Seaweeds or marine macro algae are primitive non-flowering plants without true root, stem and leaves. They form one of the commercially important marine living renewable resources. They are the only source for the production of phytochemicals such as agar, carrageenan and algin. Seaweeds occur in the intertidal, shallow and deep waters of the sea upto 180m depth and also in estuaries and backwaters. They grow on rocks, dead corals, stones, pebbles, solid substrata and on other plants.
Digital library
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Macroalgae (aka seaweed) - the quintessential ocean crop
- ~15,000 different species growing in a wide range of geographies
- Fast growth rate
- Mostly carbohydrate & protein
- Amenable to cultivation & harvest
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Drivers for seaweed cultivation in the Dutch North Sea
• No existing seaweed industry
• Development of biobased economy (agricultural crops, lignocellulose residues, microalgae,..)
• Interest in seaweeds:
- No competition with food or other land use issues
- High biomass productivity
- Versatile feedstock: numerous options for chemicals and fuels via biorefinery
- Biochemical composition: complementary (for chemicals/fuel production) to micro-algae
• Development offshore wind turbine parks
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- The ‘Seaweed Biorefinery’ project: general description
- Composition of seaweed species for biorefinery
- Biorefinery of green seaweeds (local Ulva lactuca)
- Biorefinery of brown seaweed species:
- Saccharina latissima as model feedstock
- mannitol and alginate extraction
- fermentation of mannitol/glucose to acetone, butanol and ethanol
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Seaweed, also called marine macroalgae, have a potential to be a valuable feedstock for biorefinery. Depending from seaweed type and species it is possible to extract different fatty acids, oils, natural pigments, antioxidants, high value biological components and other substances which can be potentially used in an industrial production system. The seaweed biorefinery framework presents a conceptual model for high value added product production along with production of biofuels either fluid or gaseous. This in turn reduces the cost of fuel production with maximum utilization of the biomass. The role of seaweed biorefinery concept is analysed in this paper under the perspective of bioeconomy principles and through a SWOT analysis was made to indicate the role biorefinery concept can play to support the development of sustainable bioeconomy.
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Two thirds of the world are covered by oceans, whose upper layer is inhabited by photoautotrophic organisms, known as algae. Within coastal ecosystems, marine seaweeds have been identified as a group of organisms of vital importance for ecosystem function. On rocky coasts, they form vast underwater forests of consid- erable size with a structure similar to terrestrial forests and provide diverse habitats and breeding areas for an uncountable number of organisms including fishes and crustaceans. They are an important food source not only for numerous herbivores, such as sea urchins, gastropods, and chitons, but also for detritivores such as filter feeders and zooplankton, which are feeding on degraded seaweed biomass and on energy-rich spores released in vast quantities from seaweeds. On beaches in some localities large masses of seaweeds are stranded and support meiofauna species.
Although marine seaweeds and seagrasses, altogether known as macrophytes, cover only a minute area of the world’s oceans, their production amounts to 5–10% of the total oceanic production. Carbon assimilation of kelps, large brown algae of the order Laminariales, is with 1.8 kg carbon m2 year1 similarly high as that of dense terrestrial forests and even exceeds the primary production of marine phyto- plankton up to ten times.
Seaweeds are not only of high ecological, but also of great economic impor- tance. Dried thalli are directly used as human and animal food and also as fertilizer. Extracted seaweed substances are used as stabilizers and stiffeners in food industry, cosmetics, pharmaceutical industry, and biotechnology. In future, aquaculture of seaweeds will certainly strongly intensify, especially in integrated multi-trophic aquaculture systems making use of the waste products or biomass generated by other organisms in the system. Industrial use of seaweeds will also strongly increase as basis for CO2-neutral production of ethanol and methanol as biofuels.
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"It's best to get it out of the water now or it'll start getting grazed by the little beasties," says Lars Brunner as he hauls 50kg of glistening, translucent kelp from the dark waters of the Sound of Kerrera into the boat. The long summer days mean the seaweed is rapidly storing up sugars, which snails and barnacles find delicious.
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The water-quality characteristics of a new system for the integrated culture of fish ( Sparus aurata L.) and seaweed ( Ulva lactuca L.) were examined. Seawater was recirculated between intensive fishponds and seaweed ponds. The seaweed removed most of the ammonia excreted by the fish and oxygenated the water. A model consisting of several tanks and a pilot consisting of two 100-m 3 , 100-m 2 ponds were studied. In both, the metabolically dependent water-quality parameters (dissolved oxygen, NH 4 + -N, oxidized-N, pH and phosphate) remained stable and within safe limits for the fish during over 2 years of operation. The design allowed significant increases in overall water residence time (4.9 days), compared with conventional intensive ponds, and produced a high yield of seaweed in addition to the fish. The design provides a practical solution to major management and environmental problems of land-based mariculture
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Seaweed Bioethanol Production in Japan, titled the “Ocean Sunrise Project”, aims to produce seaweed bioethanol by farming and harvesting Sargassum horneri, utilizing 4.47 million km² (sixth largest in the world) of unused areas of the exclusive economic zone (EEZ) and maritime belts of Japan. Through seaweed bioethanol production, the Project aims to combat global warming by contributing an alternative energy to fossil fuel. This paper outlines the results of the project’s feasibility research conducted by Tokyo Fisheries Promotion Foundation.
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Cyanobacteria are found globally due to their adaptation to various environments. The occurrence of cyanobacterial blooms is not a new phenomenon. The bloom-forming and toxin-producing species have been a persistent nuisance all over the world over the last decades. Evidence suggests that this trend might be attributed to a complex interplay of direct and indirect anthropogenic influences. To control cyanobacterial blooms, various strategies, including physical, chemical, and biological methods have been proposed. Nevertheless, the use of those strategies is usually not effective. The isolation of natural compounds from many aquatic and terrestrial plants and seaweeds has become an alternative approach for controlling harmful algae in aquatic systems. Seaweeds have received attention from scientists because of their bioactive compounds with antibacterial, antifungal, anti-microalgae, and antioxidant properties. The undesirable effects of cyanobacteria proliferations and potential control methods are here reviewed, focusing on the use of potent bioactive compounds, isolated from seaweeds, against microalgae and cyanobacteria growth.
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Marine Agronomy Group, CAFNRM, UH-Hilo
200 W. Kawili st., HI 96720, USA
Contact: Marine.Agronomy.Group@gmail.com
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