Digital library

  • Investigating the anti-methanogenic properties of select species of seaweed in New Zealand

    Enteric methane emissions from ruminants constitute a large proportion of agricultural greenhouse gas emissions, particularly in New Zealand. The recent increase in enteric methane emissions has driven the development of innovative strategies for mitigating these emissions. Red seaweed from the genus Asparagopsis has demonstrated elimination of enteric methane due to the presence of the active anti-methanogenic component, bromoform.

     

     

    Spatial variation in bromoform content for Asparagopsis armata throughout the North Island, New Zealand, was quantified to determine the region that produces the highest concentration of bromoform. Alongside Asparagopsis, the New Zealand red seaweed species Bonnemaisonia hamifera, Delisea compressa, Plocamium sp., Vidalia colensoi, and identified aquaculture-target seaweed species, Ecklonia radiata, and Ulva sp. B, were investigated as ruminant feed additives to reduce enteric methane emissions. Polyphenol quantification and compositional analyses were carried out for these seaweed species to provide a baseline for interpreting anti-methanogenic effects. Seaweed species were included at 0 %, 2 %, 6 %, and 10 % of feed organic matter (ryegrass hay) during in vitro fermentation assays using rumen inoculant from non-lactating cows. Total gas, methane, hydrogen, volatile fatty acid (VFA), and ammonia production were measured during the incubations.

     

     

    Bromoform concentration was highest in A. armata sampled from Matheson’s Bay at 1 % of the biomass dry weight. Species of red seaweed had a high halogen content, while E. radiata and Ulva. sp. B had a high iodine and crude protein content, respectively. Inclusions of A. armata and B. hamifera demonstrated near elimination of enteric methane production at doses of 2 and 6 % organic matter, respectively, while the remaining species (except for Ulva sp. B) caused moderate reductions at doses of 6 and 10 % organic matter in comparison to these two species. The anti-methanogenic effects of A. armata and B. hamifera resulted in a 22 % reduction in total VFA production, accompanied by changes in the relative proportions of individual VFAs, and had little or no effect on organic matter degradation.

     

     

    The effectiveness of A. armata and B. hamifera demonstrates the potential of these species for mitigating ruminant methane emissions at low inclusion rates, dependent on the concentration of their active components, while E. radiata and Ulva sp. B could be used as feed additives for nutritional benefit. The undertaking of larger scale sampling of A. armata throughout New Zealand, the identification of the active component(s) in B. hamifera, and the development of methods and infrastructure required for successful large-scale aquaculture and application of these seaweed species to livestock management systems are key areas of future research highlighted by this thesis.

    Author(s): Alisa Mihaila

  • Investigation of the effect of K. alvarezii on antioxidant enzymes, cell viability and DNA damage in male rats

    In recent years, a significant number of novel metabolites with potent pharmacological properties (antioxidant, antitumor, anti-HIV) have been discovered from marine organisms. Kappaphycus alvarezii (Doty) is a marine alga belonging to order: Gigartinales and family: Solieriaceae. It has been invasive in the Gulf of Mannar since 2000, and has a high content of the steroid phenol. This is the first report on its antioxidant properties using an animal model. This study aimed to explore the antioxidant and antigenotoxic/protective role of K. alvarezii growing in southeast coast of India in the male rat. The findings indicate that an extract of K. alvarezii is not nephrotoxic at the dose levels. The algal antioxidant activity shows similar correlation (89%; R2 = 0.8963) at varying temperature to the known antioxidant. K. alvarezii extracts exhibit significant protective effects against DNA damage induced by H2O2, which might be related to antioxidant activity. In conclusion, our results suggest that long-term daily administration of K. alvarezii extract offers enhanced antioxidant potential and protection against tissue lipid peroxidation and cell damage. Our results support the use of K. alvarezii in the food and pharmaceutical industries.

    Author(s): A. K. Kumaraguru, N. Nagarani

  • Iodine monoxide at a clean marine coastal site: observations of high frequency variations and inhomogeneous distributions

    The first in situ point observations of iodine monoxide (IO) at a clean marine site were made using a laser-induced fluorescence instrument deployed at Mace Head, Ireland in August 2007. IO mixing ratios of up to 49.8 pptv (equivalent to pmol mol−1; 1 s average) were ob- served at day-time low tide, well in excess of previous ob- served spatially-averaged maxima. A strong anti-correlation of IO mixing ratios with tide height was evident and the high time resolution of the observations showed IO peaked in the hour after low tide. The temporal delay in peak IO compared to low tide has not been observed previously but coincides with the time of peak aerosol number previously observed at Mace Head.

