Finding renewable alternative energy resources for fossil fuels substitution has become very vital due to the serious challenges faced by humankind at present such as environmental pollution, greenhouse gas emissions, climate change, crude oil price volatility, and fossil fuels exhaustion. Macroalgae (seaweeds) are fast-growing marine plants, providing several harvests per year without the need for arable land, fertilizer, and fresh water. Various types of ecosystems like coral reefs, mangrove forests, and rocky shores can efficiently host the seaweeds production systems. These characteristics have made them highly suitable feedstocks for third-generation bioethanol production. Iran has a huge potential in renewable energy resources owing to its unique geographical location and climatic features. The country borders with the Caspian Sea in the north and with the Persian Gulf and the Gulf of Oman in the south. Seaweeds farming can also play a key role in mitigating air pollution, increasing employment rate, sustaining fossil fuel resources, bioremediating contaminated water, and improving marine ecosystem in the Persian Gulf and the Gulf of Oman. In the present article, macroalgae diversity, cultivation, and their conversion and upgrading technologies into bioethanol in Iran are scrutinized and discussed. Finally, the potential of Bushehr (the Persian Gulf) and Chabahar (the Gulf of Oman) coastlines for macroalgae cultivation is investigated. These locations receive the annual solar radiation in the range of 1680‒1753 kWh/m2 and the photosynthetically active radiation (PAR) in the range of 2.6‒2.71 GJ/m2 /year with 3051‒3311.9 h sunshine per annum. Furthermore, the nutrient-rich and calm water with relatively stable pH, salinity, and temperature make these coasts suitable for macroalgae farming. A potential yield up to 147‒153 t/ha/year can be obtained if proper native/engineered species, well-situated sites, and compatible cultivation techniques are selected.
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Green seaweeds from the cosmopolitan genus Ulva are targets for land-based aquaculture and a diverse range of biomass applications, but are not currently cultivated in Aotearoa New Zealand. Therefore, the objective of this study was to identify target species and cultivars of Ulva as a first step towards establishing land-based cultivation of seaweed in Aotearoa New Zealand. We isolated 24 cultivars of Ulva from natural populations in the Bay of Plenty region of New Zealand. We compared growth and biomass productivities of 18 of these cultivars, either in their original collection morphology (e.g., blade/filamentous) and/or in cluster morphology where possible as a result of induced formation of free-floating germling clusters. Specific growth rates and biomass productivities of multiple cultivars in small-scale laboratory cultures were high (>20% day− 1 and >8 g dry weight (DW) m− 2 day− 1 respectively), with biomass increases of 5 to 8-fold per week in the fastest growing cultivars. However, there was significant variation in growth and biomass productivity among cultivars of each morphology type. Biomass productivities were highest for cultivars WB2 (blade, 7.5 g DW m− 2 day− 1 ), SW9 (blade cluster, 9.4 g DW m− 2 day− 1 ), SW8 (filamentous, 7.8 g DW m− 2 day− 1 ), and SW6 (filamentous cluster, 9.8 g DW m− 2 day− 1 ). Growth rates and biomass productivities were consistently higher for cluster compared to non-cluster morphologies for each morphology type (e.g. filamentous or blade), demonstrating that clusters are a viable option to enable free-floating cultivation of filamentous species of Ulva. These results confirm the suitability of Ulva as a target for intensive land-based aquaculture in Aotearoa New Zealand. The significant inter-cultivar variation found in the current study further highlights the importance of sampling widely and focusing on cultivar rather than species selection when identifying targets for cultivation.
