Transformation of arsenic compounds in modern intertidal sediments of Iriomote Island, Japan

The arsenic accumulation process in intertidal sediments of Iriomote Island, Japan, is analyzed as a naturally balanced arsenic-fixation system. Major and minor element chemistry is analyzed by X-ray fluorescence photometry, mineralogy is investigated by X-ray diffractometry, and four arsenic compounds are characterized by hydrogen-generated atomic absorption photometry. It is found that arsenic is accumulated by iron hydroxides/oxides precipitated following the decomposition of humic acids in the shallower sediment, and is subsequently incorporated into iron sulfide minerals at depth. The arsenic is immobile during incorporation into arsenic-bearing phases, suggesting that arsenic is unlikely to be released into the porewater under natural conditions in early diagenesis. The formation and decomposition of arsenic-bearing organic compounds appear to be associated with the formation and decomposition of arsenic in oxyhydroxides/oxides, suggesting that microbial activity may play an important role in controlling the behavior of arsenic and arsenic-bearing phases in the sediment column.     

West Nile virus in American crows (Corvus brachyrhynchos) in Canada: projecting the influence of climate change

The present study examined the influence of climate change on the spread of West Nile virus (WNV) in Canada among American crows (Corvus brachyrhynchos) by first identifying the significant climatic and environmental determinants of positive WNV cases in American crow specimens from 2009 to 2013. Using this information, we projected climate change scenarios on the potential spread of WNV in American crow species in Canada for three time periods: 2015–2039, 2040–2069, and 2070–2099. Using bird specimen, meteorological and land-use data, the statistical association between positive WNV cases in American crows and the environment was assessed by means of a general linear mixed model. Statistical results revealed that temperature and precipitation were significantly related to positive cases of WNV in American crows. Thus, climate change projections of summer mean temperature averages were projected for the three time periods. Climate change scenarios were created and imported into Quantum Geographic Information System (QGIS) and an algorithm was applied using the raster calculator to spatially delineate current and future areas of risk. Spatial analyses revealed that increased warming in the near future may increase the latitudinal extension of WNV in American crows in Canada.     

Cause and countermeasure of long-period oscillations of moored ships and the quantification of surge and heave amplitudes

Long-period oscillations of moored ships whose periods are about 1 or 2 min cause many troubles in many ports and harbours. It is necessary to investigate these phenomena and verify their causes and countermeasures in each case because they are strongly dependent on the environment of each port and harbour. From this point of view, long-period oscillations of moored ships in the Port of Shibushi in Japan were investigated by means of wave observations, the image processing of moored ship motions using the video camera and motion-capture software and numerical simulations. From observation results, the relationship between offshore long-period waves and long-period oscillations of moored ships was recognized and surge and heave amplitudes were quantified by using wave data in order to forecast moored ship motions. Furthermore, from observation and numerical results, it was revealed that long-period waves with the peak period of 120 s from the offshore typhoon kept or exaggerated the local harbour oscillation of 60–70 s and it caused long-period oscillations of moored ships. Numerical results in case of reducing the reflection coefficient of the target berth implied that it ceased the local harbour oscillation and it would give an effective countermeasure to reduce long-period oscillations of moored ships in the Port of Shibushi.     

Field survey of the East Java earthquake and tsunami of June 3, 1994

A field survey of the June 3, 1994 East Java earthquake tsunami was conducted within three weeks, and the distributions of the seismic intensities, tsunami heights, and human and house damages were surveyed. The seismic intensities on the south coasts of Java and Bali Islands were small for an earthquake with magnitudeM 7.6. The earthquake caused no land damage. About 40 minutes after the main shock, a huge tsunami attacked the coasts, several villages in East Java Province were damaged severely, and 223 persons perished. At Pancer Village about 70 percent of the houses were swept away and 121 persons were killed by the tsunami. The relationship between tsunami heights and distances from the source shows that the Hatori's tsunami magnitude wasm=3, which seems to be larger for the earthquake magnitude. But we should not consider this an extraordinary event because it was pointed out byHatori (1994) that the magnitudes of tsunamis in the Indonesia-Philippine region generally exceed 1–2 grade larger than those of other regions.     

