Phylogeography of the Southwestern Atlantic menhaden genus <Emphasis Type="Italic">Brevoortia</Emphasis> (Clupeidae,Alosinae)

Among pelagic fish, the Southwestern Atlantic menhaden genus Brevoortia (Clupeidae, Alosinae) constitutes an important species model to investigate the patterns of genetic differentiation. It is abundant in the Río de la Plata estuary and in the Atlantic coastal lagoons system from Uruguay and Southern Brazil. To access in the taxa discrimination and population structure in Brevoortia we perform a phylogeographic approach based on mitochondrial cytochrome b (cyt-b) sequences including 240 individuals from 16 collecting sites. Among the 720 bp cyt-b sequenced, 199 correspond to variables and 88 to phylogenetically informative sites. High values of haplotype diversity (h = 1.000) and nucleotide diversity (π = 0.061), as well as an average of 0.084 polymorphic segregating sites and 46 different haplotypes were found. Maximum likelihood analysis based on the GTR + I + G model and Bayesian inference strongly support the idea that B. aurea is the only species of the genus inhabiting the Southwestern Atlantic region. Our analyses revealed a complex population pattern characterized by the existence of long-term highly structured genetic assemblages of mixed stocks. Each monophyletic entity included individuals from different collecting sites, different age groups and collected in different years. Our data also suggest that the recruitment of unrelated mtDNA haplotypes carried out by individuals within schools could be occurring in the same nursery areas revealing the existence of many different maternal lineages. A scenario where different simultaneously and successively mixed mtDNA lineages remain historically connected through basal haplotypes among different clades could explains more accurately the complex and ordered metapopulation dynamic found in this pelagic fish.     

Spatial–temporal pattern of bluefin tuna (Thunnus thynnus L. 1758) gonad maturation across the Mediterranean Sea

Atlantic bluefin tuna (BFT; Thunnus thynnus) is a migrating species straddling the North Atlantic Ocean and Mediterranean Sea. It is assumed that this species is divided into a western and an eastern stock, which spawn in the Gulf of Mexico and the Mediterranean Sea, respectively. To learn more about the reproductive behavior of the eastern BFT stock, we tracked gonadal development in adult fish that were sampled between April and July during three consecutive years (2003–2005). Sampling campaigns were carried out using common fishing methods at selected locations within the Mediterranean Sea, namely Levantine Sea, Malta, and Balearic Islands. An additional sampling point, Barbate, was situated northwest of the Straits of Gibraltar along the Atlantic coast. Morphometric parameters such as the total body mass (M _B) and the weights of the gonads (M _G) were recorded, and the respective gonadosomatic index (GSI) values were calculated. The data collected revealed two important trends: (1) GSI values are higher in fish caught in the eastern rather than the western locations across the Mediterranean Sea, and (2) the GSI reaches maximum values between late May and early June in Levantine Sea (eastern Mediterranean Sea), and only 2 and 4 weeks later in the central (Malta) and western (Balearic Islands) locations, respectively. The advanced gonadal development in BFT correlates well with higher sea surface temperatures. Our findings also distinguish the northern Levantine Sea BFT population (mean M _B 78.41 ± 4.13 kg), and the Barbate BFT population with the greatest M _B (all fish sampled > 100 kg). These data reflect a situation in which the eastern Mediterranean basin may function as a habitat for young BFT, until they gain a larger M _B and are able to move to the Atlantic Ocean. However, the existence of genetically discrete BFT populations in the Mediterranean Sea cannot be ruled out.     

On the sudden disappearance of Egeria densa from a Ramsar wetland site of Southern Chile: A climatic event trigger model

Contemporary shallow lakes theory proposes that these ecosystems may experience abrupt regime shifts due to small changes in controlling variables or triggers. So far, these triggers have been related mostly to nutrients as the immediate driver. During May 2004 the río Cruces wetland, a Ramsar site located in Southern Chile, underwent a major regime shift, from a clear water state, vastly dominated by the invasive macrophyte Egeria densa, to a turbid water state. In this article we show, through the analysis of long-term meteorological data that late fall 2004 was anomalous due to the presence of a high-pressure cell that persisted most of the month of May over Southern Chile. This climatic event caused an almost complete absence of precipitations and lower temperatures during this period, including several freezing nights. Eco-physiological experiments showed that 6 h exposure to desiccation kill the macrophyte. We developed a simple-biology dynamic model, under Stella Research 9.1, to show that the climatic anomaly of May 2004, plus the increased sedimentation of the wetland's floodplains, and the associated response of E. densa, explains its sudden disappearance from río Cruces wetland.     