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Brief Background
- Ardtoe was set up by the UK Seafish Industry Authority as an aquaculture research facility in 1964 and quickly gained an international reputation in the hatchery production of finfish and shellfish juveniles
- When we took over the lab in 2005, we scaled up the existing finfish hatchery (initially cod and turbot but also now wrasse) from the then laboratory scale to fully commercial levels
- We have since developed a shellfish hatchery operation, again taking it from an initial experimental level to it present commercial scale
- We are thus no strangers to kinds of problems that are inevitably involved in taking any technology from pilot to a fully commercial scale
- I will today therefore try to outline the constraints to large scale commercial seaweed seedling production, as we see them, and how we have been tackling those constraints
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Nets in traditional Porphyra mariculture are seeded with conchospores derived from the conchocelis phase, and spend a nursery period in culture tanks or calm coastal waters until they reach several centimeters in length. Some species of Porphyra can regenerate the foliose phase directly through asexual reproduction, which suggests that the time, infrastructure, and costs associated with conchocelis culture might be avoided by seeding nets with asexual spores. Here, we present work from a short-term mariculture study using nets seeded with asexual spores (neutral spores) of a native Maine species of Porphyra. Porphyra umbilicalis (L.) Kutzing was selected for this proof of concept research because of its reproductive biology, abundance across seasons in Maine, and evidence of its promise as a mariculture crop. We studied the maturation, release, and germination of the neutral spores to develop an appropriate seeding protocol for nets, followed by development of a nursery raceway to provide an easily manipulated environment for the seeded nets. Neutral spores were produced throughout the year on the central Maine coast,however, there was a temporal variability in the number and survival of released neutral spores, depending upon thallus position in the intertidal zone. Small thalli were strictly vegetative, but most thalli reproduced by neutral spores- sexual reproduction was absent. Neutral spores germinated quickly at 10 and 15 'C, but germination was delayed at 5 degrees C. Unlike some algal zygotes and spores, neutral spores of R umbilicalis required light to germinate; however, irradiances of 25 and 100 mu mol photons M-2 S-1 were equally sufficient for germination. Rafts of seeded nets were deployed in Cobscook Bay, Maine, at two distances from salmon aquaculture pens and at a control site on a nearby, fallow aquaculture site (no salmon). There was no difference in nitrogen content of harvested thalli; however, both the density and the surface area of harvested thalli were different among the sites. The possible causes of these differences are discussed in the context of potential use of Pumbilicalis in IMTA.
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SEAWEEDS AND MICROALGAE: AN OVERVIEW FOR UNLOCKING THEIR POTENTIAL IN GLOBAL AQUACULTURE DEVELOPMENT
ivABSTRACTAlgae, includingseaweeds and microalgae, contribute nearly 30 percent of worldaquaculture production (measured inwetweight), primarily from seaweeds. Seaweeds andmicroalgae generate socio-economic benefits to tens of thousands of households, primarilyin coastal communities,includingnumerous women empowered by seaweed cultivation.Various human health contributions, environmental benefits and ecosystem servicesofseaweeds and microalgaehave drawn increasing attention to untapped potential of seaweedand microalgae cultivation. Highly imbalanced production and consumption acrossgeographic regions implies a great potential in the development of seaweed and microalgaecultivation.Yetjoint efforts of governments, the industry, the scientific community,internationalorganizations,civil societies,and other stakeholdersorexperts are needed torealize the potential. This documentexamines the status and trends of global algaeproduction with a focus on algae cultivation, recognizes the algae sector’s existing andpotential contributions and benefits, highlights a variety of constraints and challenges overthe sector’s sustainable development, and discusses lessons learned and way forward tounlock full potential in algae cultivation and FAO’s roles in the process. From a balancedperspective that recognizes not only the potential of algae but also constraints andchallenges upon the realization of the potential, information and knowledge provided bythis document can facilitate evidence-based policymaking and sector management in algaedevelopment at the global, regional and national levels
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Bacterial resistance to pharmaceutical drugs is on rise, which emphasizes the need for screening of new drugs from natural resources. Seaweeds from the marine ecosystem are important source of bioactive compounds making them one of the major subjects for screening of various pharmaceutical drugs. So here, we assessed the bacterial growth inhibitory functions of four seaweeds Sargassum wightii, Gracillaria edulis, G. corticata and Ulva lactuca of Andaman Sea and Bay of Bengal, India respectively against three pathogens Pseudomonas aeruginosa, Eischeira coli and Staphylococcus aureus. Solvent extraction of four seaweeds was performed using 70% methanol, ethanol and ethyl acetate. Agar well diffusion method was used to test the bioactivity of seaweeds against pathogens. S. wightii,G. edulis and U. lactuca were observed with better solvent extracts compared to G. corticata. Methanol extract of S. wightii was observed with the highest (29.0 ± 1.22) zone of inhibition (ZOI) and ethyl acetate extract of U. lactuca was observed with the lowest ZOI (5.0 ± 0.0) against S. aureus. Butanol extract of S. wightii was observed with the highest ZOI (14.0 ± 0.83) against P. aeruginosa, whereas G. edulis methanol extract and U. lactuca ethyl-acetate extract were observed with the lowest ZOI (6.0 ± 0.0). For E. coli, butanol and methanol extracts of G. edulis and U. lactuca showed the highest (12.0 ± 0.54) and the lowest (6.0 ± 0.0). Our preliminary results suggest bioactivity of S. wightii, G. edulis and U. lactuca showed positive results. Further biochemical characterization of S. wightiishould be carried out for potential bioactive compounds against human pathogens. Our results suggest bioactive compounds from seaweeds can be used as pharmaceutical drugs.
