucheuma.

    In the Pacific island context, the culture of seaweed could be beneficial for rural development. Owing to the low technology involved in farming and the small initial capital investment required, seaweed culture holds considerable promise for developing exports, providing employment, as an alternative source of income for rural fisherman and for exploiting extensive reef and lagoon areas suitable for mariculture purposes. Fiji started an arrangement of restoration programme of Eucheuma culture in 1989.

    During the Second Technical Sub-committee Meeting of the Forum Fisheries Committee 16th Meeting held at Majuro in April 1989, a special meeting on seaweed culture development was organized among the Eucheuma growing and interested countries. In this meeting the countries emphasized the need for studies on marketing of dried Eucheuma, production economics and development of other potential seaweeds culture.

    In response to this regional need together with aiming at promotion of Eucheuma culture in Fiji, the SPADP organized a workshop on seaweed culture and marketing for both the region and the country of Fiji, in association with the Marine Colloids Division and the Fiji Fisheries Division. The main objectives of this workshop were to:

    Encourage Eucheuma seaweed culture in the Pacific region by describing and practically demonstrating appropriate culture techniques including introduction of a newly developed culture practice;

    • Demonstrate baling processes and explain product quality control for the export market;

    • Provide opportunities for the exchange of up-dated information, and discussion on the present situation, trends and constraints of international seaweed culture and marketing with international experts and marketing authorities.

    We wish to thank the regional participants who prepared country reports, all the people of Kiuva village who accepted our field tour, for the warm-hearted and unforgettable hospitality shown to the participants, the staff of the Fiji Fisheries Division who arranged for the installation of the baling machine, the University of the South Pacific who kindly hosted the workshop, and the Marine Colloids Division's staff and the invited experts for their invaluable contribution.

    It is the workshop organizer and the editor's hope that the proceedings of this workshop will be a valuable resource for both those interested in setting up seaweed farms and government officials who need to assess the prospects for seaweed farming in their countries.

    Author(s): ROBERTO FOSCARINI, TIM ADAMS

  • Primary productivity of seaweeds in the lagoon of Minicoy atoll of Laccadive archipelago

    Net primary production (NPP) of 10 commonly available seaweeds varied from 2 to 10 g C/m3/day. The NPP of Enteromorpha compressa and Hypnea valentiae were the highest and that of Caulerpapeltata was the lowest. The mean of NPP of these 10 seaweeds when measured individually was 5.68 g C/m3/d and that of all seaweeds incubated collectively registered 5.32 g C/m3/d. Hence it is presumed that the probable rate of NPP of seaweed community contributing to Minicoy lagoon is approximately 5g/C/m3/d. Except for C.peltata E.compressa and Gelidiella acerosa. The NPP of other species was higher at bottom than at the surface of the lagoon. The results obtained are discussed in the light of distribution of seaweed in Minicoy Lagoon.

    Author(s): Kaladharan, P, Kandan, S

  • Pretreatment and co-digestion of wastewater sludge for biogas production: Recent research advances and trends

    Currently, sludge is not considered as a waste any more, since it is capable of producing valuable products. Besides land disposal and thermochemical processes (i.e. pyrolysis, combustion, gasification), biological processes appear as promising valorisation routes to treat wastewater sludge efficiently. Anaerobic digestion (AD) processes are already being applied at industrial scales for the effective disposal and valorisation of sludge. However, methane yields from sludge anaerobic digestion remain low compared to other types of organic waste. Thus, pretreatment and co-digestion contribute to improve the degradability of organic matter and methane potential of sludge, respectively. This paper reviews the recent achievements in sludge pretreatment and codigestion with other substrates such as the organic fraction of municipal solid waste, fatty waste, lignocellulosic and algal biomass. Furthermore, recent studies combining co-digestion and pretreatment are examined. The paper also provides recommendations to better manage sludge recovery by taking into account multiple aspects such as techno-economic feasibility, the effect of pretreatment on both the physico-chemical properties of sludge and the quality of digestate. The socio-environmental and legislative aspects are also essential in order to ensure the sustainability of the process.

    Author(s): D. Elalami, H. Carrere, F. Monlau, K. Abdelouahdi, A. Oukarroum, A. Barakat

  • Preparation of Bioethanol from Brown Seaweed (Sargassum Sp.)

