Showing papers by "Indonesian Institute of Sciences published in 2008"

One-third of reef-building corals face elevated extinction risk from climate change and local impacts

Abstract: The conservation status of 845 zooxanthellate reef-building coral species was assessed by using International Union for Conservation of Nature Red List Criteria. Of the 704 species that could be assigned conservation status, 32.8% are in categories with elevated risk of extinction. Declines in abundance are associated with bleaching and diseases driven by elevated sea surface temperatures, with extinction risk further exacerbated by local-scale anthropogenic disturbances. The proportion of corals threatened with extinction has increased dramatically in recent decades and exceeds that of most terrestrial groups. The Caribbean has the largest proportion of corals in high extinction risk categories, whereas the Coral Triangle (western Pacific) has the highest proportion of species in all categories of elevated extinction risk. Our results emphasize the widespread plight of coral reefs and the urgent need to enact conservation measures.

Earthquake Supercycles Inferred from Sea-Level Changes Recorded in the Corals of West Sumatra

Abstract: Records of relative sea-level change extracted from corals of the Mentawai islands, Sumatra, imply that this 700-kilometer-long section of the Sunda megathrust has generated broadly similar sequences of great earthquakes about every two centuries for at least the past 700 years. The moment magnitude 8.4 earthquake of September 2007 represents the first in a series of large partial failures of the Mentawai section that will probably be completed within the next several decades.

Heterogeneous coupling of the Sumatran megathrust constrained by geodetic and paleogeodetic measurements

Abstract: Geodetic and paleogeodetic measurements of interseismic strain above the Sumatran portion of the Sunda subduction zone reveal a heterogeneous pattern of coupling. Annual banding in corals provides vertical rates of deformation spanning the last half of the 20th century, and repeated GPS surveys between 1991 and 2001 and continuous measurements at GPS stations operated since 2002 provide horizontal velocities. Near the equator, the megathrust is locked over a narrow width of only a few tens of kilometers. In contrast, the locked fault zone is up to about 175 km wide in areas where great interplate earthquakes have occurred in the past. Formal inversion of the data reveals that these strongly coupled patches are roughly coincident with asperities that ruptured during these events. The correlation is most spectacular for rupture of the M_w 8.7 Nias-Simeulue earthquake of 2005, which released half of the moment deficit that had accumulated since its previous rupture in 1861, suggesting that this earthquake was overdue. Beneath the Mentawai islands, strong coupling is observed within the overlapping rupture areas of the great earthquakes of 1797 and 1833. The accumulated slip deficit since these events is slowly reaching the amount of slip that occurred during the 1833 earthquake but already exceeds the slip that occurred during the 1797 earthquake. Thus, rerupture of part of the Mentawai patch in September 2007 was not a surprise. In contrast, coupling is low below the Batu islands near the equator and around Enggano island at about 5°S, where only moderate earthquakes (M_w < 8.0) have occurred in the past two centuries. The correlation of large seismic asperities with patches that are locked during the interseismic period suggests that they are persistent features. This interpretation is reinforced by the fact that the large locked patches and great ruptures occur beneath persistent geomorphologic features, the largest outer arc islands. Depth- and convergence-rate-dependent temperature might influence the pattern of coupling, through its effect on the rheology of the plate interface, but other influences are required to account for the observed along-strike heterogeneity of coupling. In particular, subduction of the Investigator Fracture Zone could be the cause for the low coupling near the equator.

Recent intensification of tropical climate variability in the Indian Ocean

Abstract: Coral records from a range of sites extend the index of the Indian Ocean Dipole back to 1846. Indian Ocean Dipole events increased in strength and frequency in the twentieth century, coincident with the development of direct feedbacks with the Asian Monsoon. The interplay of the El Nino Southern Oscillation, Asian monsoon and Indian Ocean Dipole (IOD)1,2,3 drives climatic extremes in and around the Indian Ocean. Historical4,5 and proxy6,7,8,9 records reveal changes in the behaviour of the El Nino Southern Oscillation and the Asian monsoon over recent decades10,11,12. However, reliable instrumental records of the IOD cover only the past 50 years1,3, and there is no consensus on long-term variability of the IOD or its possible response to greenhouse gas forcing13. Here we use a suite of coral oxygen-isotope records to reconstruct a basin-wide index of IOD behaviour since AD 1846. Our record reveals an increase in the frequency and strength of IOD events during the twentieth century, which is associated with enhanced seasonal upwelling in the eastern Indian Ocean. Although the El Nino Southern Oscillation has historically influenced the variability of both the IOD and the Asian monsoon3,8,10, we find that the recent intensification of the IOD coincides with the development of direct, positive IOD–monsoon feedbacks. We suggest that projected greenhouse warming may lead to a redistribution of rainfall across the Indian Ocean and a growing interdependence between the IOD and Asian monsoon precipitation variability.

