Distribution of recent ostracoda in offshore sediment around Pulau Besar, Johor

The study on distribution of ostracods in offshore sediment was made around Pulau Besar, Johor. A total of 11 stations were chooser. A total of 47 species, both living and dead belonging to 37 genera and 18 families were collected and had been identified. A total of 1063 dead specimens and 932 living specimens of ostracoda were found in the study area. The dominant species was Pistocythereis cribriformis and the dominant family was Trachyleberididae. Family that had the most high species diversity was Trachlyeberididae with 14 species. Several physico-chemical parameters were measured in-situ including temperature, salinity, dissolved oxygen and depth. The values for each of these parameters range from 27.05-30.80oC, 31.20-34.01 ppt, 6.90-11.93 mg/L and 6.60-20.50 m, respectively. For ex-situ physico-chemical parameters such as percentage of organic matter, sand, clay and silt with the range values for each parameter were 1.98-7.58%, 74.87-95.05%, 0.05-24.21% and 0.75-9.74%, respectively. The sediment texture in this study area can be categorized as silty sand, very fine sand, fine sand, medium sand and coarse sand. Shannon-Wiener diversity Index, H(S) was highest at ST 6 station with 2.91 and lowest at ST 11 station with 2.26. The abundance and diversity of ostracod were most related to the character of the sediment. The percentage of silt were positively and significantly correlated with the abundance of ostracods while temperature and percentage of sand are negatively and significantly correlated with benthic ostracod abundance. Other parameters do not show any significant correlation

Kepelbagaian dan kelimpahan foraminifera di sedimen permukaan sekitar Delta Sungai Kelantan, Malaysia

Suatu kajian telah dijalankan untuk menentukan kepelbagaian dan kelimpahan foraminifera di sedimen permukaan sekitar delta Sungai Kelantan memandangkan kajian foraminifera terutamanya di perairan marin Malaysia amat kurang. Sejumlah 22 stesen daripada dua garisan transek telah ditentukan sebagai kawasan persampelan. Sebanyak 10,317 individu foraminifera yang terdiri daripada 27 famili, 34 genus dan 55 spesies telah ditemui di kawasan kajian. Secara keseluruhannya, famili Hauerinidae mencatatkan kepelbagaian spesies tertinggi (10 spesies) manakala famili paling dominan dengan jumlah individu tertinggi ialah Rotaliidae (26.14%). Spesies dominan dan paling melimpah di kawasan kajian ialah Asterorotalia pulchella (17.24%) dan Operculina ammonoides (10.19%). Indeks kepelbagaian spesies, H’ yang dicatatkan ialah antara 0.5 hingga 3.1 manakala indeks kekayaan spesies, α adalah antara 1.5 hingga 7.9. Kelimpahan dan kepelbagaian spesies tertinggi (α=7.9, H’=3.1) dicatatkan pada stesen 21 yang terletak di laut terbuka dengan kedalaman air sebanyak 36.8 m dan bersaliniti 32.2 ppt mendekati laut normal. Nilai H’ dan α terendah dicatatkan pada stesen yang berdekatan dengan muara sungai yang cetek dan bersaliniti lebih rendah. Secara keseluruhannya, nilai indeks kepelbagaian yang dicatatkan di kawasan kajian adalah menepati persekitaran marin berair cetek. Kesimpulannya, kepelbagaian dan kelimpahan foraminifera di kawasan kajian dipengaruhi oleh kedalaman dan saliniti air

Taburan dan kepelbagaian foraminifera bentik di dalam sedimen permukaan sekitar Delta Sungai Pahang, Pahang, Malaysia

