Digital library

  • Harvesting and potential uses of selected red seaweeds in the Philippines with emerging high-value applications

    While seaweed cultivation is indeed practiced globally, it is by no means a mature industry. In part, this is because that in spite of the tremendous biodiversity available within this “polyphyletic rag bag” of distantly-related photosynthetic organisms, very few species have actually been studied sufficiently to bring them into domestication for production. This is not unlike the situation with terrestrial agronomy.

    The history of extensive cultivation of seaweeds is several centuries old. One of the major, global centers for innovation and production of industrial-scale quantities of biomass for processing has been the Philippines and in turn the Coral Triangle.

    However, the species and strains of seaweeds currently in cultivation, often clonally propagated on account of their relative ease of producing propagules, have been victim to their own success. Farmers and industry have simply used the same, limited pool of biomass and techniques for too long. This has led to declines in yield and quality of constituents due to loss of vigor and increased incidences of pests and diseases. Innovation is urgently required both in the choice candidate species for cultivation and also the necessary steps and techniques required for the reliable and sustainable production of industrial quantities of biomass.

    Once again, the Philippines is at the forefront of leading technologies for the selection of novel candidate species for responsible, phyconomic activities. These species are economically valuable candidates, not only for their colloidal constituents, but also the more innovative applications of biologically active compounds from seaweeds used for the benefit of human, animal, plant and microbial products. Selected examples of these biologically active constituents and their applications are briefly reviewed.

    This chapter summarizes advances being made in the Philippines and outlines developments in several candidate species as future cultivated, marine crops.

    Author(s): Anicia Q. Hurtado, Rexie Magdugo, Alan T. Critchley

  • Hatchery experience and useful lessons from Isostichopus fuscus in Ecuador and Mexico

    This paper summarises lessons learned from captive breeding of the sea cucumber Isostichopus fuscus in land-based installations on the coast of Ecuador and Mexico. This species has been intensively fished in Mexico, along mainland Ecuador and around the Galapagos Islands. Management efforts have traditionally been challenged by local economic and social conditions. Populations of I. fuscus have thus been severely depleted over the past decades, generating interest in aquaculture and restocking. Spawning, fertilisation, larval rearing, disease control and juvenile growth have been documented in two privately owned hatcheries. Data from trials conducted in Ecuador over several years indicate that, under optimal conditions, juveniles can be grown to a size of ~8 cm in length in 3.5 months and to commercial size in ~18 months. Preliminary tests have shown that growing juvenile sea cucumbers in shrimp ponds is feasible. In Mexico, successful spawnings were restricted to late summer and autumn/fall months, when cultures of larvae and early juveniles yielded growth rates similar to or greater than those recorded in Ecuador. Grow-out of juveniles in shrimp ponds was impeded in both countries by skin infections, leading to high mortality rates, whereas juveniles placed in cages in the ocean (in Mexico) exhibited reasonable growth rates and better survival (to 90%). Overall, studies demonstrate that, with proper disease control, millions of juvenile I. fuscus can be reared in captivity annually, thus providing an alternative to fisheries, or a way to maintain sustainable harvests and eventually contribute to restoration of the natural populations.

    Author(s): Jean-François Hamel, Victor M. Arriaga Haro, Ramon Espinoza, Roberto H. Ycaza, Annie Mercier

  • Healing and regeneration responses in Gigartina skottsbergii (Rhodophyta, Gigartinales): optimization of vegetative propagation for cultivation

    The red alga Gigartina skottsbergii is becoming increasingly valuable as a resource to providing the raw material for the carrageenan industry established in Chile and elsewhere. As a result, wild stocks of the species are subject to intense harvesting by local fishermen. With the current levels of harvesting, it seems likely that natural stands of G. skottsbergii will soon collapse. Although cultivation seems an alternative, knowledge regarding the biology of the species is exceedingly limited. This study reports the first attempt to determine the optimal conditions for vegetative propagation of this species in the laboratory. For this purpose, the processes of wound healing and regeneration of frond fragments and haptera were studied under controlled conditions of temperature, light, and media strength. Our results demonstrated that excised tissues of G. skottsbergii were able to seal the exposed areas in approximately 20 days, by a wound healing process characterized by a re-differentiation of medullary cells into a normal cortex. Our data also demonstrated that frond fragments are better than haptera for propagation purposes. The development of new cortical tissue at the cut surface is followed, within 60 days, by localized blade-like outgrowths along the repaired area. Furthermore, the healing and regenerative responses in both frond fragments and haptera differed in efficiency according to the various combinations of factors, with optimum of 10–15 ◦C, 5 µmol m−2 s−1 and plain seawater or standard SFC medium for the fronds. The two types of responses were negatively affected by seawater enriched with a double concentration of nutrients.

