Search results for "Fish"

Comparison of testing acute toxicity on embryo of zebrafish, Brachydanio rerio and RTG-2 cytotoxicity as possible alternatives to the acute fish test

1995

Abstract The present study compares two possible alternative methods to replace the acute fish test. Fertilized eggs of zebrafish, Brachydanio rerio were used to investigate the acute toxicity of chemicals. Different toxicological endpoints such as coagulation of the eggs, development of gastrulation, number of somites, development of organs, circulation, heartbeat, otolithanlage and pigmentation have been examined during the embryonic development of zebrafish within the first 48 h. Differences to the normal development were measured by these endpoints. Chemicals have been examined in a preliminary approach with respect to their cytotoxicity on the RTG-2 cells (Rainbow Trout Gonad). The vit…

Mapping field-scale spatial patterns of size and activity of the denitrifier community

2009

International audience; There is ample evidence that microbial processes can exhibit large variations in activity on a field scale. However, very little is known about the spatial distribution of the microbial communities mediating these processes. Here we used geostatistical modelling to explore spatial patterns of size and activity of the denitrifying community, a functional guild involved in N-cycling, in a grassland field subjected to different cattle grazing regimes. We observed a non-random distribution pattern of the size of the denitrifier community estimated by quantification of the denitrification genes copy numbers with a macro-scale spatial dependence (6–16 m) and mapped the dis…

Do conservative agriculture practices increase soil water repellency? A case study in citrus-cropped soils

2012

Water repellency is a property of soils that inhibits or delays infiltration. Long-term conservation practices as no-tillage, manure addition, application of herbicides may contribute to increase soil organic matter and, hence, soil water repellency. In this research, we have studied the effect of long-term addition of plant residues and organic manure, no-tillage and no chemical fertilization (MNT), annual addition of plant residues and no-tillage (NT), application of conventional herbicides and no-tillage (H), and conventional tillage (CT) on soil water repellency in Mediterranean calcareous citrus-cropped soils (Eastern Spain). Slight water repellency was observed in MNT soils, which may…

Anthropogenic noise: the behavioural responses of Sparus aurata juveniles as the basis for a numerical model.

2019

Underwater noise is mainly produced by anthropogenic activities and has increased in recent years. The Marine Strategy Framework Directive aims to monitor “continuous low frequency sound” trends in ambient noise in particular at 1/3rd octave bands centered at 63 and 125 Hz. The aim of this work is to evaluate the possibility of using the results of Sparus aurata juvenile’s behavior for parameterizing a numerical model of the fish behavior. The fishes were stressed with white noise filtered with a band pass filter at 1/3 octave band centered respectively at 63 Hz, 125 Hz, 500 Hz, and 1 kHz (SPL: 140-150 dB re 1µPa). We performed three test replicas for the control (without any sound emission…

Is the Fisher effect non-linear? some evidence for Spain, 1963–2002

2005

In this paper the role of non-linearities in the relationship between nominal interest rates and inflation is examined, in order to shed some additional light on the mostly unfavourable evidence on the presence of a full Fisher effect. The analysis is applied to the case of Spain for the period 1963–2002, which allows previous results on the subject to be re-examined and extended. The empirical methodology makes use of recent developments on threshold cointegration, so that cointegration between a pair of variables should be expected only once a certain threshold was reached.

A revised model for lipid-normalizing δ13C values from aquatic organisms, with implications for isotope mixing models

2006

1. Stable isotope analyses coupled with mixing models are being used increasingly to evaluate ecological management issues and questions. Such applications of stable isotope analyses often require simultaneous carbon and nitrogen analyses from the same sample. Correction of the carbon isotope values to take account of the varying content of 13 C-depleted lipids is then frequently achieved by a lipid-normalization procedure using a model describing the relationship between change in δ 13 C following lipid removal and the original C:N ratio of a sample. 2. We evaluated the applicability of two widely used normalization models using empirical data for muscle tissue from a wide range of fish an…

Will nutrient cycles in a tropical montane forest in Ecuador be affected by a changing element composition of rainfall?

2009

Organic Fertilization in Traditional Mediterranean Grapevine Orchards Mediates Changes in Soil Microbial Community Structure and Enhances Soil Fertil…

2016

Soil microbial populations and their functions related to nutrient cycling contribute substantially to the regulation of soil fertility and the sustainability of agroecosystems. A field experiment was performed to assess the medium-term effect of a mineral fertilizer and two organic fertilization systems with different nitrogen sources on the soil microbial community biomass, structure, and composition (phospholipid fatty acids, pattern, and abundance), microbial activity (basal respiration, dehydrogenase, protease, urease, β-glucosidase, and total amount of phosphomonoesterase activities), and physical (aggregate stability) and chemical (total organic C, total N, available P and water-solu…

Soil-Water Interactions Unveiled by Fast Field Cycling NMR Relaxometry

2017

Seawater carbonate chemistry and fish communities properties off CO2 seeps in Japan

2020

Ocean acidification will likely change the structure and function of coastal marine ecosystems over coming decades. Volcanic carbon dioxide seeps generate dissolved CO2 and pH gradients that provide realistic insights into the direction and magnitude of these changes. Here, we used fish and benthic community surveys to assess the spatio-temporal dynamics of fish community properties off CO2 seeps in Japan. Adding to previous evidence from ocean acidification ecosystem studies conducted elsewhere, our findings documented shifts from calcified to non-calcified habitats with reduced benthic complexity. In addition, we found that such habitat transition led to decreased diversity of associated …