iTRAQ-based proteomic profiling of the marine medaka (Oryzias melastigma) gonad exposed to BDE-47

A recent study demonstrated that 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) may have an adverse effect on the reproduction in marine medaka (Oryzias melastigma), but the molecular mechanisms remain largely unknown. In this study, we investigated the protein expression profiles of male and female gonads of O. melastigma exposed to dietary BDE-47 at two dosages (0.65 and 1.30 μg/g/day, respectively) for 21 days. Extracted proteins were labeled with iTRAQ and analyzed on a MALDI TOF/TOF analyzer, as results, 133 and 144 unique proteins were identified in testis and ovary, respective, and they exerted dose- and sex-dependent expression patterns. In testis, among the 42 differentially expressed proteins; down-regulation of histone variants and parvalbumins implicated BDE-47 may disrupt the spermatogenesis and induce sterility in fishes. In ovary, 38 proteins were differentially expressed; the elevation of vitellogenins and apolipoprotein A–I expression indicated BDE-47 acts as an estrogen-mimicking compound and led to reproductive impairment in O. melastigma.     

Bathymetric and geochemical investigation of Kawah Ijen Crater Lake, East Java, Indonesia

A bathymetric survey of Kawah Ijen crater lake was conducted by acoustic sounding in 1996 to compare the lake morphology with those measured in 1922, 1925 and 1938, and to calculate the present lake volume. Even though the lake experienced several hydrothermal eruptions, the maximum depth became shallower (182 m) than before (200 m), resulting in a reduced lake volume (3.0×10⁷ m³).Fifty-two major and minor constituents including rare earth elements and polythionates (PT) of the lake waters at various depths were determined by ICP-AES, ICP-MS and HPLC, respectively. These ions except for several volatile elements are taken up by lake fringe through congruent dissolution of pyroclastics of Kawah Ijen volcano. Most ions are homogeneously distributed throughout the lake, although PT showed a considerable vertical variation. Rare earth elements (REE) in the Kawah Ijen water as well as those from other hyper-acidic crater lakes show distribution patterns likely due to the three rock dissolution (preferential, congruent and residual) types, and their logarithmic concentrations linearly depend upon the pH values of the lake waters.Using the PT degradation kinetics data, production rates of PT, injection rates of SO₂ and H₂S into the lake were estimated to be 114, 86 and 30 tons/day, respectively. Also travel time of the spring water at the Banyupahit Riverhead from Kawah Ijen was estimated to be 600–1000 days through the consideration of decreasing rates of PT. Molten sulfur stocks containing Sn, Cu, Bi sulfides and Pb-barite exposed on the inner crater slope were presumed to be extinct molten sulfur pools at the former lake bottom. This was strongly supported by the barite precipitation temperature estimated through the consideration of the temperature dependence of Pb-chlorocomplex formation.     

Magnotospheric imaging of high latitude ion outflows

High latitude ion outflows mostly consist of upward streaming O⁺ and He⁺ emanating from the ionosphere. At heights above 1000 km, these flows consist of cold and hot components which resonantly scatter solar extreme ultraviolet (EUV) light, however, the ion populations respond differently to Doppler shifting resulting from the large relative velocities between the ions and the Sun. The possibility of optical detection of the Doppler effect on the scattering rate will be discussed for the O⁺ (83.4 nm) ions. We have contrasted the EUV solar resonance images of these outflows by simulations of the 30.4 nm He⁺ and 83.4 nm O⁺ emissions for both quiet and disturbed geomagnetic conditions. Input data for the 1000 km level has been obtained from the EICS instrument aboard the Dynamics Explorer satellite. Our results show emission rates of 50 and 56 milli-Rayleighs at 30.4 nm for quiet and disturbed conditions and 65 and 75 milli-Rayleighs at 83.4 nm for quiet and disturbed conditions, respectively, obtained for a polar orbiting satellite and viewing radially outward. We also find that an imager at an equatorial distance of 9 R_E or more is in a favorable position for detecting ion outflows, particularly when the plasmapause is depressed in latitude. However, an occultation disk is necessary to obscure the bright plasmaspheric emissions.     

Observations on the biota of an estuarine beach at Hardys Bay (NSW, Australia) following a spillage of aldrin

An industrial accident resulted in a spillage of aldrin onto an estuarine beach at Hardys Bay, New South Wales. Samples of water and sediment were taken 3 weeks later to measure the level of contamination resulting from the spill. The abundances of some intertidal biota were also determined at the site of the spillage and in other uncontaminated areas.