    Author(s): Renato Westermeier, Jessica Beltrán, Juan A. Correa, Alejandro H. Buschmann

  • Hepatoprotective effect of seaweeds' methanol extract against carbon tetrachloride-induced poisoning in rats

    Three species of marine brown macroalgae (seaweeds), Myagropsis myagroides, Sargassum henslowianum and S. siliquastrum collected from Tung Ping Chau, Hong Kong were studied for their curative effects on hepatotoxicity caused by carbon tetrachloride (CCl4) in male Sprague-Dawley rats. A single suitable oral dose of 1.25 ml kg−1 of 20% CCl4 was used as a model hepatotoxin to produce significantly elevated levels of serum glutamic pyruvic transaminase (SGPT) and glutamic oxaloacetic transaminase (SGOT). Gavage oral administration of 300 mg kg−1 of methanol crude extract from S. siliquastrum 6 h post-treatment of CCl4 significantly reduced the CCl4-induced acute elevation in the levels of SGPT and SGOT in rats. Similar results, though at a less effective level, were achieved for extracts fromS. henslowianum and M. myagroides. These results indicate that these seaweeds may contain some active principles in their methanol extracts which acted as an antidote against the hepatotoxicity induced by CCl4. Further investigation is necessary to clarify and characterize the active component(s) in the extracts.

    Author(s): Put O. Ang, Jr., Vincent E. C. Ooi, Chun-Kwan Wong

  • Heterofucan from Sargassum filipendula Induces Apoptosis in HeLa Cells

    Fucan is a term used to denominate a family of sulfated polysaccharides rich in sulfated l-fucose. Heterofucan SF-1.5v was extracted from the brown seaweed Sargassum filipendula by proteolytic digestion followed by sequential acetone precipitation. This fucan showed antiproliferative activity on Hela cells and induced apoptosis. However, SF-1.5v was not able to activate caspases. Moreover, SF-1.5v induced glycogen synthase kinase (GSK) activation, but this protein is not involved in the heterofucan SF-1.5v induced apoptosis mechanism. In addition, ERK, p38, p53, pAKT and NFκB were not affected by the presence of SF-1.5v. We determined that SF-1.5v induces apoptosis in HeLa mainly by mitochondrial release of apoptosis-inducing factor (AIF) into cytosol. In addition, SF-1.5v decreases the expression of anti-apoptotic protein Bcl-2 and increased expression of apoptogenic protein Bax. These results are significant in that they provide a mechanistic framework for further exploring the use of SF-1.5v as a novel chemotherapeutics against human cervical cancer.

    Author(s): Hugo Alexandre Oliveira Rocha, Edda Lisboa Leite, Ivan Rui Lopes Albuquerque, Raniere Fagundes Melo-Silveira, Jailma Almeida-Lima, Mariana Santana Santos Pereira Costa, Rafael Barros Gomes Camara, Nednaldo Dantas-Santos, Leonardo Thiago Duarte Barreto Nobre, Ruth Medeiros Oliveira, Cinthia Beatrice Silva Telles, Leandro Silva Costa

  • High monospore-producing mutants obtained by treatment with MNNG in Porphyra yezoensis Ueda (Bangiales, Rhodophyta)

    Two high monospore-producing pigmentation mutants were obtained by treatment with MNNG in Porphyra yezoensis Veda. The mutants produced many monospores in young gametophytic blades (l month old) and old large blades (3 months old). Monospore production of the mutants was affected by the culture conditions. The higher the temperature and/or the light intensity, the more the number of monospores released. When the conchospores and monospores of the mutants were in a monoculture at 15 and 20 DC, they did not develop into large blades because their germlings repeatedly released many monospores. However, they developed into large blades when they were in a co-culture with the large gametophytic blades of the wild-type or other pigmentation mutants. One high monospore-producing red mutant (rm-l) was genetically characterized by crossing with the wild-type which does not easily release monospores. In the F1gametophytic blades from heterozygous conchocelis produced in the crosses, there were unsectored blades (2 types) and sectored blades (6 types) consisting of 2, 3 or 4 sectors having both parental color phenotypes. Sectors of both parental colors appeared in the F1sectored blades in the proportion IW:1.03R, indicating that the mutant rm-l has a mutation for its color phenotype. In the 4-week-old FI blades, high monospore production occurred only in the unsectored red blades and the red sectors of the sectored blades. These results indicate that the tendency of high monospore production is associated with the color phenotype of the mutant, suggesting that high monospore production of the mutant rm-l is controlled by gene(s), which is closely linked with the gene for the mutant color.

