Marine Research in Indonesia (MRI - E-Journal)
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THE OXYSTOMATOUS CRABS OF THE BARUNA EXPEDITION
No full textOxystomata constitutes the smallest number of species among the Brachyura collected during the BARUNA EXPEDITION. Fourteen species, among which of two the idetification is doubtful, have been studied and included in this paper. Though only few species recorded, many of them are to be more closely studied to ascertain their true position In taxonomy
POLLUTION OF COASTAL AREAS OF JAKARTA BAY: WATER QUALITY AND BIOLOGICAL RESPONSES
No full textCoastal development, growing urbanization and industrialization are the most important stressors of coral reefs worldwide. Jakarta is one of the largest megacities worldwide. The coral reefs of the Thousand Islands north of Jakarta have degraded dramatically over the last 30-40 years. While large-scale gradients (i.e., regional drivers) have been extensively studied and shown shifts and declines in coral cover and composition, local drivers and their impact on spatial community composition have been neglected. The aim of our study is to investigate the spatial impact of anthropogenic stressors on local and regional scales on coral reefs north of Jakarta. Our results demonstrate that reefs in the north of the Thousand Islands are separated from the reefs in Jakarta Bay (JB), where a direct impact of Jakarta can be seen. Local anthropogenic effects rather than regional gradients have shaped a spatial patchwork of differentially degraded reefs along the nearshore islands. The main anthropogenic stressor is pollution and sedimentation rate, NO2, PO4 and chlorophyll-a explain over 80% of the variation. Surfactants and diesel-borne compounds from sewage and bilge water discharges are common pollutants. Responses to combinations of selected pollutant with elevated temperature (+3°C) were determined in the metabolic performance of the coral reef fish Siganus guttatus. During combined exposure, metabolic depression was observed. Effects of pollutants were not amplified by elevated temperature. In a study about two dominant soft coral genera, Sarcophyton spp. and Nephthea spp., on dissolved inorganic nutrients (DIN), turbidity (NTU), and sedimentation combined with measurements of photosynthetic yield and respiratory electron system (ETS) activity water quality seems to control the relative abundance and physiology of dominant soft corals in JB. In order to reverse or prevent phase shifts from hard to soft corals, there is a need to manage the water quality better. It is concluded that the intense anthropogenic pressure from local as well as regional sources is responsible for the spatial structure and health of reefs. Therefore, improved spatial management with a focus on both local and regional stressors is needed for effective marine conservation
SEASONAL FLUCTUATIONS IN THE SURFACE SALINITY ALONG THE COAST OF THE SOUTHERN PART OF KALIMANTAN (BORNEO)
No full textThe westerly current of the Java Sea from the southeast is branched to the north, along the eastcoast of Kalimantan (Borneo) as far as Cape Mangkalihat. This current brings high saline water, over 34.0 ‰, and increases the salinity along the coast of the southern part of Kalimantan, working together with the decreasing rains. In the westmonsoon, when the westward current has retreated and the easterly current from the South China Sea has developed, the northerly current along the eastcoast is replaced by a southerly current, from ,the Pacific. Under influence of the increasing rains and the large outflow of the rivers in the southern part of Kalimantan the salinity decreases rapidly, until a minimum value. This minimum is found irregularly during the diffferent months of the westmonsoon or the succeeding transition period. The lowest values are found in Sukadana Bay (29.0 ‰) and off Bandjarmasin (± 24.0 ‰). The further from this place, the higher the values. The maximum salinity is found during the months September and October in accordance with the minimum rainfall. The highest values are found in the eastern part of the investigated area (34.5 ‰). To the west it is lower, the more it is mixed with the low-saline water of the Java Sea. The salinity in the Karimata Strait is about 33.0 to 33.5 ‰
ON SOME SPECIES OF EUMEDONINAE FROM INDO-MALAYAN REGION
No full textIn their paper, EUMEDONINAE DU VIETNAM (Crustacea), R. Serene, T.V. Duc and N.V. Luom (1958) give an account on the genera and species of the subfamily Eumedoninae. But unfortunately some species are not sufficiently studied, especially those not collected and examined by the authors and only worked out by the reference of other publications. The present note is intended to suffice, if not all, the insufficiency in the above mentioned paper. The species studied in this note include: Proechinoecus sculptus Ward 1934. Ceratocarcinus longimanus Adams & White 1848. Zebrida adamsi White 1847. Rhabdonotus pictus A. Milne Edwards 1878
