Soil C and N models that integrate microbial diversity

Industrial agriculture is yearly responsible for the loss of 55–100 Pg of historical soil carbon and 9.9 Tg of reactive nitrogen worldwide. Therefore, management practices should be adapted to preserve ecological processes and reduce inputs and environmental impacts. In particular, the management of soil organic matter (SOM) is a key factor influencing C and N cycles. Soil microorganisms play a central role in SOM dynamics. For instance, microbial diversity may explain up to 77 % of carbon mineralisation activities. However, soil microbial diversity is actually rarely taken into account in models of C and N dynamics. Here, we review the influence of microbial diversity on C and N dynamics, and the integration of microbial diversity in soil C and N models. We found that a gain of microbial richness and evenness enhances soil C and N dynamics on the average, though the improvement of C and N dynamics depends on the composition of microbial community. We reviewed 50 models integrating soil microbial diversity. More than 90 % of models integrate microbial diversity with discrete compartments representing conceptual functional groups (64 %) or identified taxonomic groups interacting in a food web (28 %). Half of the models have not been tested against an empirical dataset while the other half mainly consider fixed parameters. This is due to the difficulty to link taxonomic and functional diversity.     

Catalytic activities and mechanism of formaldehyde oxidation over gold supported on MnO<Subscript>2</Subscript> microsphere catalysts at room temperature

MnO₂ microspheres with various surface structures were prepared using the hydrothermal method, and Au/MnO₂ catalysts were synthesized using the sol-gel method. We obtained three MnO₂ microspheres and Au/MnO₂ samples: coherent solid spheres covered with wire-like nanostructures, solid spheres with nanosheets, and hierarchical hollow microspheres with nanoplatelets and nanorods. We investigated the properties and catalytic activities of formaldehyde oxidation at room temperature. Crystalline structures of MnO₂ are the main factor affecting the catalytic activities of these samples, and γ-MnO₂ shows high catalytic performance. The excellent redox properties are responsible for the catalytic ability of γ-MnO₂. The gold-supported interaction can change the redox properties of catalysts and accelerate surface oxygen species transition, which can account for the catalytic activity enhancement of Au/MnO₂. We also studied intermediate species. The dioxymethylene (DOM) and formate species formed on the catalyst surface were considered intermediates, and were ultimately transformed into hydrocarbonate and carbonate and then decomposed into CO₂. A proposed mechanism of formaldehyde oxidation over Au/MnO₂ catalysts was also obtained.     

Trends in the development of Estonian coastal land cover and landscapes caused by natural changes and human impact

The structure of coastal land cover in Estonia is intricate and exhibits considerable differences from site to site. The diverse geomorphology of the seashores is one of the key factors affecting the speed and magnitude of land cover changes. Likewise, the history of human inhabitance on the coast has also shaped the character of land cover. The Estonian coastal zone has experienced abrupt and radical changes in land ownership and its related land use during the last century. The main objectives of this paper are: 1) to give an overview of land use and the trends of development of land cover pattern along different parts of the Estonian coast; and 2) to analyze the relationships of natural and human processes and their cumulative impact on the evolution of coastal land cover pattern in Estonia. This study is based on results obtained during fieldwork in the study areas and on the analysis of large-scale (1:10,000) historical maps. In agriculturally dominant coastal areas, the traditional open landscape of fields and grassland at the beginning of the 20th century had been replaced by woodland and grasslands with shrubs by the start of the 21st century. Expansion of reed beds in areas of former seashore grasslands is another striking phenomenon. The structure of land cover on forested coasts has been fairly stable during the last 100 years. Areas of urban sprawl are characterised by dramatic changes in land cover structure. Rapidly increasing population and expanding settlements imposes on the ecological balance of the fragile dune forests in the coastal zone.     

CFD Investigation of Particle Deposition in a Horizontal Looped Turbulent Pipe Flow

This paper presents comprehensive 3D numerical investigations on depositions of particles flowing through a horizontal pipe loop consisting of four bends. The multiphase mixture model available in FLUENT 6.2 was used in this study. In this numerical simulation, five different particle sizes have been used as secondary phases to calculate real multiphase effect in which inter-particle interaction has been considered. The deposition of particles along the periphery of the pipe wall was investigated as a function of particle size and fluid velocity. The simulations showed that near the upstream of the bends, maximum particle concentration occurred at the bottom of the pipe. However, downstream the bends, the maximum particle concentration occurred at an angle of 60° from the bottom. The larger particles clearly showed deposition near the bottom wall except downstream. As expected, the smaller particles showed less tendency of deposition and lesser at higher velocity. This numerical investigation showed qualitative agreement with the experiments conducted by Commonwealth Scientific and Industrial Research Organisation, Melbourne team for similar conditions.     

