Soil

Diurnal activity is characteristic of many toad species, including Bufo granulosus from the Brazilian semi-arid biome called the Caatinga. Because of their patterns of activity, juvenile toads are exposed to hot and dehydrating conditions. Our investigation focuses on temperature and water relationships, and is based on the prediction that anuran diurnal activity in a semi-arid environment must be associated with morphological, physiological and behavioral traits enhancing thermal tolerances, capacity for performance at high temperatures and water balance. To test specific hypothesis related with this prediction, we investigated postmetamorphic B. granulosus and collected data on thermal tolerances and preferences, thermal safety margins, thermal dependence of locomotor behavior, thermal and kinetic properties of citrate synthase (CS), and skin morphophysiology. This information was compared with additional data from adult conspecifics and adult toads from sympatric species or from species from more moderate environments. We found that juvenile B. granulosus exhibit the highest critical maximum temperature reported for toads (44.2°C) and are well suited to move at high temperatures. However, and in contrast with juveniles of other Bufo species, they do not show thermal preferences in a gradient and appear to hydroregulate more than thermoregulate. The CS of adult and juvenile toads shows typical patterns of thermal sensibility, but the thermal stability of this enzyme is much higher in juveniles than in adult Bufo of any other species studied. The inguinal skin exhibits a complex folding pattern and seems highly specialized for capillary water uptake. Diurnal activity in juvenile B. granulosus is possible given high thermal tolerances, keen ability to detect and uptake water, and avoidance behaviors. Comparative Biochemistry and Physiology, Part A 147 (2007) 647 -657 www.elsevier.com/locate/cbpa ☆ This paper is part of the 3rd special issue of CBP dedicated to The Face of Latin American Comparative Biochemistry and Physiology organized by Marcelo Hermes-Lima (Brazil) and co-edited by Carlos Navas (Brazil), Rene Beleboni (Brazil), Rodrigo Stabeli (Brazil), Tania Zenteno-Savín (Mexico) and the editors of CBP. This issue is dedicated to the memory of two exceptional men, Peter L. Lutz, one of the pioneers of comparative and integrative physiology, and Cicero Lima, journalist, science lover and Hermes-Lima's dad.

The aim of the present work was to evaluate the effects of two soil management systems so called sustainable treatment (ST) and conventional treatment (CT) on the composition and on genetic, functional, and metabolic diversity of soil microbial communities in a Mediterranean olive orchard. The ST system included no-tillage, integrated chemical fertilization, and organic matter inputs from drip irrigation, spontaneous cover crops, and pruning material. Microbial analyses were carried out by an integrated approach of culture-dependent (microbial cultures and Biolog) and culture-independent methods (denaturing gradient gel electrophoresis [DGGE]). After 7 years of treatment, average olive yield was 8.4 and 3.1 t ha j1 year j1 in ST and CT, respectively. Conventional treatment had a significantly higher number of total culturable bacteria and actinomycetes compared with ST, whereas fungi were significantly lower. In ST, the number of ammonifying bacteria, proteolytic bacteria, and Azotobacter in the wetted areas under the drippers (ST-WET) was significantly higher than along interrows (ST-INTER). The DGGE analysis of microbial 16S/18S rDNA showed differences between ST and CT, whereas 16S/18S rRNA DGGE bands of ST-WET clustered differently from those of CT and ST-INTER. Some Biolog metabolic indexes were significantly different between ST and CT. The results revealed qualitative and quantitative changes of soil microbial communities in response to sustainable agricultural practices that stimulate soil microorganism activity and improve olive yield and fruit quality.

Transmission assessment surveys (TAS) for lymphatic filariasis have been proposed as a platform to assess the impact of mass drug administration (MDA) on soil-transmitted helminths (STHs). This study used computer simulation and field data from pre- and post-MDA settings across Kenya to evaluate the performance and cost-effectiveness of the TAS design for STH assessment compared with alternative survey designs. Variations in the TAS design and different sample sizes and diagnostic methods were also evaluated. The district-level TAS design correctly classified more districts compared with standard STH designs in pre-MDA settings. Aggregating districts into larger evaluation areas in a TAS design decreased performance, whereas age group sampled and sample size had minimal impact. The low diagnostic sensitivity of Kato-Katz and mini-FLOTAC methods was found to increase misclassification. We recommend using a district-level TAS among children 8-10 years of age to assess STH but suggest ...

Nationally and internationally there are an increasing number of legal initiatives to protect the ecological processes in soil. This article describes the legal situation concerning the protection of natural functions of soil in Europe (mainly The Netherlands (since 1987) and Germany (since 1998)). Examples of processes to be protected comprise the element cycles, the degradation of pollutants, and the conversion of organic matter. These processes are performed by organisms, and therefore, there is a growing consensus that protection of soil biodiversity is necessary for the survival of humans and the above-ground ecosystems. It is discussed that protection of soil ecosystems needs requires definitions and aims for the ecological quality of soil (as already provided for aquatic ecosystems). Taking into account that most soils are privately owned, legal initiatives are necessary to clarify responsibilities and to direct research toward the implementation of reproducible and standardized methods to determine the ecological quality of soil. r 2005 Elsevier Inc. All rights reserved.

The aim of our research was to obtain information on the isotopic fingerprint of nitrous oxide (N 2 O) associated with its production and consumption during denitrification. An arable soil was preincubated at high moisture content and subsequently amended with glucose (400 kg C ha −1 ) and KNO 3 (80 kg N ha −1 ) and kept at 85% water-filled pore space. Twelve replicate samples of the soil were incubated for 13 days under a helium-oxygen atmosphere, simultaneously measuring gas fluxes (N 2 O, N 2 and CO 2 ) and isotope signatures (δ 18 O-N 2 O, δ 15 N bulk -N 2 O, δ 15 N α , δ 15 N β and 15 N site preference) of emitted N 2 O. The maximum N 2 O flux (6.9 ± 1.8 kg N ha −1 day −1 ) occurred 3 days after amendment application, followed by the maximum N 2 flux on day 4 (6.6 ± 3.0 kg N ha −1 day −1 ). The δ 15 N bulk was initially −34.4‰ and increased to +4.5‰ during the periods of maximum N 2 flux, demonstrating fractionation during N 2 O reduction, and then decreased. The δ 18 O-N 2 O also increased, peaking with the maximum N 2 flux and remaining stable afterwards. The site preference (SP) decreased from the initial +7.5 to −2.1‰ when the N 2 O flux peaked, and then simultaneously increased with the appearance of the N 2 peak to +8.6‰ and remained stable thereafter, even when the O 2 supply was removed. We suggest that this results from a non-homogenous distribution of NO − 3 in the soil, possibly linked to the KNO 3 amendments to the soil, causing the creation of several NO − 3 pools, which affected differently the isotopic signature of N 2 O and the N 2 O and N 2 fluxes during the various stages of the process. The N 2 O isotopologue values reflected the temporal patterns observed in N 2 O and N 2 fluxes. A concurrent increase in 15 N site preference and δ 18 O of N 2 O was found to be indicative of N 2 O reduction to N 2 .