A genome-wide survey of HD-Zip genes in rice and analysis of drought-responsive family members

Abstract: The homeodomain leucine zipper (HD-Zip) genes encode transcription factors that have diverse functions in plant development and have often been implicated in stress adaptation. The HD-Zip genes are the most abundant group of homeobox (HB) genes in plants and do not occur in other eukaryotes. This paper describes the complete annotation of the HD-Zip families I, II and III from rice and compares these gene families with Arabidopsis in a phylogeny reconstruction. Orthologous pairs of rice and Arabidopsis HD-Zip genes were predicted based on neighbour joining and maximum parsimony (MP) trees with support of conserved intron-exon organization. Additionally, a number of HD-Zip genes appeared to be unique to rice. Searching of EST and cDNA databases and expression analysis using RT-PCR showed that 30 out of 31 predicted rice HD-Zip genes are expressed. Most HD-Zip genes were broadly expressed in mature plants and seedlings, but others showed more organ specific patterns. Like in Arabidopsis and other dicots, a subset of the rice HD-Zip I and II genes was found to be regulated by drought stress. We identified both drought-induced and drought-repressed HD-Zip genes and demonstrate that these genes are differentially regulated in drought-sensitive versus drought-tolerant rice cultivars. The drought-repressed HD-Zip family I gene, Oshox4, was selected for promoter-GUS analysis, showing that drought-responsiveness of Oshox4 is controlled by the promoter and that Oshox4 expression is predominantly vascular-specific. Loss-of-function analysis of Oshox4 revealed no specific phenotype, but overexpression analysis suggested a role for Oshox4 in elongation and maturation processes. © 2007 The Author(s).

The biogeochemistry of tropical lakes: A case study from Lake Matano, Indonesia

Abstract: We examined the chemical composition of the water column of Lake Matano, Sulawesi Island, Indonesia, to document how the high abundances of Fe (hydr)oxides in tropical soils and minimal seasonal temperature variability affect biogeochemical cycling in lakes. Lake Matano exhibits weak thermal stratification, yet a persistent pycnocline separates an oxic epilimnion from anoxic meta- and hypolimnions. The concentration of soluble P in the epilimnetic waters is very low and can be attributed to scavenging by Fe (hydr)oxides. Chromium concentrations in the epilimnion are high (up to 180 nmol L21), but below U.S. Environmental Protection Agency guidelines for aquatic ecosystems. The concentration of chromium decreases sharply across the oxic–anoxic boundary, revealing that the hypolimnion is a sink for Cr. Flux calculations using a one-dimensional transportreaction model for the water column fail to satisfy mass balance requirements and indicate that sediment transport and diagenesis play an important role in the exchange of Fe, Mn, P, and Cr between the epilimnion and hypolimnion. Exchange of water between the epilimnion and hypolimnion is slow and on a time scale similar to temperate meromictic lakes. This limits recycling of P and N to the epilimnion and removal of Cr to the hypolimnion, both of which likely restrict primary production in the epilimnion. Owing to the slow exchange, steep concentration gradients in Fe and Mn species develop in the metalimnion. These concentration gradients are

Phylogeography and genetic diversity of a widespread Old World butterfly, Lampides boeticus (Lepidoptera: Lycaenidae)

