The story of seaweed will take us from a medicine hut in southern Chile to a high-tech seaweed nursery in Stamford, Connecticut, and from biofuels to beer, as we discover the surprising history and bright future of marine vegetables. Along the way, we uncover the role kelp can play in supporting U.S. fishermen, cleaning up coastal waters, and even helping make salmon farms more sustainable.
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Kappaphycus is one of the most significant, economically valuable red seaweeds, cultivated in tropical and sub-tropical waters. This alga demands a relatively high market value globally, due to applications of the kappa carrageenan colloid that is industrially extracted from the biomass. Carrageenan is widely used in food, pharmaceuticals, nutraceuticals and for aquaculture applications.
The first successful commercial cultivation of Kappaphycus (previously called Eucheuma) was recorded from the southern Philippines. It took more than five years of fi eld trials from 1967 to the early 70s in order to domesticate Kappaphycus for reliable commercial cultivation. The first commercial quantities of “cottonii” produced from extensive cultivation were obtained in 1974 with a total production of 8,000 t. Dramatic increases in production were achieved and the Philippines was the leading producer of Kappaphycus for 33 years until it was overtaken by Indonesia in 2008. It was in 1978, when Kappaphycus farming first saw successful adoption in Indonesia under the initiative of the Copenhagen Pectin Factory. Due to these successes, Kappaphycus farming has also grown commercially in East Africa, Fiji Is., India, Malaysia, Vietnam, Cambodia, Myanmar and southern China, although their volumes are minimal when compared to Indonesia and the Philippines. On the other hand, Latin American (Argentina, Colombia, Brazil, Equador, Venezuela, Mexico, and Peru) and the Caribbean countries (St. Lucia, Jamaica, and Panama) are even more recent entrants to Kappaphycus cultivation. Most information comes from published pilot-plot, demonstration farms and scientifi c studies, as such, only relatively small commercial quantities are produced presently.
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Background: Kappaphycus alvarezii is the 5th world’s most cultivated macroalgae, since it is an essential source of carrageenan, widely used in food industry. However, K. alvarezii is an unexplored biomass for green biorefinery conversion, since its composition includes valuable proteins, lipids, phenolic compounds, among others. Although there are reviews on K. Alvarezii cultivation and pharmacological properties, no information is available regarding extraction techniques applied to this algae biomass. Therefore, this review covers the lack of information on biorefinery concept applied to K. alvarezii and suggest sequential extractions to recover carra- geenan and high-added value molecules by using non-conventional methods.
Scope and approach: This critical review presents the most recent data on K. alvarezii, including its scientific trends, production and potential. It also deals with non-traditional methods for sequential extractions applied to K. alvarezii. The search for available data was extended to the group of red algae to consider the concept of biorefinery.
Key findings and conclusions: K. alvarezii biomass can be used to obtain chlorophyll, β-carotene, essential amino acids (aspartic acid, glutamic acid and phenylalanine) and phytohormones (indole acetic acid, zeatin, kinetin and gibberellic acid). Therefore, we provide several sustainable insights to sequentially recovery carrageenan and other bioactive compounds from K. alvarezii.
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The secretariat of the Pacific Community (SPC) commissioned the Institute of Marine Resources (IMR) of The University of the South Pacific to: 1) conduct a literature review of the introductions of the seaweed Kappaphycus alvarezii to Pacific Islands Countries and the current state of seaweed farming in these countries and 2) to field-test their proposed quarantine protocol for introducing K. alvarezii to new locations.
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A cytogenetic investigation on male and female reproductive cells of Aglaothamnion oosumiense Itono indicates that the sexuality of this species might be determined by a sex chromosome. Chromosome counts in female and male gametophytes gave 37 and 36, respectively. Sex ratio of gametophytes was 1:1. Both male-derived and female-derived bisexual plants were observed. Bisexual plants were different in gross morphology and position of carpogonial branches from normal unisexual gametophytes. The chromosome number of female-derived bisexual plants was N=37 and male-derived bisexual plants was N=36. Some male plants developed parasporangia in addition. The paraspore germlings showed the same chromosome number as the male plants. The fertilized carpogonium and gonimoblast cells had 2N = ca. 70 chromosomes.
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Recent breakthroughs have elevated algae as a promising biological solution to environmental challenges. Particular species of algae can provide low-impact, non-fossil substitutes for liquid fuel and plastics and can decrease enteric fermentation emissions from cattle. Now, a recent Nature Geoscience paper quantifies the role of kelp and other macroalgae in the global carbon cycle. The peculiarities of seaweed carbon cycling may skirt “permanence” issues that have plagued other biological carbon sinks, such as terrestrial forests. Future research may enable business and government to recruit kelp forest rehabilitation as an additional approach to climate change mitigation.
