Green macroalgae (Chlorophyta) currently represent a residual fraction (<1%) of global seaweed biomass production landings. In turn, red (Rhodophyta) and brown (Ochrophyta) macroalgae dominate the remaining percentage of aquaculture production, exceeding 32 million tonnes per annum. However, the industry relies on a relatively low number of species, in which as few as seven macroalgal genera collectively represent the bulk of global production metrics. At present, innovation and increased sustainability of the industry calls for diversification of macroalgal species/strains in aquaculture to counteract potential adverse effects ensuing from genetic impoverishment, decreased resilience to disease and climate change. Despite the dominance of red and brown seaweed regarding production figures, aquaculture of green macroalgae has witnessed an increasing trend in productivity and diversification over the last decades, particularly in Asia, where green seaweed taxa often occupy specific market niches in the food sector. Furthermore, growing interest in green seaweeds in aquaculture has been highlighted for different applications in emerging western markets (eg IMTA, biorefineries, food delicacies), owing to a unique diversity of cytomorphologies, ecophysiological traits, propagation capacities and bioactive compounds featured by this group of macroalgae. Cultivation technologies are relatively well developed, but sustainability assessments are scarce and required to unlock the potential of green seaweeds. Although it is likely that green macroalgae will remain occupying specialised market niches, in which high-value products are favoured, we argue that aquaculture of chlorophytan taxa presents itself as a compelling option under the current quest for commercial diversification of products and expansion of the sector.
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A groundfish net was modified to limit its bottom contact and to improve escapement of bottom-tending fish species. A model was first evaluated in the flume tank facility of Memorial University, followed by field trials. Two trawl configurations were tested against a Control, during fishing experiments in 2007 and 2008. In the first configuration, the goal was to fish the net approximately 1.5' off the seabed, to retain cod and haddock while reducing catches of flounders and other demersal species. In the second rig, the Experimental trawl was fished up to 3' off the seabed, to retain haddock while reducing catches of cod, flounders and other demersal species.
Flume tank tests indicated that a stable condition and proper fishing heights were achieved with a combination of floats on the headrope, footrope and ground gear, combined with weights attached to the wing ends. Field trials followed the recommendations developed in the laboratory, and video observation revealed a stable fishing condition, with little contact with the seabed. Catch information was hampered by low fish availability, but indicated that the correct escapement pattern was occurring, with the exception of higher-than-desired escapement of haddock during the second experiment.
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Seaweed has the ability to use carbon from the environment through photosynthesis to produce biomass. The aim of this study is to estimate carbon sequestration by seaweed aquaculture as a strategy for climate change mitigation. The study was undertaken at Gerupuk Bay, Lombok Island, West Nusa Tenggara Province, Indonesia. Four seaweed variants, such as Kappaphycus alvarezii var. Tambalang and Maumere, K. striatum and Eucheuma denticulatum, were cultivated with long-line system for three cultivation periods, starting from July to November, 2013. Each cultivation period was taken about 45 days. Parameters including weight increasement and carbon content of seaweeds were measured every 15 days of culture for each cultivation period in order to calculate carbon sequestration rate. The results showed that E. denticulatum had the highest carbon sequestration rate and significantly different (P < 0.05) compared with other variants for every cultivation period. Different seaweed variants have different capacity on carbon sequestration. Optimal utilization of the potential area for seaweed aquaculture could reduce a great quantity of CO 2 from the atmosphere and help to mitigate global climate change process.
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Rapid and frequent air service to Hawaii has brought about a stronger west- ernization in food choices and food habits than was possible 30 or 40 years ago. The transport of more fresh foods from the Orient is also possible. Western fast- food establishments such as McDonald's and Kentucky Fried Chicken are pa- tronized as heavily as similar places in California. They have nearly entirely replaced "saiinin stands" of pre-World War II where a bowl of noodles and a bamboo stick of barbecued meat could be had quickly. Chinese restaurants are the favorite choice of students in ethnobotany at the University of Hawaii (polls taken in 1976, 1977), but there is no question that a hamburger or hot dog is everyone's favorite food, regardless of ethnic background.
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A novel seawater-based pretreatment process was developed to improve the hydrolysis yield of brown (Laminaria digitata), green (Ulva linza) and red (Porphyra umbilicalis) macroalgae. Pre-treated with 5% sulphuric acid at 121°C, 15minutes, L. digitata, U. linza and P. umbilicalis liberated 64.63±0.30%, 69.19±0.11% and 63.03±0.04% sugar in seawater compared with 52.82±0.16%, 45.93±0.37% and 48.60±0.07% in reverse-osmosis water, respectively. Low hydrolysis yields (2.6–11.7%) were observed in alkali and hydrothermal pretreatment of macroalgae, although seawater led to relatively higher yields. SEM images of hydrolyzed macroalgae showed that reverse-osmosis water caused contortions in the remaining cell walls following acid and hydrothermal pre-treatments in the L. digitata and U. linza samples. Fed-batch fermentations using concentrated green seaweed hydrolysates and seawater with marine yeast Wickerhamomyces anomalus M15 produced 48.24±0.01g/L ethanol with an overall yield of 0.329g/g available sugars. Overall, using seawater in hydrolysis of seaweed increased sugar hydrolysis yield and subsequent bioethanol production.
