ISSN 0079-0435: Marine Research in Indonesia Vol. 32, No. 2, 2007

SEDIMEN TRANSPORT IN THE BASIN OF PULAU BAII PORT, BENGKULU
D.K. Mihardja, Supiyati, and T Suprijo

Abstract
The 2D horizontal model has been simulated to investigate a sedimentation and erosion pattern in the basin of Pulau Baai port – Bengkulu Sumatera. The model was verified with observed data from the Indonesian Research Center for Marine Geology (Arifin et al., 2001). The simulation results of the hydrodynamic model shows a good agreement with the observed data. In regard to the elevation of sea level, the difference between simulation and the observed data is about 4.6 cm, giving averaged error of about 2.93 %, and the difference in velocity is 6.8 cm/s or in the order of error of about 20.1 %. The results of the model on sediment transport qualitatively show comparable values to the observed ones, although in some parts of the area, the model is still to be adjusted. Simulation results show that the strong current occurs in the harbor channel during the time of spring flood tide with a speed of about 95.4 cm/s, while the ebb current is 54.1 cm/s. The results of the model on sediment transport show that the erosion area occurs in the northeastern part of the basin and sedimentation takes place in the southwestern to southeastern of the channel. The channel port is generally eroded, and sedimentation occurs in the mouth and the western part of offshoreward of the channel, and erosion is identified in the eastern part of the offshoreward of the channel.

Keywords: Sediment transport, Tidal current, Numerical model, Pulau Baai port Bengkulu, Sumatra

NUTRIENT CONCENTRATIONS AND pH IN THE CISADANE ESTUARINE AND COASTAL WATERS
Muswerry Muchtar

Abstract
The study on the fluctuation of dissolved nutrient concentrations and acidity (pH) in the Cisadane Estuary was carried out in May 2004 October 2004 and July 2005. Inorganic phosphate, nitrate and silicate of the surface water were analyzed, using Spectrophotometer and pH was measured with a pH meter. Generally the nutrient concentrations in the estuary were higher compared to those in the coastal and offshore areas. The concentrations were gradually becoming lower and lower toward the open sea. Their fluctuation depended not only on the environmental condition but also on the water volume from the land and the mangrove forest in that area.

Keywords: Nutrient, Acidity (pH), Cisadane Estuary, Coastal water, Java Sea

SEASONAL VARIATION OF NITROGEN CYCLING IN MANILA BAY
Mitsuru Hayashi, Tetsuo Yanagi and Maria Lourdes San Diego-Mcglone

Abstract
Seasonal variation in nitrogen cycling at the upper layer of the Pasig River estuary in Manila Bay was calculated during January 1996 to December 1998 by using the numerical ecosystem model. Chl.a and DIN concentrations are relatively low, river discharge is small, and solar radiation is strong from March to May in dry season. The main reason of low chl.a concentration is that the solar radiation is too strong. On the other hand, as DIN concentration is relatively high and solar radiation is optimum, chl.a concentration is relatively high from August to December in rainy season. Main source of DIN in rainy season is the vertical transport from the lower layer due to the strong estuarine circulation.

Keywords: Manila Bay, Numerical ecosystem model, Nitrogen cycling, Seasonal variation

DIVERSITY AND COMMUNITY STRUCTURE OF MACROALGAE AT KOH TAEN, HAAD KHANOM-MU KOH TALE TAI, MARINE NATIONAL PARK, NAKHON SI THAMMARAT PROVINCE, THAILAND
Anchana Prathep, Anuchit Darakrai, Piyalap Tantiprapas, Jaruwan Mayakun, Pimonrat Thongroy, Bongkot Wichachucherd, Sutinee Sinutok

Abstract
The diversity and community structure of macroalgae at Koh Taen, Haad Khanom-Mu Koh Tale Tai, marine National Park, Nakhon Si Thammarat Province, Thailand were investigated from 1st- 5th October 2005 (preliminary survey). Out of a total of 41 species: 15 species each of green and red algae, 9 species of brown algae and 2 species of blue green algae were found. In the area, subsequently four sites were established for monitoring. Quadrat sampling was employed to assess the abundance of macroalgae. In total sixty quadrats were monitored each month from October 2005 to April 2007. We report the variations of diversity and abundance of macroalgae among sites and seasons and speculate about what might cause such variations.

