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Challenge 02: Protect and restore ecosystems and biodiversity

Permanent URI for this collectionhttps://repository.unesco.gov.ph/handle/123456789/21

Ocean Decade


Challenge 02:
Protect and restore ecosystems and biodiversity



Understand the effects of multiple stressors on ocean ecosystems, and develop solutions to monitor, protect, manage and restore ecosystems and their biodiversity under changing environmental, social and climate conditions.

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Now showing 1 - 10 of 132
  • Juvenile scleractinian assemblage and its association with adults and benthos at shallow and upper mesophotic depths in fringing and atoll reefs in the Philippines
    Albelda, Ritzelle L.; Cabaitan, Patrick C.; Sinniger, Frederic P.; Dumalagan, Edwin Jr; Quimpo, Timothy Joseph R.; Olavides, Ronald Dionnie D.; Munar, Jeffrey C.; Villanoy, Cesar L.; Siringan, Fernando (Elsevier B.V, 2020-10-15)
    The juvenile stage is a critical part of a scleractinian’s life history as it is when they are highly vulnerable to various post-settlement mortality processes, which influence the structure of adult scleractinian assemblages. Although numerous studies have been done to understand dynamics of juvenile assemblages at shallow water reefs (SWRs), similar studies on deeper and less explored reefs, such as mesophotic coral ecosystems (MCEs) remain limited. Using diver-based photo-quadrat method, we aimed to examine how juvenile scleractinian assemblages vary from SWRs (shallow: 3 to 10 m and middle: 10 to 20 m) to upper MCEs (deep: 30 to 40 m) in the fringing and atoll reefs in the Apo Reef Natural Park, Philippines. We also aimed to understand the potential association of juvenile scleractinian densities with adult scleractinian densities and benthic cover. A total of 12 families were recorded for both juveniles and adults with Poritidae being the most abundant, followed by Pocilloporidae and Acroporidae (and Merulinidae for juveniles only). Juvenile densities (ranging from 14 to 36 individuals/m2) varied among depth zone and reef type interactions and had a bimodal distribution, with the middle zone having the lowest density compared to the shallow and deep zones. Juvenile densities were correlated to benthic cover, particularly to high algal cover in the middle zone and availability of bare hard substrate in the shallow zone. Adult densities were also correlated with juvenile densities, but not commonly in the middle zone, emphasizing that it is only one of the many variables that contribute to juvenile assemblages. This study is the first to document juvenile scleractinian assemblages, how they vary from SWRs to MCEs in the Philippines and the Coral Triangle, and demonstrates the importance of benthos and adult brood stock in shaping juvenile scleractinian assemblages across depth zones.
  • Fish farm effluents alter reef benthic assemblages and reduce coral settlement
    Quimpo, Timothy Joseph R.; Ligson, Charlon A.; Manogan, Dana P.; Requilme, Jeremiah Noelle; Albelda, Ritzelle L.; Conaco, Cecilia; Cabaitan, Patrick C. (Elsevier Ltd., 2020)
    Fish farming in coastal areas is a rapidly growing industry. However, unregulated fish farming practices that release massive amounts of unconsumed feed and fecal material into the water column, can result in a nutrient enriched environment that extends to nearby reef systems. To understand the impact of fish farm effluent on coral settlement, we tested the settlement rate of Pocillopora acuta larvae on artificial substrates conditioned for 12 weeks at three sites with increasing distance (2–10 km) from fish farms in Bolinao, Philippines. Sites far from the fish farms had higher biofilm and crustose coralline algae cover. In contrast, the site closest to the fish farms, where nutrient levels were higher, had greater sediment and turf algae cover. Tiles conditioned at the farther sites promoted higher (6–8%) larval settlement whereas tiles from the nearer site had lower settlement (3%). These findings show that fish farm effluents can indirectly affect coral settlement on adjacent reefs by promoting growth of other biota that may inhibit larval settlement and by reducing the availability of suitable substrate.
  • Feeding ecology and trophic role of sea urchins in a tropical seagrass community
    Klumpp, David W.; Salita-Espinosa, J. T.; Fortes, M. D. (Elsevier BV, 1993-04)
