Short-term effects of clearfelling on soil CO2, CH4, and N2O fluxes in a Sitka spruce plantation

We examined the effects of forest clearfelling on the fluxes of soil CO₂, CH₄, and N₂O in a Sitka spruce (Picea sitchensis (Bong.) Carr.) plantation on an organic-rich peaty gley soil, in Northern England. Soil CO₂, CH₄, N₂O as well as environmental factors such as soil temperature, soil water content, and depth to the water table were recorded in two mature stands for one growing season, at the end of which one of the two stands was felled and one was left as control. Monitoring of the same parameters continued thereafter for a second growing season. For the first 10 months after clearfelling, there was a significant decrease in soil CO₂ efflux, with an average efflux rate of 4.0 g m⁻² d⁻¹ in the mature stand (40-year) and 2.7 g m⁻² d⁻¹ in clearfelled site (CF). Clearfelling turned the soil from a sink (−0.37 mg m⁻² d⁻¹) for CH₄ to a net source (2.01 mg m⁻² d⁻¹). For the same period, soil N₂O fluxes averaged 0.57 mg m⁻² d⁻¹ in the CF and 0.23 mg m⁻² d⁻¹ in the 40-year stand. Clearfelling affected environmental factors and lead to higher daily soil temperatures during the summer period, while it caused an increase in the soil water content and a rise in the water table depth. Despite clearfelling, CO₂ remained the dominant greenhouse gas in terms of its greenhouse warming potential.     

Malolactic fermentation in wine with Lactobacillus casei cells immobilized on Delignified cellulosic material

In this work Lactobacillus casei ATCC 393 cells immobilized on delignified cellulosic material (DCM) were used for malolactic fermentation (MLF) of wine. Wine was produced using yeast cells immobilized on DCM at 20 degrees C, and after alcoholic fermentation, MLF at 27 degrees C followed using immobilized L. casei ATCC 393 cells. A total of 11 repeated alcoholic and subsequent MLF batches were performed within a period of 1 month. As the repeated MLF batches proceeded, the MLF activity of the immobilized biocatalyst was reduced. Malic acid degradation was reduced from 80 to 2%, pH was reduced by 0.5-0.1 unit, acetic acid concentrations were slightly reduced or remained stable (0.002 g/L), the higher alcohols 1-propanol, isobutyl alcohol, and amyl alcohol were decreased by 84, 23, and 11%, respectively, and ethyl acetate concentration was increased by approximately 56%. Wine samples were analyzed by GC-MS before and after MLF, revealing some qualitative differences.     

Prioritizing marine invasive alien species in the European Union through horizon scanning

1. The disproportionately low presence of marine species in the list of invasive alien species (IAS) of Union concern of the European Union (EU) Regulation 1143/2014 does not fully acknowledge the threat they pose to the EU marine environment.
2. In this study, the first EU‐scale Horizon Scanning (HS) focusing on marine alien species was performed, aiming to deliver a ranked list of species that should be of high priority for risk assessment (Article 5 of the EU IAS Regulation).
3. Species absent from or with a limited distribution in EU marine waters were targeted. In total, 363 alien species were initially screened for HS by a panel of experts, including a broad range of taxonomic groups. Species were scored for their likelihood of arrival, establishment, spread, and impact in EU waters.
4. A consensus workshop ranked 267 species, including a subset of 26 prioritized species. These species are considered to be mainly introduced by shipping (fouling and ballast water), via the Suez Canal, and aquaculture activities. The 26 priority species were also scrutinized in terms of feasibility of their management; 18 of them were suggested for performing risk assessments on the basis of the EU IAS Regulation.
5. Since biological invasions are dynamic and connected with accelerated globalization and diversified human activities, we recommend HS to be repeated periodically to review the species already listed and assess new ones.

     

Thermoperiodic effects on larval growth parameters of the Sesamia nonagrioides (Lepidoptera: Noctuidae)

The effect of five constant (10, 15, 20, 25 and 30°C) and the corresponding cycling (25:10, 27.5:12.5, 30:15, 32.5:17.5 and 35:20°C) temperatures at a photoperiod of 16:8 (L:D) h on the development and biometry (HCW, weight) of larva of Sesamia nonagrioides (Lef) Lepidoptera–Noctuidae were investigated. Larvae under both temperature treatments seemed to complete six instars. Final mean head capsule widths did not differ significantly between constant and cycling temperatures. Larval weights increased considerably through larval period under all temperature regimes. However, alternating temperatures were not shown to stimulate larval weight or head capsule widths compared with those of constant temperatures, although tended to result in shorter larval developmental periods. Results are discussed regarding development and seasonal biology of the species.     

