Journal Articles - UP - MSI
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- Nutrient limitation of the tropical seagrass Enhalus acoroides (L.) Royle in Cape Bolinao, NW PhilippinesTerrados, Jorge; Agawin, N.; Duarte, Carlos M.; Fortes, Miguel D.; Kamp-Nielsen, L.; Borum, J. (Elsevier BV, 1999-11)Experimental additions of nutrients to the sediment of Enhalus acoroides stands were performed at four sites and three times along the year in Cape Bolinao, NW Philippines to test the hypothesis that seagrass growth in tropical environments is limited by the availability of nutrients. Both the nitrogen content (as % DW) and the nitrogen incorporation of E. acoroides leaves increased after the addition of nutrients. The size (g DW per shoot) and the leaf growth rates (g DW per shoot d−1) of E. acoroides shoots also increased after the addition of nutrients. Nitrogen rather than phosphorus was the nutrient limiting shoot size and leaf growth of E. acoroides in the area. The extent of nutrient limitation of E. acoroides showed high variability both in space and time which cannot be directly linked with differences in light or nutrient availability among the experimental sites.
- Physiological and ecological aspects of coral transplantationYap, H. T.; Alvarez, R. M.; Custodio, H. M.; Dizon, R. M. (Elsevier BV, 1998-10)The growth and mortality of transplants of two species of scleractinian corals, Porites cylindrica Dana and P. rus Forskal (1775), were monitored over 16 months in a reef in the northwestern Philippines. Transplants were in two sizes (nubbin, ∼8 cm in length; and fist-sized, ∼8 cm in diameter) and deployed at two depths (1 and 10 m). Specimens at the shallow depth had more rapid growth than the deeper ones. Light had significant effects on coral growth while temperature, salinity, water motion and sedimentation did not. Smaller corals consistently registered greater percentage increases in size as compared to the larger ones. Small transplants of P. cylindrica showed higher percentage growth rates than those of P. rus. Contrary to expectations, there were no differences in transplant mortality due to size. Over the course of the experiment, mortality was generally confined to the shallow depth. It was brought about either by algal competition or by strong water movement.
- Temporal changes in the abundance, leaf growth and photosynthesis of three co-occurring Philippine seagrassesAgawin, N.; Duarte, C. M.; Fortes, M. D.; Uri, J. S.; Vermaat, J. (Elsevier BV, 2001-06)The analysis of the temporal changes in shoot density, areal leaf biomass, leaf growth and parameters of the photosynthesis–irradiance relationship of three tropical seagrass species (Enhalus acoroides, Thalassia hemprichii and Cymodocea rotundata), co-existing in a shallow subtidal meadow in Cape Bolinao, Philippines, shows that species-specific traits are significant sources of temporal variability, and indicates that these seagrass species respond differently to a common environmental forcing. Species-specific differences are much less important as source of variability of the temporal change in chlorophyll concentration of seagrass leaves. The results indicate that the temporal changes in photosynthetic performance of these seagrasses were driven by environmental forcing and their specific responses to it mostly, but the temporal change in their abundance and leaf growth was also controlled by other factors. The significant contribution of species-specific factors in the temporal changes of biomass, growth and photosynthetic performance of co-occurring seagrass species in Cape Bolinao should contribute to the maintenance of the multispecific, highly productive meadows characteristic of pristine coastal ecosystems in Southeast (SE) Asia.
- Are seagrass growth and survival constrained by the reducing conditions of the sediment?Terrados, J.; Duarte, C. M.; Kamp-Nielsen, L.; Agawin, N.; Gacia, E.; Lacap, D.; Fortes, M. D.; Borum, J.; Lubanski, M.; Greve, T. (Elsevier BV, 1999-11)A literature review of the effects of the reducing conditions of the sediment on seagrass metabolism, growth and survival, and of the morphological and physiological adaptations that seagrasses show to cope with sediment anoxia is presented and major gaps in knowledge are identified. The hypothesis that sediment anoxia controls the survival of seagrasses was tested experimentally by increasing the oxygen demand of the sediment with the addition of sucrose. Experiments were performed in a tropical (Southeast Asia) multispecific seagrass meadow, a Mediterranean Cymodocea nodosa meadow, and a temperate Zostera marina meadow. Sulfide levels in pore water and vertical redox profiles were used to characterise the effects of the sucrose additions on the sediment, while plant responses were quantified through the changes in shoot density and leaf growth. Sulfide levels in pore water increased and sediment redox potential decreased after the addition of sucrose to the sediment of different seagrass meadows. The effect of the addition of sucrose to the sediment of seagrasses was species-specific. Leaf growth was reduced and shoot mortality increased in some of the tropical species (e.g., Thalassia hemprichii), but not in others. Neither mortality nor leaf growth of the Mediterranean species C. nodosa was affected by sucrose additions, and only leaf growth was reduced two months after the addition of sucrose in Z. marina. Our results suggest that increased sediment anoxia might be a factor promoting growth inhibition and mortality in seagrasses, although strong differences have been found among different species and environments.