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This study was conducted as part of a kelp forest project which aim is to acquire knowledge about biodiversity and productivity in kelp forest areas. The epiphytic algae associated with the stipe of Laminaria hyperborea (Gunnerus) Foslie are important as habitat and food source for numerous faunal species along the Norwegian coastline. My investigations were performed on samples taken from kelp stipes in the area of Finnøy, Norway, in April, June, September and November 2005. I address questions of how the epiphytic community structure and primary production relates to a gradient of wave exposure, and the seasonal aspects of these relationships were also brought into the analyses. Both univariate and multivariate statistical methods were used in this approach. The amount of biomass found on a stipe was first of all related to the length of the stipe, and stipe lengths increased with increasing levels of wave exposure. A definite peak in total biomass was found in September. The species composition of epiphytes on the kelp stipes showed variation with increasing exposure. However, the variation within sites with the same index of exposure was also very high, suggesting that differences on a smaller scale may be of great importance. Differences in the species composition between sampling periods were also found. I conclude that both epiphyte species composition and productivity in kelp forest areas are affected by wave exposure, or some factors related to wave exposure, and that the structures of these epiphytic communities change through the season.
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Progress has been made toward the long-term goal of growing macroalgae in the sea as a future source of substitute natural gas. This annual report discusses progress made to: 1) measure macroalgal yield, 2) enhance yield by row planting and selective harvesting, 3) genetically breed high-producing plants, 4) devise methods for planting kelps and 5) maintain and extend collaborative research efforts and communication with scientists working on macroalgal biomass production in Japan, China and elsewhere. The report discusses kelp biology and macroalgal mariculture in general terms, the theories that have been proposed and the existing data base in the scientific literature. Particular attention is given to new techniques used to make in-the-sea hydrodynamic and light-climate measurements and rnicrospectrophotometric measurements of DNA levels in kelp sporophytes and gametophytes. New and effective tank, dish and in-the-sea planting and culture methods have been successfully employed in a co-funded program to establish a new kelp bed. Other co-funded work in genetics and marine farm engineering is mentioned in the report. A list of ten publications resulting from this work is included. The report suggests that in the distant future, the 1,000 acre natural kelp forest, recently leased to NMI by the State of California, could be used along with on-shore facilities provided by Southern California Gas Company, for pilot-scale demonstration project.
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Coastal eutrophication and its associated harmful algal blooms have emerged as one of the most severe environmental problems worldwide. Seaweed cultivation has been widely encouraged to control eutrophication and algal blooms. Among them, cultivated kelp (Saccharina japonica) dominates primarily by production and area. However, the responses of water quality and phytoplankton community to kelp farming remain unclear. Here, thirteen cruises were conducted in the kelp farms and control areas in the turbid, highly eutrophic Xiangshan Bay of the East China Sea from 2008 to 2015. Results indicated that kelp cultivation slightly increased dissolved oxygen and pH, but reduced dissolved inorganic nitrogen and phosphorus. We estimated that kelp harvesting would remove 297 t of nitrogen and 42 t of phosphorus from this bay annually. Because of decreased flow velocity, turbulence, and sediment resuspension, kelp farming greatly reduced suspended solids and increased transparency, resulting in increases in phytoplankton chlorophyll a and abundance. Additionally, kelp farming appreciably increased phytoplankton species number, Marglef richness, and Shannon–Wiener diversity indices by 51.6%, 40.1%, and 13.1%, respectively. Analysis of similarity and similarity percentages demonstrated that phytoplankton community composition differed significantly between the farm and control area, which was mostly attributed to long-chained diatoms and single-celled dinoflagellates. However, after the kelp harvesting, all measurements of water quality and phytoplankton biomass, diversity, and community composition exhibited no significant difference. Our study highlights that kelp cultivation alleviates eutrophication and acidification and enhances phytoplankton diversity, thus providing guidance for macroalgal aquaculture and remediation in eutrophic waters.
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The recent expansion of kelp farming in Alaska has Julie Decker, chair of the Alaska Mariculture Task Force, excited.
“The 2018 Alaska Mariculture Development Plan aims to grow the mariculture industry in Alaska by $100 million in the next 20 years,” Decker explains. “The new applications we have seen from kelp farmers over the last two years are pretty exciting.”
Wild fish capture is still king in Alaska, where growing finfish is illegal. That leaves mariculture, the farming of all other aquatic species, to balance the highly seasonal work of ocean fishing. Oysters are the top cultured species in the state. But the industry for sugar kelp (saccharina) and ribbon kelp (alaria) is expanding.
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Marine Agronomy Group, CAFNRM, UH-Hilo
200 W. Kawili st., HI 96720, USA
Contact: Marine.Agronomy.Group@gmail.com
Funding for this web portal is provided by the World Wildlife Fund and the University of Hawaii-Hilo.