    The grazing impact of urchins on seagrass and algal resources, and the relative importance of this to the lower-level trophic flux of a tropical seagrass community were investigated. Thalassia hemprichii (Ehrenb.) Aschers. accounted for 80–93% of seagrass frond biomass at Bolinao in the Philippines. Growth rate of seagrass was 6.6 mm per shoot day−1, or 2.3 mg AFDW per shoot day−1. Production of seagrass fronds per unit area of seagrass bed varied with location from 870 to 1850 mg AFDW m−2 day−1. Urchin density ranged from 0.9 to 4.2 m−2, with Tripneustes gratilla (L.) and Salmacis sphaeroides (L.) being the most common species. Tripneustes gratilla fed mostly on attached seagrass fronds (77–89% of diet), especially Thalassia hemprichii, whereas S. sphaeroides was a generalist, consuming Thalassia hemprichii fronds (13–65%), detached seagrass debris (5–39%), the red alga Amphiroa fragilissima (L.) Lamour. (0–30%), algal-coated sediment and rubble (0–51%) in proportions that varied with the availability of preferred food types. Live Thalassia hemprichii fronds were clearly preferred over macroalgae or dead seagrass fronds by Tripneustes gratilla, but S. sphaeroides consumed all three food types without preference. Both urchins avoided the common brown alga, Sargassum crassifolium J. Agardh. Urchins absorbed 73–76% of organic matter in seagrass fronds with epiphytes (75% of DW), and 55% of that in epiphyte-free fronds. Seagrass debris and the macroalgae A. fragilissima were of lower food quality as they were lower in organic matter, and this matter was absorbed less efficiently by urchins. Rates of ingestion (IR in g WW per urchin day−1) were proportional to body weight (W in g WW) according to the functions: IR = 0.56W0.34 (T. gratilla) and IR = 0.17W0.53 (Salmacis sphaeroides). Predicted grazing impact of urchins on seagrass resources varied spatially and temporally. Estimated annual grazing rate at the main study site was 158 g AFDW m−2, equivalent to 24% of annual seagrass production, but owing to large changes in urchin population structure and density, grazing impact is expected to vary from < 5% to > 100% at different times of year. A synthesis of knowledge on the lower-level trophic pathways in this system indicates that seagrass-urchin and periphyton-epifauna grazing interactions are both important in their contribution to overall trophic flux.
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    Trends in growth and mortality of three coral species (Anthozoa: Scleractinia), including effects of transplantation
    Yap, H. T.; Alino, P. M.; Gomez, E. D. (Inter-Research Science Center, 1992)
    Three ecologically dominant coral species in a northern Philippine reef were compared in terms of growth and mortality and responses to transplantation. The purpose of this study was to examine the feasibility of using the species concerned in establishing new coral populations through deliberate fragmentation. The species, Acropora hyacinthus, Pocillopora damicornis and Pavona frondifera, displayed distinct differences which could be related to their respective life-history strategies. A. hyacinthus showed tendencies towards an r-mode, with rapid linear growth but also high mortality rates. Response to transplantation was poor. Pocillopora damicornis had intermediate linear growth rates and relatively high mortality. Transplants fared poorly in the initial part of the experiment though they showed successful adaptation after a year. Mortality rates of both A. hyacinthus and P. damicornis were increased by high temperatures during certain times of the year. Pavona frondifera had the highest linear growth rates and no mortality, tending towards a K-mode of life history strategy. It showed the best response to transplantation This species is thus a suitable candidate for large-scale reef restoration.
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    Detection of horizontal gene transfer in the genome of the choanoflagellate Salpingoeca rosetta
    Matriano, Danielle M.; Alegado, Rosanna A.; Conaco, Cecilia (Springer, 2021-03-16)
    Horizontal gene transfer (HGT), the movement of heritable materials between distantly related organisms, is crucial in eukaryotic evolution. However, the scale of HGT in choanoflagellates, the closest unicellular relatives of metazoans, and its possible roles in the evolution of animal multicellularity remains unexplored. We identified at least 175 candidate HGTs in the genome of the colonial choanoflagellate Salpingoeca rosetta using sequence-based tests. The majority of these were orthologous to genes in bacterial and microalgal lineages, yet displayed genomic features consistent with the rest of the S. rosetta genome—evidence of ancient acquisition events. Putative functions include enzymes involved in amino acid and carbohydrate metabolism, cell signaling, and the synthesis of extracellular matrix components. Functions of candidate HGTs may have contributed to the ability of choanoflagellates to assimilate novel metabolites, thereby supporting adaptation, survival in diverse ecological niches, and response to external cues that are possibly critical in the evolution of multicellularity in choanoflagellates.
