A New Coastal Marine Ecosystem Model Study Coupled with Hydrodynamics and Tidal Flat Ecosystem Effect

A new coastal marine ecosystem model was developed, which was composed of pelagic and benthic ecosystems, and was applied to Mikawa Bay, Japan. This model deals with variations of biochemical and physical interactions among dissolved oxygen and C–N–P species (composition formed out of carbon, nitrogen and phosphorus elements) so that it resolves the flux dynamics of carbon, nitrogen, phosphorus and oxygen elements. The physical and biochemical mechanism figured in this model is constructed for the purpose of simulating the estuarine lower trophic ecosystem, in areas where the sea was too deep for light to reach the sea-bottom. As a result of coupling the benthic with pelagic system, the effect of process of sedimentation and nutrient diffusion back to the pelagic system could be indicated. In addition, by implementing the tidal flat ecosystem model's calculation result, the integrated model can include the effect of water purification in tidal flats where the light can reach the sea-bottom, and where sea-weed, sea grass and benthic algae exist. In this study, the model indicates that oxygen-depleted water exists at the sea-bottom especially in summer mainly caused by an increase of oxygen consumption in the benthic system and a decrease of the vertical mixing water process. Furthermore, by comparing the case – with the tidal flat ecosystem model and the case without it, the effect of water purification of tidal flat estuaries was indicated. From the viewpoint of a short time scale, the tidal flat has the potential to restrict red tide (rapid increase of phytoplankton), and from the viewpoint of a long time scale, it restricts the sedimentation of detritus. Restricting the sedimentation prevents oxygen-depleted water occurring in the coastal marine system of Mikawa Bay.     

Strong interaction between the ring system and the ionosphere of saturn

An abnormally low electron density in the Saturnian ionosphere observed by the radio occultation experiment of the Pioneer 11 may be explained in terms of the contamination of water in the Saturnian upper atmosphere from its ring system.     

The structure of cometary atmospheres

The temperature distributions in cometary atmospheres at various heliocentric distances for comets of Bennett and Encke types have been calculated by taking into account heating due to the absorption of solar ultraviolet radiation, cooling by H₂O far infrared emission, and various dynamical processes (expansion, advection, and thermal conduction). The agreement of the results with the observations is in general satisfactory. The conversion of CH₄ and NH₃ to CO and N₂ through thermochemical reaction with H₂O is concluded to be impossible, since the temperature is too low at a heliocentric distance 1.5 AU where CO⁺ ions begin to be observable.     

Spatial distribution of deuterium in atmospheric water vapor: Diagnosing sources and the mixing of atmospheric moisture

We measured the stable isotopic composition of hydrogen (δD) within atmospheric water vapor collected simultaneously at six sites in the vicinity of a lake (Lake Kasumigaura, Eastern Japan) to determine its spatial distribution characteristics and thereby diagnose sources and mixing of atmospheric moisture. The measured spatial distribution of δD showed no relation to distance from the lake, although it showed a correlation with the distribution of the water-vapor mixing ratio Q. For two of the three sampling days, we found a simple two-component (i.e., water vapor transpiring from local land surfaces and pre-existing vapor in the background atmosphere) mixing line in a Keeling plot (i.e., δ − 1/Q diagram). On a third day, however, contributions from lake evaporation were detected in addition to the above components. On this day, lake-derived vapor accounted for approximately 10-20% of atmospheric water vapor at the sites located leeward of the lake. The observed differences in mixing patterns among sampling days can be explained by a simple atmospheric moisture budget. Thus, it is likely that simultaneous isotopic measurements of atmospheric water vapor at multiple locations with aid of Keeling plot are capable of giving us useful information in diagnosing the sources and mixing pattern of the vapor.     

Determination of Bromine and Iodine in Twenty-three Geochemical Reference Materials by ICP-MS

Trace amounts (from nanogram to microgram levels) of bromine and iodine were determined by inductively coupled plasma-mass spectrometry (ICP-MS) in twenty-three geochemical reference materials issued by the GSJ, USGS, IAEA etc. The pyrohydrolysis technique was used to separate bromine and iodine from samples analysed in the form of powder. The accuracy and precision of the experimental values were assessed by the comparative analysis of well established reference materials such as USGS AGV-1, BCR-1 and IGGE GBW07312. The measured values agreed well with reported values within a 10% error range. We also report reliable new data for these elements in these geochemical reference materials.     

Tectono–Magmatic Evolution and Metallogenesis along the Northeast Jiangxi Deep Fault, China

