Idris, B. A. G.

Ismail, A.

Kassim, Zaleha

Kusnan, Misri

Universiti Putra Malaysia Institutional Repository

FOR Category F11100: Environmental SciencesMEIOBENTHOS OF MALACCA STRAITS AND USEOF N/C RATIO AS BIOLOGICAL INDICATOR FORCOASTAL POLLUTIONB.A.G. Idris, M. Kusnan, Z. Kassim and A. IsmailFaculty of Sciences and Environmental StudiesUniversiti Putra Malaysia, 43400 UPM, Serdang, Selangor,MalaysiaKeywords: bioindicator, invertebrate, Malacca Straits,meiobenthos, pollution.IntroductionMeiobenthos is a microcospic invertebrate with body size ofless than 1 mm, lives in bottom sediments of fresh water andmarine habitats. Twenty-two out of 33 metazoan phyla arerepresented in meiobenthos taxa. Meiobenthos can be foundin any type of sediment, from muddy sediment to rough sandand gravel. Certain taxon can be found on seagrasses,seaweeds and amongst corals. Some meiobenthos adapt tolife in the sediment as a mesobenthic or interstitial organism.Due to its benthic nature and a very short life cycle, it wasfound recently that meiobenthos is a very reliable and goodbiological indicator for detection of coastal pollution (Hig-gins and Theil 1988; Subramanium et al.1988). In Malaysia,there are very little studies on subtidal meiobenthos. Studiesby Idris et al. (1994a, 1994b) revolved around intertidal areaonly. The studies on meiobenthos in Asia especially in sub-tidal area are very rare except for some studies in Japan andChina, and in the Indian Ocean.Materials and MethodsThe sampling was carried out at six stations along two tran-sects lines in subtidal areas in the Straits of Malacca. Boxcorer with size of 20X30X50 cm was used to sample thesediments. Sediment samples were then sliced with thicknessof about 2 cm each. For each slice, three replicates of sub-samples were taken using hand corer of 2.2 cm in diameter(3.7994 crrr'), The samples were preserved in 5% of neutral-ised formaline with rose Bengal added. In the laboratory thepreserved samples were elutriased by using modified Bois-seau Apparatus and were sieved using 1 mm dan 42 urnmesh sizes nets. Sediment samples and meiobenthos whichwere caught in the 42 um net were washed into the petridishes and were decanted through sieves six to eight times.The meiobenthos samples were then sorted and counted us-ing binocular dissecting microscope. All meiobenthos taxawere identified using guide from Higgins and Theil (1988).Results and DiscussionNine taxa of meiobenthos were recorded from subtidal areasof the Malacca Straits, namely Foraminifera, OstracodaPolychaeta, Nematoda, Copepoda, Tardigrada, Oligochaeta,Kinorhyncha, and Cumacea. The mean density of meioben-thos in the subtidal areas of the Malacca Straits was332.2±83.5 individuaVlOcm2. Among all the taxa, it wasfound that the most dominant taxon was Foraminifera with amean density of 220.7±65.6/lOcm2 or 66.43%, followed byNematoda (41.3±12.8110cm or 12.44%), Ostracoda(31.8±8.9!lOcm2 or 9.58%) and Polychaeta (20.8±6.9/lOcm2or 10.54%). Foraminifera were the most dominant taxon atall stations and depth, while Tardigrada, Cumacea and Kino-rhyncha were present but in low density. The study on ver-tical distribution of meiobenthos taxa and its density in sub-tidal areas of the Malacca Straits showed that all taxa ofmeiobenthos stayed at the top 6 cm of the sediment layer andreduced rapidly with increase in depth. In term of density itwas found that 83.65 % of meiobenthos density accumulatedin the first 6 cm of the sediment layers. Only two taxa sur-vived up to 20 cm of the sediment layers, that is Foraminiferaand Ostracoda.ConclusionsMeiobenthos may be used as a bioindicator of organic pollu-tion.ReferencesHiggins, R.P., and Thiel, H. 1988. In: Introduction to the study ofMeiofauna. Smithsonian Institute Press, Washington D.C. p.l1-33.Idris, A.G., Bani Amin, B. and Khairul Azman, Y. 1994a.Meiofaunain Three Types of Sediments in Port Dickson Area and use ofN:C ratio in determinants of Coastal Pollution. International Con-ference on Applied Ecology and Biology of Benthic Organisms,Malaysia. p. 32.Idris, A.G., Misri, K. and Mokhtar, D. 1994b. Meiobenthos in Sea-grass Area of Sibu Island. International Conference on AppliedEcology and Biology of Benthic Organisms, Malaysia. p. 16.Subramanian, V., Jha, P.K., Van-Grieken, R. and Bett, B. 1988.Monitoring with meiofauna. Mar. Pollut. Bull. 19: 293-295.Supported by IRPA Grant 08-02-04-0019279

Meiobenthos of Malacca Straits and use of n/c ratio as biological indicator for coastal pollution

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Meiobenthos of Malacca Straits and use of n/c ratio as biological indicator for coastal pollution

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