    In this study, brown seaweed (Sargassumsp.) was used to produce bioethanolby using enzymatic liquefaction and saccharification method. Bioethanol frombrown seaweed (Sargassumsp.) was more commercial than using any otherstarch based raw materials because it can be easily collected on Chaung Thabeach in Myanmar without any impact on environment. In this regard, theproductivity of bioethanol from brown seaweed (Sargassumsp.) wasdetermined by separate hydrolysis and fermentation (SHF) with yeasts. Twotypes of yeasts were used.Saccharomyces cerevisiaewas used for glucosefermentation in brown seaweed and selected nitrogen fixing yeast isolate(N3,N18,N24) were used for mannitol fermentation which consist plenty inbrown seaweed. The effects of enzymatic liquefaction, enzymaticsaccharification and fermentation on this sample were studied. From thefermentation studies, brown seaweed (Sargassumsp.) gave the ethanolpercent by weight of 2.56% usingSaccharomyces cerevisiaeonly and 4.1% byusing mixture of yeastSaccharomyces cerevisiaeand selected nitrogen fixingyeast isolate. The maximum yield of crude ethanol was 32.5% by fermentatingyeast mixture ofSaccharomyces cerevisiaeand nitrogen fixing yeast isolate.When it was fermented by just onlySaccharomyces cerevisiae,yield of crudeethanol percent was 20.3%.

    Author(s): Nway Mon Mon Oo, Tint Tint Kywe

  • Preliminary understanding on the ash behavior of algae during co-gasification in an entrained flow reactor

    Algae are considered as a promising alternative fuel to produce energy due to its advantages such as high production yield, short growth cycle and flexible growing environment. Unfortunately, ash-related issues restrict its thermochemical utilization due to the high ash content and especially the high alkali metal concentration. In this paper, the gasification performance and ash behavior were experimentally analysed for three macro- and micro-algal species. Clear differences in the proximate and ultimate compositions were found between the cultivated algae used in this study and macroalgae (seaweed) harvested from the marine environments. Algal biomass generally contained higher Na and P contents than lignocellulosic biomass. Microalgae also had a relatively high mineral content due to the impurities in the harvesting process which included centrifugal pumping followed by sedimentation. Co-gasification of 20 wt% algae with softwood was investigated using an entrained flow reactor. The addition of both macroalgal species Derbersia tenuissima and Oedogonium to softwood had a limited influence on the gas yields and carbon conversion. On the other hand, the addition of the microalgal species Scenedesmus significantly decreased the main gas yields and carbon conversion. Moreover, the addition of algae clearly changed the residual ash composition of the base fuel. Finally, a preliminary understanding of the ash behavior of the tested algae blends was obtained through the analysis of the fuel ashes and the collected residual ashes. Fouling and corrosion were presumably occurred during the co-gasification of wood/macroalgae blends in view of the high alkali metal content. Microalga Scenedesmus had a high mineral content which could potentially capture the alkali metal in the ash and mitigate fouling when gasified with softwood. The growing environment and harvesting method were found to be significantly affecting the ash behavior implying the need for careful consideration regarding co-gasification process.

    Author(s): Youjian Zhu, Philip J. van Eyk, Christoffer Boman, Markus Broström, Kawnish Kirtania, Patrycja Piotrowska, Dan Bostrom, Rocky de Nys, Sankar Bhattacharya, Francesco G. Gentili, Peter J. Ashman

  • Preliminary study of Eucheuma and Gracilaria culture off Kenya

    Bilateral scientific agreements between Kenya and Belgium resulted in 3 marine research projects along the Kenyan coast:

    1. 1984-1988. Ecology and management of the coastal zone. 

    2. 1988-1991. Floristics, faunistics and ecology of Kenyan coastal biotopes. 

    3. 1989-1991. Dynamics and assessment of Kenyan mangrove ecosystems.

    Research is done in and from the Kenya Marine and Fisheries Research Institute at Mombasa.

    The local staff scientists working on phycology are mostly interested in developing a proper plan for the harvesting of natural populations, mariculture and use of commercially important seaweeds. It was obvious that a broad survey of the Kenyan coastal water was needed, to look at potential sites for significant stands of commercially important seaweeds. The conclusion of this fieldwork is that there are no beds of such seaweeds available for wild harvest along the Kenyan coast (except maybe for Gracilaria corticata and G. salicornia). Any exploitation of existing stands of commercially important seaweeds will cause irreparable damage to the primary productivity in the coastal zone and drastically change the biotope where they occur.