Alternative amendment for soluble phosphorus removal from poultry litter

Background, aim, and scope  

Alum (aluminum sulfate) is the currently preferred chemical amendment for phosphorus (P) treatment in poultry litter (PL). Aluminum-based drinking-water treatment residuals (Al-WTRs) are the waste by-product of the drinking-water treatment process and have been effectively used to remove P from aqueous solutions, but their effectiveness in PL water extracts has not been studied in detail. Elevated cost associated with alum could be minimized by using the equally effective WTRs to remove soluble P from PL, and they can be obtained at a minimal cost from drinking-water treatment plants.     

Chitosan-polypropylene imine dendrimer hybrid: a new ecological biomordant for cochineal dyeing of wool

The classical use of synthetic dyes is causing issues of environmental pollution and heath risk. As a consequence natural dyes are gaining interest, but the use of natural dyes still includes toxic reagents such as metals as mordants and acids to enhance color and yield. Therefore, we designed a new chitosan-polypropylene imine dendrimer hybrid at 0–2000 mg/L to treat wool before dyeing with cochineal. We compared dye exhaustion, color depth, color characteristics, and color fastness of the new process with dyed pristine and metal mordanted wool. Results show that wool pretreatment improved dye exhaustion from 48 to 88 %, shifted saturation point toward lower dye concentration from 3000 to 1000 mg/L, and improved color depth from 13.68 for pristine wool and 15.17 for metal mordanted wool to 23.89 for the new process.     

Solar radiation prediction using boosted decision tree regression model: A case study in Malaysia

Environmental Science and Pollution Research - Reliable and accurate prediction model capturing the changes in solar radiation is essential in the power generation and renewable carbon-free energy...     

Triterpene saponin hemi-biosynthesis of a leaf beetle’s (<Emphasis Type="Italic">Platyphora kollari</Emphasis>) defensive secretion

The adults of the leaf beetle Platyphora kollari (Chrysomelidae) are able to metabolise the oleanane triterpene β-amyrin (1) into the glycoside 3-O-β-d-glucopyranosyl-(1→4)-β-d-glucuronopyranosyl-hederagenin (2) that is stored in their defensive glands. The aim of this study was to test the hypothesis that oleanolic acid (3) is an intermediate in the conversion of 1 into 2 and to check whether the sequestration of pentacyclic triterpenes is selective in favour of β-amyrin (1). To this end, adults of P. kollari were fed with Ipomoea batatas leaf disks painted with a solution of [2,2,3-²H₃]oleanolic acid or [2,2,3-²H₃]α-amyrin and the secretion of their defensive glands analysed by HPLC–ESIMS. The data presented in this work indicated that the first step of the transformation of β-amyrin (1) into the sequestered glycoside 2 is its oxidation into oleanolic acid (3) and that this conversion is selective but not specific in favour of β-amyrin (1).     

The IPBES Conceptual Framework: An Unhelpful Start

The Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) have recently launched themselves as the UN-sanctioned instrument for conserving nature. They seek to establish themselves as the authority in this field alongside the well-known Intergovernmental Panel on Climate Change in climate science. Quickly following or even before recent publication of their conceptual framework in two biology journals, they were already underway building upon it. This headlong push, we believe, is ill advised. We show how the framework is unsound as a foundation for further work—in a number of ways and perhaps even by its authors’ own lights. It is therefore urgent that the IPBES thoroughly and thoughtfully reconsider their framework before too much effort is wasted.     

A novel application of concentrated solar thermal energy in foundries

Scrap preheating in foundries is a technology that saves melting energy, leading to economic and environmental benefits. The proposed method in this paper utilizes solar thermal energy for preheating scrap, effected through a parabolic trough concentrator that focuses sunlight onto a receiver which carries the metallic scrap. Scraps of various thicknesses were placed on the receiver to study the heat absorption by them. Experimental results revealed the pattern with which heat is gained by the scrap, the efficiency of the process and how it is affected as the scrap gains heat. The inferences from them gave practical guidelines on handling scraps for best possible energy savings. Based on the experiments conducted, preheat of up to 160 °C and a maximum efficiency of 70 % and a minimum efficiency of 40 % could be achieved across the time elapsed and heat gained by the scrap. Calculations show that this technology has the potential to save around 8 % of the energy consumption in foundries. Cumulative benefits are very encouraging: 180.45 million kWh of energy savings and 203,905 t of carbon emissions cut per year across the globe. This research reveals immense scope for this technology to be adopted by foundries throughout the world.