Influence of decomposition on chemical properties of plant- and manure-derived dissolved organic matter and sorption to goethite

Sorption of dissolved organic matter (DOM) plays an important role in maintaining the fertility and quality of soils in agricultural ecosystems. Few studies have examined the effects of decomposition on DOM sorption and chemical characteristics. This study investigated the sorption to goethite (alpha-FeOOH) of fresh and decomposed hydrophilic (HPL) and hydrophobic (HPB) DOM fractions extracted from the shoots and roots of crimson clover (Trifolium incarnatum L.), corn (Zea mays L.), soybean [Glycine max (L.) Merr.], hairy vetch (Vicia villosa L.), and dairy and poultry manures. Sorption was positively related to apparent molecular weight (MWAP), aromaticity as measured by absorptivity at 280 nm, and phenolic acid content. A 10-d laboratory microbial decomposition of the source organic matter generally increased the sorption of the extracted DOM onto goethite. The decomposition effect on sorption was greater for the HPL fractions than for the HPB fractions. There was a decrease in the MWAP values of the DOM samples following sorption to goethite. In many cases the reduction in MWAP was large, indicating a strong preference by goethite for the higher MWAP DOM fractions. The results of this laboratory-based research demonstrate that microbial processes affect the chemical characteristics of DOM which may affect the distribution of soil organic C pools.     

Respiration and ammonia excretion by marine metazooplankton taxa: synthesis toward a global-bathymetric model

For thirteen representative taxa of metazooplankton from various depth horizons (<4,200 m) of the world’s oceans, respiration rate (681 datasets on 390 species) and ammonia excretion rate (266 datasets on 190 species) are compiled and analyzed as a function of body mass (dry mass, carbon or nitrogen), habitat temperature, habitat depth and taxon. Stepwise-regression analyses reveal that body mass is the most important parameter, followed by habitat temperature and habitat depth, whereas taxon is of lesser importance for both rates. The resultant multiple regression equations show that both respiration rate and ammonia excretion rate (per individual) increase with increase in body mass and habitat temperature, but decrease with habitat depth. Some taxa are characterized by significantly higher or lower rates of respiration or ammonia excretion than the others. Overall, the global-bathymetric models explain 93.4–94.2 % of the variance of respiration data and 80.8–89.7 % of the variance of ammonia excretion data. The atomic O:N ratios (respiration/ammonia excretion) are largely independent of body mass, habitat temperature, habitat depth and taxon, with a median of 17.8. The present results are discussed in light of the methodological constraints and the standing hypotheses for the relationship between metabolic rate and temperature. Perspectives for model improvement and possible application of it to plankton-imaging systems for rapid assessment of the role of metazooplankton in C or N cycles in the pelagic ecosystem are briefly discussed.     

Respiration and ammonia excretion of euphausiid crustaceans: synthesis toward a global-bathymetric model

Respiration and ammonia excretion rates of 19–24 euphausiids from the epipelagic through bathypelagic zones of the world’s oceans were compiled. Body mass (expressed in terms of dry mass, carbon or nitrogen), habitat temperature and sampling depth were designated as parameters in multiple regression analysis. Results suggested that the three parameters were highly significant, contributing 71–89 % of the variance in respiration rates and 69–81 % of the variance in ammonia excretion rates. Atomic O:N ratios derived from simultaneous measurements of respiration and ammonia excretion rates ranged from 11 to 90 (median: 27), and no appreciable effects of the three parameters on O:N ratios were detected. If global-bathymetric models for the metabolism and chemical composition of copepods and chaetognaths are compared with those of euphausiids, it becomes evident that euphausiids are unique in that they maintain high metabolic rates and accumulate moderate amounts of energy reserves (lipids).     

Hydrogen peroxide as a new defensive compound in “benzoyl cyanide” producing polydesmid millipedes

Hydrogen peroxide was newly and simultaneously demonstrated with well-known hydrogen cyanide as a component of defensive secretions of “benzoyl cyanide” producing polydesmid millipedes. Presence of hydrogen peroxide was successively evidenced by Trinder reagent’s spray with colorless as well as oily smears of defensive secretions containing benzoyl cyanide and hydrogen cyanide by alkaline picrate paper treatment. Linear correlation was demonstrated between quantities of hydrogen peroxide and benzoyl cyanide. By qualitative assay, seven benzoyl cyanide containing polydesmidans (six species of adults and one species of a nymph at stadium I) tested positive to Trinder reagent, indicative of the presence of hydrogen peroxide (together with hydrogen cyanide), while two cyanogenic species without benzoyl cyanide exhibited negative responses to the reagent. Two types of millipedes were elucidated as species of cyanogenic Polydesmida.     