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At a Seaweed Workshop organized earlier this year by Maine Sea Grant and principally funded by Maine Aquaculture Innovation Center, Tollef Olsen commented that although he has been referring to seaweed as “the virtuous vegetable,” he’s wondered if instead, he should describe it as “the versatile vegetable.” Presentations given by participants at the conference revealed that both descriptions are apt.
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Eating seaweed is a little alien to most people; and a large number of those who have experienced it have not yet graduated further than the nori sheets used to wrap sushi. Yet seaweed or marine algae – to give them their correct name – are bang on trend. There have been more than 29,000 micro algae and seaweed-based products launched into the consumer marketplace since 2010, half of which were launched in the past year. And it’s not just the specialist retailers that are cashing in; the major grocery chains are now stocking seaweed lines too. In the United Kingdom, for example, Marks & Spencer (M&S) rolled out seaweed-based products from three different brands nationwide in April. A month later, Tesco also launched a new range. Even celebrity chef Jamie Oliver has been publicly praising seaweed as a food – further stoking consumer interest.
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Seaweed production (both culture and natural) has increased compared with in the past. It occupies a strong position in the food supply and meets global food demand. Seaweed emerges as a powerful tool to mitigate and adapt to climate change. It acts as a carbon sink by sequestrating carbon from the atmosphere into the ocean. It can reduce the carbon emission from agricultural fields by improving the soil quality. It also minimizes the emissions of methane gas when mixed in cattle food. Seaweed increases the pH of water thus reducing the ocean acidification phenomena. As a result, aquatic organisms such as finfish, shellfish, corals, and invertebrates find a suitable place to live in. It produces trace gas (e.g., volatile brominated and iodinated halocarbons) that deplete the ozone. Seaweed dampens wave energy during storms and protects the coast as climate change adaptation. Seaweed provides oxygen to the ocean water, which minimizes the issue of de-oxygenation. It offers habitats and food for important components of the marine ecosystem that have a great impact on the climate. Seaweed provides biofuels, fertilizer, medicine, and food for human consumption. In this review, we emphasize the role of seaweed in climate change mitigation and adaptation. Seaweed cultivation can be optimized to get maximum climate benefits and increase the livelihood status of the seaweed farmer.
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We compared post-harvest processing of two species of Ulva (chlorophyta) using 36 washing time-by-temperature combinations. We quantified the yield of crystallized salt after evaporation of the washing water as a target product and characterized the composition of salts and processed biomass, with the additional aim of improving the composition of the processed biomass for production of fertilizer, feed or fuel. Washing of biomass of Ulva ohnoi and Ulva tepida effectively reduced its mineral content with concomitant production of crystalline salts with Na:K ratios of 1.1-2.2 and a maximum of 19% soluble fiber (ulvan). The maximum yield of salt was 29% of the biomass for U. ohnoi and 36% for U. tepida. Salts from both species have potential for human health applications and functional foods. Washing increased the energy content of the biomass from both species by 20-50% to a maximum of 18 MJ kg-1 and protein contents by 11-24% to a maximum of 27.4%. The production of seaweed salt is therefore a novel first step in a cascading biorefinery model for the utilization of macroalgal biomass which simultaneously improves the quality of the processed biomass for production of fertilizer, feed or fuel.
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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.