- Influence of light, water motion, and stocking density on the growth and pigment content of Halymenia durvillei (Rhodophyceae) under laboratory conditionsRula, Najeen Arabelle M.; Ganzon-Fortes, Edna T.; Pante, Ma. Josefa R.; Trono, Gavino C. (Springer, 2021-05-17)The tropical red seaweed Halymenia durvillei Bory de Saint Vincent is a potential source of the high-value pigments, r-phycoerythrin (RPE) and r-phycocyanin (RPC). The unique properties of these pigments find many applications—from food to cosmetics, pharmaceuticals, and biomedical research. This study aimed to improve the land-based culture technology of H. durvillei by determining the appropriate combination of light, water motion, and stocking density that would result in high growth performance and high RPE and RPC content. Combinations of two light levels (full light, 100% and reduced light, 67%), two water motion levels (low and moderate), and three stocking densities (50, 100, and 200 g) were studied using 64.5-L glass tanks with flow-through seawater and aeration systems at the outdoor land-based seaweed nursery in Bolinao, Pangasinan, Philippines. After 6 weeks of culture, growth performance (growth rate and productivity) of H. durvillei and phycobiliprotein content were best under a combination of full light (100%), moderate water motion, and 50-g stocking density. The generally low light regime during the experimental period, which coincided with the cold, dry season characterized by shorter days and overcast skies, may have influenced H. durvillei to maximize the use of available resources such as light and possible increased nutrient availability from water motion to promote growth and phycobiliprotein synthesis. Treatments with low stocking densities generally showed satisfactory growth and phycobiliprotein content. This study provides groundwork for future research into mechanisms by which these and other factors affect the growth and physiology of H. durvillei in culture.
- Summer heatwave impacts on the European kelp Saccharina latissima across its latitudinal distribution gradientDiehl, Nora; Roleda, Michael Y.; Bartsch, Inka; Karsten, Ulf; Bischof, Kai (Frontiers Media SA, 2021-10-11)Kelps are important foundation species in coastal ecosystems currently experiencing pronounced shifts in their distribution patterns caused by ocean warming. While some populations found at species’ warm distribution edges have been recently observed to decline, expansions of some species have been recorded at their cold distribution edges. Reduced population resilience can contribute to kelp habitat loss, hence, understanding intraspecific variations in physiological responses across a species’ latitudinal distribution is crucial for its conservation. To investigate potential local responses of the broadly distributed kelp Saccharina latissima to marine heatwaves in summer, we collected sporophytes from five locations in Europe (Spitsbergen, Bodø, Bergen, Helgoland, Locmariaquer), including populations exposed to the coldest and warmest local temperature regimes. Meristematic tissue from sporophytes was subjected to increasing temperatures of Δ+2, Δ+4 and Δ+6°C above the respective mean summer temperatures (control, Δ±0°C) characteristic for each site. Survival and corresponding physiological and biochemical traits were analyzed. Vitality (optimum quantum yield, Fv/Fm) and growth were monitored over time and biochemical responses were measured at the end of the experiment. Growth was highest in northern and lowest in southern populations. Overall, northern populations from Spitsbergen, Bodø and Bergen were largely unaffected by increasing summer temperatures up to Δ+6°C. Conversely, sporophytes from Helgoland and Locmariaquer were markedly stressed at Δ+6°C: occurrence of tissue necrosis, reduced Fv/Fm, and a significantly elevated de-epoxidation state of the xanthophyll cycle (DPS). The variations in phlorotannins, mannitol and tissue C and N contents were independent of temperature treatments and latitudinal distribution pattern. Pronounced site-specific variability in response to increasing temperatures implies that exceeding a threshold above the mean summer temperature exclusively affect rear-edge (southernmost) populations.Abiotic temperature data used in this manuscript were produced with the Giovanni online data system, developed and maintained by the NASA GES DISC. Sampling in France was conducted in accordance with the French legislation on the Access to Genetic Resources and Benefit-Sharing. We also acknowledge the MODIS mission scientists and associated NASA personnel for the production of the data used in this research effort. This study has been conducted at the Alfred Wegener Institute for Polar and Marine Research (AWI), Bremerhaven and at the AWIPEV Research Station in Ny-Ålesund, Svalbard. We are grateful to the station staff of AWIPEV for support and logistics and to the scientific diving teams on Spitsbergen and Helgoland for sampling. We thank A. Wagner (AWI) for sampling support on Helgoland and his support in the setting up of the experiments, and also J. Müller (University of Rostock) for running the C:N analyzer. B. Meyer-Schlosser (University of Bremen) supported sampling and pigment analyses.