Abstract: Evolutionary genetics provides a rich theoretical framework for empirical studies of phylogeography. Investigations of intraspecific genetic variation can uncover new putative species while allowing inference into the evolutionary origin and history of extant populations. With a distribution on four continents ranging throughout most of the Old World, Lampides boeticus (Lepidoptera: Lycaenidae) is one of the most widely distributed species of butterfly. It is placed in a monotypic genus with no commonly accepted subspecies. Here, we investigate the demographic history and taxonomic status of this widespread species, and screen for the presence or absence of the bacterial endosymbiont Wolbachia. We performed phylogenetic, population genetic, and phylogeographic analyses using 1799 bp of mitochondrial sequence data from 57 specimens collected throughout the species' range. Most of the samples (>90%) were nearly genetically identical, with uncorrected pairwise sequence differences of 0 – 0.5% across geographic distances > 9,000 km. However, five samples from central Thailand, Madagascar, northern Australia and the Moluccas formed two divergent clades differing from the majority of samples by uncorrected pairwise distances ranging from 1.79 – 2.21%. Phylogenetic analyses suggest that L. boeticus is almost certainly monophyletic, with all sampled genes coalescing well after the divergence from three closely related taxa included for outgroup comparisons. Analyses of molecular diversity indicate that most L. boeticus individuals in extant populations are descended from one or two relatively recent population bottlenecks. The combined analyses suggest a scenario in which the most recent common ancestor of L. boeticus and its sister taxon lived in the African region approximately 7 Mya; extant lineages of L. boeticus began spreading throughout the Old World at least 1.5 Mya. More recently, expansion after population bottlenecks approximately 1.4 Mya seem to have displaced most of the ancestral polymorphism throughout its range, though at least two early-branching lineages still persist. One of these lineages, in northern Australia and the Moluccas, may have experienced accelerated differentiation due to infection with the bacterial endosymbiont Wolbachia, which affects reproduction. Examination of a haplotype network suggests that Australia has been colonized by the species several times. While there is little evidence for the existence of morphologically cryptic species, these results suggest a complex history affected by repeated dispersal events.

Community Structure of Soil Bacteria in a Tropical Rainforest Several Years After Fire

Abstract: The bacterial community structure in soil of a tropical rainforest in East Kalimantan, Indonesia, where forest fires occurred in 1997-1998, was analysed by denaturing gradient gel electrophoresis (DGGE) with soil samples collected from the area in 2001 and 2002. The study sites were composed of a control forest area without fire damage, a lightly-burned forest area, and a heavily-burned forest area. DGGE band patterns showed that there were many common bacterial taxa across the areas although the vegetation is not the same. In addition, it was indicated that a change of vegetation in burned areas brought the change in bacterial community structure during 2001-2002. It was also indicated that, depending on a perspective, community structure of soil bacteria in post-fire non-climax forest several years after fire can be more heterogeneous compared with that in unburned climax forest. The dominant soil bacteria in the field of the present study were Acidobacteria, Actinobaceria, and Alphaproteobacteria based on the DNA sequences of DGGE bands, although they were not dominant among the culturable bacteria from the same soil samples.

Groundwater recharge and discharge processes in the Jakarta groundwater basin, Indonesia

Abstract: Proper management of groundwater resources requires knowledge of the processes of recharge and discharge associated with a groundwater basin Such processes have been identified in the Jakarta groundwater basin, Indonesia using a theory that describes the simultaneous transfer of heat and fluid in a porous medium Temperature-depth profiles in monitoring wells are used to determine the geothermal gradient To examine the rules of groundwater flow in the distortion of the isotherms in this area, several methods are compared Subsurface temperature distribution is strongly affected by heat advection due to groundwater flow Under natural flow conditions, the recharge area is assumed to occur in the hills and uplands, which are located on the periphery of the Jakarta basin, and the discharge area is located in the central and northern part of the Jakarta groundwater basin A transition area, which could act as local recharge and discharge areas, occupies the middle of the lowland Subsurface temperatures show good correlation with the groundwater flow conditions, and the data yield important information on the location of recharge and discharge areas

The value of differently managed cacao plantations for forest bird conservation in Sulawesi, Indonesia

