UPV Digital RepositoryUPV-DRUniversity of the Philippines Visayas
 

UPV Theses and Dissertations

Permanent URI for this communityhttps://hdl.handle.net/20.500.14583/10

Browse

Filters

1983 - 198912010 - 20191

Settings

Discipline: search.filters.discipline.FisheriesKeyword: search.filters.keyword.salinity

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Does a coral reef enhance the productivity of its surrounding waters?
    Peñafiel, Christen P. (University of the Philippines Visayas, 2019-06)
    Coral reefs have long been assumed and continually claimed to be origins of very high productivity, but how they attract organisms from and export nutrients to their neighboring waters remains largely unknown. Specifically, this study aimed at determining the space-time dynamics of nutrients and biomass redistribution around Hibotkan Rock Sanctuary (HRS), Banate, Iloilo, a sanctuary reef established by Municipal Fisheries Ordinance No. 12 covering an area of 25 ha. Twelve (12) sampling stations were established for space-time nutrient profiling, phytoplankton count, and supplementary measurements of water parameters, and four (4) stations for fish (biomass) visual survey. Results were analyzed using spatio-temporal plots and the Pearson correlation matrix (5% significant level). Nitrite was observed to be limiting, while nitrate was the most abundant in the waters of HRS. The predominant temporal variations of nutrients followed the flood tide (FT) and ebb tide (ET) cycles. In general, the tidal current direction appeared to control the redistribution of the nutrients (NO3-, NO2-, PO43-, and SiO44-). This study further revealed that stations of high nutrient concentration usually coincided with low levels of dissolved oxygen (DO). Species of fish observed were all indigenous and well-known inhabitants of the coral reefs. Furthermore, no other families of fishes (such as those of commercial value) were caught on record. Overall, there was no clear indication of import or export of living biomass in the HRS area. It can be inferred from the results that the fabled high productivity of coral reefs has no clear scientific basis; consequently, the Marine Protected Areas (MPAs) concept also appears to have no solid foundation.
  • Thumbnail Image
    Item
    The effects of different salinity and organic matter levels on the growth of blue-green algae
    Bantillo, Rosario R. (University of the Philippines Visayas, 1983-03)
    A one-month culture of lab-lab to determine the growth of blue-green algae in three levels of salinity ( 15 ppt = S1, 30 ppt = S2 and 45 ppt S3) and two levels of organic matter (3.4 to 4.4% = OM1 and 6.5 to 7.8% = OM2) was conducted using a twenty-two plastic containers (diameter = 43 cm; height = 49 cm) at the University of the Philippines in the Visayas Brackishwater Aquaculture Center, Leganes, Iloilo. The study utilized a 3 x 2 factorial experiment in completely randomized design with three replicates. Organic matter levels of the soil affected the chemical properties of soil and water (available phosphorus, reactive phosphorus, ammonia-nitrogen and pH). The higher the organic matter level, the higher the pH and the concentrations of ammonia and phosphorus. On the other hand, salinity did not apparently affect the fluctuations in ammonia, phosphorus and pH due to water replenishment to maintain treatment levels of salinity. Earlier rapid growth of blue-green algae commencing on the 3rd to the 15th day was observed at higher organic matter level. While at lower organic matter level, this occurred only on the 18th to the 28th day. Blue-green algae population (units/ml) was observed highest in treatment IV (S1 OM2; 1,262,113) followed by treatments III (S3OM1 761,338); II (S2OM1; 514,788); I (S1 OM1 494,375); V (S2OM2; 413,750); and, the lowest was obtained from treatment VI (S3OM2; 394,275). The relative percentage proportion of blue-green algae in the lab-lab complex showed that it composed 17.7% in treatment IV, 16.86 % in treatment III, 16.64% in treatment II, 15.82% in treatment I, 15.2% in treatment V and 14.9% in treatment VI. These, however, did not significantlyvary among treatments. A low correlation coefficient (r) between the population count and the selected parameters: reactive phosphorus, water pH, soil pH and available phosphorus was obtained while a negative correlation was obtained between the population and ammonia-nitrogen. Significantly higher biomass (ash-free dry weight) of lab-lab was obtained in higher organic matter (OM2) and at 45 ppt salinity (S3). The highest biomass (ash-free dry weight) was obtained in treatment VI (S3OM2; 0.160 g/cm2) while the lowest was obtained in treatment I (S1OM1 0.012 g/cm2). The algal count of lab-lab also showed a significant difference in the organic matter levels but no significant difference on the salinity levels. The highest algal count was obtained in treatment V (S2OM2; 6,773,542 units/ml) and the lowest count was obtained in treatment II (S2 OM1; 2,328,792 units/ml). However, the primary productivity based on O2 production showed a significantly higher production in the lower organic matter and at higher salinity level (30 ppt.). The highest O2 concentration was obtained in treatment III (S3OM1 5.759 ppm) and the lowest was obtained in treatment V (S2 OM2; 4.19 ppm).