- Latitudinal variation in growth and survival of juvenile corals in the West and South PacificNozawa, Yoko; Villanueva, Ronald D.; Munasik, Munasik; Roeroe, Kakaskasen Andreas; Mezaki, Takuma; Kawai, Takashi; Guest, James; Arakaki, Seiji; Suzuki, Go; Tanangonan, Jean J. B.; Ang, Put O.; Edmunds, Peter J. (Springer, 2021-08-18)Reef-building corals are found across > 30° of latitude from tropical to temperate regions, where they occupy habitats greatly differing in seawater temperature and light regimes. It remains largely unknown, however, how the demography of corals differs across this gradient of environmental conditions. Variation in coral growth is especially important to coral populations, because aspects of coral demography are dependent on colony size, with both fecundity and survivorship increasing with larger colonies. Here we tested for latitudinal variation in annual growth rate and survival of juvenile corals, using 11 study locations extending from 17° S to 33° N in the West and South Pacific. Regression analyses revealed a significant decline in annual growth rates with increasing latitude, whereas no significant latitudinal pattern was detected in annual survival. Seawater temperature showed a significant and positive association with annual growth rates. Growth rates varied among the four common genera, allowing them to be ranked Acropora > Pocillopora > Porites > Dipsastraea. Acropora and Pocillopora showed more variation in growth rates across latitudes than Porites and Dipsastraea. Although the present data have limitations with regard to difference in depths, survey periods, and replication among locations, they provide evidence that a higher capacity for growth of individual colonies may facilitate population growth, and hence population recovery following disturbances, at lower latitudes. These trends are likely to be best developed in Acropora and Pocillopora, which have high rates of colony growth.We appreciate volunteers, students, and assistants for data collection. Y.N. especially thank H.-S. Hsieh and C.-H. Liu for data measurement, and V. Denis for his comments on the manuscript. Comments from two anonymous reviewers improve our manuscript greatly. The study was funded by the thematic research grant of Academia Sinica (23-2g) and an internal research grant of Biodiversity Research Center, Academia Sinica to Y.N. The Okinawa survey was partly supported by the Japan Society for the Promotion of Science through NEXT Program #GR083. Temperature data for the Okinawa site were provided by the coral reef survey of Monitoring Sites 1000 Project, operated by the Ministry of the Environment, Japan. Temperature data for Moorea were provided by the Moorea Coral Reef LTER, funded by the US National Science Foundation (OCE-0417412).
- Transcriptome analysis of growth variation in early juvenile stage sandfish Holothuria scabraOrdoñez, June Feliciano F.; Galindez, Gihanna Gaye S.T.; Gulay, Karina Therese; Ravago-Gotanco, Rachel (Elsevier, 2021-12)The sandfish Holothuria scabra is a high-value tropical sea cucumber species representing a major mariculture prospect across the Indo-Pacific. Advancements in culture technology, rearing, and processing present options for augmenting capture production, stock restoration, and sustainable livelihood activities from hatchery-produced sandfish. Further improvements in mariculture production may be gained from the application of genomic technologies to improve performance traits such as growth. In this study, we performed de novo transcriptome assembly and characterization of fast- and slow-growing juvenile H. scabra from three Philippine populations. Analyses revealed 66 unigenes that were consistently differentially regulated in fast-growing sandfish and found to be associated with immune response and metabolism. Further, we identified microsatellite and single nucleotide polymorphism markers potentially associated with fast growth. These findings provide insight on potential genomic determinants underlying growth regulation in early juvenile sandfish which will be useful for further functional studies.The authors are grateful to the following individuals and institutions for providing samples and facilitating their collection: D. Ticao of (Finfish Hatcheries, Inc.); Dr. M.A. Juinio-Menez, ˜ J.R. Gorospe, C. Edullantes, B. Rodriguez, A. Rioja, T. Catbagan, and G. Peralta of Bolinao Marine Laboratory, University of the Philippines Marine Science Institute; and E. Tech (Palawan Aquaculture Corp.).
