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  • The Protection and Management of the Sargasso Sea

    The Sargasso Sea is a fundamentally important part of the world’s ocean, located within the North Atlantic sub-tropical gyre with its boundaries defined by the surrounding currents. It is the only sea without land boundaries with water depths ranging from the surface coral reefs of Bermuda to abyssal plains at 4500 m. The Sargasso Sea’s importance derives from the interdependent mix of its physical structure and properties, its ecosystems, its role in global scale ocean and earth system processes, its socio-economic and cultural values, and its role in global scientific research. Despite this, the Sargasso Sea is threatened by a range of human activities that either directly adversely impact it or have the potential to do so. Being open ocean, the Sargasso Sea is part of the High Seas, the area of ocean that covers nearly 50% of the earth’s surface but which is beyond the jurisdiction and responsibility of any national government, and as such it enjoys little protection. To promote the importance of the Sargasso Sea, the Sargasso Sea Alliance was created under the leadership of the Government of Bermuda in 2010. This report provides a summary of the scientific and other supporting evidence for the importance of the Sargasso Sea and is intended to develop international recognition of this; to start the process of establishing appropriate management and precautionary regimes within existing agreements; and to stimulate a wider debate on appropriate management and protection for the High Seas.

    Nine reasons why the Sargasso Sea is important are described and discussed. It is a place of legend with a rich history of great importance to Bermuda; it has an iconic ecosystem based upon floating Sargassum, the world’s only holopelagic seaweed, hosting a rich and diverse community including ten endemic species; it provides essential habitat for nurturing a wide diversity of species many of which are endangered or threatened; it is the only breeding location for the threatened European and American eels; it lies within a large ocean gyre which concentrates pollutants and which has a variety of oceanographic processes that impact its productivity and species diversity; it plays a disproportionately large role in global ocean processes of carbon sequestration; it is of major importance for global scientific research and monitoring and is home to the world’s longest ocean time series of measurements; it has significant values to local and world-wide economies; and it is threatened by activities including over-fishing, pollution, shipping, and Sargassum harvesting.

    Apart from over-fishing many of the threats are potential, with few direct causal relationships between specific activities and adverse impacts. But there is accumulative evidence that the Sargasso Sea is being adversely impacted by human activities, and with the possibility of new uses for Sargassum in the future, the lack of direct scientific evidence does not preclude international action through the established precautionary approach. The opportunity to recognise the importance of the Sargasso Sea and to develop and implement procedures to protect this iconic region and the wider High Seas should be taken before it is too late. 

    Author(s): V. Vats, T. M. Trott, S. Thorrold, W. Swartz, V. R. Sumaila, A. Stevenson, D. K. Steinberg, A. N. S. Siuda, D. A. Seigel, J. Roberts, P. Rouja, J. Pitt, A. J. Peters, L. Parson, N. B. Nelson, R. Moffitt, F. W. Ming, P. I. Miller, M. J. Miller, S. A. McKenna, M. W. Lomas, A. H. Knap, R. J. Johnson, A. Hemphill, R. Hanel, P. Halpin, J. Hallett, M. Gollock, S. Gulick, S.J. Giovannoni, K. M. Gjerde, R. Edwards, C. A. Carlson, B. Causey, M. H. Conte, S. Christiansen, J. Cleary, J. Donnelly, S. A. Earle, D. d’A Laffoley, H. S. J. Roe, M. V. Angel, J. Ardron, N. R. Bates, I. L. Boyd, S. Brooke, K. N. Buck

  • The properties of red seaweed (Kappaphycus alvarezii) and its effect on mammary carcinogenesis

