Challenge 03: Sustainably feed the global population
Permanent URI for this collectionhttps://repository.unesco.gov.ph/handle/123456789/22
Ocean Decade
Challenge 03:
Sustainably feed the global population
Generate knowledge, support innovation and develop solutions to optimize the role of the ocean in sustainably nourishing the world’s population under changing environmental, social and climate conditions.
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- Clonal propagation of Eucheuma denticulatum and Kappaphycus alvarezii for Philippine seaweed farmsDawes, C. J.; Trono, G. C.; Lluisma, A. O. (Springer, 1993-06)Technique improvement and cost reduction of branch culture, micropropagation, and callus production of carrageenan-yielding seaweeds Kappaphycus alvarezii and Eucheuma denticulatum is presented. Low cost branch culture is possible by enriching seawater with 0.1% coconut water with 1 mg l−1 indole-3-butyric acid for 24 h wk−1 or continuous culture with 0.01% Algafer, a Philippine fertilizer. Micropropagation of 0.5 cm explants had almost 100% new branch production demonstrating the viability of callus regenerated plants. The use of carrageenan as a media for callus production was not effective when compared to agar. Propagules of both species, transferred from the University of the Philippine Marine Science Institute (UPMSI) culture facility to the field, showed daily percent growth rates of 5 to 5.5% d−1 over 84 days. Based on the costs of the UPMSI laboratory, a culture facility in the seaweed farming area is estimated to cost about U. S. $22000 during the initial year and 58% less the second year.
- Impacts of aquaculture nutrient sources: ammonium uptake of commercially important eucheumatoids depends on phosphate levelsNarvarte, Bienson Ceasar V.; Hinaloc, Lourie Ann R.; Gonzaga, Shienna Mae C.; Roleda, Michael Y. (Springer, 2023-09-14)In an integrated multitrophic aquaculture (IMTA) system, seaweeds serve as extractive species that utilize excess nutrients, thereby reducing the risk of eutrophication and promoting sustainable aquaculture. However, the use of excessive fish feeds and the resultant faecal waste as nutrient streams can contribute to variations in nitrogen and phosphorus levels (e.g., primarily NH4+ and PO4−3) in the surrounding area and this may impact the physiology of the integrated seaweeds, particularly on how these species take up inorganic nutrients. In this study, the effect of different PO4−3 levels on NH4+ uptake of the three commercially important eucheumatoids Kappaphycus alvarezii, Kappaphycus striatus and Eucheuma denticulatum was examined under laboratory conditions. Seaweed thalli (n = 4) were incubated in seawater media containing 30 µM NH4+, and 0, 0.5, 1.0, 1.5, 3.0 or 5.0 µM PO4−3 for 1 h under a saturating light level of 116 ± 7.13 µmol photons m−2 s−1 inside a temperature-controlled laboratory. Species-specific responses to PO4−3 levels were observed. For K. alvarezii, maximum NH4+ uptake (17.8 ± 1.6 µmol gDW−1 h−1) was observed at 0.5 µM PO4−3 and the uptake rate declined at higher PO4−3 levels. For K. striatus, NH4+ uptake increased with increasing PO4−3 levels, with maximum N uptake (6.35 ± 0.9 µmol gDW−1 h−1) observed at 5.0 µM PO4−3. For E. denticulatum, maximum NH4+ uptake (14.6 ± 1.4 µmol gDW−1 h−1) was observed at 1.0 µM PO4−3. Our results suggest that among the three eucheumatoid species, the NH4+ uptake of K. striatus persists even at high levels of PO4−3. However, our results also showed that K. striatus had the lowest range of NH4+ uptake rates. These results should be taken into consideration when incorporating eucheumatoids in the IMTA system, where PO4−3levels significantly vary in space and time.This is contribution no. 500 from the Marine Science Institute, University of the Philippines (UPMSI), Diliman. The AlgaE Team would like to thank the Bolinao Marine Laboratory (BML) for providing the venue to conduct our experiments. BCV Narvarte and MY Roleda acknowledge the Sea6 Energy Pvt. Ltd. for sponsorship during the 24th International Seaweed Symposium (ISS) held on February 19-24, 2023, at Hobart, Tasmania, Australia. Likewise, BCV Narvarte and LAR Hinaloc would like to thank the University of the Philippines- Office of the International Linkages (UP-OIL) for providing them with a travel grant to attend the aforementioned symposium. BCV Narvarte also acknowledges the Department of Science and Technology- Philippine Council for Agriculture, Aquatic, and Natural Resources Research and Development (DOST-PCAARRD) for his PhD Scholarship (GREAT- Graduate Research and Education Assistantship for Technology Program).