Pharmacokinetics and tissue distribution of oxytetracycline in sea bass, Dicentrarchus labrax, at two water temperatures

A pharmacokinetic study of oxytetracycline (OTC) following an intravascular administration (40 mg/kg) was carried out in sea bass, Dicentrarchus labrax (110 g), at 13.5 and 22 °C water temperature. Blood, muscle and liver samples were taken at 1, 2, 4, 8, 16, 32, 64 and 128 h post-injection. The plasma data were conformed to a two-compartment model. The kinetic profile of the drug was found to be temperature dependent. The absorption half-life (t_1/2) of OTC was 0.98 and 0.192 h at 13.5 and 22 °C, respectively, whereas the elimination half-time (t_1/2β) of the drug was 69 h at 13.5 °C and 9.65 h at 22 °C. The apparent volume of distribution of the drug at steady state [V_d(ss)] was 5.62 l/kg at 13.5 °C and 2.59 l/kg at 22 °C. The mean residence time (MRT) of OTC was found to be 37.7 h at 22 °C and 71 h at 13.5 °C. The total clearance of the drug (CL_T) was calculated to be 73.5 and 68.7 ml/kg/h at 13.5 and 22 °C, respectively.

Liver levels indicated higher OTC values than respective muscle levels at all time points and for both temperatures. The elimination of OTC from tissues tested was faster at the high temperature, whereas the drug was eliminated faster from liver compared to muscle when comparisons are made at the same temperature.     

Development of a reference diet for use in indispensable amino acid requirement studies of gilthead seabream Sparus aurata L.

The development of a test diet supporting good fish growth to be used in gilthead seabream indispensable amino acid (IAA) requirement studies based on dose–response relationship was the objective of the present study. Four isonitrogenous diets, one serving as control (diet C) based on fish meal LT, and three others in which the fish meal component was reduced to 45% and the rest of the nitrogen was provided by mixtures of crystalline AA were formulated. Diet S resembled the whole body IAA profile of wild seabream. Diet D was made deficient in all IAA and a 10% excess of IAA compared with diet S was used in diet E. Triplicate groups of fish were fed the diets to satiation for 6 weeks. Growth parameters and nutrient utilization efficiencies among diets C and S were similar, while excessive supplementation of IAA negatively affected most of them, compared with the control. Whole body composition was differentiated in relation to the diet fed. No significant differences were observed among groups fed the control and diet S. As shown by the results, the presence of crystalline AA in diet S does not significantly affect growth, and could therefore serve as control diet in IAA requirement studies of gilthead seabream.     

Temperature-dependent pharmacokinetics and tissue distribution of oxolinic acid in sea bass, Dicentrarchus labrax L., after a single intravascular injection

The pharmacokinetics and tissue distribution of oxolinic acid following an intravascular administration (15 mg kg^?1 fish) were determined in sea bass, Dicentrarchus labrax L. (110 g), at 13 °C and 22 °C water temperature. The kinetic profile of the drug was found to be temperature dependent, with increased temperature having a greater effect on distribution after equilibrium and the elimination phase than on the distribution process. The distibution half‐life of oxolinic acid was 1.15 and 2.76 h at 22 °C and 13 °C respectively, whereas the elimination half‐life of the drug was 55 h at 22 °C and 315 h at 13 °C. The values of the apparent volume of distribution (1.44 L kg^?1 at 22 °C and 3.31 L kg^?1 at 13 °C) and the volume of distribution at steady state (5.2 and 14.7 L kg^?1 at the high and low temperature respectively) were considerably different between the two tested temperatures. The total body clearance of the antibiotic was found to be low (1.47 L kg^?1 day^?1 at 22 °C and 0.80 L kg^?1 day^?1 at 13 °C). Lower rates of elimination were found for the liver compared with muscle, the difference increasing with increasing temperature, while elimination rates from the serum were higher than those of other tissues, especially at the high temperature.     

Phyllocnistis citrella and its parasitoids in three citrus species in Greece

The relative abundance as well as the percentage of parasitism of Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) and its parasitoids were studied in a citrus orchard with orange, mandarin and lemon trees in Greece. Infestation of P. citrella on each citrus host, as expressed by the number of mines per leaf, was significantly higher on lemon than on mandarin. The P. citrella parasitoid complex included the native species Neochrysocharis formosa and Pnigalio pectinicornis, as well as the introduced Citrostichus phyllocnistoides. The most abundant of those was N. formosa in all of the citrus species. The average percentage of parasitism was 13.1%, 13.8% and 11.7% on orange, mandarin and lemon, respectively. No significant differences in parasitism rate by each of the three parasitoid species separately were recorded among the three citrus species.