Trace element compositions of jadeite (+omphacite) in jadeitites from the Itoigawa-Ohmi district, Japan: Implications for fluid processes in subduction zones

Abstract   Trace-element compositions of jadeite (±omphacite) in jadeitites from the Itoigawa-Ohmi district of Japan, analyzed by a laser-ablation inductively coupled plasma mass spectrometry technique showed chemical zoning within individual grains and variations within each sample and between different samples. Primitive mantle-normalized patterns of jadeite in the samples generally showed high large-ion lithophile element contents, high light rare earth element/heavy rare earth element ratios and positive anomalies of high field strength elements. The studied jadeitites have no signatures of the protolith texture or mineralogy. Shapes and distributions of minerals coupled with chemical zoning within grains suggest that the jadeitites were formed by direct precipitation of minerals from aqueous fluids or complete metasomatic modification of the precursor rocks by fluids. In either case, the geochemical characteristics of jadeite are highly affected by fluids enriched in both large-ion lithophile elements and high field strength elements. The specific fluids responsible for the formation of jadeitites are related to serpentinization by slab-derived fluids in subduction zones. This process is followed by dissolving high field strength elements in the subducting crust as the fluids continue to circulate into the subducting crusts and serpentinized peridotites. The fluids have variations in chemical compositions corresponding to various degrees of water–rock interactions.     

Comparison of observed and theoretically calculated seiches of Heda Bay,Japan

We carried out observations of sea-level fluctuations simultaneously at three stations on the coast of Heda Bay, Honshu, Japan, using supersonic-type water level gauges controlled by a personal computer. Analyses of the obtained data showed predominant spectral peaks at periods of 7.6, 2.0 and 1.3 minutes for all three stations. Comparison of the observed data with numerically calculated normal oscillation modes of the bay indicates that these three spectral peaks correspond to the theoretical first, third and seventh normal modes of the basin respectively, judging from the results of cross-spectral analyses. The reason for the absence of the remaining normal modes, especially of the second or the lateral first mode of the basin, is briefly considered.     

Geospatial analysis between the environment and past incidences of West Nile virus in bird specimens in Ontario,Canada

Over recent years, the prevalence of the West Nile virus (WNV) in Canada has greatly increased due to various factors including changes in feeding behavior among WNV vectors. To understand whether changes in climate are a significant factor, the association between the environment and cases of WNV-infected bird specimens from 2009 to 2012 in Ontario, Canada, was examined using SAS and Quantum Geographic Information Systems (QGIS). Through a generalized linear mixed analysis, monthly totals of cooling degree days (CDD) and a two-way interaction between maximum temperature (Tmax) and precipitation were significantly positively associated to past incidences of WNV; while Tmax, precipitation, and a two-way interaction between CDD and precipitation were significantly negatively associated to past incidences of WNV. With the effects of increased warming, locations at higher latitudes in Canada may soon be at risk to WNV, as a positive case of WNV in a bird specimen was found close to the near north of Ontario in 2012.     

Fractionation of hydrogen isotopes during phytol biosynthesis

Deuterium (D) depletion in phytol relative to ambient water as well as other lipids has been widely observed in various biological and geological samples; however, the mechanism for the depletion remains unknown. We have determined the hydrogen isotopic compositions of phytol and its precursors in cucumber cotyledons and have evaluated the fractionation of hydrogen isotopes during phytol biosynthesis. The hydrogen isotopic compositions of geranylgeraniol, dihydrogeranylgeraniol, tetrahydrogeranylgeraniol and phytol are ?281‰, ?302‰, ?325‰ and ?345‰, respectively. The results suggest that significantly D-depleted hydrogen is incorporated stepwise during hydrogenation of geranylgeraniol to phytol. We conclude that hydrogenation is important in controlling D depletion in phytol.     

Rural Social Networks along Amazonian Rivers: Seeds,Labor and Soccer among Communities on the Napo River,Peru

Research on Amazonian communities has focussed more often on rural‐urban linkages than on links among rural communities. This is unsurprising, given the low density of population, limited intercommunity commerce, and importance of direct city‐market relations. Social relations among rural communities are also important in shaping rural livelihoods and lifeways. We report on the findings of a large‐scale census of communities in the Napo River basin in northeastern Peru (n=174). Data were gathered on intervillage crop seed acquisition and cooperative labor sharing as two key inputs in agriculture, and on intervillage soccer matches, which are integral to rural social life. We analyze the socio‐spatial networks of each practice, paying attention to settlement patterns, community ethnicity, and differential access to the uplands. We find that seeds and labor flow along soccer network lines. Rural social networks appear to be structured strongly by ethnicity (homophily) and reflect important complementarities between upland and lowland communities (weak ties).