UPV Theses and Dissertations
Permanent URI for this communityhttps://hdl.handle.net/20.500.14583/10
Browse
2 results
Search Results
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 Fungal pathogen associated with Rhizophora stylosa: A comparative study between oiled and unoiled sites within Taklong Island National Marine Reserve (TINMAR), Nueva Valencia, GuimarasBalanga-an, Kristoffer (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2009-03)Mangroves, refer to an assemblage of trees and shrubs that inhabit the coastal intertidal zone in tropical and subtropical regions. They help in the soil formation, protection, and stabilization of our coastal environment as well as serve as shelter and breeding grounds for some of our marine organisms. A mangrove habitat represents the borderline between land and sea and is considered as one of the principal places where spilled oil and associated impacts converge. Oil spill threaten mangroves by predisposing the plants to fungal attacks thereby reducing their resistance to stress and diseases. Studies also show that certain fungi species are able to utilize oil in contaminated mangrove species. This study generally aims to compare the fungal population found on the diseased leaves of Rhizophora stylosa between oiled and unoiled sites in the Taklong Island National Marine Reserve (TINMAR). It also aims to isolate, characterize and identify fungi present in diseased leaves of Rhizophora stylosa using potato dextrose agar (PDA) culture media and determine their frequency of occurrence. Leaf samples were collected from two sites in TINMAR, one of which was contaminated by oil and the other one was not. Three trees were selected to represent each of the two sampling sites (oiled and unoiled), and to each of the selected trees, three diseased leaves were collected. The results of this study showed the dominance of some species of fungi namely, Aspergillus (40%), Penicillium (20%), Cladosporium (13.33%), Monilia (6.67%), Mycelia (6.67%), Humicola (6.67%), and Pestalotiopsis (6.67%). Five out of these seven genera were isolated from the unoiled site while six of these were isolated from the oiled site. Generally, the fungal population was observed to be greater in the oiled site than in the unoiled. This preliminary data indicate that R. stylosa might still be undergoing stress due to the remaining components of the spilled oil in the area. However, this can only be resolved by further monitoring.