    Therefore the future development of the Kenyan coastal algal resources could only be realized by outdoor seaweed cultivation. 

    Author(s): Eric Coppejans

  • Potential Utilization of Various Molecules from Micro- and Macro-algae: Goals and Procedures
    Recent advances have been done in the identification, isolation and biological evaluation of use of several kinds of molecules from various algal sources. We aim to give the state of some of the current research done in this domains on both polysaccharides from the cell wall and lipids which are both known as possible sources for valuable molecules with therapeutic effects.
    Author(s):

  • Potential applications of radioprotective phytochemicals from marine algae

    The use of ionizing radiation and radioactive elements is becoming increasingly popular with the rapid developments in nuclear technology, radiotherapy, and radio diagnostic methods. However, ionizing radiation can directly or indirectly cause life-threatening complications such as cancer, radiation burns, and impaired immunity. Environmental contamination with radioactive elements and the depletion of ozone layer also contribute to the increased levels of radiation exposure. Radioprotective natural products have particularly received attention for their potential usefulness in counteracting radiation-induced damage because of their reduced toxicity compared with most drugs currently in use. Moreover, radioprotective substances are used as ingredients in cosmetic formulations in order to provide protection against ultraviolet radiation. Over the past few decades, the exploration of marine algae has revealed the presence of radioprotective phytochemicals, such as phlorotannins, polysaccharides, carotenoids and other compounds. With their promising radioprotective effects, marine algae could be a future source for discovering potential radioprotective substances for development as useful in therapeutics.

    Author(s): Jae-Young Oh, I.P. Shanura Fernando, You-Jin Jeon

  • Post Harvest Technology

    In India, the seaweeds are harvested by handpicking. In the United States rapid industrialisation has been brought 'in during 1917-1918 in harvesting the Macrocyst/s beds by mechanical harvestors (Dawson, 1966). Mathieson (1969) described the harvest of Macrocyst/s using motor-driven barges with mowers. The mechanical harvestors cut the kelp canopy just under one metre below the water surface and transport the material to the barge. This way, several hundred tons of seaweed can be cut in a day. After being harvested, the material is washed and chopped, and the algin extracted.

    Author(s): V. S. K. Chennubhotla, K. Kaliaperumal, S. Kalimuthu

  • Positive biotic interactions in freshwaters: A review and research directive

    1. Positive interspecific interactions such as mutualism, commensalism, and facilitation are globally ubiquitous. Although research on positive interactions in terrestrial and marine systems has progressed over the past few decades, comparatively little is known about them in freshwater ecosystems. However, recent advances have brought the study of positive interactions in freshwater systems to a point where synthesis is warranted. 2. In this review, we catalogue the variety of direct positive interactions described to date in freshwater ecosystems, discuss factors that could influence prevalence and impact of these interactions, and provide a framework for future research. 3. In positive interactions, organisms exchange key resources such as nutrients, protection, transportation, or habitat to a net benefit for at least one participant. A few mutualistic relationships have received research attention to date, namely seed-dispersing fishes, crayfishes and their ectosymbiotic cleaners, and communal-spawning stream fishes. Similarly, only a handful of commensalisms have been studied, primarily phoretic relationships. Facilitation via ecosystem engineering has received more attention, for example habitat modification by beavers and bioturbation by salmon. 4. It is well known that interaction outcomes vary with abiotic and biotic context. However, only a few of studies have examined context dependency in positive interactions in freshwater systems. Likewise, positive interactions incur costs as well as benefits; conceptualising interactions in terms of net cost/benefit to participants will help to clarify complex interactions. 5. It is likely that there are many positive interactions that have yet to be discovered in freshwater systems. To identify these interactions, we encourage inductive natural history studies combined with hypotheses deduced from general ecological models. Research on positive interactions must move beyond small-scale experiments and observational studies and adopt a cross-scale approach. Likewise, we must progress from reducing systems to oversimplified pairwise interactions, toward studying positive interactions in broader community contexts. Positive interactions have been greatly overlooked in applied freshwater ecology, but have great potential for conservation, restoration, and aquaculture. 

    Author(s): Samuel Silknetter, Robert P. Creed, Bryan L. Brown, Emmanuel A. Frimpong, James Skelton, Brandon K. Peoples

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