Dilute acid-soluble phosphorus in fresh air-borne tephras and fixation with an increase in active aluminum and iron

Fresh rhyolite-to-andesite tephras ground to less than 0.15 mm particles contained dilute acid-soluble phosphorus (P) as in the case of cultivated upland soils in Japan. The amount of P determined by Truog extraction (Truog P) ranged between 119 and 784 mg P₂O₅ kg^-1 in 12 rhyolite-to-andesite tephras, and that determined by a modified Bray P₂ extraction method (modified Bray P₂) ranged between 133 and 812 mg P₂O₅ kg^-1. In contrast, the Truog P-content in fresh basaltic andesite-to-basalt tephras was only 3.4–23 mg P₂O₅ kg^-1, and the modified Bray P₂-content was in the range of 41–185 mg P₂O₅ kg^-1, although the total P-content of the two tephra groups was in almost the same range.

Among 12 rhyolite-to-andesite tephras, those from Mt. Usu that erupted in 1977 and from Mt. Pinatubo that erupted in 1991 were selected for detailed studies. Fine particle size fractions of these tephras showed higher Truog P values than the coarse ones. The Truog P values further increased in the heavy fraction with a particle density of 2.8 or greater. In this heavy fraction, apatite was detected by energy dispersive X-ray (EDX) analysis, indicating the contribution of the mineral to the high Truog P. Dilute sulfuric acid treatment of the tephras at 80°C for 15 d followed by neutralization increased the amount of active Al and Fe and decreased the Truog P values of these tephras. These results suggested that the amount of apatite rapidly decreased with weathering in volcanic ash soils.     

Heavy solution methord for determination of volcanic glass content in tephras and tephra-derived soils

Abstract

Volcanic glass is the most important primary mineral for the tephra-derived soils because it is the most abundant and the most weatherable among the primary minerals. The chemical properties of volcanic glass in tephras are closely related to the rock types of tephras (Kobayashi et al. 1976; Yamada and Shoji 1983; Shoji 1986; Yamada 1988) and influence on the chemical and clay mineralogical properties of tephra-derived soils (Saigusa and Shoji 1986).     

Carotenoids in marine invertebrates living along the Kuroshio current coast

Carotenoids of the corals Acropora japonica, A. secale, and A. hyacinthus, the tridacnid clam Tridacna squamosa, the crown-of-thorns starfish Acanthaster planci, and the small sea snail Drupella fragum were investigated. The corals and the tridacnid clam are filter feeders and are associated with symbiotic zooxanthellae. Peridinin and pyrrhoxanthin, which originated from symbiotic zooxanthellae, were found to be major carotenoids in corals and the tridacnid clam. The crown-of-thorns starfish and the sea snail D. fragum are carnivorous and mainly feed on corals. Peridinin-3-acyl esters were major carotenoids in the sea snail D. fragum. On the other hand, ketocarotenoids such as 7,8-didehydroastaxanthin and astaxanthin were major carotenoids in the crown-of-thorns starfish. Carotenoids found in these marine animals closely reflected not only their metabolism but also their food chains.     

Characteristics of effluent load from a watershed including irrigation ponds

This paper describes an attempt to estimate the mass budget of irrigation ponds within a watershed and the possibilities to control the effluent load of nutrients from the watershed located in the Kyotanabe area. The paddy field lots were irrigated by the ponds and several mountain streams. In the study watershed, there were two ponds located on the upper and lower sides of a paddy area. Water could be pumped up from the lower pond to the upper pond as necessary. At the ponds, the total amount of nitrogen and phosphorus in the inflow loads including the sediment release was larger than those in the outflow loads. In SS, the effect of load reduction in the ponds was high. It is assumed that organic load reduction was not expected in the ponds. The study result indicates that it is possible to remove the nutrients in the ponds when a larger amount of water is pumped up than when the ponds are only in irrigation use. Moreover, the removal capacities of the nutrients could probably be increased in both ponds by controlling the amount of sediment releases. Electronic Publication     

Dietary utility of enzyme-treated fish meal for juvenile Pacific bluefin tuna <Emphasis Type="Italic">Thunnus orientalis</Emphasis>

ABSTRACT:   In order to develop an artificial diet, the dietary utility of enzyme-treated fish meal was investigated for juvenile Pacific bluefin tuna Thunnus orientalis (PBT). Diets containing each 63% of Chilean fish meal (FM), enzyme-treated Chilean fish meal (EC) and enzyme-treated Peruvian fish meal (EP), with 10% bonito oil and raw sand lance Ammodytes personatus (SL) were fed to juvenile tuna six times per day for one week. In a different trial, diets EC and SL were fed to tuna six times per day for 2 weeks. Only diet EC sustained similar growth or caused lower survival and higher feed efficiency, hepato- and enterosomatic indices and final carcass lipid content as compared to those of SL. Diets FM and EP led to lower specific growth rate (SGR) but similar feed efficiency, survival and hepatosomatic index, yet higher enterosomatic index. Moreover, PBT fed diet EC for 2 weeks led to similar growth performance but higher final carcass and hepatic lipid contents, and plasma cholesterol and phospholipid levels than those fed SL. Carcass fatty acid composition of diet EC group had lower 20:5  n -3 and 22:6  n -3 levels than the SL group. These results revealed that EC, as a suitable dietary protein source, could sustain growth of PBT, while dietary bonito oil led to higher carcass lipid but lower accumulation of n -3 highly unsaturated fatty acids.     

Chemical and mineralogical studies of volcanic ashes

The relationships between rock types and mineralogical properties of volcanic ashes were investigated using many volcanic ash samples from different volcanoes.

