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.
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- Ocean urea fertilization for carbon credits poses high ecological risksGlibert, Patricia M.; Azanza, Rhodora; Burford, Michele; Furuya, Ken; Abal, Eva; Al-Azri, Adnan; Al-Yamani, Faiza; Andersen, Per; Anderson, Donald M.; Beardall, John; Berg, G. Mine; Brand, Larry; Bronk, Deborah; Brookes, Justin; Burkholder, JoAnn M.; Cembella, Allan; Cochlan, William P.; Collier, Jackie L.; Collos, Yves; Diaz, Robert; Doblin, Martina; Drennen, Thomas; Dyhrman, Sonya; Fukuyo, Yasuwo; Furnas, Miles; Galloway, James; Granéli, Edna; Ha, Dao Viet; Hallegraeff, Gustaaf; Harrison, John; Harrison, Paul J.; Heil, Cynthia A.; Heimann, Kirsten; Howarth, Robert; Jauzein, Cécile; Kana, Austin A.; Kana, Todd M.; Kim, Hakgyoon; Kudela, Raphael; Legrand, Catherine; Mallin, Michael; Mulholland, Margaret; Murray, Shauna; O’Neil, Judith; Pitcher, Grant; Qi, Yuzao; Rabalais, Nancy; Raine, Robin; Seitzinger, Sybil; Salomon, Paulo S.; Solomon, Caroline; Stoecker, Diane K.; Usup, Gires; Wilson, Joanne; Yin, Kedong; Zhou, Mingjiang; Zhu, Mingyuan (Elsevier BV, 2008-06)The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many grow well on urea and some even increase their toxicity when grown on urea. Many toxic dinoflagellates form cysts which can settle to the sediment and germinate in subsequent years, forming new blooms even without further fertilization. If large-scale blooms do occur, it is likely that they will contribute to hypoxia in the bottom waters upon decomposition. Lastly, urea production requires fossil fuel usage, further limiting the potential for net carbon sequestration. The environmental and economic impacts are potentially great and need to be rigorously assessed.
- Iota-carrageenan from a newly farmed, rare variety of eucheumoid seaweed—“endong”Villanueva, R. D.; Montaño, M. N. E.; Romero, J. B. (Springer, 2008-08-02)A seaweed with the local name “endong” is a rare eucheumoid variety that has recently been farmed in Tawi-Tawi, southern Philippines. Local farmers describe it as “eel-like” because of its long, slender and smooth thalli. Being somewhat similar in appearance to the dominantly farmed seaweed “tambalang” (Kappaphycus alvarezii var. tambalangii), farmers mix their harvests of “endong” with those of “tambalang”. We analyzed the hydrocolloid extract from “endong” using spectroscopic and chemical techniques. The extract’s infrared and nuclear magnetic resonance (1H and 13C) spectra, and sulfate and 3,6-anhydrogalactose contents revealed carrageenan of the iota-type, similar to extracts from another farmed species, Eucheuma denticulatum. This result implies that “endong” carrageenan exhibits physico-chemical properties different from those of kappa-carrageenan of “tambalang”. The findings of this study are of significance to the seaweed industry, as carrageenan quality problems could potentially arise from a mixed harvest. Seaweed farmers are advised to separate their harvests of “endong” and “tambalang”.
- Effects of multiple perturbations on the survivorship of fragments of three coral speciesDizon, Romeo M.; Yap, Helen T. (Elsevier BV, 2006-08)Fist-sized fragments of Porites cylindrica, Porites rus and Pavona frondifera were deployed in single-species (P. cylindrica) and mixed-species (all three) plots in a shallow reef area in the northwestern Philippines. After 6 months, the corals in half of the plots were broken into smaller pieces to simulate an episodic physical disturbance. The survival of all corals was monitored from March 2000 to July 2001 during which the corals experienced 2 typhoons and episodes of algal overgrowth. For both intact and broken treatments, there was significantly higher survival in the mixed-species plots than in the single-species treatments. Fragment mortality varied between disturbances of varying frequencies and magnitudes, namely: one-time fragmentation stress, seasonal overgrowth by cyanobacteria and macroalgae, short-term (1 day) and long-term (more than 1 week) burial. The mixed-species assemblages had higher fragment survivorship than the monospecific assemblages during small-scale perturbations (e.g., algal overgrowth), but not in the face of subsequent, larger scale disturbances. This study emphasizes that coral responses to disturbance are both species- and context-specific.
