We investigated the patterns and controls of dissolved organic carbon (DOC) production by the giant kelp (Macrocystis pyrifera) using data from short-term in situ incubations of entire blades and portions of stipes. These data were incorporated into an empirical model of reef-scale net primary production (NPP) at Mohawk Reef in southern California, U.S.A. for an 8-yr period. Rates of DOC release of incubated blades varied unpredictably with time of year, but were significantly related to the irradiance at the sea surface during the incubations. The growth stage, C/N ratio, and epiphyte load of the blades and the temperature of the ocean during the incubations had no discernable effect on rates of DOC release. Blades produced on average 2–3 times more DOC than stipes, and stipes and blades produced on average 30% and 80% more DOC respectively during the day compared to the night. Modeled DOC NPP at the reef scale was on average highest in summer and spring (0.5 g C m22d21) and lowest in winter and autumn (0.31 g C m22d21), but it varied greatly among years for any given season as large oscillations in standing biomass led to corresponding fluctuations in reef-scale DOC NPP. The fraction of NPP released as DOC was highly variable when examined at the monthly time scale, but became much more stable at seasonal and annual time scales averaging 14% of total NPP
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Expecting that more and richer people will demand more from the land, cultivating wider fields, logging more forests, and pressing Nature, comes naturally. The past half-century of disciplined and dematerializing demand and more intense and efficient land use encourage a rational hope that humanity’s pressure will not overwhelm Nature. Beginning with the examples of crops in the large and fast-developing countries of India and China as well as the United States, we examine the recent half-century. We also look back over the past 150 years when regions like Europe and the United States became the maiden beneficiaries of chemical, biological, and mechanical innovations in agriculture from the Industrial Revolution. Organizing our analysis with the ImPACT identity, we examine the elements contributing to the use of land for crop production, including population, affluence, diet, and the performance of agricultural producers.
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The production, nitrogen fixation, and release rates and fate of dissolved organic matter of a pelagic Sargassum community have been investigated at eight stations in the Gulf Stream and the Sargasso Sea. Net production and gross nitrogen fixation rates of Sargassum and epiphytes varied significantly between stations, 328 ± 114μg C (g dry wt)−1h−1 and 18 ± 7.4μg N g−1h−1, respectively. The net release rates of dissolved organic carbon (287 ± 150μg DOC g−1h−1) also showed the same variability between stations. On the other hand, the community carbon and nitrogen content, 268 ± 4.8 and 16.9 ± 2.4 mg g dry wt−1, respectively, remained constant at all stations. The results of chemical measurements indicate that ≈ 0–50 % of the gross production was lost as a result of photosynthate release. From 14C-tracer experiments it was found that the planktonic and epiphytic heterotrophs mineralized 50–70 % of the photosynthate released by Sargassum and epiphytic algae. Based on the community gross production and fixation rates, carbon and nitrogen content, the amount of nitrogen required for the observed production rates, the Sargassum community appears to obtain a substantial part (40%) of its nitrogen from nitrogen fixation.
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Spirulina biomass accounts for 30% of the total algae biomass production globally. In conventional process of Spirulina biomass production, cultivation using chemical-based culture medium contributes 35% of the total production cost. Moreover, the environmental impact of cultivation stage is the highest among all the production stages which resulted from the extensive usage of chemicals and nutrients. Thus, various types of culture medium such as chemical-based, modified, and alternative culture medium with highlights on wastewater medium is reviewed on the recent advances of culture media for Spirulina cultivation. Further study is needed in modifying or exploring alternative culture media utilising waste, wastewater, or by-products from industrial processes to ensure the sustainability of environment and nutrients source for cultivation in the long term. Moreover, the current development of utilising wastewater medium only support the growth of Spirulina however it cannot eliminate the negative impacts of wastewater. In fact, the recent developments in coupling with wastewater treatment technology can eradicate the negative impacts of wastewater while supporting the growth of Spirulina. The application of Spirulina cultivation in wastewater able to resolve the global environmental pollution issues, produce value added product and even generate green electricity. This would benefit the society, business, and environment in achieving a sustainable circular bioeconomy.
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- Four species of seaweeds biochemically characterized for biorefinery
- Mild fractionation required to preserve chemical structure
- Seaweed carbohydrates can be hydrolyzed and fermented to ABE
- Monetizing of all fractions is needed for viable biorefinery
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Seas and oceans represent a big store for beneficial algae. It is a real fact that the importance of marine organisms as a source of new substances is growing. With marine species comprising approximately a half of the total global biodiversity, the sea offers an enormous resource for novel compounds and it is classified as the largest remaining reservoir of natural molecules to be evaluated for drug activity. A very different kind of substances have been obtained from marine organisms among other reasons because they are living in a very exigent, competitive and aggressive surrounding very different in many aspects from the terrestrial environment, a situation that demands the production of quite specific and potent active molecules. The present review is focusing on the following topics: Seaweeds in India, nutritional and medicinal values of seaweeds, antimicrobial activity of seaweeds and uses of seaweeds.