Abstract: In order to assess the potential value of differently managed cacao plantations for bird conservation on Sulawesi, we surveyed birds in near-primary forest (with limited timber and rattan extraction, and some hunting), cacao plantations with remnant forest trees and plantations lacking forest trees, from February to April 2007. A total of 16 50 x 50 m plots were visited twice and records of 87 species were obtained. Bird species richness and the number of endemics and forest specialists decreased along this gradient of forest conversion, with 20% of the forest specialists, among them 10 endemics, exclusively found in forest. Species composition changed dramatically between habitat types. Sorensen indices showed a similarity of species composition between forests and plantations of 45–60% for forest specialists and 65–71% for all species. The most important environmental variable for the diversity and composition of birds was the number of remnant rainforest trees present in the plantations. Our results suggest that large, undisturbed rainforest are most important for the conservation of forest specialists and endemics but that cacao plantations, if managed to maintain a high and diverse cover of forest trees, can harbour up to 60% of forest specialists and endemics.

Relating variation in species composition to environmental variables: a multi-taxon study in an Indonesian coral reef complex

Abstract: In order to manage and conserve coral reefs it is essential to understand the factors that structure reef communities. In Indonesia’s Jakarta Bay – Pulau Seribu reef complex, pronounced on-to-offshore variation in a number of variables was observed. Live coral cover, and echinoderm and fish species richness were higher in midshore sites than either in- or offshore sites. Variation in habitat structure, the abiotic environment, distance between sample sites and covariation of these factors separately explained 9.6 to 15.1% of the spatial variation in the composition of corals, echinoderms and fishes. Together, all three components explained > 50% of the variation in composition. This indicates that spatial and environmental factors influence the distribution of species across the study area and have important implications for the large-scale management of this reef ecosystem. Large scalemanagement and protection of these reefs will probably be important because the majority or reefs were in poor to very poor condition as exemplified by low (<25%) coral cover. The coral cover of some inshore reefs was particularly low (< 1%). Inshore coral assemblages tended to be composed of stress-tolerant or specialised pioneers of highly perturbed environments. There were also locally high densities of potentially destructive species such as the sea urchin Diadema setosum. Midshore sites had relatively high coral cover comprising Acropora and Montipora spp. that were rare or absent elsewhere, presumably due to their sensitivity to pollution and mechanical damage. Most of the offshore sites had relatively low live coral cover and were dominated by rapidly growing pioneers or by stress- or –sediment-tolerant species. Spatial variation in the composition of taxa is discussed in the context of past-and-ongoing disturbances, including land-based pollution, coral mining, sedimentation and destructive fishing practices.

Persistent elastic behavior above a megathrust rupture patch: Nias island, West Sumatra

Abstract: We quantify fore-arc deformation using fossil reefs to test the assumption commonly made in seismic cycle models that anelastic deformation of the fore arc is negligible. Elevated coral microatolls, paleoreef flats, and chenier plains show that the Sumatran outer arc island of Nias has experienced a complex pattern of relatively slow long-term uplift and subsidence during the Holocene epoch. This same island rose up to 2.9 m during the Mw 8.7 Sunda megathrust rupture in 2005. The mismatch between the 2005 and Holocene uplift patterns, along with the overall low rates of Holocene deformation, reflects the dominance of elastic strain accumulation and release along this section of the Sunda outer arc high and the relatively subordinate role of upper plate deformation in accommodating long-term plate convergence. The fraction of 2005 uplift that will be retained permanently is generally <4% for sites that experienced more than 0.25 m of coseismic uplift. Average uplift rates since the mid-Holocene range from 1.5 to −0.2 mm/a and are highest on the eastern coast of Nias, where coseismic uplift was nearly zero in 2005. The pattern of long-term uplift and subsidence is consistent with slow deformation of Nias along closely spaced folds in the north and trenchward dipping back thrusts in the southeast. Low Holocene tectonic uplift rates provide for excellent geomorphic and stratigraphic preservation of the mid-Holocene relative sea level high, which was under way by ∼7.3 ka and persisted until ∼2 ka.

