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03. Science and Technology (Natural Sciences) Committee

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In creating a culture of peace and addressing sustainable development challenges, UNESCO aims to cultivate the generation and application of scientific knowledge among its Member States. At UNACOM, we facilitate access to UNESCO’s international programmes in the sciences, such as the Intergovernmental Oceanographic Commission (IOC), Man and the Biosphere (MAB) Programme, and International Geoscience and Geoparks Programme (IGGP), among others.

Through this sector, the Commission aims to contribute to the following SDGs: 11 - Sustainable Cities and Communities, 13 - Climate Action, 14 - Life Below Water, and 15 - Life On Land. With the overarching vision of the 2023-2028 Philippine Development Plan (PDP), UNACOM targets grassroots-inspired cultural heritage and biodiversity protection and conservation, as well as multi-stakeholder partnerships for SDGs promotion.

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Author: search.filters.author.Roleda, Michael Y.UNESCO Keyword: search.filters.subject.Aquaculture

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    Impacts of aquaculture nutrient sources: ammonium uptake of commercially important eucheumatoids depends on phosphate levels
    Narvarte, 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.