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991.
The aim of this study was to test the effect of heavy‐metal contamination (Cu, Zn) on the growth of Chlorella kessleri. Two soils (Chernozem and Podzoluvisol) were contaminated with several amounts of copper and zinc (100–3000 ppm), and the effects of the soil eluates on the growth of the alga were examined over several days. The soil eluates inhibited algal growth in dependence on metal concentration and soil properties. It was shown that this algal assay, which was first developed for aquatic samples, in principle seems to be suitable also in monitoring soil contamination. 相似文献
992.
993.
Maria A. Theodoropoulou 《Water, air, and soil pollution》2007,181(1-4):235-245
In order to estimate the longitudinal and transverse dispersivities of pore networks, an explicit method, based on the calculation of the transient variation of the spatial moments of the solute concentration over a disordered medium, is used to analyze visualization miscible displacement experiments and calculate the components of velocity vector and dispersion tensor. The longitudinal dispersion coefficient commonly estimated by using the 1-D advection dispersion coefficient is smaller than that calculated by the present method which accounts for the transverse dispersivity. The numerical predictions of the contaminant spreading in a macroscopically homogeneous porous medium are reliable presuming that correct values of longitudinal and transverse dispersivity are used. 相似文献
994.
Pantelis Katharios Constantina Kokkari Aspasia Sterioti Maria Smyrli Panos G. Kalatzis 《Veterinary parasitology》2014,199(3-4):136-143
Enteromyxum leei (Myxozoa) has been identified as the aetiological agent of morbidity and mortality in captive feral parrotfish, Sparisoma cretense held at the facilities of Cretaquarium, the public aquarium of the Hellenic Centre for Marine Research in Crete. The parasite caused substantial mortality to the parrotfish exceeding 60% over a period of 3.5 months. Here we describe the course of disease, the effects of the parasite on the host based on histopathological observations and we provide morphological and molecular data on the parasite. 相似文献
995.
Alphonsine Mukamuhirwa Helena Persson Hovmalm Rodomiro Ortiz Obedi Nyamangyoku Maria Luisa Prieto–Linde Anders Ekholm Eva Johansson 《Journal of Agronomy and Crop Science》2020,206(2):252-262
The climate change will contribute drought and temperature extremes to rice growing systems, especially when cultivated in equatorial regions. To evaluate opportunities to cultivate and breed drought-tolerant rice, seven rice cultivars were evaluated in Rwanda for recurring morphological drought scores, grain yield and components, and quality characteristics. The cultivation conditions, that is site and drought treatment, impacted morphological drought scores, growth and yield attributes, while cultivar affected quality attributes. Thus, site showed a higher impact on grain yield and components than drought and cultivar, with generally a reduced grain yield at the low-temperature site, as a result of low spikelet fertility. Morphological drought scores were generally increased by drought, while drought at the reproductive stage at the high-temperature site was negative for yield and its components. The cultivars “Intsindagirabigega” and “Jyambere” were adapted to high-temperature site conditions. The cultivar “Intsindagirabigega” had the highest amylose content, and “Mpembuke,” the highest antioxidant capacity. Thus, climate change with increased temperature and drought extremes may increase rice productivity in cool areas, while especially drought at reproductive stage will be detrimental in low altitude areas with high temperature. Cultivar variation indicated opportunities for selection and breeding of climate change tolerant rice cultivars which should be of immediate priority. 相似文献
996.
Maria G. Mendoza‐Rodriguez Delbert M. Gatlin 《Journal of the World Aquaculture Society》2014,45(2):199-205
The demand for alternative feedstuffs to fish meal is anticipated to continue increasing due to fish meal's limited supply and escalating price. One group of alternative feedstuffs includes lipid‐extracted algae (LEA) by‐products from algae production for biofuels. Most LEA by‐products are known to contain relatively high levels of ash ranging from 20 to 30% of dry weight. Thus, inclusion of LEA by‐products in aquafeeds may contribute a substantial amount of ash, which potentially could have negative effects on utilization of other nutrients. To study the ash component of LEA by‐products, diatomaceous earth (DE) was used as a homogeneous source of silica ash. Therefore, two feeding trials were conducted with red drum, Sciaenops ocellatus, in a closed, recirculating system to evaluate the effects of graded levels of dietary silica ash. In Experiment 1, semi‐purified diets were formulated to contain 35% crude protein, with DE included at 0, 5, 10, 20, or 30% of dry weight in place of cellulose to provide diets with analyzed ash levels of 8.6, 12.4, 16.7, 25.5, and 33.8% of dry weight in a regression design. Similar diets were fed in Experiment 2 but DE and cellulose were restricted to no more than 20% of diet. Each diet was fed to triplicate groups of juvenile fish (initial average weight of 1.4 ± 0.2 and 2.3 ± 0.1 g) for 8 wk. In both experiments it was apparent that red drum did not respond negatively to even the highest dietary ash levels based on weight gain, feed efficiency, survival, or body composition. No apparent histological changes in the gastrointestinal tract of fish fed the graded levels of ash were observed. Therefore, inclusion of algae by‐products in diets of red drum will not be limited due to their contribution of ash. 相似文献
997.