Spatio-temporal population dynamics of the sand snail Umbonium costatum: importance of ontogenetic migration and annual recruitment variability

The spatio-temporal population dynamics of the subtidal snail Umbonium costatum (Kiener) in Hakodate Bay, northern Japan, are described over a 9-yr period (1982 to 1988, 1992). Annual variations in recruitment success not only caused the highly variable age structure of the population, but also affected its distribution pattern. In heavy recruitment years (1982, 1984 and 1988), location of the densest population differed from the other years, and the areas with 0 yr old individuals were larger. Every year, the distribution of 0 yr olds was mostly restricted to inshore (within 320 m from shore), while the distribution of adults (>0 yr) was mostly restricted to offshore (>320 m from shore). Such patterns may be generated by ontogenetic migration of cohorts to offshore areas. Ontogenetic migration also could have buffered the large annual variation in spat distribution and maintained the small variation in the distribution of adults. (Prince et al. 1988). Density-related migration has also been reported in Acmaea digitalis (Frank 1965), Patella cochlear (Branch 1974) and Patelloida alticostata (Black 1977).Dense populations of the gastropod Umbonium costatum are found in some clean subtidal sandy-bottoms in Japan, e.g. inner part of Hakodate Bay. In the bay, the age structure of U. costatum revealed predominant year-classes. The 0 yr olds were restricted to the shallowest zone (<4 m depth) and most adult (<0 yr) cohorts were restricted to 6 to 7 m depths (Noda 1991a).This paper describes the temporal variability of population structure and distributional patterns of Umbonium costatum, and examines the distribution-regulating processes.     

Feasibility investigation on a dual waste-plastics recycling system concept

Fiber-reinforced plastics (FRP) were first used as a material for boats and bath tubs about 40 years ago. Because of their great durability, wastes including FRP products are increasing. In addition, since the FRP resin is synthesized from expensive reactants, material recycling is highly desirable. Recycling using supercritical water is one solution; however, the cost of producing the high pressure and temperature needed to produce supercritical water prevents the concept from being realized. Therefore, we proposed a system concept based on dual waste-plastics recycling. A numerical survey of the results confirmed that our concept was feasible and would contribute to resource recycling as we expected. Received: January 6, 1998 / Accepted: July 23, 1999     

Carbamoyl phosphate synthetase I deficiency: molecular genetic findings and prenatal diagnosis

We report a Japanese boy who died at Day 28 of life because of severe carbamoyl phosphate synthetase I (CPS1) deficiency that was proven by enzyme assay. By analysis of cDNA and genomic DNA, he was shown to be a compound heterozygote with two point mutations of the CPS1 gene, 840G>C leading to an aberrant splicing and 1123C>T (predicting Q375X). The 840G>C was a mutation described in another Japanese family. Since his parents carried each mutation heterozygously, we performed prenatal diagnosis at 16 weeks of his mother's next gestation by multiplex PCR and melting curve analysis in a single capillary containing two-color fluorescent (LC-Red 640 and LC-Red 705) probes on LightCycler. We analyzed genomic DNA extracted from amniotic cells and found that the fetus was homozygous for the wild-type alleles. At term a healthy girl was born without hyperammonemia. Copyright © 2001 John Wiley & Sons, Ltd.     

Spatial Assessment of the Alder Tree in Kushiro Mire, Japan using Remotely Sensed Imagery – Effects of the Surrounding Land Use on Kushiro Mire

The relationship between alder (Alnus japonica) distribution and surrounding land use in Kushiro Mire was spatially assessed using remotely sensed imagery. From the result, it was found out that the expanding area of alder trees in Kushiro Mire was affected by the agricultural land area in the upper course of the river basin and flooding in the lower course of the river. The soil sediments flowing into the Kushiro Mire from the agricultural land resulted in heavy sedimentation that favors the growth of alder trees. Consequently, the number and density of alder trees has increased. The future distribution of alder trees was predicted based on the mechanism of expansion of the alder-tree area in Kushiro Mire, and it was found that large vegetation areas in Kushiro Mire will be changed to areas with alder trees.     

Multivariate approach for surface water quality mapping with special reference to nitrate enrichment in Sugadaira,Nagano Prefecture (Japan)

The hydrochemical study of the surface water along with land-use/land-cover study of its catchment area is useful for determining its suitability for support to aquatic ecosystem and agricultural purposes. The surface water quality around the wetland in Sugadaira region, Japan, is being affected both by complex hydrogeochemical processes and by anthropogenic activity, mainly intensive agricultural practices. Statistical analysis was carried out in this study using surface water chemistry data to enable hydrochemical evaluation of the water quality based on the ionic constituents, water types, and factors controlling water quality. Results show that the general trend of various ions was found to be Ca²⁺ > Mg²⁺ > Na⁺ > K⁺ and HCO₃ ⁻ > NO₃ ⁻ > SO₄ ²⁻ > Cl⁻. Spatial distribution of water chemistry shows that enrichment of NO₃ ⁻ has taken place along one side of the wetland that is exposed directly to human settlement and agricultural practices. This study is vital considering that pollution in a wetland indicates that poor health of water resources in the region not only makes the situation alarming but also calls for immediate attention.