    The edible red seaweed (Kappaphycus alvarezii) is one of the algae species which was found to be rich in nutrients and nutraceutical. Hence, K. alvarezii may have the ability to suppress cancer through its antiproliferative properties. The aim of this study was to investigate the potential compounds of K. alvarezii, cytotoxicity properties of K. alvarezii extract on breast cancer cell line (MCF-7), investigated toxicity effect of high dosage K. alvarezii extract in rats and determined the effect of K. alvarezii on 7, 12- dimethylbenz[a]anthracene (DMBA) mammary carcinogenesis in rats. The method of LCMS/MS and MTT assay were used. For animal study, sub-chronic toxicity method was used, the rats were supplemented with 2000 mg/kg body weight daily of K. alvarezii crude extracts by oral gavage. For the anticancer effect of K. alvarezii crude extracts, this study consisted of three groups of the experimental, untreated and normal group of rats. The experimental and untreated groups of rats were induced with mammary tumour with DMBA. The experimental group of rats was given with K. alvarezii crude extracts orally. The results were being used to compare with the untreated group of rats and normal group of rats. All the rats were fed with standard diet and water ad libitum. Mortality, behavior changes and tumour sizes were observed specifically. The differences between the three groups of rats were evaluated by using the ANOVA test. By using LCMS/MS method, six unknown compounds were analysed. K. alvarezii crude extract reduced the cell viability of MCF-7 from 84.91% to 0.81% and the IC50 value is 4.1 0.69 mg/mL. For sub-chronic and heavy metal toxicity studies, no significant difference was found in haematological and biochemical values of the control group and experimental group. The growth rate of tumours in the untreated group of rats was found significantly higher than the experimental group of rats. Besides that, the white blood cells level in untreated group was found significantly higher than the experimental group and the normal group. In conclusion, K. alvarezii extract might able to slow down the growth rate of the tumour cells, therefore, identification of an active compound of inhibition growth rate of the tumour cells can be positively carried out in the future.

    Author(s): Vi-Sion Chang, Patrick N. Okechukwu, Swee-Sen Teo

  • The production of hydrocarbons by Botryococcus braunii

    As Tornabene1,2 has already discussed in this and in an earlier volume, many microorganisms — photosynthetic or not — are capable of producing hydrocarbons which can account for up to 1% of the dry mass (see tables I–V in ref. 1). At the moment, it seems that there is only 1 exception described in the literature which produces a larger proportion: the unicellular green alga Botryococcus braunii.

    Author(s): Reinhard Bachofen

  • The Potential Role of Seaweeds in the Natural Manipulation of Rumen Fermentation and Methane Production

    This study is the first to evaluate the effects of five seaweeds (Ulva sp., Laminaria ochroleuca, Saccharina latissima, Gigartina sp., and Gracilaria vermiculophylla) on gas and methane production and ruminal fermentation parameters when incubated in vitro with two substrates (meadow hay and corn silage) for 24 h. Seaweeds led to lower gas production, with Gigartina sp. presenting the lowest value. When incubated with meadow hay, Ulva sp., Gigartina sp. and G. vermiculophylla decreased methane production, but with corn silage, methane production was only decreased by G. vermiculophylla. With meadow hay, L. ochroleuca and S. latissima promoted similar methane production as the control, but with corn silage, L. ochroleuca increased it. With the exception of S. latissima, all seaweeds promoted similar levels of total volatile fatty acid production. The highest proportion of acetic acid was produced with Ulva sp., G. vermiculophylla, and S. latissima; the highest proportion of butyric acid with the control and L. ochroleuca; and the highest proportion of iso-valeric acid with Gigartina sp. These results reveal the potential of seaweeds to mitigate ruminal methane production and the importance of the basal diet. To efficiently use seaweeds as feed ingredients with nutritional and environmental benefits, more research is required to determine the mechanisms underlying seaweed and substrate interactions.

    Author(s): Ana R. J. Cabrita, Hugo M. Oliveira, Carla Mendonça, António J. M. Fonseca, Margarida R.G. Maia

  • The potential of Ulva diversity in southern Portugal for a sustainable food and feed industry