Three weeks after the spill, samples of water were not contaminated by aldrin but samples of sediment from the surface in the vicinity of the drain contained aldrin. In comparison to uncontaminated locations the abundances of crustacea were greatly reduced in the vicinity of the drain but abundances of polychaetes were not significantly different. The field data on the relative susceptibility of the two groups of animals agrees well with laboratory derived LC50 data for crustacea and polychaetes.

The study suggests that degree of contamination of water and sediment may not always be an accurate reflection of acute impact on biota, and that different components of the biota can show different reactions to the presence of a toxic chemical.     

Engineering source model for strong ground motion

A new engineering source model consistent with seismological concepts for simulating strong-motion accelerograms (SMAs) is presented in this paper. The source region is modeled as a horizontally layered elastic medium to cater for site dependency. The moment field acting on the rupture plane is decomposed into space and time functions, which is a novel concept. The spatial and temporal components are determined for six well-recorded earthquakes using the corresponding recorded SMA. The obtained spatial variations indicate that they can be modeled as an anisotropic random field. The temporal components of all the six events are transients, with typical frequency spectra. Based on these results, a simplified source model is proposed for the synthesis of SMA during strong earthquakes. The model is validated by simulating strong-motion acceleration time histories at stations deliberately kept out of the modeling exercise. It is found that the present model is efficient in simulating observed time histories. The proposed model is also illustrated by simulating an ensemble of acceleration time histories for the Kutch earthquake of 26th January 2001 using only the few known source parameters.     

Geochemistry of surface sediments in tsunami-affected Sri Lankan lagoons regarding environmental implications

The December 26, 2004 Indian Ocean tsunami was one of the largest in human history, devastating the coastal wetlands of surrounding countries. This study present the chemical analyses of tsunamigenic and pre-tsunami sediments from Hikkaduwa and Hambantota lagoons in southern Sri Lanka, to assess their geochemical composition, their source, and subsequent environmental impacts. Principal component analysis of the tsunami sediments shows that 42% of the total variance is accounted for calcium oxide and Sr. That is, the tsunami deposits are rich in biogenic phases derived from shallow marine sediments. High organic matter contents of the tsunami sediments of up to 80 wt% also support this interpretation. The association of chlorine (<9.4 wt%), brome (<170?mg/kg), arsenic (<17?mg/kg), iron (III) oxide (<12.9 wt%) and sulfur (<7.6 wt%) accounts for 33% of the variance, reflecting higher salinity. This further suggests that the sediments were mainly derived from a marine environment, rather than from non-marine sands and/or soils. Immobile element contents and relations (thorium, scandium and zirconium) suggest that the tsunami sediment source was mostly felsic in composition, with some mafic component, and mixed with predominantly shallow marine shelf or slope sediments. Additional compositional variations in the tsunami sediments in both lagoons may be associated with variations of wave strength along the coast and by the morphology of the continental shelf. Lower elemental abundances in Hambantota lagoon sediments compared to Hikkaduwa equivalents may thus reflect a greater non-marine component in the former, and greater shelf sediment component in the latter.     

Geodynamics and underlying bedrock of the magnetically active crust layer of the Lut block,Eastern Iran

The Curie point depth map of Eastern Iran was constituted from spectral analysis of the aeromagnetic data. The reduction to pole (RTP) was applied to the magnetic anomaly data. The Curie point depth values from 165 overlapping blocks, 100 × 100 km in size, have been estimated. The Curie point depth method provides a relationship between the 2-D FFT power spectrum of the magnetic anomalies and the depth of magnetic sources by transforming the spatial data into the frequency domain. The centroid and top depth of the magnetic sources (respectively Z₀ and Z_t) is calculated from radially averaged log power spectrum for each block. Finally, the Curie point depth of Eastern Iran is obtained by Z_b = 2Z₀–Z_t. The highest value of 24 km is located in eastern and western boundaries of the Lut block, and the lowest value of 12 km is located at north of study area. The shallow depths in the Curie-point depth map are well correlated with the young volcanic areas and geothermal potential fields. Geothermal gradient ranging from 24 to 45°C/km. The deduced thermal structure in eastern Iran has a relationship with orogenic collapse associated with delamination of thickened lithospheric root between the Lut and Afghan continental blocks.