03. Science and Technology (Natural Sciences) Committee
Permanent URI for this communityhttps://repository.unesco.gov.ph/handle/123456789/3
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.
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.
Browse
10 results
Search Results
- Notes on the induced spawning and larval rearing of the Asian moon scallop, Amusium pleuronectes (Linné), in the laboratoryBelda, C. A.; Del Norte, A. G. C. (Elsevier, 1988-08)Sexual and chemical stimulations were effective in inducing the scallop, Amusium pleuronectes (Linné), to spawn sperm only, whereas thermal stimulation was not at all successful. Chemical stimulation consisted of serotonin injections into the ripe gonads. Fertilizable eggs were obtained by stripping gametes from the ovaries. Cleavage of zygotes (72.4 μm mean diameter) occured 1 h after fertilization. Trochophores (58.9–111.2 μm in length) and straight-hinge veligers or D-veligers (80.0–130.2 μm) were observed in less than 24 h. Five days after fertilization, the umbone stage (101.6–169.1 μm) was reached. Crawling pediveligers (174.0–250.0 μm) appeared after 9 days. Seawater in the culture vessels was changed 24 h after fertilization and every other day thereafter. The larvae were fed on Isochrysis galbana (Tahitian strain) at an initial concentration of 30 cells/gml.
- Diurnal and diel patterns in the photosynthetic performance of the agarophyte Gelidiella acerosaGanzon-Fortes, E. T. (Walter de Gruyter, 1997)Photosynthesis of the red alga Gelidiella acerosa was monitored on diurnal (during the day) and diel (24 h period) bases using the oxygen evolution technique in a closed system. Natural sunlight and artificial light were used to assess uniformity in the diurnal photosynthetic responses. Photosynthesis-irradiance (P-I) curves were also determined diurnally. On a diel basis, maximal photosynthetic rates occurred at day time and minimal rates occurred at night. Diurnally, photosynthesis fluctuated in different patterns depending on PFDs used. Under saturating but not photoinhibiting FFDs, photosynthesis exhibited an early morning minimum (a few hours after sunrise), a midday-noon maximum, sustained until late afternoon, then declined at or after sunset. However, when exposure to high PFDs (above 1200 μιηοΐ photons m"~s") were prolonged, i.e. from morning until afternoon, the photosynthetic performance suffered a depression starting from noon and persisting until afternoon. When PFDs lowered late in the afternoon, recovery of photosynthetic performance commenced resulting in increased photosynthetic rates. The P-I curve data corroborate findings of experiments using saturating but not photoinhibiting PFDs. The morning P-I curve had lower Pm and alpha, and higher Ik and Is values than the identical noon and afternoon P-I curves. This suggested that photosynthetic performance was yet inefficient in the morning but performed efficiently near midday until the afternoon. An endogenous circadian clock was implicated to have influenced the diurnal and diel patterns in the photosynthetic performance of G. acerosa. Photoinhibition was the other factor suspected to have altered the diurnal pattern.
- Genetic structure of giant clam (Tridacna derasa) populations from reefs in the Indo-PacificMacaranas, J. M.; Ablan, C. A.; Pante, M. J. R.; Benzie, J. A. H.; Williams, S. T. (Springer, 1992-06)Large genetic differences were observed among the Great Barrier Reef (GBR), Fiji and Philippine populations of Tridacna derasa (Roding) sampled in 1989 and 1990 (Nei's unbiased genetic distance, D,=0.137 to 0.341). This result contrasted strongly with the low genetic distance (D=0.032) reported previously for the giant clam T. maxima over similar geographical scales. No significant genetic differentiation was observed among most populations from the GBR (mean D=0.007), consistent with the high gene exchange expected in this highly connected reef system. However, significant differentiation resulting from differences in the frequencies of less common alleles between the North-Central GBR and South GBR (Swain region) were observed. Historical isolation of blocks of the Central Indo-West Pacific from the GBR and present-day restrictions to gene exchange between the GBR, Fiji and the Philippines as a result of oceanographic current patterns, were thought to be responsible for the high degree of genetic differentiation of T. derasa populations. The relevance of these findings to clam mariculture and reef restocking are briefly discussed.
- Five new sesquiterpenes from the red alga Laurencia flexilisde Nys, Rocky; Wright, Anthony D.; König, Gabriele M.; Sticher, Otto; Alino, Perry M. (American Chemical Society (ACS), 1993-06)The red alga Laurencia flexilis, collected from Philippine waters, yielded five new sesquiterpenoid metabolites, 3,4-epoxypalisadin A [1], 5B-acetoxypalisadin A [2], 12-bromopalisadin B [3], palisading C [4], and 5B-hydroxypalisadin B [5]. The known metabolites 6-10 were also isolated The unambiguous assignments of H- and C-nmr spectral data for compounds 7 and 8 are reported for the first time.
- The farmed Eucheuma species (Gigartinales, Rhodophyta) in Danajon Reef, Philippines: Carrageenan propertiesAzanza-Corrales, R.; Sa-a, P. (Springer, 1990-09)Six cultured ‘strains’ of Eucheuma denticulatum and E. alvarezii, from which stocks can be selected for the development of a Eucheuma ‘seedling bank’, were tested for their carrageenan quality from June to November 1988. Percent yield of all the varieties taken together was apparently higher in June, becoming lower in November (regression, r −0.785, probability, p ⩽ 0.001). Stepwise regression analysis was done to determine the existence of any relationship between any of the following parameters: gel strength, viscosity, sulfate content, month of sampling, and yield, whether taken individually or in combination. Results show variations of the yield with the month of sampling. ANOVA was performed to test whether there are differences in sulfate levels, gel strength, and viscosity between the Eucheuma alvarezii morphotypes. There was no significant difference between the green and the brown types.
