Alaria esculenta is a brown seaweed with a great potential for biomass production due to its high productivity and high content of carbohydrates, proteins, vitamins, minerals and bioactive compounds like phlorotannins and pigments. Alaria cultivation is performed either by collection and settlement of zoospores on ropes to develop seedlings, or by production of the seedlings from vegetative gametophyte cultures. Contrary to the zoospore technique, the use of gametophyte cultures has the potential to provide a constant, year-round supply of seedlings. There is a need for optimizing the production methods such as the maintenance of the gametophyte cultures, gametogenesis, seeding process and deployment time. The purpose of this dissertation is to optimize several parameters involved in Alaria cultivation using vegetative gametophytes and provide qualitative and quantitative information related to kelp phlorotannins. Optical density and in vivo fluorescence were evaluated as an alternative method to estimate gametophyte biomass. Both methods showed linearity with the dry weight. The cultures were also supplemented with a possible growth enhancer and the effect evaluated on the cultures, however no growth improvements were noticed on these cultures. When the seedlings production is initiated, the fertility of vegetative gametophytes needs to be switched on. The fertility induction was evaluated with three different photoperiod regimes under white light, where the best performance was accomplished by 23 hours light over 8 days. The seeding density is the next step to optimize seaweed industry. Higher and lower densities bring several disadvantages to the development of the sporophytes. Thus, four densities of fertile gametophyte cultures were tested, where a density per dry weight of 0.8 mg/mL produced the most acceptable number of sporophytes on the twines. For the estimation of sporophyte growth, manual measurements, such as sporophytes counting and length measurement, are extremely time-consuming methods. An alternative method based on image analysis was tested to estimate the percentage of growth of the seedlings and compared with the manual method. The image analysis method was shown to have a good relationship with the sporophyte measurements, bringing a faster and easier way to estimate the seedlings growth. A. esculenta and S. latissima could represent a viable source of phlorotannins (PHL) due to the fast and efficient grow of these species. The juvenile stages of these species had an average of 4.11 and 3.08 mg PHL/g algae, respectively. It was also observed that the phlorotannin content in the Alaria gametophytes increased during fertilization. Two forms of phloroglucinol were documented in both species but due to the lack of studies related with the phlorotannin characterization of these species no more compounds were identified.
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Seaweeds play essential ecological and biogeochemical roles and support important industrial applications. Sustaining natural populations of seaweeds under climate change while simultaneously putting seaweeds to use in climate solutions requires that we weave together disparate lines of inquiry—the ecological and the industrial—to create a more holistic perspective and integrated research agenda. Innovation in the use of seaweeds must be more than aspirational—it requires evidence of effectiveness in the short term, and a promise to sustain nature and people in the long term.
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The Philippines has abundant aquatic resources. Seaweeds are one of these aquatic products which are found in lagoons and reed areas all over the country. The country is one of the few around the world which pioneered in the farming of these plants in substantial quantities. The Philippines is noted for the culture of seaweeds along with Japan, China, Korea, and Taiwan.
Seaweeds are a good source of colloidal materials which are used as gelling agents, emulsifiers, stabilizers, in pharmaceutical, cosmetic, and food products. They also contribute to important food items, fertilizers, and animal feeds. According to the Food and Agriculture Organization (FAO), commercial production of seaweeds through farming is at present limited to a few countries in East Asia making these a high value crop with a high demand in the world market.
Sargassum is a genus of brown algae (class Phaecophyceae) macroalga (seaweed) under the order Fucales. Numerous species are distributed throughout the temperate and tropical oceans of the world, where they generally inhabit shallow water and coral reefs. However, the genus may be best known for its planktonic (free- floating).
Sargassum as algae has developed multicellular structure. Sargassum is characterized by long, highly branchy fronds which gives its leafy appearance. Many have bladders filled with air which help these float. In the open water, these bladders keep the Sargassum free-floating near the surface of the water so that it can photosynthesize energy. In area where Sargassum is anchored to the bottom, these bladders help the seaweed stretch towards the light, creating the forests of seaweed effect which gently undulate with the water waves.
There are a number of uses for Sargassum. In some regions, for example, it is collected as fertilizer. It is also a food source, especially in Japan, where it may be added to soups and fermented with other ingredients in soy sauce to create a specific flavor. Many animals use Sargassum as home, as the seaweed provides shelter due to their abundant fronds, along with a hiding place from predators and a source of food.
Seaweeds have been harvested because of their significant contributions in many ways. The most obvious use of these multicellular is a food source. People from different cultures have discovered that many seaweeds are eligible, especially some of the red and brown algae. They are consumed in a variety of ways. They may be raw, cooked or dried. In addition, seaweeds can also add variety and taste to bland foods. The reason why the farming or mariculture of seaweeds is a growing business is because they are good source of some vitamins, minerals, and some are said to contain substantial amounts of proteins.
