Undergraduate Special Problem
Permanent URI for this collectionhttps://hdl.handle.net/20.500.14583/30
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Item Temporal variation in the subtidal macroinfaunal composition of a NaGISA seagrass bed in southern Guimaras, Philippines between 2015 and 2016Bacabac, Earl Jeroh I. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2019-06)Seagrass meadows are amongst the most abundant and diverse ecosystems when it comes to biodiversity but due to stress induced by natural and anthropogenic factors, a worldwide decline threatens the vital ecological functions of these habitats. Studying the infauna provides clues and information about the complexity of seagrass ecosystems and provides information that would facilitate better seagrass area management and associated conservation efforts. The NaGISA sampling protocol was conducted in Calaparan seagrass bed in TINMAR, Guimaras, Philippines between Sept. 2015 and 2016. Overall macrofaunal density was recorded at 21,954.80 ± 36,109.62 ind.m'2 with macrofaunal density higher in 2015 than in 2016 albeit, insignificant except for capitellid polychaetes. Community structure analysis also found similarity in dominance patterns in the subtidal zone with other soft-bottom macrofaunal studies in the Philippines with polychaetes, nematodes, and crustaceans as the respective dominant macrofaunal groups observed. Dominant polychaete families were also found to be cosmopolitan and opportunistic. Granulometric analysis characterized the sediment as pebble to medium sand with mid phi values ranging from -3.69 to 1.10 but poor sorting in all sampling points was observed. Cymodoceaceans dominated the subtidal zone in both years (Halodule pinnifolia in 2015; Cymodocea rotundata in 2016). Correlation analysis showed macrofaunal densities to have a significantly strong negative relationship with sorting index and percent gravel while a strong positive relationship with percent seagrass cover. The poor sediment sorting, coarse sediment character, and seagrass cover were the primary factors influencing the observed decrease in macrofaunal density but the decrease is considered normal for the variability of macrofauna in the area. A clearer picture of macrofaunal interactions would be provided with comparison to intertidal macrofauna of the area in the sampling years and data on additional factors that were not measured in the study.Item Composition of abundance of meiofaunal assemblages found in Banate Bay during NE monsoon and early summerArrivas, Johny Kevin B. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2015-05)The study was conducted in Banate Bay, Philippines to describe the composition and abundance of the meiofaunal assemblage in the area. Field sampling was done during December 2012 and March 2013. A total of 41 taxa were identified, dominated by nematodes followed by harpacticoid copepods. The overall mean density of meiofauna in the shallow waters of Banate bay was 28.8 ind.cm'2. The high meiofaunal density recorded in the present study was due to sediment granulometry, water depth and percent organic matter. Macrofauna: meiofauna ratio was also high due to sparse number of macrofauna observed and the physical disturbances associated with seasonal rainfall. The highest density was recorded in March 2013 and the lowest was recorded in December 2012, albeit no significant difference. The temporal distribution of meiofauna was positively correlated with salinity (R = 0.59). Seasonal rainfall also influenced the meiofaunal abundance by affecting turbidity and salinity as well as causing physical disturbances (e.g., storm). Spatial distribution of meiofauna between the stations was influenced by salinity rather than the sediment granulometry, organic matter and turbidity.