    A long path-differential optical absorption spectroscopy instrument (with a 2 × 6.8 km folded path across Roundstone Bay) was also based at the site for 3 days during the point measurement observation period. Both instruments show similar temporal trends but the point measurements of IO are a factor of ∼6–10 times greater than the spatially averaged IO mixing ratios, providing direct empirical evidence of the presence of inhomogeneities in the IO mixing ratio near the intertidal region.

    Author(s): R. Commane, K. Seitz, C. S. E. Bale, W. J. Bloss, J. Buxmann, T. Ingham, U. Platt, D. Pohler, D. E. Heard

  • Is inland aquaculture the panacea for Sierra Leone’s decline in marine fish stocks?

    The literature on fisheries for developing countries often cites inland aquaculture as a promising source of wealth creation for a nation in terms of revenue generation from export products. However, in this paper we argue that inland aquaculture has a greater prospect of success if it focuses on social welfare – i.e. alleviating food insecurity and poverty in coastal fishing communities, particularly those that are experiencing increased and unsustainable fishing pressure on marine fish. Nevertheless, promoting inland aquaculture in coastal areas faces many chal- lenges, including financial, legal, political, environmental, logistical, educational, and attitudinal obstacles. Our study investigates these challenges in two coastal communities in Sierra Leone – Tombo and Goderich – where declining levels of marine fish catches are intensifying efforts to provide alternative or supplementary forms of employment for artisanal fishers, but where knowledge and experience of, and enthusiasm and funding for, inland aquaculture are limited. The research is based on the perceptions of 51 key informant interviewees and 199 survey questionnaire respondents. The main findings of the fieldwork are as follows. (1) Few local fishers were familiar with inland aquaculture and its potential benefits. (2) There were land tenure problems (for example, women were excluded from ownership of land). (3) There was little funding to buy/rent land and equipment. (4) Despite declining fish stocks, respondents were reluctant to take up full-time fish farming because of the easier option of fishing. Our findings suggest that greater uptake of inland aquaculture is more likely if presented to local fishers as a supplementary livelihood activity rather than an alternative occupation to marine capture fishing. Our study reinforces the importance of understanding local fishers’ cultures, values, and pref- erences before introducing a new livelihood activity.

    Author(s): Nwamaka Okeke-Ogbuafor, Selina Stead, Tim Gray

  • Is Red Seaweed the Next Big Thing in Plant-Based Protein?
    Earlier this year, GFI announced the winners of our inaugural Competitive Research Grant Program. Thanks to the generosity of two visionary donors, we were able to allocate three million dollars in research funding to fourteen scientists from all corners of the globe—from Estonia to China to Israel—for critical, open-access research in plant-based and cell-based protein.
     
    Over the next few months, we will dive into each project with the scientists leading the charge. Today we start off in the U.S., where technologist and ocean entrepreneur Beth Zotter is researching a unique source of plant-based protein: red seaweed. Red seaweed has a high protein content and a remarkable umami flavor. Its “red-meat like attributes” are perfectly fit for alternative protein products.
     
    Zotter and her team at Trophic LLC are creating a method of protein extraction specifically for seaweed. They aim to test different protein concentrates to find the best fit based on cost and quality, as well as to characterize the taste and texture of different species. Zotter is transforming the possibilities for seaweed. She spoke to us about how the plant “can feed the world,” the importance of nori, and even a species that tastes like bacon.
    Author(s): Tara DiMaio

  • Is there a need for seaweed in human nutrition?

    In the Far East and Pacific Islands, there has been a long tradition of consuming seaweed as sea vegetables, while in Western countries the main use of seaweed has been as source of phycocolloids (alginate, carrageenan and agar) used as thickening and gelling agents in various industrial applications, including food processing. Seaweed is also a source of compounds with protective health effects. The beneficial effects of seaweed on human health appear to derive from the presence of three categories of constituents (fibre, proteins and minerals) as well as metabolites with antioxidant properties, including carotenoids, polyphenols, vitamins and polyunsaturated fatty acids.

    Author(s): H. Marfaing, Y. Lerat

  • Isolation and characterization of alginate-degrading bacteria for disposal of seaweed wastes

    Aims: Isolation of novel alginate degrading bacteria for the disposal of seaweed waste in composting process.