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Pharmacological properties of native carrageenan (k) extracted from Kappaphycus alvarezii and commercial carrageenan (Sigma-Aldrich) were evaluated using in vitro antioxidant, anticancer and antidiabetic studies. Phytochemical analysis of native and commercial carrageenans showed the presence of alkaloids, saponins, steroids, gums & mucilages and carbohydrate. Both native and commercial carrageenans exhibited better antioxidant activities such as total antioxidant capacity (87 ± 0.47 and 82.6 ± 0.47mg A.A/g), hydroxyl radical scavenging activity (61.4 ± 0.27 and 58.66 ± 0.31mg/ml), nitric oxide radical scavenging activity (80.42 ± 0.22 and 73.66 ± 0.22mg/ml), DPPH radical scavenging activity (56.26 ± 0.20 and 53.67 ± 0.082mg/ml) and reducing power assay (46.57 ± 0.32 and 42.54 ± 0.27mg/ml) at the maximum concentration of 100mg/ml carrageenans. These results indicated that native carrageenan from K. alvarezii possessed better antioxidant potential in comparison with commercial carrageenan. Anticancer activities of both carrageenans showed excellent inhibition on the growth of breast, colon, liver and osteosarcoma cell lines at the maximum concentration of 150mg/ml. Native carrageenan exhibited an excellent anticancer activity on colon carcinoma cell lines (67.66 ± 0.168%) with the IC50 value of 73.87mg/ml and commercial carrageenan possessed a potent inhibition on the growth of breast cancer cell lines (67.33 ± 0.077%) with the IC50 value of 123.8mg/ml. These results clearly indicated the beneficial effect of native and commercial carrageenans as anticancer agents being a free radical scavenger. Anti-diabetic property of both carrageenans showed inhibition effect on a- glucosidase enzyme. The inhibitory effect depends on concentration of carrageenans and it was recorded that maximum (74.49 ±1.05 and 67.42 ± 0.63) inhibitory effect of a- glucosidase enzyme at 500mg/ml concentration.
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Seaweed is a general nomenclature used species of algae and marine plants breed in water bodies like rivers and oceans. They grow in a wide range of sizes from microscopic to stupendous. Seaweed, or macroalgae as it is known scientifically, includes over 10,000 species of the fastest growing plants on earth. Seaweeds come in an amazing variety of beautiful shapes, colors and sizes, and are found in all of the World. They are most abundant in shallow rocky coastal areas, especially where they are exposed at low tide. Seaweed is taxonomically classified under four groups according to the color of photosynthetic pigments namely red algae (rhodophyta), brown algae (phaeophyta), green algae (chlorophyta), and blue-green algae (cyanophyta).
Seaweeds are one of the most nutritionally and therapeutically valuable foods. Their value to health is largely due to their high mineral content and the therapeutic sulfated polysaccharides. Seaweeds are also a source of all the known vitamins, chlorophylls, lignans, polyphenols, antioxidants and chemical diversity including pigments, polysacccharides, organic, and inorganic compounds which are used as animal fodder, food, nutraceuticals, pharmaceuticals, and cosmeceutical.
The aim of this review is to accumulate in brief, the therapeutics and medicinal uses of seaweed on the some mentioned ailments.
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The development of a sustainable bio-based economy has drawn much attention in recent years, and research to find smart solutions to the many inherent challenges has intensified. In nature, perhaps the best example of an authentic sustainable system is oxygenic photosynthesis. The biochemistry of this intricate process is empowered by solar radiation influx and performed by hierarchically organized complexes composed by photoreceptors, inorganic catalysts, and enzymes which define specific niches for optimizing light-to-energy conversion. The success of this process relies on its capability to exploit the almost inexhaustible reservoirs of sunlight, water, and carbon dioxide to transform photonic energy into chemical energy such as stored in adenosine triphosphate. Oxygenic photosynthesis is responsible for most of the oxygen, fossil fuels, and biomass on our planet. So, even after a few billion years of evolution, this process unceasingly supports life on earth, and probably soon also in outer-space, and inspires the development of enabling technologies for a sustainable global economy and ecosystem. The following review covers some of the major milestones reached in photosynthesis research, each reflecting lasting routes of innovation in agriculture, environmental protection, and clean energy production.
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Photosynthetic responses to temperature were examined in tetrasporophytes of Lomentaria baileyana and Lomentaria orcadensis (Rhodophyta). These species have different temperature ranges for growth that reflect seasonal temperature extremes in their natural distributions. L. baileyana is a temperate-subtropical species which grows between 15 and 33°C, whereas L. orcadensis is a boreal-temperate species which grows between 10 and 20°C. Interspecific differences in the photosynthetic responses to temperature were similar to those for growth, suggesting that photosynthesis may determine the temperature range over which Lomentaria tetrasporophytes can grow. Light-saturated rates of photosynthesis were higher in L. orcadensis below 15°C, whereas L. baileyana could photosynthesize at temperatures above 30°C, which inhibited photosynthesis in L. orcadensis. These differences were attributable to genetic adaptations of photosynthetic metabolism because both species were grown under identical conditions for several months prior to the experiments. Phycoerythrin fluorescence studies and photosynthesis-irradiance responses determined in red and green light indicated that the high-temperature-induced breakdown of energy transfer from phycoerythrin to the photosynthetic reaction centres occurred at a lower temperature in L. orcadensis than in L. baileyana. Low-temperature-enhanced photoinhibition may account for the decreased photosynthetic performance of L. baileyana at temperatures below 15°C.
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Marine Agronomy Group, CAFNRM, UH-Hilo
200 W. Kawili st., HI 96720, USA
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Funding for this web portal is provided by the World Wildlife Fund and the University of Hawaii-Hilo.