    Author(s): Yusho Aruga, Yuji Fujita, Xing-Hong Yan

  • High spatial resolution spectrometry of rafting macroalgae (Sargassum)

    Data with 0.4-m spatial resolution acquired ~2 km off the southeast Florida coast using the airborne Portable Hyperspectral Imager for Low-Light Spectroscopy (PHILLS) have been analyzed with the objective of identifying drifting surface macroalgae (Sargassum) through its spectral signature in at-sensor radiance. The observed spectral features of Sargassum include a peak at a wavelength of ~0.570 mum and a photosynthetic 'red edge' between 0.673 and 0.699 mum. Sargassum also exhibits high radiance in the reflected near-infrared but is impacted by the atmospheric absorption bands of water vapor at 0.720 mum and oxygen at 0.756 mum. The spectral signature is clearest and largest in amplitude where the Sargassum occurs as small surface aggregations, or rafts, which tend to lie at the downwind ends of narrow Sargassum windrows. The quantity of floating Sargassum was estimated within a single pixel by linearly mixing a spectrum of Sargassum-free water with varying percentages of a spectrum from a pixel assumed completely filled with floating plants. For our study site about 2.3% of the ocean area is classified as having some Sargassum coverage, with pixels completely filled with Sargassum being rare (only 0.2% of the classified Sargassum pixels) and pixels with the least-resolvable amount of Sargassum (~10% filled) being the most common.

    Author(s): David Gillis, Jeffrey H. Bowles, George O. Marmorino, Karl Szekielda

  • High yield cultivation of marine macroalga Ulva lactuca in a multi-tubular airlift photobioreactor: A scalable model for quality feedstock

     

    Conventional off-shore and on-shore cultivation methods for marine macroalgae are both inadequate to pitch macroalgae as scalable renewable feedstock that can be grown across all coastal locations. With on-shore cultivation likely to be sustainable and preferred over eco-damaging open seas cultivation, new reactor systems need to be developed for on-shore cultivation of seaweeds at scale. The present work is an attempt to use the indigenously designed vertical multi-tubular air-lift photobioreactor system to grow Ulva lactuca through the entire year under natural conditions. Optimized operation of the 1000 L photobioreactor assembly demonstrated a year-round averaged productivity of 0.87 kg m−2.d−1 (fresh weight) implying 1800 ton.ha−1.y−1 feedstock production. Carbon dioxide supplementation (5%), optimized circulation velocity (0.25–0.35 m/s), and managing nitrogen supply (17 ppm), under natural light intensities (500–1400 μmol m−2.s−1) provided a year-round sustained and continuous production of Ulva lactuca biomass. The photobioreactor system designed as a modular, linearly scalable, and resilient system operates with low land and water footprints, and gives a multi-fold increase in renewable feedstock production compared to the conventional sea-based and other on-shore tank-based practices.

    For the video summary of this article, see the file in the supplemental data.

    Author(s): Prashant Savvashe, Akanksha Mhatre-Naik, Gayatri Pillai, Juilee Palkar, Mayur Sathe, Reena Pandita, C.R.K. Reddy, Arvind M. Lali

  • High-Frequency Dynamics of Ocean pH: A Multi- Ecosystem Comparison

    The effect of Ocean Acidification (OA) on marine biota is quasi-predictable at best. While perturbation studies, in the form of incubations under elevated pCO2, reveal sensitivities and responses of individual species, one missing link in the OA story results from a chronic lack of pH data specific to a given species' natural habitat. Here, we present a compilation of continuous, high-resolution time series of upper ocean pH, collected using autonomous sensors, over a variety of ecosystems ranging from polar to tropical, open-ocean to coastal, kelp forest to coral reef. These observations reveal a continuum of month-long pH variability with standard deviations from 0.004 to 0.277 and ranges spanning 0.024 to 1.430 pH units. The nature of the observed variability was also highly site-dependent, with characteristic diel, semi-diurnal, and stochastic patterns of varying amplitudes. These biome-specific pH signatures disclose current levels of exposure to both high and low dissolved CO2, often demonstrating that resident organisms are already experiencing pH regimes that are not predicted until 2100. Our data provide a first step toward crystallizing the biophysical link between environmental history of pH exposure and physiological resilience of marine organisms to fluctuations in seawater CO2. Knowledge of this spatial and temporal variation in seawater chemistry allows us to improve the design of OA experiments: we can test organisms with a priori expectations of their tolerance guardrails, based on their natural range of exposure. Such hypothesis-testing will provide a deeper understanding of the effects of OA. Both intuitively simple to understand and powerfully informative, these and similar comparative time series can help guide management efforts to identify areas of marine habitat that can serve as refugia to acidification as well as areas that are particularly vulnerable to future ocean change.

    Author(s): Gretchen E. Hofmann, Jennifer E. Smith, Kenneth S. Johnson, Uwe Send, Lisa A. Levin, Fiorenza Micheli, Adina Paytan, Nichole N. Price, Brittany Peterson, Yuichiro Takeshita, Paul G. Matson, Elizabeth Derse Crook, Kristy J. Kroeker, Maria Cristina Gambi, Emily B. Rivest, Christina A. Frieder, Pauline C. Yu, Todd R. Martz

  • History of US Department of Energy macroalgae projects – major conclusions
    • Crude Oil Prices 
    • Market Size for Main Algae Chemical and Fuel Products
    • Types of Algae
    Author(s): John Benemann

Pages