998.
F. García‐Orenes A. Roldán J. Mataix‐Solera A. Cerdà M. Campoy V. Arcenegui F. Caravaca 《Soil Use and Management》2012,28(4):571-579
Unsuitable agricultural practices can cause loss in soil quality and erodibility to thus increase or trigger desertification under Mediterranean conditions. A field experiment was performed at the El Teularet‐Sierra de Enguera Experimental Station (eastern Spain) to assess the influence during a 5‐yr period of different agricultural practices on physical and chemical indicators of soil quality (total and water‐soluble carbohydrates, glomalin‐related soil proteins (GRSP), total organic carbon, aggregate stability (AS), vegetation cover and soil erosion). The management practices included residual herbicide use, ploughing, ploughing + oats, addition of oat straw mulch and a control (land abandonment). Adjacent soil under natural vegetation was used as a reference for local, high‐quality soil and as a control for comparison with the agricultural soils under different management practices. Oat straw mulching led to higher levels of water‐soluble carbohydrates, GRSP and AS and lower soil erosion rates, resulting in values similar to those in the soil under native vegetation. The lowest levels of carbohydrates and GRSP were for the plots that were treated with herbicide or were ploughed. The maintenance of and increases in stable aggregates promoted by the different agricultural management practices over the years were attributed to increases in labile organic fractions such as carbohydrates and to the GRSP content. The results demonstrate that land abandonment (control plot) or the use of a cover (plants or straw) contributes to increases in soil quality and reduces the risk of erosion. The research also shows that sustainable agricultural management allows soil to recover and that the use of straw mulching is the most effective management strategy. 相似文献
999.
Lana Resende de ALMEIDA Marina Amaral ALVES Ana Maria Obino MASTELLA Rafael GARRETT Maria João Ramos PEREIRA 《Integrative zoology》2023,18(3):518-529
Chemical profiles of non-invasive biological material, such as feces, have great potential to study elusive animals or those with low population densities. Here, we use a metabolomic approach to evaluate Neotropical mustelids as a biological model to describe the diversity of the metabolites present in fecal samples, as well as to evaluate the potential of chemical profiles for taxonomic discrimination. We collected fecal samples from captive individuals of 5 species of mustelids occurring in Brazil and analyzed them by liquid chromatography coupled to high-resolution mass spectrometry. Over 200 compounds have been annotated; “bile acids, alcohols and derivatives” was the most expressive class in the metabolome of all the species. We successfully discriminated 3 taxonomic groups: 1—tayra (Eira barbara); 2—otters (Lontra longicaudis and Pteronura brasiliensis; 1); and 3—grisons (Galictis vittata and Galictis cuja). Several compounds seemed to be associated with food intake and the digestive process, while others were found for the first time in Neotropical mustelids. We concluded that mustelids show high metabolome diversity and that species-specific identification through metabolomic profiles is possible, thus contributing to the development and implementation of additional non-invasive approaches in the study of mustelids. 相似文献
1000.
Rose?Marie?O.?F.?Sousa José?S.?Rosa Cláudia?A.?Silva Maria?Teresa?M.?Almeida M.?Teresa?Novo Ana?C.?Cunha Manuel?Fernandes-FerreiraEmail author 《Journal of pest science》2015,88(2):413-426
Plant-based products, namely essential oils (EOs), are environmentally friendly alternatives for the control of disease vectors, hosts and/or parasites. Here, we studied the general toxicity and biopesticidal potential of EOs and phenylpropanoids from Foeniculum vulgare var. vulgare (bitter fennel), a perennial plant well adapted to temperate climates. EO/compound toxicity was tested against a freshwater snail and potential intermediate host of Fasciola hepatica (Radix peregra), a mosquito and former European malaria vector (Anopheles atroparvus) and one of the most damaging plant-parasitic nematodes, the root-knot nematode (Meloidogyne javanica). Lethal concentrations (LC50; LC90) of EOs (infrutescences/stems with leaves) and compounds were calculated by probit analysis. All displayed noteworthy activity against R. peregra adults (LC50 21–39 µg ml?1) and A. atroparvus larvae (LC50 16–56 µg ml?1). trans-Anethole revealed acute nematicidal activity after 24 and 48 h (LC50 310 and 249 µg ml?1, respectively), and estragole (1,000 µg ml?1) showed some effectiveness against M. javanica hatching and juveniles after 15 days. Plant and EO yields were determined to evaluate the bitter fennel productivity. The chemical composition of the EOs was analyzed by gas chromatography coupled to mass spectrometry. EOs extracted from whole plants, infrutescences and stems with leaves were characterized by estragole-dominant profiles (28–65 %), considerable amounts of phellandrene (10–34 %) and fenchone (6–16 %), and minor trans-anethole contents (1–4 %). Although additional toxicological studies against nontarget organisms are required, our study demonstrates that bitter fennel is a productive source of molluscicides and larvicides, and thus a potential sustainable biological agent to control particular host species, namely freshwater snails and mosquitoes. 相似文献