Suatu kajian mengenai taburan dan kepelbagaian spesies Foraminifera bentik di dalam sedimen permukaan telah dijalankan di sekitar Delta Sungai Pahang, Pahang. Sebanyak 33 sampel sedimen telah diambil bagi tujuan ini. Hasilnya, sebanyak 82 spesies, 45 genus dan 29 famili telah berjaya dikenal pasti daripada sejumlah 28,501 individu Foraminifera. Stesen 5 mencatatkan jumlah kehadiran Foraminifera paling tinggi iaitu sebanyak 5,543 individu. Stesen 11 pula mencatatkan jumlah kehadiran paling rendah dengan hanya 46 individu sahaja. Spesies yang paling dominan dan melimpah (>10%) ialah Amphistegina lessonni (4,790 individu) dan Amphistegina gibbosa (4,490 individu). Kemudian, diikuti oleh Elphidium advenum, Operculina ammonoides dan Asterorotalia pulchella (>5%). Bagi famili pula, Amphisteginidae merupakan famili paling dominan dengan mencatatkan jumlah individu tertinggi iaitu 9,280 (mewakili 32.6% daripada keseluruhan individu). Famili Hauerinidae mencatatkan kepelbagaian spesies yang paling tinggi iaitu sebanyak 24 spesies telah berjaya dijumpai. Indeks kepelbagaian spesies, H’ yang dicatatkan adalah antara 1.1 dan 3.1. Manakala indeks kekayaan spesies, α adalah antara 2.0 dan 9.4

Taburan ostrakod di dalam sedimen luar pantai di sekitar Pulau Tinggi, Johor = Distribution of ostracods in offshore sediment around Pulau Tinggi, Johor

A study was conducted to determine the distribution of ostracods in offshore sediment around Pulau Tinggi, Johor. A total of 11 stations were determined as sampling area. The abundance of ostracods is high in this study area. A total of 1,975 specimens were found belonging to 16 families, 36 genera and 51 species. Family Trachyleberididae has the highest diversity of species with 19 species recorded and the most dominant family with 589 specimens. The most dominant species is Loxoconcha malayensis with 131 specimens. Several in-situ physico-chemical parameters such as temperature, dissolved oxygen (DO), depth, salinity and pH were measured. The range values for each of these parameters are 26.29-29.02oC, 4.49-6.87 mg/l, 8.30-35.00 m, 34.01-38.90 ppt and 8.11-8.20, respectively. For ex-situ physico-chemical parameters such as percentage of organic matter, sand, clay and silt, the range values for each parameters were 4.91-10.73%, 88.41-97.26%, 0.84-7.49% and 1.89-6.22%, respectively. The sediment texture in this study area can be categorized as fine, medium and coarse sand. The most dominant texture is medium sand. Correlation analysis shows that salinity, the percentages of organic matter, clay and silt are positively and significantly correlated with the abundance of ostracods while temperature and percentage of sand are negatively and significantly correlated with ostracod abundance. Other parameters do not show any significant correlation

Sediment Sources and Dispersion on the Western Sunda Shelf, Malay Peninsula, Southern South China Sea

Thirty-nine surface sediment samples collected from the western Sunda Shelf off the Malay Peninsula (WSSMP) in the southern South China Sea (SCS) were analysed for grain size, major and trace elemental compositions, and light/heavy mineral contents to trace the sediment sources and their transport mechanisms in the study area. In the WSSMP, the surface sediments are relatively poorly sorted but transportable. A principal component analysis of 37 elements and grain size fractions indicates that the surface sediments can be grouped into four major assemblages in the study area. Integrating with the light/heavy minerals data in the 63–125 μm fractions of the surface sediment samples, to better trace the sediment sources of the coarse-grained components in the marine environment, the study area can be further divided into four sediment provinces. Province I is located in the northwestern part of the study area. The concentrations of TiO2, Na2O, garnet, siderite, and glauconite in Province I were higher than in the other provinces. The main sediment source for this province originated from the Kelantan River and the Gulf of Thailand transported by the northeastern monsoon current. Province II is located offshore of the Pahang and Endau Rivers. The percentages of TiO2, rare earth elements, Al2O3, quartz, plagioclase, hypersthene, and magnetite in the surface sediments were typically higher in this province than in the other provinces. The Pahang and Endau rivers provide most of the sediments to this province, which are transported by southward coastal currents. Province III is located in the northeastern and eastern parts of the study area, where the coarse-grained sediment fraction had relatively high hornblende and biotite contents. Sediments in this province are mostly transported from the Mekong River during the northeastern monsoon. The other parts of the study area belong to Province IV, where the surface sediment elemental and mineral concentrations were mostly between those of the other three provinces. Therefore, we suggest that Province IV has a mixed source due to inputs from the surrounding rivers