    The food and feed industry surpass their sustainable boundaries and global food security is one of society's biggest challenges today. Macroalgae of the genus Ulva have been identified as a suitable candidate for cultivation, with various applications within the food and feed industry. This work discusses the sustainability performance of Ulva cultivation and identifies the potential of Ulva species in southern Portugal for their use in the food and feed industry. It was tested, which species are available in different coastal and lagoon habitats and whether species identity or environmental conditions have a stronger effect on the seaweed’s protein content and fatty acid profile, to find out, whether the selection of one Ulva species is favorable over another for cultivation. Ulva species were collected at coastal and lagoon locations in southern Portugal and genetically identified, using the tufA gene sequences. Ulva rigida, Ulva flexuosa, Ulva fasciata, Ulva australis and Ulva compressa were identified as potential cultivation candidates. U. australis has not previously been reported in southern Portugal. Protein content in U. rigida sampled in coastal locations was higher (p < 0.01) compared to lagoon locations, but not different among species within the Ria Formosa (p = 0.363). Fatty acid profiles were not different across locations (p = 0.739). However, U. compressa had a higher PUFA content than U. rigida and U. fasciata within the Ria Formosa (p = 0.0245). Results suggest that U. compressa might be more a more suitable Ulva candidate for PUFA production and that protein content in seaweeds may be more susceptible to environmental conditions. In southern Portugal, Ulva is still an underexploited resource but has the potential to be part of the solution to overcome food security challenges in the future.

    Author(s): Leona Ritter - von Stein

  • The potential of macroalgae for beef production systems in Northern Australia

    The extensive grazing systems across northern Australia support approximately 50 % of the national beef herd. Livestock productivity is affected by seasonal variation in pasture quality and quantity. Intensifying livestock production in the north is a challenge, but has been recognised as priority for the Australian economy. Macroalgae offer a sustainable and novel dietary supplement for cattle due to its high nutrient value and biomass production, which are generally superior to forages used in ruminant production systems. This paper highlights some of the existing literature associated with the use of macroalgae for beef cattle and discusses the potential of green freshwater (Cladophora vagabunda, Oedogonium sp., Spirogyra sp.) and marine macroalgae (Cladophora coelothrix, Derbesia tenuissima, Ulva ohnoi) as feed supplements in northern Australian livestock production systems. Crude protein content of the six species of green macroalgae discussed here ranged from 75.4 to 339.1 g kg−1 dry weight (DW). Dietary mineral limitations in northern livestock production systems include phosphorous (P), sulfur (S) and nitrogen. Four of the six macroalgae species had high P content, ranging from 1.4 to 5 g kg−1 DW. Sulfur varied between species, ranging from 2.9 to 57.5 g kg−1 DW, with marine macroalgae having a higher sulfur concentration than freshwater macroalgae. This review demonstrates that green macroalgae have considerable potential to supply a high-protein, high-phosphorous feed supplement for northern livestock production systems dependent on extensive unimproved pastures.

    Author(s): Lorenna Machado, Robert D. Kinley, Marie Magnusson, Rocky de Nys, Nigel W. Tomkins

  • The potential of bacteria isolated from ruminal contents of seaweed-eating North Ronaldsay sheep to hydrolyse seaweed components and produce methane by anaerobic digestion in vitro

    The production of methane biofuel from seaweeds is limited by the hydrolysis of polysaccharides. Therumen microbiota of seaweed-eating North Ronald-say sheep was studied for polysaccharidic bacterial isolates degrading brown-seaweed polysaccharides. Only nine isolates out of 65 utilized >90% of the polysaccharide they were isolated on. The nine isolates (eight Prevotellaspp. and one Clostridiumbutyricum) utilized whole Laminaria hyperborea extract and a range of seaweed polysaccharides, including alginate (seven out of nine isolates), laminarin and carboxymethylcellulose (eight out of nineisolates); while two out of nine isolates additionally hydrolysed fucoidan to some extent. Crude enzyme extracts from three of the isolates studied further had diverse glycosidases and polysaccharidase activities; particularly against laminarin and alginate (two isolates were shown to have alginate lyase activity) and notably fucoidan and carageenan (one isolate). Inserial culture rumen microbiota hydrolysed a range of seaweed polysaccharides (fucoidan to a notably lesser degree) and homogenates of L. hyperborea, mixed Fucusspp. and Ascophyllum nodosum to produce methane and acetate. The rumen microbiota and isolates represent potential adjunct organismsor enzymes which may improve hydrolysis ofseaweed components and thus improve the efficiencyof seaweed anaerobic digestion for methane biofuel production.