    We thank Joshua Dizon and Francis Tablizo of the Philippine Genome Center Core Facility for Bioinformatics for assistance with scripts and database construction. We thank Becca Lensing (University of Hawai’i), Cheryl Andam (University of New Hampshire), Deo Onda and Ron Leonard Dy (University of the Philippines) for insightful comments and suggestions on the analysis and interpretation of the data. This work was supported by thesis grants from the Department of Science and Technology Accelerated Science and Technology Human Resource Development Program-National Science Consortium (DOST-ASTHRDP-NSC) and the University of the Philippines Marine Science Institute to DM.
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    Sexual reproduction in the soft coral Lobophytum schoedei in Bolinao‐Anda Reef Complex, Pangasinan, northwestern Philippines
    Baran, Christine C.; Baria‐Rodriguez, Maria Vanessa (Wiley, 2021-04-02)
    The characterization of early life-history strategies of soft corals is important in understanding population maintenance, replenishment, and recovery in disturbed coral reefs. This study examined the sexual reproduction of the soft coral Lobophytum schoedei in the Bolinao-Anda Reef Complex (BARC), a degraded reef in northwestern Philippines. Reproductive strategies such as sexuality, sex ratio, fecundity, and reproductive timing were examined. Random colonies of L. schoedei were sampled a few weeks before the predicted time of spawning to assess fecundity (n = 73 colonies), and sexuality and sex ratio (n = 221 colonies). Monthly sampling of tagged colonies of L. schoedei (n = 20) was done over 13 months to determine the reproductive timing through polyp dissection. Peak of annual spawning was inferred based on the presence of large gametes and their absence in the next sampling period. Results showed that L. schoedei is a gonochoric broadcast spawner with 1:1.1 sex ratio. Although oogenesis and spermatogenesis exhibited overlapping cycles, both gametes matured and spawned in April, coinciding with increasing sea surface temperature. Prior to spawning, oocytes and spermaries ranged 300–633 µm and 150–337 µm in diameter, respectively. Mean female fecundity was 6.7 ± 3.9 oocytes per polyp and male fecundity was 39.2 ± 22.5 (±SD) spermaries per polyp. Some of these results, including the low number of oocytes produced by female polyps, may be caused by sexual reproduction in a degraded reef environment. Understanding these reproductive traits may be useful for predicting the resiliency of populations of L. schoedei in response to ongoing and future environmental change.
  • Thecal tabulation, body scale morphology and phylogeny of Heterocapsa philippinensis sp. nov. (Peridiniales, Dinophyceae) from the Philippines
    Benico, Garry; Lum, Wai Mun; Takahashi, Kazuya; Yñiguez, Aletta T.; Iwataki, Mitsunori (Elsevier, 2021-08)
    The thecal tabulation and body scale structure of the marine armoured dinoflagellate Heterocapsa, isolated from Philippines, were examined using LM, SEM and TEM, and its phylogenetic position was inferred from ITS and LSU rDNA sequences. Cells were ovoid and the plate tabulation (Po, cp, X, 5′, 3a, 7′′, 6c, 5s, 5′′′, 2′′′′) was consistent with most Heterocapsa species. The second anterior intercalary plate (2a) had a circular pattern with a thick marginal border free of pores. The nucleus was longitudinally elongated and curved, and located at the dorsal side of the cell. Discoid lobes of brownish chloroplast were peripherally distributed, and a pyrenoid was positioned at the centre. The triradiate body scales, measuring 250–300 nm in diameter, consisted of a roundish basal plate with six radiating ridges, nine peripheral uprights/spines, and three radiating spines. These components were identical to those of H. pseudotriquetra and H. steinii, except for the roundish outline of basal plate. Molecular phylogeny showed that the species clustered with H. pseudotriquetra and H. steinii. This species was differentiated from all other Heterocapsa species in the sausage-shaped nucleus and circular pattern on the 2a plate. This study proposed a novel species Heterocapsa philippinensis sp. nov. for the isolate.