Challenge 04: Develop a sustainable and equitable ocean economy
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Ocean Decade
Challenge 04:
Develop a sustainable and equitable ocean economy
Generate knowledge, support innovation and multi-sectoral partnerships and develop solutions for equitable, resilient and sustainable development of the ocean economy under changing environmental, social and climate conditions.
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- Macroinfaunal biomass and energy flow in a shallow reef flat of the northwestern PhilippinesNacorda, Hildie Maria E.; Yap, Helen T. (Springer, 1996-12)Macrofaunal biomass of the Lucero reef flat in the northwestern Philippines accounted for 9 to 52% of total sediment organic matter, and did not exhibit any significant temporal trend. The polychaetes and crustaceans consistently alternated as biomass dominants; the latter group showed monthly and seasonal variations along with the chaetognaths, molluscs, chordates, and chelicerates, among the major groups (p<0.05). Faunal abundance correlated significantly with biomass. Salinity, mean sediment grain size, sediment heterogeneity, and total organic matter were found to significantly influence faunal biomass. The sandy substrate community was characteristically heterotrophic throughout the monitoring period, i.e., P/R<1. Hourly rates of net primary production (p n ) did not exhibit any significant diurnal pattern. Monthly comparisons yielded significant differences for estimates of daily gross primary production, P, and respiration, R. Values of P were relatively low, and ranged from 2240 (± 1526 S.D.) to 4890 (± 1377) mg O2 m−2 d−1 while R ranged from 3744 (± 1504) to 6879 (± 903) mg O2 m−2 d−1. R was lower during the dry warm months than the wet months. Multiple regression analyses indicate that primary production was a positive function of light intensity and temperature, and a negative correlate of salinity (adjusted R 2 = 0.2444, p< 0.05). Respiration (r) did not appear to relate with any environmental variable, with total macroinfaunal abundance nor with biomass. Results of the study suggest that other heterotrophic components of the sand community were probably responsible for most of the energy consumption, and that these may be dependent on external sources of organic matter.
- Wound healing in cultured Eucheuma alvareziivar. tambalang DotyAzanza-Corrales, R.; Dawes, C. J. (Walter de Gruyter GmbH, 1989)Wound healing in segments of Eucheuma alvarezii var. tambalang grown in enriched media in the laboratory can be divided into four stages based on histological and cytological changes. During the first stage, approximately 2—4 days after wounding, proteinaceous and phenolic substances concentrate on pit plugs of cells adjacent to the wounded surface. In the second stage, about the sixth day, cellular extensions are produced from the pits of medullary and cortical cells of sub-wound layer. During the third stage, about the 8th day, the cellular extensions divide several times and elongate towards the surface. A new cortical or wound tissue is formed during the fourth stage beginning on the 12th day. The wound tissue is continuous with the old cortex within 3 weeks.
- Laboratory and field growth studies of commercial strains of Eucheuma denticulatum and Kappaphycus alvarezii in the PhilippinesDawes, Clinton J.; Lluisma, A. O.; Trono, G. C. (Springer, 1994-02)Daily growth rates of 0.1 to 8.4% d-1 for the brown form and 0.2 to 6.3% d-1 of the green form were measured for 3 to 5-cm long branches of the tropical red seaweed Kappaphycus alvarezii cultured in the laboratory. Highest growth rates were found using inexpensive enrichments such as soil water and coconut water supplemented with 0.7 mM N and 13 µM P and with a liquid fertilizer, Algafer, produced from seaweeds in the Philippines. Laboratory grown branches of both K. alvarezii and Eucheuma denticulatum transplanted to rafts in the field showed daily growth rates of 4.4 to 8.9% d-1, as high or higher than other reported growth rates. The studies, carried out in the Philippines, demonstrate the viability and high yield of laboratory cultivars and methods to keep laboratory culture costs low.
- Differences in biomass production and carrageenan yields among four strains of farmed carrageenophytes in Northern Bohol, PhilippinesTrono, Gavino C.; Lluisma, Arturo O. (Springer, 1992-11)Comparative studies on the biomass and carrageenan production of two strains of Eucheuma denticulatum and two strains of Kappaphycus alvarezii were made to assess the seasonality in their production capacities. The high and similar refined carrageenan (RC) yields (43–53% of dry wt.) of the four strains in the first cropping season (June–October) coincided with their high biomass production with plants averaging from 1.1 to 1.8 kg each at harvest. The poor RC yields (21–33%) recorded in the second cropping (October–February) coincided with their season of low biomass (av. wt: 0.34 to 1.0 kg). The four strains, however, recorded contrasting performance in the third cropping season (February–July) with the two E. denticulatum strains recording high RC yields (43 and 42.5%) together with high biomass (av. wt: 1.5 and 1.6 kg) in contrast to the low RC yields (30 and 39%) and low biomass (av. wt. 0.21 and 0.28 kg) of the two K. alvarezii strains. Records for semi-refined carrageenan (SRC) yields in the second and third cropping seasons were quite consistent and similar for the four strains (42–55%), except in the second cropping where the two K. alvarezii strains recorded low SRC. These differences in production potentials highlight the need for cropping management of the four strains to improve their cropping performance.
- 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.
- 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.