Overexpression of poplar cellulase accelerates growth and disturbs the closing movements of leaves in sengon

Abstract: In this study, poplar (Populus alba) cellulase (PaPopCel1) was overexpressed in a tropical Leguminosae tree, sengon (Paraserianthes falcataria), by the Agrobacterium tumefaciens method. PaPopCel1 overexpression increased the length and width of stems with larger leaves, which showed a moderately higher density of green color than leaves of the wild type. The pairs of leaves on the transgenic plants closed more slowly during sunset than those on the wild-type plants. When main veins from each genotype were excised and placed on a paper towel, however, the leaves of the transgenic plants closed more rapidly than those of the wild-type plant. Based on carbohydrate analyses of cell walls, the leaves of the transgenic plants contained less wall-bound xyloglucan than those of the wild-type plants. In situ xyloglucan endotransglucosylase activity showed that the incorporation of whole xyloglucan, potentially for wall tightening, occurred in the parenchyma cells (motor cells) of the petiolule pulvinus attached to the main vein, although the transgenic plant incorporated less whole xyloglucan than the wild-type plant. These observations support the hypothesis that the paracrystalline sites of cellulose microfibrils are attacked by poplar cellulase, which loosens xyloglucan intercalation, resulting in an irreversible wall modification. This process could be the reason why the overexpression of poplar cellulase both promotes plant growth and disturbs the biological clock of the plant by altering the closing movements of the leaves of the plant.

REVIEW: Research Ethnobotany in Indonesia and the Future Perspectives

Abstract: Indonesia is not only rich in its biodiversity but it is also well known as a country with high diversity of ethnicities. Each ethnic group has extensive experienced in the utilization and conservation of biological and ecological diversity. This biocultural richness has provided ethnobotanical researchers with endless research opportunities. Ethnobotanical study has a long history in Indonesia and dates back to the early Dutch colonization period when Dutch explorers and naturalists recorded the uses of plants used by the natives for food, medicine, buildings materials, etc. Based on research on Java, Hasskarl (1845) recorded 900 species of plants used by Indonesian communities. Previously, Rumphius (1750) in his monumental book "Herbarium Amboinense", reported the uses of several hundreds plants from Ambon and its vicinity. Recently, Indonesian scientists from both government and non-government organizations have given more attention to the importance of ethnobotany as a means of elaborating traditional knowledge, especially for economically useful and scientifically undiscovered plants. The talk will focus on ethnobotanical research performed by LIPI scientists at the Research Center for Biology in Bogor and the Indonesia Botanic Gardens. During the last 20 years, since the Indonesia' Ethnobotanical Museum was established. Indonesian scientists have documented the importance of ethnobotany, ethnomedicine, ethnomycology, ethnoentomology, and ethnoecology for conservation of traditional knowledge in relation to the economic botany and to other applied sciences. The meaning and scope of ethnobotany and its status including the future prospects, its contribution to the exploitation and conservation will be discuses in this paper.© 2008 Jurusan Biologi FMIPA UNS SurakartaKey words: ethnobotany, ethnomedicine, ethnomycology, ethnoecology, traditional knowledge, use of plants, Indonesia.

The plankton community of Lake Matano: factors regulating plankton composition and relative abundance in an ancient, tropical lake of Indonesia

Abstract: Recent evidence reveals that food webs within the Malili Lakes, Sulawesi, Indonesia, support community assemblages that are made up primarily of endemic species. It has been suggested that many of the species radiations, as well as the paucity of cosmopolitan species in the lakes, are related to resource limitation. In order to substantiate the possibility that resource limitation is playing such an important role, a study of the phytoplankton and zooplankton communities of Lake Matano was implemented between 2000 and 2004. We determined species diversity, relative abundances, size ranges, and total biomass for the phytoplankton and zooplankton, including the distribution of ovigerous individuals throughout the epilimnion of Lake Matano in three field seasons. The phytoplankton community exhibited very low biomass (<15 μg l−1) and species richness was depressed. The zooplankton assemblage was also limited in biomass (2.5 mg l−1) and consisted only of three taxa including the endemic calanoid Eodiaptomus wolterecki var. matanensis, the endemic cyclopoid, Tropocyclops matanensis and the rotifer Horaella brehmi. Zooplankton were very small (<600 lm body length), and spatial habitat partitioning was observed, with Tropocylops being confined to below 80 m, while rotifer and calanoid species were consistently observed above 80 m. Less than 0.1% of the calanoid copepods in each year were egg-bearing, suggesting very low population turnover rates. It was concluded that chemical factors as opposed to physical or biological processes were regulating the observed very low standing crops of phytoplankton which in turn supports a very minimal zooplankton community restricted in both species composition and abundance. As chemical factors are a function of the catchment basin of Lake Matano, it is predicted that resource limitation has long played an important role in shaping the unique endemic assemblages currently observed in the food web of the lake.