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With seaweed resources certainly not inferior to those of Japan or any other country, and probably much superior, the United States may be. said practically to ignore these valuable products except at a few points on its extensive coast. Statistics recently gathered give the paltry sum of $35,000 as the value of the marine algre prepared in the United States in one year. The business is practically restricted to Massachusetts, and is addressed to a single species, the "Irish moss" {('hondrux crin- pus). Considerable quantities of seaweeds are used as fertilizer on farms adjacent to the coast, but this is not a commercial enterprise. In Monterey and Santa Barbara counties, Cal., the Chinese fishermen dry certain algse for food, medicine, and fertilizer; in 1899 the quantity prepared was 35,K24 pounds, valued at $896. There is undoubtedly a good opportunity to develop the seaweed industry of every section of the United States coasts, and to establish a profitable trade in the various species and preparations of marine alga? along the new lines indicated in the foregoing paper on the Japanese seaweed industry, as well as by increasing the output of the species already sparingly utilized. To this end the following information and suggestions are offered in regard to some of the useful alga? of the United States.
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The anaerobic digestion is a well-established process for the treatment of organic solid waste, pursuing its conversion into a methane rich gas destined to energy generation. Research has largely dealt with the enhancement of the overall bioconversion yields, providing several strategies to maximize the production of biomethane from the anaerobic processing of a wide variety of substrates. Nevertheless, the valorization of the process effluents should be pursued as well, especially if the anaerobic digestion is regarded in the light of the circular economy principles. Aim of this work is in identifying the state of the art of the strategies to manage the digestate from the anaerobic processing of the organic fractions of municipal solid waste. Conventional approaches are described and novel solutions are figured out in order to highlight their potential scale up as well as to address future research perspectives.
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An estimated 6% of human greenhouse gas emissions are the result of enteric methane production by cows. Asparagopsis taxiformis, a semi-tropical alga, is one solution. Supplementation of this alga to cows at a small percentage of their daily intake has reduced methane emissions by over 98% in trials. This success has led to multiple commercialization attempts globally, although no Asparagopsis taxiformis company has yet proved its viability. This thesis investigates the commercial viability of factory Asparagopsis taxiformis production, via a case study. The focal firm is Swedish start-up Volta Greentech, the first and only factory-based Asparagopsis taxiformis producers. This work draws on grounded theory and stakeholder theory perspectives to elicit key opportunities and barriers facing the case-study firm. Data was collected from interviews with 26 key external stakeholders and 7 team members, 2 multi-day observations of company operations, a workshop with the team and extensive literature and grey paper review. Three major barriers - production of Asparagopsis taxiformis, risks associated with Asparagopsis taxiformis and competition from other enteric-methane-reducing measures were identified and investigated further. Six short-term opportunities were also identified and investigated. These are political support, celebrity endorsement, a new funding mechanism for the Asparagopsis-taxiformis-fed cow-products, collaboration with other algae experts, symbiotic production mechanisms in the factory and capitalizing on alternative uses of Asparagopsis taxiformis. This investigation concludes that Volta Greentech is a radical and innovative venture, and a useful model for understanding factory produced Asparagopsis taxiformis production. This case is used to highlight how and why support should be provided for such innovative ventures.
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Chondracanthus chamissoi is part of the diet of coastal people from Peru and is exported dehydrated to Asian countries for direct consumption. Although it is considered endemic to Peru and Chile, its range has extended to distant regions, such as Korea, Japan, and France. Using morphological and molecular approaches, we examined specimens from Peru assigned to C. chamissoi (including the taxon of uncertain status Chondracanthus glomeratus) to improve phylogenetic and geographical information and characterize its morphological variability. Twenty‐one localities on the Peruvian coast were sampled, obtaining 102 COI and 27 rbcL sequences. To differentiate both entities, morphological characters such as thallus size, consistency, arrangement of main and secondary axes, branching patterns and location of reproductive structures, were analyzed on 46 specimens. While morphological characteristics are clearly contrasting among the two groups, both COI and rbcL phylogenies revealed a well‐supported clade with no genetic differentiation between the two morphologies. Therefore, the phylogenies indicate that C. chamissoi and C. glomeratus form a single taxonomic entity with high morphological variability, large geographic distribution and at least two morphological forms. The smaller form of C. chamissoi can be identified as C. chamissoi f. glomeratus. Such morphological variability can be of interest for future aquaculture development.
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Species of the genus Ulva are used for human consumption due to their nutritional qualities and we assess a new filamentous species, Ulva tepida. A critical step is to quantify the yield and quality of biomass over multiple harvests to ensure consistency throughout the production cycle. To do this, ropes were seeded with U. tepida and harvested fortnightly over 6 weeks of outdoor cultivation with biomass yield and quality quantified for each harvest. This cycle was repeated a further two times. The yield of biomass was not significantly different between harvests (13.6–23.0 g dry weight (dw) m-1 rope), however, the final harvest was highly variable. Consequently, we recommend a production cycle of two harvests. The quality of biomass, as determined by the key biochemical parameters for these two sequential harvests, was consistent. Carbohydrates were the major component (45 % dw) and were primarily dietary fibre (27 % dw) consisting of insoluble (18 % dw) and soluble (9 % dw, equates to ulvan) fibre, with consistent values between harvests. Protein, as the sum of amino acids (17 % dw), was also consistent between harvests. Similarly, the content of ash (31 % dw) and lipids (3 % dw), as well as the composition of minerals and fatty acids was consistent. These results quantify, for the first time, no negative effects of multiple harvests on the yield and quality of biomass and support this technique to optimise productivity and quality.
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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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