- Differential survival of coral transplants on various substrates under elevated water temperaturesYap, Helen T. (Elsevier BV, 2004-08)Closely related scleractinian coral species that exhibited similar survival patterns under relatively normal field conditions responded very differently to the occurrence of an environmental disturbance. The two species studied were Porites cylindrica and Porites rus which occur in the same reef zones in shallow reef flats. Transplants of both species were evenly distributed and attached to three different types of substrate: live coral colonies of P. cylindrica, dead coral colonies (also of P. cylindrica), and epoxy coated metal grids that were raised above the sandy substrate. With the onset of above-normal water temperatures due to the El Niño episode of 1998, P. cylindrica transplants immediately showed signs of bleaching stress and tissue necrosis, followed by algal overgrowth and mortality soon afterwards. In contrast, transplants of P. rus bleached more slowly and suffered less mortality, with a few actually showing signs of recovery at the end of the experimental period which covered a total of 14 weeks. These differences in responses could be attributed to properties of the symbiotic zooxanthellae, of the host coral tissue itself, or both. Over-all, survival was good on the metal grids (average of 35%), and on the live coral (average of 22%). It was poor on the dead coral (average of 6%). The metal grids as well as live coral tissue apparently provided a favorable substrate for the attached coral fragments, even for those of a different species. Under the conditions of this particular study, attachment of live coral fragments on already dead colonies for the purpose of increasing live coral cover on the reef did not yield favorable results. This is an area that requires further investigation.
- Remote sensing of coral reefs and their physical environmentMumby, Peter J.; Skirving, William; Strong, Alan E.; Hardy, John T.; LeDrew, Ellsworth F.; Hochberg, Eric J.; Stumpf, Rick P.; David, Laura T. (Elsevier BV, 2004-02)There has been a vast improvement in access to remotely sensed data in just a few recent years. This revolution of information is the result of heavy investment in new technology by governments and industry, rapid developments in computing power and storage, and easy dissemination of data over the internet. Today, remotely sensed data are available to virtually anyone with a desktop computer. Here, we review the status of one of the most popular areas of marine remote sensing research: coral reefs. Previous reviews have focused on the ability of remote sensing to map the structure and habitat composition of coral reefs, but have neglected to consider the physical environment in which reefs occur. We provide a holistic review of what can, might, and cannot be mapped using remote sensing at this time. We cover aspects of reef structure and health but also discuss the diversity of physical environmental data such as temperature, winds, solar radiation and water quality. There have been numerous recent advances in the remote sensing of reefs and we hope that this paper enhances awareness of the diverse data sources available, and helps practitioners identify realistic objectives for remote sensing in coral reef areas.
- Effects of elevated seawater temperature and nitrate enrichment on the branching coral Porites cylindrica in the absence of particulate foodNordemar, I.; Nyström, M.; Dizon, R. (Springer, 2003-01-24)Compounded disturbances are becoming increasingly common on coral reefs. Impacts of global warming, which is generally perceived as the most serious threat to coral reefs today, often coincide with various common anthropogenic disturbances, such as pollution and overharvesting. To better evaluate the impact of global warming, interactions between elevated temperature and background disturbance should be investigated. In this study, the physiological response of the reef-building coral Porites cylindrica was investigated, when exposed to enrichment of dissolved inorganic nitrate (+15 μM for 14 days) and elevated seawater temperature (+2ºC for 48 h), in the absence of particulate food. It was shown that P. cylindrica was able to tolerate the temperature exposure without losing symbiotic microalgae or chlorophyll pigments, although the photosynthetic capacity was affected. Nitrate enrichment significantly reduced primary production rate, although zooxanthella population density and chlorophyll concentrations were not affected. The combination of elevated temperature and nitrate enrichment produced an even more pronounced reduction of the production rate. Since coral respiration rate remained unaffected by the treatments, this implies that the corals were unable to acclimate to impaired photosynthesis. However, there was no indication of subsequently reduced tissue growth or increased host catabolism based on tissue biomass measurements. On the other hand, all corals, including controls, lost tissue biomass during the exposure, suggesting a dependence on particulate food. Our results imply that corals on nutrient-exposed reefs may be more stressed during periods of elevated temperature, compared to corals in more pristine areas.
- Sexual reproduction in SE Asian seagrasses: The absence of a seed bank in Thalassia hemprichiiRollon, Rene N.; Vermaat, Jan E.; Nacorda, Hildie Maria E. (Elsevier BV, 2003-02)We report the absence of a persistent seed bank in Thalassia hemprichii in NW Philippine seagrass beds. The survival of buried seeds was assessed experimentally since such a capacity is a prerequisite for the formation of seed bank. We found a rapid germination of non-dormant seeds and development into seedlings. Such seedlings could not survive under buried conditions (5 and 10 cm) for longer than a week.