Variation in longevity and traits of leaves among co-occurring understorey plants in a tropical montane forest

Abstract: The relationship between leaf longevity and other leaf traits was compared among different life-form categories (trees, herbs, climbers and epiphytes) of 101 plant species in a tropical montane forest on Mt. Halimun, West Java, Indonesia. We applied the Cox proportional hazards regression to estimate the leaf longevity of each species from 30 mo of census data. We examined whether estimated longevity was explained by either species life-form categories, taxonomic groupings (eudicots, monocots, magnoliids and chloranthales, and ferns) or such leaf traits as leaf area, leaf mass per area (LMA), mass-based leaf nitrogen, penetrometer reading, condensed-tannin-free total phenolics and condensed tannin. There was a wide-ranged interspecific variation in leaf longevity, mostly 10-50 mo, similarly across life-form categories. LMA showed a strong positive influence on leaf longevity. We found that relationships between leaf longevity and some leaf traits were different among various life forms. Trees tended to have high LMA, while climbers tended to have low LMA at the same leaf longevity. We hypothesize that such difference among life forms reflects shoot architecture characteristics. Multi-shoot trees with branching architecture need to have self-supporting leaves, whereas semi-epiphytic climbers can maintain relatively low biomass investment to leaves hanging or relying upon the mechanical support from host plants.

REVIEW: Symbiosis between the Giant Clams (Bivalvia: Cardiidae) and Zooxanthellae (Dinophyceae)

Abstract: Giant clams are the largest bivalves in the world that maintain a mutual relationship with zooxanthellae. Individual giant clam can harbor heterogeneous zooxanthellae, at least four taxa in genus Symbiodinium. The Symbiodinium lives in the zooxanthellal tubular system, a tube structure arising from one of the diverticular duct of the clam’s stomach. Since the numbers of zooxanthellae is the one of some significant factors contributing to the clams growth and survival, the giant clams need to adjust the number of zooxanthellae for physiological reason with unclear mechanism. The important role of the symbiotic relationship to the clams can be seen on the survival, growth and nutrition of the clams. There are at least two significant factors determining the symbiosis, i.e. water temperature in related with level of light intensities and ammonium-phosphate rate. Some topic is still unclear, i.e. the determination of species in genus Symbiodinium, the mechanism for adjusting the population numbers of the algae and what kind of environmental factors determining the symbiosis. Thereby further research is still needed to clarify those missing.© 2008 Jurusan Biologi FMIPA UNS SurakartaKey words: giant clams, zooxanthellae, Symbiodinium, symbiosis

Antioxidant compound from the rhizomes of Kaempferia rotunda L.

Abstract: This research aimed to investigate the antioxidant effect from rhizomes of K. rotunda for finding the active compounds by DPPH free radical scavenging activity assay. The chloroform-soluble extract of the rhizomes of K. rotunda showed significant scavenging effect on the on 1,1-diphenyl-2-picryl hydrazyl (DPPH) free radicals (IC50 = 180 microg mL(-1)). Two compounds of the chloroform-soluble extract were isolated and identified. Compound 1, 2'-hydroxy-4,4',6'-trimethoxy-chalcone was found as the active constituent (IC50 = 142 microg mL(-1)). Compound 2, (+)-crotepoxide, was inactive (IC50 = 1516 microg mL(-1)). The structures of compounds 1 and 2 were identified based on the basis of spectral evidence, Mass Spectrophotometry (MS) and 2D-NMR (2 dimension of Nuclear Magnetic Resonance) data including Heteromolecular Multiple Quantum Coherence (HMQC) and Heteromolecular Multiple Bond Correlation (HMBC) and comparison to published values.

