Germination differentiation patterns of wild and domesticated columnar cacti in a gradient of artificial selection intensity

Germination of wild and managed populations of columnar cacti was compared to analyze differences associated to management intensity. The species studied: Polaskia chende, Escontria chiotilla, Myrtillocactus schenckii, Polaskia chichipe, and Stenocereus pruinosus are in a gradient from lower to higher management intensity, respectively. Within each species wild, silvicultural, and cultivated populations also represent a gradient from lower to higher management intensity. We hypothesized that seeds of plants under higher management intensity would require more water to germinate than others since managed environments are relatively wetter than unmanaged environments. Such pattern could be visualized within and among species according to management intensity. We tested germination of seeds from different populations of the different species to the water potentials: 0.0, ?0.2, ?0.4, ?0.6, ?0.8, and ?1.0 MPa. In all species studied seeds of managed populations had significantly more mass than seeds from wild populations. Each species had different susceptibility to water availability decrease, which could be related to particular adaptations to drought resistance. Stenocereus pruinosus and Polaskia chende were the most and least susceptible species, respectively. In control treatments of all species, seeds of managed populations had higher germination rate than seeds from wild populations, but when water availability decreased the pattern was the contrary. Our results suggest that artificial selection for larger fruits and heavier seeds in plants established in wetter environments have affected germination patterns. Although species have particular critical points of water availability for germination, differences in germination patterns are more pronounced according to management and artificial selection intensity.     

Dynamics of Atmospheric Aerosol Number Size Distributions in the Eastern Mediterranean During the ��SUB-AERO�� Project

Measurements of number size distributions of submicron aerosols have been performed at the Eastern part of Mediterranean as part of an extensive measurement campaign to study photo-oxidants and aerosols (SUB-AERO Project). The measurements were made at the Finokalia station on the island of Crete (Greece) and onboard the research vessel ??Aegaeon??. Two campaigns were performed during July 2000 and January 2001 using two scanning mobility particle sizers. The particle distributions measured in the range between 7.8 < d _p < 327 nm during the summer measurements and between 7.5 < d _p < 316 nm during the winter measurements, where d _p is the mobility particle diameter. The concentration of ultrafine particles (7.5 < d _p < 30 nm) was higher during the winter period and varied mainly between 5 × 10¹ and 2 × 10³?cm^?3 with concentration peak values for this mode exceeding 1 × 10⁴?cm^?3. During the summer campaign, an average number concentration of 1 × 10²?cm^?3 at Finokalia and about 5 × 10¹?cm^?3 aboard the ??Aegaeon?? vessel was measured. An average concentration of 1 × 10³?cm^?3 was measured for the particles in the size range between 30 and 100 nm, whereas in the size range 100?C300 nm, the measured concentration ranged between 1 × 10² and 5 × 10³?cm^?3. Diurnal patterns in number concentrations were observed in connection with the transport of air masses and local sources. During the winter period, three nucleation events were observed in connection with the appearance of a particle mode at 20 nm.     

Evaluation of Deammonification Process by Response Surface Models

The influence of the operational variables on the Anammox process has been generally researched considering each variable separately. However, the optimization of the process also requires the identification of the more significant variables and their possible interactions. Response surface models were successfully applied to evaluate the performance of the Anammox process in a deammonification system (i.e., one-stage biofilm Anammox process) taking into account the combined effects caused by two sets of three variables. Specific Anammox activity was measured by a manometric method and used as the response variable. The obtained models pointed out that the significant variables were the temperature, the value of pH, and the ratio between the unionized species of the substrates (free ammonia and free nitrous acid (FA/FNA)). There were interactions among them caused by chemical equilibriums. Total nitrogen concentration and ammonium concentration were found to be not significant in the tested range. According to the models, the optimum values of temperature, pH, and free ammonia to free nitrous acid ratio within the test ranges were, respectively, 30°C, 7.0, and 0.3. Further research at higher temperatures and lower values of pH and FA/FNA ratios would be necessary in order to find the absolute optimum conditions for the process. The obtained model can be also useful in order to develop control strategies that take into account the significant variables and their optimum ranges. A strategy to control deammonification reactors has been proposed, according to the results of the modeling.     