- Structural analysis of carrageenan from farmed varieties of Philippine seaweedAguilan, J. T.; Broom, J. E.; Hemmingson, J. A.; Dayrit, F. M.; Montaño, M. N. E.; Dancel, M. C. A.; Niñonuevo, M. R.; Furneaux, R. H. (Walter de Gruyter GmbH, 2003-01-10)Kappaphycus alvarezii, Eucheuma denticulatum and, more recently, Kappaphycus sp. ‘Sacol’ variety, are the carrageenan-containing red seaweeds currently farmed in the Philippines. The Kappaphycus sp. ‘Sacol’ variety is of particular interest to the Philippine seaweed industry because of its improved resistance to ‘ice-ice’ disease and its fast growing characteristics. Here we report on the detailed chemical analysis of the carrageenan from this species. The native and alkali-modified carrageenans from Kappaphycus sp. ‘Sacol’ variety were characterized by FT-IR, 1H and 13C NMR spectroscopy, and constituent sugar and methylation analyses and were compared to those from K. alvarezii, K. cottonii and Eucheuma denticulatum. The three Kappaphycus species contained predominantly κ-carrageenan with low levels of ι-carrageenan, methylated carrageenan and μ-precursor residues, while Eucheuma denticulatum contained predominantly ι-carrageenan with significant amounts of ν-precursor residues. Taxonomic classification of Kappaphycus species based on morphology has proved to be difficult because of their known plasticity. Molecular analysis using the rbcL sequence revealed that the Kappaphycus sp. ‘Sacol’ variety is most likely a form of K. cottonii.
- Population genetic structure of the milkfish, Chanos chanos , based on PCR-RFLP analysis of the mitochondrial control region.Ravago-Gotanco, Rachel G.; Juinio-Meñez, Ma. Antonette (Springer, 2003-06-24)The milkfish, Chanos chanos (Forsskål, 1775) is a pelagic, monotypic gonorhynchiform widely distributed in the tropical Indo-Pacific. This study evaluates temporal variability of milkfish samples from the Philippine archipelago, and spatial variability at two geographic scales based on restriction fragment length polymorphism (RFLP) analysis of a portion of the mitochondrial control region. High levels of genetic diversity characterize the milkfish control region (mean h=0.908, π=1.59%), with 74 haplotypes detected among the 367 fish analyzed. For temporal analysis of Philippine samples, milkfish were collected over 2 years from three sites (inter-annual variation), and sampled twice within a year during different seasons at four sites (intra-annual variation). No significant temporal variability was detected between or within years. Significant spatial differentiation among the Philippine samples was observed (F ST=0.006, P<0.05), with two northeastern samples, Claveria and Dingalan, found to be genetically distinct. However, an hierarchical analysis of molecular variance (AMOVA), where samples were grouped into four geographic regions, revealed very low levels of genetic partitioning, with less than 1% of the total variation attributed to between-region differences, and lack of genetic structure. Nonetheless, the existence of putative northeastern Philippine populations is not discounted. Strong genetic structure across broad geographical scales was revealed by AMOVA, with 11% of the molecular variance based on haplotype frequencies allocated between three distinct groups: Indian Ocean, west Pacific (Philippines) and north central Pacific (Hawaii) The broad-scale genetic structure points to limited gene flow among disjunct Indo-Pacific populations.
- Survivorship of coral juveniles in a fish farm environmentVillanueva, Ronald D.; Yap, Helen T.; Montaño, Marco Nemesio E. (Elsevier, 2005-01)Intensive fish farming is an emerging coastal activity that can potentially enhance sedimentation and promote eutrophication in fringing coral reefs. Here, we investigate the effect of fish farm effluent on the juvenile survivorship of the reef-building coral Seriatopora caliendrum. One-month old juvenile corals (on terracotta tiles) were deployed in fish farm and reference (reef) sites in Bolinao, the Philippines at a depth of 2 m. After forty days, no survivor was recovered in the fish farm, while survivorship was low (11%) in the reference site, with the survivors’ growth rate at 3.3 polyps mo−1 or 1.3 mm2 mo−1. The fish farm deployed tiles were covered with muddy sediment and were colonized by barnacles, whereas those in the reference site were overgrown by a short stand of filamentous macroalgae. Environmental monitoring revealed higher nutrient levels (ammonia and phosphate), sedimentation rate, and organic matter flux, as well as diminished water transparency and dissolved oxygen levels in the fish farm compared to the reference site. Hence, intensive fish farming offers a suite of physical, chemical and biological modifications of the coastal marine environment which have a detrimental effect on the survivorship of coral juveniles.