Processes regulating the community composition and relative abundance of taxa in the diatom communities of the Malili Lakes, Sulawesi Island, Indonesia

Abstract: Although high levels of endemism have been reported on Sulawesi Island for almost 150 years, the aquatic systems of the island have received little attention until recently. The diatoms of the ancient Malili Lakes, located on central Sulawesi, exhibit levels of endemism unequaled elsewhere in the world. Interestingly, the diatom community of the lakes is taxonomically impoverished, and the entire order Centrales is conspicuous by its absence. In this article we review the mechanisms contributing to the development and maintenance of community composition and relative abundance of taxa within the system, at within-lake and system-wide scales. Our findings demonstrate that stochastic processes related to biogeography and colonization have had little influence on the diatom flora of the lakes, and deterministic processes related to competition, selection, speciation, and adaptive radiation, functioning on very small spatial scales, have contributed greatly to the diversity, community structure, and endemism of the system.

Geomagnetic field variations during the last 400 kyr in the western equatorial Pacific: Paleointensity‐inclination correlation revisited

Abstract: [1] A paleomagnetic study was conducted on four piston cores newly obtained from the West Caroline Basin in the western equatorial Pacific in order to investigate variations in paleointensity and inclination during the last 400 kyr. An inclination-intensity correlation was previously reported in this region using giant piston cores, but the quality of the paleomagnetic data of the younger end, the last ca. 300 kyr, was needed to be checked because the upper part of the giant piston cores could suffer from perturbation by oversampling. Age control is based on the oxygen-isotope ratios for one core and inter-core correlation using relative paleointensity for other cores. Stacked curves of paleointensity and inclination were constructed from the four cores. It was confirmed that variations on the order of 104 to 105 years occur in inclination as well as paleointensity. A cross-correlation analysis showed that significant in-phase correlation occurs between intensity and inclination for periods longer than about 25 kyr, and power spectra of both paleointensity and inclination variations have peaks at ∼100 kyr periods. The regional paleointensity stack with higher resolution than the Sint-800 stack (Guyodo and Valet, 1999) should be useful for paleointensity-assisted chronostratigraphy.

Gene flow at the margin of Lake Matano’s adaptive sailfin silverside radiation: Telmatherinidae of River Petea in Sulawesi

Abstract: Classical speciation concepts focus almost exclusively on the evolution of strict reproductive isolation as a prerequisite for speciation. However, there is a growing body of evidence indicating that speciation is possible despite or even triggered by gene flow among populations or species. Previous findings indicate that introgressive hybridization is a dominant phenomenon in the adaptive radiation of sailfin silversides (Telmatherinidae) endemic to Lake Matano (Sulawesi). In this study, we investigate patterns of genotypic and phenotypic variation of “sharpfin” sailfin silversides in the outlet area of L. Matano and six locations along River Petea, which is the only connection between L. Matano and other lakes and streams of the Malili Lakes system. Fieldwork revealed no hints for a previously cited major waterfall in River Petea, which was thought to separate L. Matano’s sailfin silverside radiation from the diversity of the downstream lake drainages. Likewise, genomic (AFLP) and morphometric data suggest high levels of gene flow between upper and lower stretches of this river, as well as between riverine Petea and lacustrine Matano populations. Increasing levels of genotypic and phenotypic dissimilarity are correlated with distance over a remarkably short geographic range.

Floristics and structure of a lowland dipterocarp forest at wanariset samboja, east kalimantan, indonesia

Abstract: KARTAWINATA, K., PURWANINGSIH, PARTOMIHARDJO, T., YUSUF, R., ABDULHADI, R. & RISWAN,S. 2008.Floristics and structure of a lowland dipterocarp forest at Wanariset Samboja, East Kalimantan, Indonesia.Reinwardtia 12(4): 301– 323. — The results of a floristic inventory of trees with DBH < 10 cm in a lowland dipterocarp forest in East Kalimantan show that 553 species of 192 genera in 62 families, represented by 5847 individuals, with the total basal 2 area of 350.01 m occurred in the plot of 10.5 hectare sampled. The two leading families in terms of number of species were Myrtaceae and Lauraceae while according to the total sum of importance values for families were Dipterocarpaceae and Euphorbiaceae. The forest had the second highest species richness in Indonesia. We recorded 225 species of dipterocarps , constituting 4.53 % of total species with basal area of 85.53 m . or 24.44 % of the total basal area in the plot. Shorea laevis (a diptererocarp) and Pholidocarpus majadum, (a palm) were the most prominent species occurring here and were two of the ten leading species. The species-area curve rose steadily even up to an area of 10.5 hectare, with a very slight indication of levelling off at about five hectares, indicating high heterogeneity of the forest. Three largest trees were Shorea pauciflora (DBH = 196.50 cm) Dipterocarpus cornutus (DBH = 170.90 cm), and Alstonia scholaris (DBH = 170.00 cm) , Some species could be identified as fruit trees and medicinal plants.