    Methods and results: Decomposition of alginate polymers was checked by the 3,5-dinitrosalicylic acid (DNS) method for reducing sugar, and absorbance at 235 nm for unsaturated sugar. A bacterium A7 was isolated from wakame compost and confirmed to belong to the genus Gracilibacillus by partial 16S rDNA analysis. The optimum condition for the growth of A7 in a medium containing 5 g l(-1) of sodium alginate is as follows: pH, 8.5-9.5; NaCl, 0.5 mol l(-1); temperature, 30 degrees C and polypeptone as nutrient content, 2-5 g l(-1). In a laboratory-scale composting experiment, the alginate content in wakame compost decreased to 14.3% after 72 h of composting from an initial value of 36%, indicating the effectiveness of alginate decomposition of A7 in wakame composting.

    Conclusions: The bacterium A7 was found to be alginate lyase-producing in genus Gracilibacillus and effective in degrading alginate to oligosaccharides in wakame during composting process.

    Significance and impact of the study: Development of new methods for the disposal of marine wastes and production of functional products.

     
    Author(s): J.-C. Tang, H. Taniguchi, H. Chu, Q. Zhou, S. Nagata

  • Isolation and culture of protoplasts from agar yielding seaweed Gracilaria edulis (Gmelin) Silva

    Viable protoplasts were isolated from cultured thailus of agar yeilding red seaweed Gracilaria edulis using an enzyme mixture of 3% ONOZUKA R-10 cellulase 3% R-10 macerozyme, 1 % agarase and 1% pectinase in a seaweed protoplast washing medium (SPW) containing seawater and 1 M mannitol. After repeated washing wiih sterile medium, the protoplasts were maintained in light and attempts were made on electrofusion of protoplasts.

    Author(s): Kaladharan, P, Gopinathan, C P, Bindhu, K B, Smitha, K S, Gireesh, R

  • Journal of Fisheries and Aquatic Science

    Background and Objective: Eucheumatoid cultivation is increasing and a variety of methods exist that can increase production. However, new cultivation approaches are rarely reported. The objective of study was to examine a new method of seaweed cultivation: The floating cage.

    Materials and Methods: The growth rate of Eucheuma denticulatum and Kappahycus alvarezii was assessed in floating cages from March-November, 2015 and compared with that in the traditional longline approach. Propagule wet weight was measured daily to document growth rates. Correlation coefficients between growth rate and environmental factors were calculated using simple linear models (Pearsonʼs) and statistically analyzed by SPSS Version 24.

    Results: Growth rates of both species in floating cages were faster than on longline and thallus morphology was better. For E. denticulatum, the daily specific growth rate (SGR) in floating cages varied from a low of 2.68% to a high of 3.32%, but the respective rates on longline were 1.67 and 2.91%. For K. alvarezii cultivated in floating cages, the highest and lowest rates were 3.1 and 2.1% but, when cultivated on longline, the respective rates were 2.9 and 1.71%.

    Conclusion: Therefore, it was concluded that cultivation of E. denticulatum and K. alvarezii using floating cages resulted in higher growth rates compared to cultivation on longline. The difference in results comes from reduced herbivore attack when the plants are in the protective cages.

    Author(s): Ma'ruf Kasim , Ahmad Mustafa, Muzuni Jalil, Wardha Jalil

  • Ka Pili Kai: Limu gifts from the sea

    The legendary Dr. Isabella (Izzie) Kauakea Aiona Abbott, fondly (and aptly) nicknamed "The First Lady of Limu", would have celebrated her 100th birthday this year. In tribute to her, and to celebrate the importance of limu (seaweed) to Hawai'i dating back more than a century, we are dedicating this issue of Ka Pili Kai to Izzie and her legacy. Not only was she a world-renowned scientist, author, professor, mentor, and inspiration to all who knew her, but she also embodied the true spirit of one who dedicated her life to ensuring that the next generation of students of all different backgrounds and cultures had invaluable opportunities to learn and thrive. In the pages of this issue you will read firsthand accounts from just a handful of people, among many, whose lives she shaped, and who are now in a position to carry on her legacy. 

    In another very special tribute to Izzie this year, a brand-new species of red algae, Martensia abbottiae, first found on the deep coral reefs off the coast of Moloka'i, Hawai'i, was named after her. 

    I invite you to browse this issue to read more about Izzie through engaging stories and images, and also learn how limu has helped shape the history of Hawai'i and its people. 

     

    Cindy Knapman

    Hawai'i Sea Grant Communications Leader 

    Author(s): Darren T. Lerner, Heather Dudock, Cindy Knapman, Rachel Lentz, Darren T. Lerner, Maya Walton , Josh McDaniel, Lurline Wailana McGregor, Paula Moehlenkamp, Celia Smith , Miwa Tamanaha, Bill Thomas, Kawika Winter , Andre P. Seale

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