The Role of Leaky Boreholes in the Contamination of a Regional Confined Aquifer. A Case Study: The Campo de Cartagena Region, Spain

Poorly constructed wells (leaky or without a gravel pack) and abandoned wells can behave as conduits for the interconnection of aquifers at different depths and facilitate the transfer of contaminants between these aquifers. This is the case with Campo de Cartagena (SE Spain) where the primary land use is intensive irrigated agriculture, along with a high density of wells. The unconfined aquifer is heavily impacted by a high concentration of nitrate associated with agricultural activities. The present work provides a methodological approach to evaluate the impact of the unconfined aquifer on the water quality of the confined aquifer caused by leaky wells in high-density areas of production wells. The research approach included the use of geochemical and isotopic tools; specifically, nitrate was used as a tracer for evaluating the impact, and the code MIX_PROGRAM was used for mixing calculations. Results show an increase of the impact of the unconfined aquifer on the confined aquifer along the groundwater flow direction toward the coast, although this general pattern is controlled by local factors (pumping, intensity of agricultural practices, density of wells, and groundwater residence time).     

Lead Isotopic and Metallic Pollution Record in Tree Rings from the Copperbelt Mining�CSmelting Area, Zambia

The composition of tree rings and soils was studied at several locations affected by smelting and transportation in the vicinity of Kitwe (Copperbelt, Zambia). The contents of cobalt (Co), copper (Cu), manganese (Mn), and lead (Pb) and the ²⁰⁶Pb/²⁰⁷Pb isotope ratios in the tree rings were interpreted in relation to potential sources of contamination such as smelter production, acidification of the environment, soil composition, raw material processing, and atmospheric suspended particulate matter (SPM). The highest Co contents in the tree rings correspond to maximum ore production in the mid-1970s. Acidification through SO₂ emissions is documented in the increased Mn contents from the mid-1980s. The isotopic composition of the tree rings of the studied tree species varies in the interval 1.16?C1.34 and the youngest parts of all the studied trees exhibit a low ²⁰⁶Pb/²⁰⁷Pb ratio (<1.17). The soil isotope composition varies in the range ²⁰⁶Pb/²⁰⁷Pb?=?1.18?C1.35. The Pb isotope composition in the soils and tree rings was formed by a combination of lithogenic Pb (²⁰⁶Pb/²⁰⁷Pb????1.3), Pb in processed ores (²⁰⁶Pb/²⁰⁷Pb????1.2), and SPM (automobile) Pb (²⁰⁶Pb/²⁰⁷Pb??1.1). As the soils in the distant region have high ²⁰⁶Pb/²⁰⁷Pb ratios (>1.3) in the whole profile and simultaneously the youngest parts of the tree rings of tree species growing in this soil have a low ²⁰⁶Pb/²⁰⁷Pb ratio (<1.17), it can be assumed that the Pb in the youngest parts of the tree species is derived from absorption of SPM Pb through the bark rather than root uptake. The absence of Pb with a low ²⁰⁶Pb/²⁰⁷Pb ratio in soils in the distant area is probably affected by fires in the herbaceous and bush undergrowth and plant litter, which prevents Pb from biomass from entering the soil and mobilize it back into the atmosphere.     

Full-Scale Remediation of a Jet Fuel-Contaminated Soil: Assessment of Biodegradation, Volatilization, and Bioavailability

Here, we addressed biodegradation vs. volatilization processes, and also bioavailability limitations during biopile remediation of soil initially contaminated by more than 5,000 mg/kg of hydrocarbons. In order to select bioremediation strategies, we first conducted a biotreatability study, which included geochemical, textural, and microbiological characterization of the soil matrix. Next, we implemented five bioremediation approaches onsite in real-scale biopiles. In order to monitor hydrocarbon depletion and to distinguish between biological and non-biological processes, we analyzed chemical biomarkers by means of gas chromatography?Cmass spectrometry. In addition, a comprehensive study of soil grain size and its implications on bioavailability were studied. Furthermore, the evolution of microbial populations was also examined. Two of the strategies implemented in the biopiles (the combination of a slow-release fertilizer and a surfactant, and the use of an oleophilic fertilizer respectively) reduced the soil hydrocarbon content to under 500 mg/kg in 5 months. Additional results from this study indicate that volatilization was the predominant degradation process for light hydrocarbons (below 12 carbon atoms), whereas heavier compounds were mainly biodegraded. However, even in the most favorable situation, a residual concentration of hydrocarbons linked to the finer fraction of the soil was found.     

