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AGROVOC Keyword: search.filters.agrovoc.salinityCommittee Chair: search.filters.chair.Padilla, Philip Ian

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    Temporal variation in the subtidal macroinfaunal composition of a NaGISA seagrass bed in southern Guimaras, Philippines between 2015 and 2016
    Bacabac, 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.
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    Phytoplankton assemblages in contrasting seasons in the area of Banate Bay, Iloilo, Philippines
    Alvarez, Rose Ann T. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2019-06)
    Banate Bay in Iloilo is one of the major food and occupation contributors in the Panay Island because of its rich biodiversity. This study investigated the phytoplankton assemblage and their diversity with respect to the contrasting seasons namely; December 2012 and June 2013 on the pre-selected nine (9) stations of the Coastal Ecosystem Conservation and Adaptive Management (CECAM) Project. Physicochemical parameters such as salinity, turbidity, DO, and pH did not display seasonality but total suspended solids (TSS) did, with increased values resulting from run-off from the surrounding watershed and rivers. Principal Component Analysis divided the stations during the two months into groups. Station B3 during June 2013 possessed low salinity level, low turbidity level, low pH level and a very high DO level. While the other stations during June 2013 and all the stations during December 2012 possessed higher salinity levels, higher turbidity levels, higher pH levels and lower DO levels. While the PC2 of PCA divided the stations according to the TSS levels and the temperature. All stations during December 2012 showed characteristics of higher TSS levels and lower temperatures while stations during June 2013 were observed to have low TSS levels and higher temperatures. A total of 86 genera falling under six families were identified from the samples, namely: bacillariophyceae (49 genera), dinophyceae (24 genera), cyanophyceae (6 genera), silicoflagellate (4 genera), chlorophyceae (1 genus), euglenophyceae (1 genus) and Miscellaneous (2 genera). In December 2012, a total of 84 genera were identified and 86 genera in June 2013. The top 10 genera with the highest mean densities were Bacteriastrum, Chaetoceros, Eutintinnus, Guinardia, Leptocylindricus, Lioloma, Protoperidinium, Thallasiothrix and Trichodesmium. Pearson’s correlation analysis revealed that water temperature and TSS were the most significant parameters influencing the distribution and seasonal shift in phytoplankton families and genera such as Bacillariophyceae, Others (composed of Euglenophyceae, Chlorophyceae, Myrionecta, and Globigerina), Protoperidinium, and Guinardia. pH and DO had minor influence on phytoplankton distribution. Shannon- Wiener diversity index as a pollution index suggested that the study area was incipiently polluted at stations Bl, B2, and B3 and marginally polluted at Stations B4, B5, GN1, GN2, GS1, and GS2. Despite potential effects of various human activities, the water quality and phytoplankton assemblage of this area has not reached an alarming situation. The current study provides valuable baseline data.