Keywords: Diversity, Community, Macroalgae, Koh Taen, Thailand

MACROALGAE DIVERSITY AND LIFE FORMS OF INTER-TIDAL ROCKY SHORES
Muta Harah Zakaria1, Wong Siaw Chia, Japar Sidik Bujang, Aziz Arshad and Hisao Ogawa

Abstract
A study on macroalgae diversity and life form was carried out at inter-tidal rocky shores of Similajau National Park, Bintulu, Sarawak. Thirty five species were identified in this study, of which 15 belong to the division Rhodophyta, 12 to the Chlorophyta and 8 to Phaeophyta. Fifteen species are new records to the Park. Irrespective of areas, macroalgae from the three divisions; Chlorophyta, Phaeophyta and Rhodophyta did not show any distinct zonation. There was high number of macroalgae species in rocky area related to the sandy area. The high representation of macroalgae from rocky area reflects the availability of stable substrate and microhabitats for the occurrence and diversity of macroalgae species. The sandy area lacks hard structure responsible for the relatively low diversity of macroalgae. Four types of macroalgae life forms were identified namely epilithic, epipelic, epizoic and epiphytic. The general distribution, occurrence and a list of the macroalgae is presented.


Keywords: diversity, distribution, percent cover, percent frequency, life forms

THREE SPECIES OF SARGASSUM (PHAEOPHYCEAE) WITH COMPRESSED PRIMARY BRANCHES IN THE GULF OF THAILAND
Thidarat Noiraksar, Tetsuro Ajisaka and Hisao Ogawa

Abstract
Three species of Sargassum with compressed primary branches, S. binderi Sonder, S. oligocystum Montagne and S. swartzii (Turner) C.A. Agardh, have been described from the Gulf of Thailand. S. swartzii is the first record of this species from the coast of Thailand. A key for these three species and for each species descriptions have been completed. The clear distinction among these three species is clearly shown and discussed. S. binderi has slender lanceolate leaves, a dentate margin along the compressed stem of its vesicles, and clear spines along the whole margin of the flattened receptacles. S. oligocystum has broader lanceolate leaves with an acute to rounded apex, almost entire, spherical vesicles, and only few spines on the margin of the slightly compressed receptacles. S. swartzii has linear lanceolate leaves, pointed or crowned vesicles, and few spines near the tip of its almost terete receptacles.

Keywords: Phaeophyceae, Sargassum binderi, S. oligocystum, S. swartzii, the Gulf of Thailand

MANGROVE IN THE COASTAL ZONE OF LAMPUNG BAY PROVINCE OF LAMPUNG: A PRELIMINARY STUDY
Pramudji

Abstract
Study on mangrove forest in the coastal zone of Lampung Bay, Province of Lampung was carried out on March 12 – 30, 2007. The data was collected from 8 stations, (Pidada Bay, Limbungan, Puhawang Kecil Island, Kalangan, Klagian Island, Kapuran, Ringgung, and Hurun Bay) based on the transect method. The result showed that the mangrove in the coastal zone of Lampung Bay was dominated by Rhizophora apiculata. The floristic composition of mangrove in this area consisted of 31 species. Recently, the extent of mangrove in the coastal zone of Lampung Bay was decreasing due to conversion of mangrove into human settlement, fishpond, road, and uncontrolled mangrove exploitation. This situation leads to the depletion of the living organisms which inhabit this area.

PRELIMINARY EVIDENCE OF GROWTH INFLUENCE ON CARBON STABLE ISOTOPE COMPOSITION OF UNDARIA PINNATIFIDA
Matheus Carvalho de CARVALHO, Ken-Ichi HAYASHIZAKI, Hisao OGAWA, Ryusuke KADO

Abstract
Cultured sporophytic thalli of Undaria pinnatifida were collected at different periods of the year from Okkirai Bay, northeastern Japan. ´13C of the thalli collected in January was much higher than that of the thalli collected in March, and young thalli collected in March showed a tendency towards lower ´13C values comparing with adult ones. U. pinnatifida thalli grew fast in January, while young thalli in March showed slow growth due to the light limitation caused by shading adult thalli. Therefore, the growth rate of thallus may relate to ´13C. Ongoing studies aim to quantitatively describe this relation and to search similar results for other species.

Keywords: ´13C, Undaria pinnatifida, Gross primary production.