Geomagnetic field variations during the last 400 kyr in the western equatorial Pacific: Paleointensity-inclination correlation revisited

Abstract: [1] A paleomagnetic study was conducted on four piston cores newly obtained from the West Caroline Basin in the western equatorial Pacific in order to investigate variations in paleointensity and inclination during the last 400 kyr. An inclination-intensity correlation was previously reported in this region using giant piston cores, but the quality of the paleomagnetic data of the younger end, the last ca. 300 kyr, was needed to be checked because the upper part of the giant piston cores could suffer from perturbation by oversampling. Age control is based on the oxygen-isotope ratios for one core and inter-core correlation using relative paleointensity for other cores. Stacked curves of paleointensity and inclination were constructed from the four cores. It was confirmed that variations on the order of 104 to 105 years occur in inclination as well as paleointensity. A cross-correlation analysis showed that significant in-phase correlation occurs between intensity and inclination for periods longer than about 25 kyr, and power spectra of both paleointensity and inclination variations have peaks at ∼100 kyr periods. The regional paleointensity stack with higher resolution than the Sint-800 stack (Guyodo and Valet, 1999) should be useful for paleointensity-assisted chronostratigraphy.

Identification of cytotoxic compound from Artocarpus communis leaves against P-388 cells.

Abstract: In the course of continuing research for finding bioactive compounds from Indonesian plants, the leaves of Artocarpus communis was extracted by ethanol. This extract partitioned with n-hexane-water (1:4) and then water extract was partitioned with dichloromethane. Dichloromethane extract was purified by column chromatography techniques on silica gel to afford yellow crystal (F-1). Based on LC-MS, 1H-NMR and 13C-NMR (1D and 2D) spectra and compared with previous spectral data, it was identified as prenylated flavonoid, 1-(2,4-dihydroxyphenyl)-3-[8-hydroxy-2-methyl-2-(4-methyl-3-pentenyl)-2H-1-benzopyran-5-yl] 1-propanone. This compound showed significant cytotoxicity against murine P-388 leukemia cells.

Biodiversity, distribution, and abundance of the tropical anguillid eels in the indonesian waters

Abstract: In order to understand biodiversity, distribution, and abundance among the tropical anguillid eels in the Indonesian waters, inshore migration mechanism of the juvenile anguillid eel (glass eel) to the estuaries of western, central, and eastern region of Indonesian waters were examined using both morphology and genetic analyses. A total of 9 species/sub species of anguillid eels (Anguilla bicolor bicolor, A. nebulosa nebulosa, A. bicolor pacifica, A. interioris, A. borneensis, A. celebesensis, A. marinorata, A. obscura and A. megastoma) were recognized to recruit at the mouth of 15 rivers through Indonesian archipelago. Species/subspecies diversity and distribution of recruiting juveniles differs in the estuaries of each region. In the western region that represented by estuary of Krueng Aceh, Batang Antokan, Air Kertaun, Cibaliung, Citanduy, Progo, and Pacitan Rivers, three species and sub species (A. bicolor bicolor, A. nebulosa nebulosa and A. bicolor pacifica) were found. In the central region that represented by estuary of Mahakam, Palu, Dumoga, Poigar, Bone, and Poso Rivers, five species and sub species (A. borneensis, A. celebesensis, A. marinorata, A. bicolor pacilica and A. interioris) were found. In the eastern region that represented by estuary of Akelamo and Pami Rivers, four species (A. marinorata, A. interioris, A. obscura and A. megastoma) were found. During the 6 months investigation from May to October 2005, abundance of the juveniles was higher in the central region compared with western and eastern regions. These results were suggested that inshore migration mechanism of tropical anguillid eels recruiting in tropical estuaries of Indonesian waters differs among regions.