Formal education and disaster response of children: evidence from coastal villages in Indonesia

Natural Hazards - Although children are exposed to a high mortality risk during disasters, what determines their disaster response, especially during earthquakes, remains largely unexplored. The...     

Effects of spilled oil on microbial communities in a tidal flat

Effects of spilled oil on microbial communities in tidal flats were examined by use of a simulator for a tidal flat ecosystem. The simulator is composed of a wave generator, a tide control device, and a tidal flat. Sediment for the tidal flat was obtained at a natural tidal flat in Hiroshima Bay, Japan. After stabilizing the benthic organisms, fuel oil C was added to the surface of the flat at 1 lm(-2). Although the total number of micro-organisms remained at 1.5-3.5 x 10(9) cells g(-1) dry sediment irrespective of the addition of oil, bacterial communities which were analyzed based on the 16S rDNA showed clear changes after the addition of fuel oil C and after a subsequent recovery period. Bacterial colonies were randomly isolated from the oil-supplemented sediment during the experiments, and the isolates were examined for susceptibility to hydrocarbons in order to screen the oil-susceptible bacteria. The proportion of oil-susceptible bacteria in the isolates decreased with the addition of the oil. Oil-susceptible bacteria showed an inability to assimilate petroleum compounds as well as an inhibition of growth. The possibility of using oil-susceptible bacteria as an indicator of bioremediation in tidal flats was discussed.     

Concentrations of 222 Rn, Its Short-Lived Daughters And 212 Pb And Their Ratios Under Complex Atmospheric Conditions And Topography

Atmospheric activity concentrations of ²¹²Pb and short-lived ²²²Rndaughters, together with meteorological elements, have been observed continuously atthree sites at Kamisaibara Village in Japan. In addition, atmospheric activity concentrationof ²²²Rn, equilibrium-equivalent concentration of ²²²Rn and conditionsof the lower atmosphere were observed for three intensive observation periods at Akawase,one of the three sites in Kamisaibara Village. The equilibrium-equivalent concentration of²²²Rn is almost the same as the atmospheric activity concentration of short-lived²²²Rn daughters.The activity concentrations of ²¹²Pb and the short-lived ²²²Rn daughtersand their ratio were low in the daytime owing to convective mixing, and high at nightowing to the surface-based inversion during periods of no precipitation. Their variationshave several patterns corresponding to the scale of the drainage wind or weak mixing.Mechanical mixing due to strong winds through both day and night during the first andsecond observation periods made the atmospheric activity concentrations of ²¹²Pb and the short-lived ²²²Rn daughters continuously low. However, their ratios werecontinuously high during the first period yet continuously low during the second period.This difference can be explained by the effect ofextraction of ²²⁰Rn and ²²²Rndue to strong winds and snow cover. There were also cases in which the ratio of theatmospheric activity concentration of ²¹²Pb to that of the short-lived ²²²Rndaughters at night was equal to or less than the ratio in the daytime. Thisinverse trend, asin the periods of no precipitation mentioned above, is considered to be due to near-neutralconditions on these nights.We find a difference in the ratio of the equilibrium-equivalent concentration of²²²Rn (the activity concentration of short-lived ²²²Rn daughters) tothe activity concentration of ²²²Rn during the first observation period and thatduring the second. The difference can be explained by snow cover on the ground. Wealso find differences among the ratios of the activity concentration of the short-lived²²²Rn daughters to that of ²²²Rn during the three observation periods.These differences can be explained by the submergence of paddy fields.     

Holocene evolution of an estuary on a tectonically rising coast: the Pakarae River locality, eastern North Island, New Zealand

Estuarine and beach deposits in the vicinity of the present coastline at Pakarae River record the infilling of an estuary and subsequent development of a sequence of seven marine terraces during Holocene time.

At the maximum of the last glaciation about 18,000 years ago the shoreline at the ancestral Pakarae River was approximately 20 km east of the present shoreline. By about 9000 years BP the sea had transgressed across most of that coastal plain to lie within a few hundred metres of the base of the present coastal hills. Seventeen radiocarbon ages from estuarine deposits record the overall rise in post-glacial sea level, but in the period c. 9500-7000 yrs BP there are reversals to the overall rising trend. Between 9500 and 8500 yrs BP there appears to have been a eustatic fall in sea level of at least 4 m. This observation is supported by data from several other localities around New Zealand. Maximum transgression occurred about 6500–7000 yrs BP when the sea reached the base of hillslopes and an extensive estuary existed behind a barrier bar.

Since that time the barrier bar disappeared, probably due to stranding in an uplift event, and the coastline advanced progressively outward toward its present position. Coastal progradation (sea level regression) and subsequent erosion have occurred in association with episodic large earthquakes at about 6700, 5400, 3910, 2450, 1570, 1000 and 600 yrs BP. The present distribution of terraces has been influenced by coastal erosion, which has removed all trace of some terraces from some areas, and river erosion has modified the marine terraces near the river.     

Secondary mineral formation associated with respiration of nontronite,NAu-1 by iron reducing bacteria

Experimental batch and miscible-flow cultures were studied in order to determine the mechanistic pathways of microbial Fe(III) respiration in ferruginous smectite clay, NAu-1. The primary purpose was to resolve if alteration of smectite and release of Fe precedes microbial respiration. Alteration of NAu-1, represented by the morphological and mineralogical changes, occurred regardless of the extent of microbial Fe(III) reduction in all of our experimental systems, including those that contained heat-killed bacteria and those in which O₂, rather than Fe(III), was the primary terminal electron acceptor. The solid alteration products observed under transmission electron microscopy included poorly crystalline smectite with diffuse electron diffraction signals, discrete grains of Fe-free amorphous aluminosilicate with increased Al/Si ratio, Fe-rich grains, and amorphous Si globules in the immediate vicinity of bacterial cells and extracellular polymeric substances. In reducing systems, Fe was also found as siderite. The small amount of Fe partitioned to the aqueous phase was primarily in the form of dissolved Fe(III) species even in the systems in which Fe(III) was the primary terminal electron acceptor for microbial respiration. From these observations, we conclude that microbial respiration of Fe(III) in our laboratory systems proceeded through the following: (1) alteration of NAu-1 and concurrent release of Fe(III) from the octahedral sheets of NAu-1; and (2) subsequent microbial respiration of Fe(III).