GROWTH RESPONSES OF FIVE NON TOXIC ALEXANDRIUM SPECIES (DINOPHYCEAE) TO TEMPERATURE AND SALINITY
Po-Teen Lim, Chui-Pin Leaw, Shinnosuke Kaga, Katsushi Sekiguchi, Takehiko Ogata

Abstract
Growth response of five clonal cultures of Alexandrium obtained from tropical and temperate waters were examined. Experiments were carried out in eighteen variable temperature-salinity conditions (temperatures of 15 oC, 20 oC, and 25oC; salinities between 5 to 30 psu) under constant illumination of 150 ± 10.0 µmol m-2 s-1 at 15:9 light:dark photo-cycle. Our results showed optimum growth of all Alexandrium species at 20 - 25oC. The salinity range for optimum growth however varied among the species. Growth rates of A. affine, A. insuetum, and A. fraterculus (0.28 – 0.37 day-1) were higher than those of A. leei and A. pseudogoniaulax under the same culture conditions (0.14 – 0.22 day-1). The three temperate species showed positive growth at suboptimum temperature, 15 oC, but the tropical species did not grow and died off. Salinity tolerance of the five species in decreasing order was A. pseudogoniaulax > A. leei > A. insuetum > A. affine > A. fraterculus. Results of the present study showed vast variations in salinity tolerance among the Alexandrium species regardless the geographical origins. Adaptation of the temperate species at higher temperature indicated that the species might proliferate in warm tropical waters.

Keywords: Alexandrium, Growth, Salinity, Temperature

POSSIBLE OCCURRENCE OF TOXIC AND HARMFUL PHYTOPLANKTON IN LEMBAR BAY, LOMBOK, INDONESIA
Boy Rahardjo Sidharta, Hilman Ahyadi

Abstract
Harmful Algal Bloom (HAB) incidences in Indonesian waters were increasingly occurred from time to time. Extensive and continous studies in this field are needed to be done in more areas in the country. This objective of this present survey were to determine the occurrence of potential toxic and harmful marine microalgae in Lombok, to reveal the diversity of marine microalgae found in the area, and to give some information on the occurrence of HAB phytoplankton in Lombok island. Plankton samples were taken from six stations in Lembar bay, Lombok on February, 2007. This survey found 23 marine microalgae species and two of those were potentially harmful and toxic, namely Dinophysis caudata and Gymnodinium catenatum. Four species, such as Ceratium spp, Dinophysis miles, Prorocentrum gracile, and P. micans, were noted to be harmful though so far no report on adverse effect caused by these microalgae in the area. Diatom Chaetoceros spp were the most abundant phytoplankton in almost all of the sampling areas and followed by Ceratium furca and Protoperidinium sp.

Keywords: HAB, Lombok island, Dinophysis caudata, Gymnodinium catenatum.

THE PHYLOGENETIC TREE OF ALEXANDRIUM, PROROCENTRUM AND PSEUDO-NITZSCHIA OF HARMFUL AND TOXIC ALGAE IN VIETNAM COASTAL WATERS BASED ON SEQUENCES OF 18S rDNA, ITS1-5.8S - ITS2 GENE FRAGMENTS AND SINGLE CELL – PCR METHOD
Dang Diem Hong, Ngo Thi Hoai Thu, Hoang Sy Nam, Hoang Minh Hien, Luyen Quoc Hai, Dao Viet Ha, Yasuo Fukuyo and Mitsunori Iwataki

Abstract
Molecular biological techniques support the identification of microalgae of Vietnam. Prorocentrum, Alexandrium and Pseudo-nitzschia are main harmful and toxic microalgal genera found in Vietnam coastal waters. The results of morphology and nucleotide sequence analysis of 18S rDNA and ITS1-5.8S-ITS2 gene obtained from genomic DNA have shown that the Prorocentrum sp. 3 (isolated from Cat Ba, Hai Phong on October, 2004), Alexandrium sp. 5 (collected on October, 2004) and Pseudo-nitzschia sp. G3 (colleted in Do Son, Hai Phong on December, 2005) belonging to Prorocentrum mexicanum (the homological percent of 99.9% with sequencing of P. mexicanum in Genbank of Y16232, AY886763), A. minutum (99.8% - AJ535388, DQ168664) and Pseudo-nitzschia pungens (98.8% - AY544769, DQ166533), respectively. The obtained results indicated that the exceptional fresh samples, for Prorocentrum genus which may be preserved at 25% ethanol, 4% formaldehyde, 1% glutaraldehyde, while Alexandrium genus – at 25% ethanol, and Pseudo-nitzschia genus - 4% formaldehyde and 1% glutaraldehyde for two weeks have not effected on their analysis of sequences generated by Single Cell PCR method. In these studied samples, the nucleotide sequences obtained from genomic DNA and Single-cell PCR methods were the same with the homological percent more than 99%. Application of this method to samples collected from Phu Quoc Island, southern part of Vietnam, in 27-29, June, 2006 showed that Prorocentrum mican and P. sigmoisdes were found.

Keywords: Prorocentrum, Alexandrium, Pseudo-nitzschia, phylogenetic analysis, SC-PCR method