    Author(s): Alastair D. Sutherland, Susan Withers, Allan G. Williams

  • The Potential for Upscaling Kelp (Saccharina latissima) Cultivation in Salmon-Driven Integrated Multi-Trophic Aquaculture (IMTA)

    Integrated multi-trophic aquaculture (IMTA) has the potential of reducing open-cage fish farming impacts on the environment while also introducing new value chains. The aim of this study was to investigate the growth and composition of the kelp Saccharina latissima in salmon-driven IMTA, and to assess the spatial extent of the influence of salmon derived nitrogen in order to evaluate the upscaling potential for IMTA. S. latissima was cultivated 100, 200, and 1,000 m east and 1,000 m west of a 5,000 tons salmon farm in Western Norway from February to September 2013. The proportion of salmon derived nitrogen available for the kelp showed a clear decline with distance from the farm. Accordingly, the kelp cultivated near the salmon cages grew faster during the spring season, and growth rate decreased with increasing distance from the farm. A spatially explicit numerical model system (SINMOD), including compartments for dissolved nutrients and kelp growth, was tuned to the field data and used to investigate the potential for upscaling IMTA production. The model was used to introduce a new metric—the impacted area IA—for the areal effects of IMTA in terms of the increase in production by IMTA. The model showed that a 25 hectare kelp farm in the vicinity of the studied salmon farm could take up 1.6 of the 13.5 tons of dissolved inorganic nitrogen released during kelp cultivation, amounting to almost 12% of the ammonia released during the cultivation period from February to June. The 25 hectare kelp farm would have a production yield of 1,125 tons fresh weight (FW), being 60% more than that of a non-IMTA kelp farm, while a 20% increase of kelp FW could be obtained over a 110 hectar area in salmon-driven IMTA. To achieve an even mass balance, an area of approximately 220 ha−1 would be needed to cultivate enough kelp to fix an equivalent of the nitrogen released by the fish.

    Author(s): Julia Fossberg, Silje Forbord, Ole Jacob Broch, Arne M. Malzahn, Henrice Jansen, Aleksander Handå, Henny Førde, Maria Bergvik, Anne Lise Fleddum, Jorunn Skjermo, Yngvar Olsen

  • The Potential for Seaweed Culture to Provide Ecosystem Services and Useful Products

    The oceans cover 70% of Earth yet they yield only 1.5% (117 million metric tons (mt)) of the 7.6 billion mt of food that we produce each year. Can we make more productive use of them? If so, how and, in light of challenges now faced by global agriculture, should we try? This paper addresses these questions by looking at seaweed farming and the idea that a parallel, photosynthetically driven system of food production, a 'Marine Agronomy', could be developed at sea to supplement the food we grow on land.

    Author(s): John Forster

  • The Potential for Seaweed as Livestock Feed, Workshop Report 2020

    Enteric methane emissions from ruminant animals raised for meat and milk are a significant contributor across the globe to anthropogenic climate change. Early studies suggest seaweeds offer a promising, natural approach to enteric methane mitigation. In terms of suitability for animal consumption, numerous anecdotal observations exist from different parts of the world of cows and sheep grazing on seaweed along the shoreline. However, to date limited science has emerged that conclusively demonstrates the effect of seaweed as feed, or as a feed ingredient, on animal health and well-being.

    For beef and dairy farmers, it is critically important to maintain or improve animal health, performance and productivity. While feeding seaweed to cows and other ruminants may help curb methane outputs, no farmer will use seaweed as a feed ingredient if the product adversely impacts animals. As a developing area of science, many questions must be asked and answered before it is determined that seaweed-based ingredients are effective, safe, profitable, and sustainable along every step of the value chain, from ocean to farm to human consumption.

    Promising new developments, combined with broad interest in this emerging area of science, prompted the need for in-depth discussions into the potential for seaweed supplements to both mitigate enteric methane and improve livestock production. Moreover, an important paper has emerged, Key Considerations for the Use of Seaweed to Reduce Enteric Methane Emissions From Cattle, which takes a comprehensive look at the issue and will be a key benchmark for work ahead.

    Author(s):

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