ON THE OCCURRENCE OF UPWELLING IN THE SOUTHERN MAKASSAR STRAIT
No full textThe possibility of upwelling occuring off the coast of Sulawesi in the Southern Makassar Strait has been discussed by earlier workers (see e.g. Veen 1953, and Wyrtki 1961). Surface salinity data show higher values in June or July along the southwest coast of Sulawesi than the rest area to the west of it. The months June and July coincide with the southeast monsoon in the area. It is believed that the presence of such high salinity could only be due to the process of upwelling. As already mentioned in these works (e.g. by Wyrtki, 1961) during the southeast monsoon, the west-going surface currents coming from the Northern Makassar Strait and the Flores Sea pass the area, and flow into the Java Sea. It is thought that part of the water masses transported by the currents originate from subsurface layer off Makassar coast
SEASONAL FEATURE OF THE HYDROLOGY OF THE BALI STRAIT
No full textUsing the data in the file of the Lembaga Oseanologi Nasional (LON = National Institute of Oceanology), Jakarta, it is shown that the hydrological features at the surface of the Bali Strait are closely related to the meteorological factors of the region. Furthermore, based on the data obtained from the four oceanographical cruises organized by LON in the strait, the features at subsurface layer are analyzed. The influence of the current system south of Java and the upwelling associated with it are also discussed
OBSERVATION ON BEACH EROSION AND CORAL DESTRUCTION BY REMOTE SENSING TECHNIQUES
No full textRemote sensing techniques were used to observe beach erosion at Sengkidu Beach, Labuan Amuk, east coast of Bali. Erosion was caused by wave actions flowing over destructed coral reef. Aerial photography was found useful in obtaining first hand information of the destructed corals and its affects on the beach
COMPARISONS OF ESTUARINE MANAGEMENT NEEDS OF A TROPICAL PACIFIC MEXICAN HARBOUR AND A TEMPERATE CALIFORNIA HARBOUR
No full textTwo areas of the eastern Pacific are compared, the southern California wetlands south of Point Conception and Mazatlan, Mexico. The historical development of both areas is important in considering their present biological status. Southern California has been subjected to intensive population growth and urbanization while Mazatlan has remained relatively unchanged. Both areas are compared biologically in regards to the fish population, thermal gradients in the harbors, salinity, nitrate, nitrite and phosphate distributions. The economic importance of the harbors is recognized, however it is essential that measures are taken to restore or retain existing wetlands that are associated with the harbors. The harbors can serve as shelters for various organisms if water quality can either be maintained (as in the case of Mazatlan) or improved, and if input of toxic and excessive nutrients is limited
PRODUCTIVITY OF DIATOMS IN CULTURE AND IN MARINE HABITATS
No full textThe diatom dominated phytoplankton net primary production in different areas of the ocean (from 100-1000 mg C. m-2. day-1) and in estuaries (up to 2000 mg C. m-2. day-1) is compared with the maximum productivity of marine diatoms in culture (50 g C . m-2 . day-1) for Cyclotella cryptica (Centrales, Diatomeae) and 1000 mg C . m-2. day-1 for Coscinodiscus asteromphalus (Centrales, Diatomeae). The rate of C-assimilation as a measure of primary production is critically discussed in relation to the different factors regulating the reproduction of cells and the production of organic material. The evaluation of another parameter for primary production: light dependent protein synthesis (LPS) is proposed, which brings reproduction of phytoplankton cells and the production of organic material closer together. As an example of the requirement for more information about the potential growth and production rate of diatom species, some results on the cultivation of the tropical shallow water diatom Bellerochea yucatanensis V. STOSCH (Centrales, Diatomeae) are presented. At 30 C this species has a specific growth rate (µ max) of = 4.4 divisions per day and 4 divisions per day at 34°C with an average cell size of 34 x 26 ? m. The temperature range of this species is from 12°C (µ = 0.3) to 35°C (µ = 2)
COMPARISON OF TWO SAMPLING METHODS (CORER AND IN SITU SEDIMENT SIPPER METHODS) FOR THE PORE WATER OF SEDIMENT
No full textEffect of two sampling techniques (i.e. corer and sipper samplers) of sediment pore water on measured concentrations of phosphate, nitrate and ammonia was examined. The concentrations of nitrate and ammonia in relation to sediment depth (vertical variations) collected by corer and sipper sampler do not show significant differences, while for phosphate concentrations significant differences occurred. The advantages and disadvantages of both techniques are discussed