- Age, growth, and population structure of Conomurex luhunuasSanchez-Escalona, Katherine; Aliño, Porfirio (National Fisheries Research and Development Institute, 2022-12)Age and growth dynamics of Conomurex luhuanus were investigated to determine the population structure. Age-specific change in shell shape determined with geometric morphometrics revealed discrimination of shape between 0-3 years old at 99–100% while 3–4 years old can be separated with 81% certainty. Using the age discrimination data, K and L∞ were estimated at 1.00 year and 7.28 cm, respectively. Recruitment is bimodal with natural mortality (M) of 0.71 and fishing mortality (F) approximated at 3.92 year. The exploitation rate (E) is 0.85 year, indicating probable overharvesting of the population under study. The presence of a deep-water population, age-specific burying behavior, and bimodal recruitment pattern are possible resilience factors.The study was supported by a grant from PCAARRD-DOST.
- Increased coral larval supply enhances recruitment for coral and fish habitat restorationHarrison, Peter L.; dela Cruz, Dexter W.; Cameron, Kerry A.; Cabaitan, Patrick C. (Frontiers Media SA, 2021-12-01)Loss of foundation reef-corals is eroding the viability of reef communities and ecosystem function in many regions globally. Coral populations are naturally resilient but when breeding corals decline, larval supply becomes limiting and natural recruitment is insufficient for maintaining or restoring depleted populations. Passive management approaches are important but in some regions they are proving inadequate for protecting reefs, therefore active additional intervention and effective coral restoration techniques are needed. Coral spawning events produce trillions of embryos that can be used for mass larval rearing and settlement on degraded but recoverable reef areas. We supplied 4.6 million Acropora tenuis larvae contained in fine mesh enclosures in situ on three degraded reef plots in the northwestern Philippines during a five day settlement period to initiate restoration. Initial mean larval settlement was very high (210.2 ± 86.4 spat per tile) on natural coral skeleton settlement tiles in the larval-enhanced plots, whereas no larvae settled on tiles in control plots. High mortality occurred during early post-settlement life stages as expected, however, juvenile coral survivorship stabilised once colonies had grown into visible-sized recruits on the reef by 10 months. Most recruits survived and grew rapidly, resulting in significantly increased rates of coral recruitment and density in larval-enhanced plots. After two years growth, mean colony size reached 11.1 ± 0.61 cm mean diameter, and colonies larger than 13 cm mean diameter were gravid and spawned, the fastest growth to reproductive size recorded for broadcast spawning corals. After three years, mean colony size reached 17 ± 1.7 cm mean diameter, with a mean density of 5.7 ± 1.25 colonies per m–2, and most colonies were sexually reproductive. Coral cover increased significantly in larval plots compared with control plots, primarily from A. tenuis recruitment and growth. Total production cost for each of the 220 colonies within the restored breeding population after three years was United States $17.80 per colony. A small but significant increase in fish abundance occurred in larval plots in 2018, with higher abundance of pomacentrids and corallivore chaetodontids coinciding with growth of A. tenuis colonies. In addition, innovative techniques for capturing coral spawn slicks and larval culture in pools in situ were successfully developed that can be scaled-up for mass production of larvae on reefs in future. These results confirm that enhancing larval supply significantly increases settlement and coral recruitment on reefs, enabling rapid re-establishment of breeding coral populations and enhancing fish abundance, even on degraded reef areas.We thank the Australian Centre for International Agricultural Research (ACIAR) for funding this research: grant ACIAR/FIS/2014/063 to PH, PC and J. Bennett. Thanks to ACIAR staff Chris Barlow, Ann Fleming, and Mai Alagcan for their ongoing support. Sincere thanks to the Galsim Family for use of Tanduyong Island as a field research base during the coral restoration fieldwork. We also thank staff and students at the Bolinao Marine Laboratory, Marine Science Institute, University of the Philippines, Diliman for their assistance with reef work: Elizabeth Gomez, Charlon Ligson, Rickdane Gomez and Fernando Castrence (including fish surveys), Marcos Ponce, Joey Cabasan, Sheldon Boco, Gabriel de Guzman, Albert Ponce, and Allan Abuan. We also thank Grant Cameron for field support and helping design, build and refine the prototype floating spawn catcher frames in 2016 and 2017.