- Fisheries Administrative Order No. 1. Organization and functions of the Bureau of Fisheries.(Department of Agriculture and Natural Resources, 1947-07-01)
- Effect of starvation on development and survivorship of naupliar Calanus pacificus (Brodsky)Lopez, M. D. G. (Elsevier, 1996-10)In the marine planktonic copepod, Calanus pacificus (Brodsky), survivorship and development rate during the remaining naupliar stages were reduced when initial feeding was delayed for ~ 10 h after molting into naupliar stage III (NIII). In otherwise well-fed stages NIII-NVI, development and survivorship were reduced after starvation periods > 6 h and > 14 h, respectively. Molting rate and survivorship were lower in response to transient starvation than in response to constantly low food supplies. Stage NV was the least sensitive to transient starvation, while stages NIII and NVI were the most susceptible. Molting rates were reduced even after abundant food was subsequently provided. Thus, ambient food concentration at the time a population is sampled may not be an adequate index of future cohort success. Estimates of fine-scale to micro-scale particle distributions in situ suggest that NIII, the first feeding stage, is the instar most likely to experience short starvation periods if hatching occurs well below phytoplankton-rich strata.
- Feeding and diel vertical migration cycles of Metridia gerlachei (Giesbrecht) in coastal waters of the Antarctic PeninsulaLopez, M. D. G.; Huntley, M. E. (Springer, 1995-01)Diel vertical migration and feeding cycles of adult female Metridia gerlachei in the upper 290 m of a 335-m water column were measured during a total of 65 h in two periods of early summer (Dec 20–21 and Dec 25–26, 1991). Samples collected in eight depth strata by 35 MOCNESS tows (333-μm mesh) were analyzed for abundance and mean individual gut pigment content. Most of the copepod population was concentrated in a 50-m depth interval at all times. Feeding began simultaneously with nocturnal ascent from a depth of 200–250 m at ≈ 18:00 h (local time), when the relative change in ambient light intensity was greatest. Ingestion rate increased exponentially (ki = 0.988 h−1) at double the gut evacuation rate (ke = 0.488 h−1) as the population moved upward at 22.3–26.5 m h−1 through increasing concentrations of particulate chlorophyll-a. Although the bulk of the population did not move to depths shallower than 50 m, and began its downward migration at a rate of 20.8–31.7 mh−1 in complete darkness, individual females continued to make brief excursions into chlorophyll-rich surface waters (4–8 μg l−1) during the first few hours of population descent. Ingestion rate diminished abruptly by one order of magnitude (ki = 0.068 h−1) at dawn (≈ 03∶30 h). Within four more hours, the population had reached its daytime depth and gut pigment content remained constant at a minimum value until the next migration cycle. No feeding appeared to take place at depth during the day. Ingestion by M. gerlachei females removed < 4% of daily primary production, with only ≈ 20% of this amount being removed from surface waters by active vertical transport.
- Reproduction in Eucheuma denticulatum (Burman) Collins and Hervey and Kappaphycus alvarezii (Doty) Doty farmed in Danajon Reef, PhilippinesAzanza-Corrales, Rhodora; Mamauag, Samuel S.; Alfiler, E.; Orolfo, M. J. (Elsevier, 1992-04)Occurrence of reproductive structures in seven forms belonging to two species of carrageenophytes, Eucheuma denticulatum and Kappaphycus alvarezii was determined at a farming site at Danajon Reef, Northern Bohol, Philippines during 1987 and 1988. Reproductive plants of these forms were encountered throughout the study period although not all three structures (asexual or tetrasporic form and sexual male and female forms) were represented in each form. For K. alvarezii forms, taking the ‘browns’ (EAB1 and EAB2) and the ‘greens’ (EAG1 and EAG2) collectively, male and female reproductive structures were found throughout the year but no tetrasporic thalli were encountered. Only male and tetrasporic structures were observed for E. denticulatum (EDB and EDG) while the ‘sacul type’ ( EAG3 ) had both structures present throughout the study period. Analysis of variance revealed significant difference (P < 0.05) in the frequencies of reproductive structures of each form.
- The farmed Euchema species in Danajon Reef, Philippines: Vegetative and reproductive structuresAzanza-Corrales, R. (Springer, 1990-03)As part of the information needed for applied research on hybridization of these economically important species, the vegetative and reproductive structures of Eucheuma denticulatum (Burman) Collins and Hervey, and Eucheuma alvarezii Doty being farmed in Danajon Reef, were studied. All cultured ‘strains’ suspected to have developed from original stocks apparently introduced into the area about twelve years ago were sampled monthly from February 1987 to November 1988. Analyses of fresh free-hand and plastic embedded sections revealed the sexual (male, female) and asexual (tetrasporic) structures in E. alvarezii var.tambalang Doty and the absence of the female in E. denticulatum, indicating the suitability of the former species for future manipulative experiments.