Abstract: From the southernmost part of Jiangsu province to the northeastern part of Jiangxi province, China, the Northeast Jiangxi Deep Fault runs for about 400 km length with a width of 30 to 40 km. This fault marks the suture zone of two ter-ranes of Proterozoic age. At the both sides of the fault, Yanshanian granitic activity is recognized. That is, the Dexing-Wuyuan porphyry belt on the NW side of the fault, and the Damaoshan-Lingshan granite belt on the SE side. The former activity is characterized by the occurrence of small stocks of granodioritic composition, rich in siderophile elements but poor in LIL elements. No distinct Eu anomaly is recognized in the REE pattern, and a low initial ⁸⁷Sr/⁸⁶Sr ratio is reported. Magnetite, sphene and apatite are observed as accessory minerals. On the contrary, granitic activity on the SE side of the fault is characterized by the occurrence of composite batholiths, in general of granitic to monzogranitic composition, rich in LIL and alkali elements but poor in siderophile and alkali earth elements. A strong Eu anamaly is recognized in the REE pattern, and initial ⁸⁷Sr/⁸⁶Sr ratios are as high as 0. 716. Fluorite, zircon and REE minerals are observed as accessory minerals. These two contrasting granitic activities are refered to as syntexis– and transformation–types, respectively, following the classification commonly used in China, and have similar petrochemical characteristics to those defined for the magnetite– and ilmenite–series, and I– and S-type granitoids. Considering that the above igneous activity occurred far from the supposed subduction zone along the East Coast of China, intracontinental A-type (continent to continent) subduction is proposed to have occurred northwestwards along the NE Jiangxi Deep Fault during Yanshanian time due to a strong compressional stress from SE to NW. A-type subduction introduced the continental slab to some depth, and resulted in the production of the paired granitic activity observed on both sides of the fault. Many mineral deposits are associated with both granitic belts. In the Dexing-Wuyuan porphyry belt, the Dexing porphyry Cu and Yinshan polymetallic deposits are representative, whereas in the Damaoshan-Lingshan granite belt, several tens of rare metal deposits are known such as the Geyuan Nb–Ta–W–Sn deposits. Metal assemblages of those deposits reflect the source materials of magmas in both granitic belts.     

Rare-earth and trace elements in the Quaternary volcanic rocks of Hokkaido,Japan

Seven rare-earth elements (La, Ce, Sm, Eu, Tb, Yb, Lu) and Co, Cr, Sc, Ba, Hf and Th have been determined by non-destructive neutron activation analysis on the Quaternary volcanic rocks in Hokkaido, Japan. The trace-element abundances are discussed in terms of the petrological problems, particularly the origin of calc-alkali magma. On the basis of the La/Sm ratio and the contents of K, Ba, Th and La, lateral variations in the contents of trace elements exist across the Kurile and the northern Honshū arcs. The calc-alkali rocks can be classified into three types which correspond to Kuno's three basalt-magma types. There is no essential difference in the rare-earth patterns between the basaltic rocks and the associated calc-alkali rocks in each petrographic province. This suggests that the calcalkali rocks may be derived from the basaltic magmas by fractional crystallization under certain conditions.     

An experimental study of the partitioning of K,Rb, Cs,Sr and Ba between clinopyroxene and liquid at high pressures

The partition coefficients of K, Rb, Cs, Sr and Ba between clinopyroxene and liquid were experimentally determined in the system diopside-albite-anorthite-water at 15–30 kb and 1100–1200°C. Clinopyroxene and liquid (glass) were separated by a new technique (differential dissolution technique—DDT) and analyzed by isotope dilution. The partition coefficients lie in the range 0.054–0.081 for Sr, 0.0014–0.0026 for K, 0.00078–0.0023 for Ba, 0.0010–0.0041 for Rb, 0.00035–0.0036 for Cs. Variations of the partition coefficients with pressure, temperature and composition of the phases are relatively small, though no systematic study of these parameters was attempted.     

Japanese early-warning for debris flows and slope failures using rainfall indices with Radial Basis Function Network

Early-warning systems for natural disasters are important tools for disaster risk reduction and for achieving sustainable development and livelihoods. In 2005, the Japanese government initiated a new nationwide early-warning system for landslides disasters. The main methodology of the system is to set a criterion for occurrences of debris flows and slope failures based on several rainfall indices (60-min cumulative rainfall and soil–water index) in each 5-km grid mesh covering all of Japan. Because many of the records of mass movements are lacking in scientific precision on timing and location, the system applies Radial Basis Function Network methods to set the criterion based primarily on rainfall data recorded as not triggering disasters. Since the end of March 2007, under torrential rainfall conditions, early-warning information has been disseminated as part of weather news using TV, radio, and the Internet. Because of the increasing worldwide recognition of the importance of early-warning systems for natural disaster reduction, the aim of this article is to introduce the new Japanese early-warning system to the international landslide community. In this article, the method, the system, and the result of its application to landslide disasters in 2009 are presented.     

Seasonal changes of the South American monsoon system during the Mid-Holocene in the CMIP5 simulations

The South American Monsoon System (SAMS) is a major climatic feature of South America, and its domain extends from Amazon to La Plata basin. The SAMS region is vulnerable to variations of climate and precipitation patterns, which could impact economic activities and lead to potential societal consequences. In the face of a warming future scenario, the importance of the study of the past climate with numerical simulations is to evaluate the climate models and to assure the reliability of future projections. Here we investigate the Mid-Holocene SAMS, evaluating changes in strength, life cycle and associated dynamical mechanisms in ten Earth System Models simulations. Our results show that the SAMS was weaker in the Mid-Holocene than in the pre-industrial climate in December–January–February (DJF), but stronger in September–October–November (SON). This is probably a consequence of insolation variations in the Mid-Holocene, which contributed to changes in the moisture flux from the Atlantic Ocean to the continent, the strength of the upper-level atmospheric circulation, and the amount of precipitation over the SAMS region. Moreover, we suggest that the life cycle of the SAMS was altered during the Mid-Holocene, with an earlier onset and demise. Our results also indicate that Mid-Holocene SAMS changes are connected to precipitation variations near Northeast Brazil, in a dipole configuration of precipitation between western Amazon and Northeast Brazil, due to the influence of the Walker cell. Finally, this study highlights a need for improvement of the numerical models to better simulate the amount of precipitation over South America and the upper-level circulation over western Amazon in SON, which are crucial factors for a more realistic representation of the SAMS.