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    Community structure, biomass productivity and carbon stock assessment of mangroves in Barangay Tabon, Batan Bay, Aklan
    Bermeo, Ma. Ramela Angela C. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2013-04)
    The study aimed to assess the community structure, biomass productivity, and carbon stock assessment of mangroves in Barangay Tabon, Batan Bay, Aklan using the plot method. Specifically, it aimed to: 1. determine selected physical and chemical factors such as water salinity, water pH, soil temperature and characterization of soil substrates, 2. identify true mangrove species present in the area, 3. describe the community structure in terms of Stand Basal Area, Stems per Hectare, Relative Density, Relative Frequency, Relative Dominance, Importance Value, Shannon-Index of Diversity, Zonation Pattern, Seedling and Sapling Density, 4. assess the biomass productivity (both wood biomass, and litter fall), 5. estimate the amount of carbon stored in the mangrove forest (using allometric equation). A total of twenty-one true mangrove species belonging to 12 families were identified. Family Rhizophoraceae was the most represented with five species namely Bruguiera cylindrica, Ceriops decandra, Rhizophora apiculata, R. mucronata, and R. stylosa. The rest were also well represented namely Family Avicenniaceae- Avicennia alba, A. officinalis, A. marina, and A. rumphiana; Family Combretaceae- Lumnitzera littorea and Limnutzera racemosa; Family Sonneratiaceae- Sonneratia alba, and Sonneratia caseolaris; Family Acanthaceae- Acanthus ebracteatus; Family Bombacaceae- Camptostemon philippinensis; Family Euphorbiaceae- Excoecaria agallocha; Family Meliaceae- Xylocarpus moluccensis; Family Myrsinaceae- Aegiceras corniculatum; Family Myrtaceae- Osbornia octodonta; Family Arecaceae- Nypa fruticans; Family Rubiaceae- Scyphiphora hydrophyllacea. Basal area ranged from 0.11m2/ha for Ceriops decandra to 68.78m2/ha for Sonneratia alba. Avicennia marina had the highest stems per hectare with 22,600 stems/ha, while Bruguiera cylindrica had the lowest with 100 stems/ha. Avicennia marina occurred in all plots with 137 trees/ha and had the highest relative density of 38.38% and relative frequency of 38.42%. Sonneratia alba had the highest relative dominance of 48.49% while the lowest was Ceriops decandra with 0.08%. Avicennia alba, Bruguiera cylindrica, and Ceriops decandra had the lowest relative densities and frequencies at 0.3%. The most important species was Avicennia marina (107.6) and the least important species was Ceriops decandra (0.68). The area was considered to be diverse at 0.7206. On per transect basis, the highest index of diversity recorded was in Transect 2, while the lowest was in Transect 1. Avicennia and Sonneratia species occured both in the low intertidal zone (seaward) and mid-intertidal zone (transitional zone). Rhizophora, Nypa, Camptostemon, Osbornia, Lumnitzera, Bruguiera, Ceriops, Exoecaria, and Aegiceras were found in the mid-intertidal zone (transitional zone). Xylocarpus, Scyphiphora, and Acanthus occurred in high intertidal zone (landward). Avicennia rumphiana had the highest seedlings density of 1001 seedlings/ha, whereas Rhizophora mucronata had the highest saplings density of 96 saplings/ha. The lowest seedling and sapling density was Rhizophora apiculata (Iseedling/ha) and Camptostemon philippinensis (lsapling/ha) respectively. The species with the highest computed biomass of 1,287.78 tons/ha and carbon stock of 579.5 tons/ha was Sonneratia alba. The lowest was Ceriops decandra with biomass of 0.06 tons/ha and carbon stock of 0.03 tons/ha. A total of 2,080 tons/ha biomass and 936.34 tons/ha carbon stock was determined. Based on the litter fall, Transect 2 has the highest leaf fall weighing 580.4g. Litter weight was highest in January 2013 and lowest in December 2012 in all sampling sites.
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    Ingestion rate of Charybdis feriatus zoea on Brachionus and Artemia nauplii
    Abarca, Jinky G. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2003-04)
    A study was conducted to determine if presence of Brachionus will affect ingestion of Charybdis feriatus larvae on the Artemia and to find out the rate of ingestion with increasing density of Artemia. The experiment was conducted using 10-ml capacity vials filled with 6 ml of seawater (26-30 ppt). Increasing densities of Artemia were prepared (0.5, 2.5, 5.0, 10.0, and 20 ind/ml). In one set-up, Brachionus (15 ind/ml) was added. In another set, Brachionus was absent. Another set-up for Artemia with and without Brachionus was prepared but without Charybdis feriatus larvae which served as the control. There were five replicates per treatment. The amount of food prey (Brachionus and Artemia) ingested is determined after 24 hours of feeding on the first day of every zoeal stage (Zl, Z2, Z3, Z4, and Z5). The number of prey ingested by the crab larvae was then calculated. The prey organisms left in containers were then examined under the microscope for missing body parts. The results showed a trend of increasing ingestion rate with increasing Artemia density. This is observed both in treatments with and without Brachionus. The ingestion rate of C. feriatus larvae on the rotifer Brachionus plicatilis showed no trend. However, in zoea 1, there was a trend of increasing ingestion on Brachionus as the feeding density increases. And in zoea 5, it was seen that there is decreasing ingestion on Brachionus as the feeding density increases. There is a trend of increasing ingestion rate on Artemia nauplii as the Charybdis feriatus larvae grow from zoea 1 to zoea 5. There is also a trend of increasing number of observed Artemia with missing body parts as the Charybdis feriatus larvae grow from zoea 1 to number of zoea 5. In addition, there is an increasing number of observed Artemia naupliii with body parts partially ingested as feeding density increases. The presence or absence of Brachionus shows no significant effect on the ingestion on Artemia at low feeding densities (0.5, 2.5, 5 and 10 ind/ml) in all zoeal stages. However, at high feeding densities (20 ind/ml) the ingestion on Artemia is significantly different as seen is zoeal stage 1, 3 and 4.