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The message of this overview is that everyone stands to benefit from nutrients and that everyone can make a contribution to promote sustainable production and use of nutrients. Whether we live in a part of the world with too much or too little nutrients, our daily decisions can make a difference. Without swift and collective action, the next generation will inherit a world where many millions may suffer from food insecurity caused by too few nutrients, where the nutrient pollution threats from too much will become more extreme, and where unsustainable use of nutrients will contribute even more to biodiversity loss and accelerating climate change. Conversely with more sustainable management of nutrients, economies can play a role in a transition to a Green Economy in the context of sustainable development and poverty eradication. The Global Overview develops these essential themes, to prepare societies to take the next steps.
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Agar yielding red alga Gracilaria edulis was successfully cultured in fibre glass tanks with running seawater at out door environment. The biomass of cultured seaweed showed a crop growth rate ranging between 3.9 - 8.0 g/day after different days of culture. The tanks stocked with lesser quantity of seed material showed better growth rate. Experiments were also conducted by providing the seed material with different quantities of NPK, Urea, Ammonium sulphate + Sodium phosphate and Potassium nitrate + Phosphate + EDTA at weekly intervals. Higher crop growth rates (CGR) of 4.3 g/day with 700 mg NPK and 5.2 g/day with 80 mg urea were attained respectively. The growth rate recorded was 3.6 g/day in the tanks provided with Ammonium sulphate + Sodium phosphate and 3.7 g/day in the tank provided with Potassium nitrate + Phosphate + EDTA. Data on the environmental and hydrological parameters from seaweed culture tanks were recorded.
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South-East Asia has traditionally been the global centre of production of tropical sea cucumbers for Chinese markets. Early research into culture methods took place outside this region, notably in India, the Pacific region and China. However, recent investment in Holothuria scabra (sandfish) culture has led to some significant advances within this region. The Philippines and Vietnam have been at the forefront of recent efforts, with involvement from substantial national programs and local institutions as well as international donors and scientific organisations. Smaller programs are ongoing in Thailand, Malaysia and Indonesia. Recent advances and simplifications in hatchery techniques are a major step forward, having promoted the development of experimental-scale sea-ranching ventures, and given rise to a small, commercial pond-based culture industry in Vietnam. Technology developments in nursery systems are likely to provide opportunities for culture enterprises in a broader range of environments than is now possible. A major research thrust in the Philippines towards developing cooperative sea-ranching enterprises has demonstrated good potential, and institutional/ legislative arrangements to ensure adequate property rights have been tested. Rotational culture with shrimp is proving successful in Vietnam, while the possibility of proximate co-culture of sandfish and shrimp has largely been ruled out. Small-scale experiments in the Philippines raise the possibility of co-culture in ponds with a number of finfish species. Current research directions are looking at diversifying technology to increase success in a range of coastal conditions, better understanding the social and biophysical conditions required for success, and finding ways of effectively scaling-out developed systems and technology.
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Sea cucumbers represent an important income source to coastal communities in many Pacific islands, but is now worth only a fraction of historical values. Sea cucumbers have been harvested for hundreds of years for trade with Asia and were probably one of the first real ‘exports’ from the Pacific islands. Unfortunately, the increase in demand and price, combined with the development of cash economies and growing coastal populations in many islands, has led to widespread overfishing of the resource across much of this region. There is a high level of interest in adoption of aquaculture techniques to restore production levels, but different capacity levels require implementation of different techniques. Some Pacific island countries and territories have completed successful research trials of hatchery and release techniques, and now have capacity to scale up this activity. Factors that work in favour of successful aquaculture include pristine marine environments, long familiarity with sea cucumbers as a commodity, and traditional marine tenure systems that in some places can provide a basis for management of released sea cucumbers. Challenges include lack of technical capacity, unproven effectiveness of sea cucumber releases and poaching.
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The Pacific oyster, Crassostrea gigas is the one of the most commercially important aquaculture species in the Japanese fisheries industry and is cultured in various Japanese coastal areas including Hokkaido. The Saroma Lake and the Akkeshi Bay with estuary, which face Ohotsuku Sea and Pacific Ocean, respectively, are major oyster production areas in Hokkaido with total annual production of about 700 tons a year. The seedling spat supplied from Miyagi known as Miyagi seedlings are widely used in Japanese oyster culturing. Therefore, when the catastrophic tsunami on March 11, 2011 damaged the Miyagi fisheries, many oyster culturing areas were heavily affected. Moreover, introduction of seedlings from geographically separated population have risks of invasion of diseases and alien organisms as hitchhiking species. Using seedlings that originated from local populations in each area is one of the approaches for decreasing some risks. For example, in the Akkeshi area, the artificial seedling spats collected from the locally protected adults are also used for aquaculture, which are marketed as the value-added oysters with shell “Kaki-Emon” and popular among consumers as local special products.
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To promote a clean, sustainable energy future through the community-based production of renewable fuels.
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“No more cutting trees for paper, no more cutting of trees to make paper. We will produced paper from red seaweed, ” said You H Churl, from South Korea, with serious facial expression.
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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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