Chemically Modified Crop Residues as a Low-Cost Technique for the Removal of Heavy Metal Ions from Wastewater

Batch adsorption experiments were carried out to evaluate the effect of type of crop residues and chemical pretreatment solutions on the removal efficiency of heavy metal ions at different concentrations of synthetic wastewater solutions. Rice straw, cotton stalks, and maize stalks were pretreated with different solutions (i.e., sulfuric acid, oxalic acid, sodium hydroxide, and distilled water as the control treatment) in order to increase their metal-binding capacity. Results indicated that cotton stalks were the best biosorbent material according to their efficiency in removal of heavy metal ions. Sodium hydroxide was the best chemical pretreatment method for stimulating the biosorption capacity of crop residues. Ions of Pb²⁺ had the highest biosorption ratio among all competitive ions, whereas Mn²⁺ ions had the lowest. The removal efficiency decreased as the concentration of heavy metal ions increased in aqueous solutions. Sorption equilibrium isotherms could be described by the Langmuir model in most cases, whereas an isotherm of S shape was observed in other cases, which did not follow the Langmuir isotherm model. In conclusion, cotton stalks pretreated with sodium hydroxide could be used as an efficient technique for wastewater remediation prior to irrigation due to its low-cost, little processing, and high biosorption capacity.     

A Potential Solution to Mitigate Phosphorus Release Following Clearfelling in Peatland Forest Catchments

Since the 1950s, large areas of upland peat have been afforested in northern European countries. Due to the poor phosphorus (P) adsorption capacity and low hydraulic permeability in blanket peat soil and increased labile P sources, harvesting these blanket peat forests can significantly increase P concentrations in the receiving aquatic systems. This paper briefly reviews the current management practices on the control of P releases from forestry in Ireland and the UK, and proposes a possible novel practice??grass seeding clearfelled areas immediately after harvesting, which should reduce P release from blanket peat forest harvesting. The study was conducted in the Burrishoole Catchment in the west of Ireland. A field trial was carried out to identify the successful native grass species that could grow quickly in the blanket peat forest. The two successful grass species??Holcus lanatus and Agrostis capillaris??were sown in three blanket peat forest study plots with areas of 100, 360, and 660 m² immediately after harvesting. Areas without grass seeding were used as controls. One year later, the P content in the aboveground vegetation biomass of the three study plots were 2.83, 0.65, and 3.07 kg P?ha^?1, respectively, which were significantly higher than the value of 0.02 kg P?ha^?1 in the control areas. The water extractable phosphorus in the three study plots were 8.44, 9.83, and 6.04 mg?(kg dry soil)^?1, respectively, which were lower than the value of 25.72 mg?(kg dry soil)^?1 in the control sites. The results indicate that grass seeding of the peatland immediately after harvesting can quickly immobilize significant amounts of P and warrants additional research as a new Best Management Practice following harvesting in the blanket peatland forest to mitigate P release.     

Responses of Biochemical Markers in the Fish Prochilodus lineatus Exposed to a Commercial Formulation of Endosulfan

Among the most extensively used compounds for the pest control in Argentinean crops is the organochlorine endosulfan. The sublethal effects of the commercial endosulfan formulation on hematology and lipid peroxidation (LPO) of the neotropical fish Prochilodus lineatus were investigated. Firstly, we calculated acute toxicity (LC₅₀) in order to define sublethal concentrations (0, 1.2, and 2.4 ??g L^?1). Hematological and oxidative stress responses were assessed at 24, 48, and 96 h. Endosulfan exposure significantly diminished the hemoglobin concentration, mean cell hemoglobin, and total plasma protein and increased white blood cells count and plasma glucose after 96 h. Exposed fish showed an alteration of the differential leukocytes count, evidenced by more thrombocytes and monocytes and less lymphocytes and neutrophils. Endosulfan increased LPO levels in intestine, liver, and brain in both sublethal concentrations. The present results suggest that endosulfan produces biochemical and physiological alterations, including immunological disorders, and it is a good inductor of oxidative stress in P. lineatus.