Search results for "fishe"
showing 10 items of 2001 documents
Soil moisture influences sorptivity and water repellency of topsoil aggregates in native grasslands
2017
Abstract Water repellency is associated to coating of soil particles by hydrophobic substances, usually of organic origin, affecting water dynamics in soil matrix. We analyzed the effect of water repellency on water sorptivity of topsoil aggregates of six soil types under three initial moisture conditions (10 kPa, 100 kPa, and air-dried). Undisturbed soil samples were collected to evaluate sorptivity in the 0–5 cm soil layer at different locations in Pampa Biome in southern Brazil. Disturbed soil samples were also collected for soil particle size distribution, particle density and organic matter content. Sorptivity test was conducted in a tension micro-infiltrometer, using distilled water a…
Connectivity assessment in Mediterranean vineyards using improved stock unearthing method, LiDAR and soil erosion field surveys
2018
The interaction between processes and landforms is accelerated in vineyards due to bare tilled soils that enhance splash, runoff, and erosion. Traditionally, in order to assess these processes, the stock unearthing method (SUM) is considered a useful methodology that uses the graft union of the vine plant as passive bio-indicator of the topsoil level changes. However, SUM assumes that the topography between the rows is planar when development of a model of the current micro-topography is performed. Thus, we consider that there is a need to develop a new methodology (ISUM: improved SUM) that, by adding new measurements in the inter-row areas (at least 3), allows inclusion of the absent micro…
Prediction of organic carbon and total nitrogen contents in organic wastes and their composts by Infrared spectroscopy and partial least square regre…
2017
Middle and near infrared (MIR and NIR) were employed to determine organic carbon (OC) and total nitrogen (TN) in different soil organic amendments including wastes, composts and mixtures of composts and organic wastes. Prediction models based on partial least squares (PLS) regression from the spectra of untreated samples were built. Different spectra preprocessing strategies were adopted and the best number of latent variable was evaluated using leave-one-out cross-validation. Attenuated total reflectance (PLS-ATR-MIR) and diffuse reflectance (PLS-DR-NIR) models were built and evaluated from root mean square error of cross validation and prediction (RMSECV and RMSEP), coefficients of determ…
Impact of wheeled and tracked tractors on soil physical properties in a mixed conifer stand
2016
Abstract: Damage to forest soil caused by vehicle traffic mainly consists of soil compaction, displacement, and rut formation. Severity of the damage depends on vehicle mass, weight of the carried loads, ground morphology, and soil properties, such as moisture. This paper investigates the impacts of two types of vehicles (tracked or wheeled tractor), traffic intensities (one or five skidding cycles) and soil moisture (24% or 13% by weight) on compaction of a loam textured soil in a mixed conifer stand of central Italy. Changes in porosity, bulk density, shear and penetration resistances were analyzed. The latter three parameters were significantly higher in the trafficked soil portions than…
An open-source instrumentation package for intensive soil hydraulic characterization
2020
International audience; We present a new open-source and modular instrumentation package composed of up to ten automatic in- filtrometers connected to data acquisition systems for automatic recording of multiple infiltration experiments. The infiltrometers are equipped with differential transducers to monitor water level changes in a Mariotte re- servoir, and, in turn, to quantify water infiltration rates. The data acquisition systems consist of low-cost components and operate on the open-source microcontroller platform Arduino. The devices were tested both in the laboratory and on different urban and agricultural soils in France and India. More specifically, we tested three procedures to t…
What is a tree in the Mediterranean Basin hotspot? A critical analysis
2019
Background: Tree species represent 20% of the vascular plant species worldwide and they play a crucial role in the global functioning of the biosphere. The Mediterranean Basin is one of the 36 world biodiversity hotspots, and it is estimated that forests covered 82% of the landscape before the first human impacts, thousands of years ago. However, the spatial distribution of the Mediterranean biodiversity is still imperfectly known, and a focus on tree species constitutes a key issue for understanding forest functioning and develop conservation strategies. Methods: We provide the first comprehensive checklist of all native tree taxa (species and subspecies) present in the Mediterranean-Europ…
Epizootiology of protozoans in farmed salmonids at northern latitudes
1997
Abstract Protozoan ectoparasites were examined in a northern salmonid fish farm over a 10-year period, June 1984–May 1994, by the same researcher, with similar catching and sampling procedures throughout. Husbandry procedures remained constant during the study, e.g., fingerlings were kept in steel tanks and yearlings in both steel tanks and earth ponds. Ichthyobodo necator, Chilodonella hexasticha and Ichthyophthirius multifilurs infections were treated with formalin, salt and malachite green-formalin baths, respectively, whenever any parasites were found. Altogether 10 790 randomly sampled salmon (Salmo solar), sea trout (S. trutta m. trutta) and brown trout (S. trutta m. lacustris) were s…
Finnish salmon resistant to Gyrodactylus salaris: a long-term study at fish farms.
1996
Abstract The occurrence of Gyrodactylus salaris on Baltic salmon ( Salmo salar ), sea trout ( S. trutta m. trutta ) and brown trout ( S. trutta m. lacustris ) was examined from 1984 to 1993 at 4 fish farms (A, B, C and D) that produce smolts for stocking in northern Finland. No G. salaris was found on the sea or brown trout, but it did occur on salmon for 6–7 years at farms B, C and D, the prevalences of infection being 9.5%, 17.7% and 8.8% for salmon yearlings and smolts during that time, respectively, but less than 1.2% for fingerlings at farms B and C. Only brood stock salmon were infected at farm A in 4 years. The abundances of G. salaris increased during the second winter of each year …
Species differences, influence of dose and application on biotransformation of phenol in fish.
1983
1. The metabolism of phenol in goldfish (Carassius auratus), rainbow trout (Salmo gairdneri) and goldenorfe ide (Leuciscus ideus melanotus) was compared. All three species produced phenyl sulphate, quinol sulphate and phenyl glucuronide. 2. The dose dependence of metabolism of phenol in goldfish was investigated. When the concn. of phenol was increased from 0.2 to 2 mg/l medium, that glucuronylated increased from 7 to 16% and that sulphated decreased from 63 to 47%. 3. The influence of mode of exposure on metabolism of phenol in goldfish was examined. Dietary exposure and uptake from medium was compared with i.p. injection. There was less metabolism in the order: dietary exposure greater th…
Signals from the deep-sea: Genetic structure, morphometric analysis, and ecological implications of Cyclothone braueri (Pisces, Gonostomatidae) early…
2020
Abstract Cyclothone braueri (Stomiiformes, Gonostomatidae) is a widely distributed fish inhabiting the mesopelagic zone of marine tropical and temperate waters. Constituting one of the largest biomasses of the ocean, C. braueri is a key element in most of the ecological processes occurring in the twilight layer. We focused on the ecological processes linked to early life stages in relation to marine pelagic environmental drivers (temperature, salinity, food availability and geostrophic currents) considering different regions of the Central Mediterranean Sea. A multivariate morphometric analysis was carried out using six parameters with the aim of discerning different larval morphotypes, whi…