The heavy mineral fraction was dominated by two pyroxenes and ferromagnetic minerals In almost all the felsic and Intermediate volcanic ashes. Therefore, It was difficult to determine the rock types of felsic and intermediate volcanic ashes according to their heavy mineral composition. It was assumed that the presence of a large quantity of hornblende was related to the origins of the volcanic ashes. On the other hand, the predominant mineral in the heavy mineral fraction of mafic volcanic ashes was volcanic glass (refractive index about 1.59), followed by olivine.

The refractive indices (γ) of plagioclases and orthopyroxenes were 1.553–1,570 and 1.703–1.715 in the felsic volcanic ashes, 1.558–1.580 and 1.705–1,715 in the intermediate ashes, and 1.565–1.576 and 1.697–1.705 in the mafic ashes, respectively. These results indicate the difficulty of determining the rock types of volcanic ashes according to the optical properties of these minerals.     

Nitrogen and oxygen isotope enrichment factors of nitrate at different denitrification rates in an agricultural soil

ABSTRACT

Quantitative evaluation of denitrification by the dual isotope approach, which measures the stable isotope ratios of nitrogen (δ¹⁵N) and oxygen (δ¹⁸O) in nitrate, has been hampered by the wide range of values reported for the ratio of enrichment factors for ¹⁵N and ¹⁸O (¹⁵ε and ¹⁸ε, respectively) during denitrification. The objectives of this study were to determine ¹⁵ε and ¹⁸ε values at different denitrification rates under controlled conditions, and to infer possible mechanisms by which the ¹⁸ε/¹⁵ε ratio is influenced under different conditions. Column experiments were conducted at 25, 15, and 10°C, which enabled determination of ¹⁵ε and ¹⁸ε at different denitrification rates, in the absence of nitrate replenishment from ammonium oxidation and other sources. The values of ¹⁵ε and ¹⁸ε ranged from ?11.8 to ?14.9‰ and from ?8.4 to ?15.9‰, respectively, with ¹⁵ε less sensitive to changes in the denitrification rates. The resultant ¹⁸ε/¹⁵ε ratio, ranging from 0.70 to 1.17, was close to the values reported for sediment incubations, and larger than those for groundwater systems. These results are consistent with the explanations that ¹⁸ε/¹⁵ε value itself is close to unity during denitrification, and that at smaller denitrification rates, concurrent reactions including re-oxidation of nitrite to nitrate lead to smaller apparent fractionation of ¹⁸O and smaller ¹⁸ε/¹⁵ε ratios. This suggests that while linear relationships between δ¹⁸O and δ¹⁵N give a strong evidence of denitrification, apparent ¹⁸ε/¹⁵ε values are site specific and depend on the ambient conditions. In evaluating denitrification in such systems, we suggest the use of ¹⁵ε in preference to ¹⁸ε because ¹⁵ε is less sensitive to denitrification rates.     

Seed and pollen transmission of <Emphasis Type="Italic">Apple latent spherical virus</Emphasis> in apple

To examine whether Apple latent spherical virus (ALSV) has spread among apple trees in an orchard, we surveyed 21 apple trees surrounding two ALSV-infected trees for virus infection using a double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). None of the 21 trees were infected, indicating that ALSV has not spread from the infected trees to the neighboring apple trees since it was first detected in 1984. We analyzed seed embryos and seedlings derived from infected trees and detected ALSV in 10 of 223 seed embryos (4.5%) and 10 of 227 seedlings (4.4%). From these results, we conclude that ALSV is seed-transmitted at a rate of ca. 4.5% in apple. We also analyzed seed embryos and seedlings from uninfected apple trees that were hand-pollinated with pollen from infected trees. We detected ALSV in only 1 of 260 seed embryos and in none of the 227 apple seedlings. This result indicated that the seed transmission rate via infected pollen is only 0–0.38%. In situ hybridization analysis of ALSV-infected apple flower buds showed that ALSV was present inside almost all pollen grains and in all ovary and ovule tissues, including the embryo sac and inner integument.     

Serological survey of Ehrlichia and Anaplasma infection of feral raccoons (Procyon lotor) in Kanagawa Prefecture, Japan

Numbers of feral raccoon; the possible reservoir animal of Ehrlichia and Anaplasma, are increasing in Japan. Thus serological methods were utilized to examine Ehrlichia and Anaplasma infection in raccoons from Kanagawa Prefecture, Japan. By using an indirect immunofluorescence assay, among 187 feral raccoons examined, 1 (0.5%) serologically reacted with Ehrlichia canis, 3 (1.6%) with Ehrlichia chaffeensis and 1 (0.5%) with Anaplasma phagocytophilum with the titers of 1:40 or more. Although screening PCR for Ehrlichia and Anaplasma species failed to detect the presence of ehrlichial DNA in serum samples, results of the serological tests suggested that the feral raccoons might be infected with some species of Ehrlichia and Anaplasma.     

Circadian locomotor activity in Japanese sea catfish <Emphasis Type="Italic">Plotosus lineatus</Emphasis>

To find out whether or not the locomotor activity of the Japanese sea catfish, Plotosus lineatus, shows a circadian rhythmicity, the locomotor activity of this catfish was recorded in a laboratory. All of the catfish recorded (n = 20) showed a nocturnal locomotor activity rhythm under a light–dark (LD) cycle (LD 12:12). The locomotor activity started after the light was turned off, and declined during the period of darkness. In five of the six catfish we examined, locomotor activity shifted gradually over the course of 3–4 days in order to synchronize to the LD cycle after it was advanced by 6 h. Locomotor activity persisted within a constant darkness (DD) in all eight of the catfish. The average free-running period of locomotor activity under DD lasted for 24.2 ± 0.4 h (mean ± SD). Thus, the present results demonstrate that the Japanese sea catfish has an endogenous circadian oscillator entrained by an LD cycle.