UPV Digital RepositoryUPV-DRUniversity of the Philippines Visayas
 

Undergraduate Special Problem

Permanent URI for this collectionhttps://hdl.handle.net/20.500.14583/30

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Start date: 2010Keyword: search.filters.keyword.Salinity

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    Species composition and distribution of mangrove soil fungi from Iloilo River, Iloilo City, Philippines
    Almoros, Peter Paul C. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2018-06)
    Fungi are very diverse and ubiquitous microorganisms. Fungal diversity is an important aspect of the ecosystem that needs to be studied. There have been many studies regarding biodiversity of fungi in terrestrial, marine and riverine environments, but studies regarding fungi found in mangrove soil still needs to be done. This study focused on determining the species composition, distribution and ecology of mangrove soil fungi in the Iloilo River, Iloilo City. Soil fungi were sampled from three areas in the river representing the downstream, midstream and upstream areas. Fungal isolates were identified based on morphological characteristics- cultural and microscopic features. There were 10 identified fungal species -Aspergillus cf. flavus, Aspergillus cf. niger, Aspergillus cf. ustus, Aspergillus cf. versicolor, Aspergillus sp. (1), Aspergillus sp. (2) and Aspergillus sp. (3), Geotrichum cf. candidum, Penicillium cf. citrinum and Penicillium sp. (1), while there were 2 unidentified species. Three of these species were very frequent across the sites -Aspergillus cf. flavus, Geotrichum cf. candidum and Penicillium cf. citrinum.
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    Salinity tolerance of the angelwing clam, Pholas orientalis larvae
    Aguaras, Lovie Grace P. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2011-03)
    Pholas orientalis, locally known as “diwal” is one of the commercially important bivalves in the Philippines due to its delicate and sweet taste. An experiment was conducted to determine the salinity tolerance of the 24-hour-old larvae of this clam when reared in different salinity levels of 25, 30, 35, and 40 ppt. The experiment lasted for 15 days at a rearing temperature of 25° C - 27° C. Determination of survival rates and water change were done twice every week. The data gathered were then analyzed using one-way ANOVA. Results showed that survival rates were significantly high at salinities of 30-35 ppt and were significantly low at salinity levels of 25 and 40 ppt. It was also observed that there was an increasing trend of mortality with prolonged exposure to different salinity levels. This could be attributed to the limited osmoregulatory capabilities of the larvae. When reared at low salinity levels, larvae were faced with the danger of too much water entry which eventually led to death. Meanwhile, when reared at high salinity levels, the larvae died due to outward movement of water which resulted to dehydration. Information on the salinity levels that could be tolerated by diwal larvae will be an important factor in the development of larval rearing techniques for successful hatchery operations. The juveniles or seeds produced in the hatchery could be used to restock the depleted resources in the wild.
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    Effects of pH and salinity on growth and survival of juvenile sea cucumber Holothuria scabra (Jaeger, 1833)
    Abagat, Christian M. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2012-03)
    Sea cucumber aquaculture could provide a solution to both enhance declining wild sea cucumber populations through restocking and provide sufficient beche-de-mer product to satisfy the increasing Asian market demand. The growth and survival of hatchery-reared Holothuria scabra juveniles at different pH-salinity levels were investigated. Juveniles were exposed for 14 days in six pH-salinity levels: Trt 1 (pH 6.5 — 6.7, 26-28 %o), Trt 2 (pH 6.5 - 6.7, normal salinity), Trt 3 (pH 7.0 - 7.2, 26-28 %o), Trt 4 (pH 7.0 — 7.2, normal salinity), Trt 5 (normal pH, 26-28 %o) and Trt 6 (normal pH, normal salinity) as the control. Multivariate analysis of variance (MANOVA) with repeated measurements revealed that pH and salinity had a significant effect on growth (length, width, and weight) and survival of H. scabra juveniles. Slight seawater desalination combined with high acidification (pH: 6.5-6.7) had lethal effects on H. scabra juveniles. While H. scabra juveniles could be reared in seawater with pH ≥ 7.0- 7.2 and salinity ≥ 26-28 %o, ambient seawater conditions remained the most suitable in rearing H. scabra juveniles for optimum growth and survival.