Vertical and horizontal distribution of marine sand-dwelling dinoflagellates in Dinawan Island, Sabah
A study on marine sand-dwelling dinoflagellates was carried out for duration of one year covering Southwest Monsoon (SWM) and Northeast Monsoon (NEM) in Dinawan Island, Sabah. Sand samples were collected from two sampling areas (coastal, and lagoon) to determine the vertical and horizontal distribut...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2012
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| Subjects: | |
| Online Access: | https://eprints.ums.edu.my/id/eprint/41804/1/24%20PAGES.pdf https://eprints.ums.edu.my/id/eprint/41804/2/FULLTEXT.pdf |
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| Summary: | A study on marine sand-dwelling dinoflagellates was carried out for duration of one year covering Southwest Monsoon (SWM) and Northeast Monsoon (NEM) in Dinawan Island, Sabah. Sand samples were collected from two sampling areas (coastal, and lagoon) to determine the vertical and horizontal distribution of sand dwelling dinoflagellates. The aim of this study was to describe the distribution of marine sand-dwelling dinoflagellates in intertidal sandy beach area particularly in tropical area. In order to analyze the vertical distribution, sand samples were collected using the modified PVC tube at 12 cm depth of sand and were divided into 0-2 cm, 2-4 cm, 4-6 cm, 6-8 cm and 8-10 cm of sand layers. While for horizontal distribution, sand samples were collected along a transect line which were divided into 6 stations with 10 m interval from beach face (0 m) toward sea (50 m). Dinoflagellate cells were identified via light and scanning electron microscopy. Overall, there were sixteen dinoflagellate species from four Orders identified. Most of the cells belong to Order Prorocentrales. There were also five harmful dinoflagellates viz. Amphidinium Carterae, Bysmatrum caponii, Peridinium Quinquecorne, Prorocentrum lima and Prorocentrum rhatymum. The number of sand-dwelling dinoflagellates were higher in the lagoon area (1496 cells g-1) compared to number of cells in the coastal area (1283 cells g-1). At the coastal area, the number of dinoflagellate cells was significantly high at 2 cm depth of sand and low at the 8 cm depth of sand. Furthermore, dinoflagellate cell abundance also significantly correlated (p<0.05; r²=0.234) with the horizontal distance. Number of dinoflagellates increased from the station at 0 m (147 cells g-1) to station 50 m (252 cells g-1). In the lagoon area, however, no significant difference was found between sand-dwelling dinoflagellate abundance and depth of sand. The granulomentric composition of sand sample was similar at all sand layers and stations (0m-S50m). In both study areas where the fine particles (0.250-0.125 mm) were dominated the granulometric composition of sand samples. Composition of fine partides were significantly different (p<0.05) with coarse particles (2.0-0.5 mm) and very fine fraction (0.063 mm). Two peaks of dinoflagellate abundance were observed 330 cells g-1 in August 2009 (SWM) and 439 cells g-1 in February 2010 (NEM). Sand-dwelJing dinoflagellates positively correlated with seawater nitrate concentration and temperature but had a negative correlation with phosphate concentration. However, no correlation was found between cell abundance (cell g-1) with sand Total Phosphorus (µM), sand Total Nitrogen (µM) and sand pH. |
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