Methodology for quantification of waste generated in Spanish railway construction works

In the last years, the European Union (EU) has been focused on the reduction of construction and demolition (C&D) waste. Specifically, in 2006, Spain generated roughly 47million tons of C&D waste, of which only 13.6% was recycled. This situation has lead to the drawing up of many regulations on C&D waste during the past years forcing EU countries to include new measures for waste prevention and recycling. Among these measures, the mandatory obligation to quantify the C&D waste expected to be originated during a construction project is mandated. However, limited data is available on civil engineering projects. Therefore, the aim of this research study is to improve C&D waste management in railway projects, by developing a model for C&D waste quantification. For this purpose, we develop two equations which estimate in advance the amount, both in weight and volume, of the C&D waste likely to be generated in railway construction projects, including the category of C&D waste generated for the entire project.     

Correlation analysis between sulphate content and leaching of sulphates in recycled aggregates from construction and demolition wastes

In some recycled aggregates applications, such as component of new concrete or roads, the total content of soluble sulphates should be measured and controlled. Restrictions are usually motivated by the resistance or stability of the new structure, and in most cases, structural concerns can be remedied by the use of techniques such as sulphur-resistant cements. However, environmental risk assessment from recycling and reuse construction products is often forgotten. The purpose of this study is to analyse the content of soluble sulphate on eleven recycled aggregates and six samples prepared in laboratory by the addition of different gypsum percentages. As points of reference, two natural aggregates were tested. An analysis of the content of the leachable amount of heavy metals regulated by European regulation was included. As a result, the correlation between solubility and leachability data allow suggest a limiting gypsum amount of 4.4% on recycled aggregates. This limit satisfies EU Landfill Directive criteria, which is currently used as reference by public Spanish Government for recycled aggregates in construction works.     

Long-range transport and re-circulation of pollutants in the western Mediterranean during the project Regional Cycles of Air Pollution in the West-Central Mediterranean Area

During the warm season (March–September), high ozone concentrations have been reported at the coastal and mountain monitoring stations of the eastern Iberia coast (Millán et al., J. Geophys. Res. 102 (D7) 8811, J. Appl. Meteorol. 4 (2000) 487). The vegetation protection threshold of current Directive 92/72/EEC and the World Health Organisation guideline for the protection of crops and semi-natural vegetation are systematically exceeded during the whole period. The main objective of the present study is to search for the origin of these chronic pollution levels: to search for the reason(s) for such high O₃ concentrations during such a long period. A mesoscale model is used to reproduce the diurnal cycle of winds and stability/layering over the Western Mediterranean Basin (WMB), at a sufficient space/temporal resolution, under a typical recursive synoptic condition during the warm season: data from the flight tracks of the European Project—Regional Cycles of Air Pollution in the West-Central Mediterranean Area—are used to substantiate the model results. Times of residence and the final distribution of pollutants entering the WMB are estimated using single-particle Lagrangian trajectories and a multiple-particle dispersion model. Our results show that the marine boundary layer and the lower troposphere in the region between the Balearic Islands and eastern Iberia are subject to a flow regime that tends to accumulate pollutants within large circulations, covering the entire western basin. We have also shown a diurnal pulsation of the Tramontana/Mistral wind regime, which can transport new pollutants into the area (background concentrations of 50–65 ppb of O₃ of continental European origin) that are added to local emissions and re-circulated within the coastal breezes at eastern Iberia for periods of more than five days. Local emissions and wind configuration contribute to increase the O₃ concentrations up to 100 ppb and even more.     

Wet and dry deposition of 129I in Seville (Spain) measured by accelerator mass spectrometry.

Iodine-129 (T1/2 = 1.57 x 10(7) yr) concentrations have been determined by accelerator mass spectrometry in rainwater samples taken at Seville (southwestern Spain) in 1996 and 1997. This technique allows a reduction in the detection limits for this radionuclide in comparison to radiometric counting and other mass spectrometric methods such as ICP-MS. Typical 129I concentrations range from 4.7 x 10(7) 129I atoms/l (19.2%) to 4.97 x 10(9) 129I atoms/l (5.9%), while 129I depositions are normally in the order of 10(8)-10(10) atoms/m2d. These values agree well with other results obtained for recent rainwater samples collected in Europe. Apart from these, the relationship between 129I deposition and some atmospheric factors has been analyzed, showing the importance of the precipitation rate and the concentration of suspended matter in it.     

Ecotoxicity assessment of slag generated in the process of recycling lead from waste batteries

The aim of this study was to evaluate the possible toxicity of the leachate produced by the residues generated in the process of recycling lead from waste batteries. These residues are slag, which once formed, is characterised by its content in ferrous sulphide, sodium carbonate as well as residual coke from the process. It also contains, as minor components, lead and other heavy metals. The slag was stored and watered periodically over a period of 6 months, its composition changing until finally becoming inert, with no exothermal activity. The slag was leached, and its ecotoxicity was determined by means of the bioluminescence test, along with its content in heavy metals. The results obtained indicate a greater degree of toxicity in the residues with a shorter storage period than the established one, and which were therefore still in the phase of decomposition. However, in the samples taken on completing 6 months of storage, the EC₅₀ value of the leachate was found to be higher than 3000 mg/l. Hence, a storage period under suitable environmental conditions which leads to inactivity of the residue as well as a decrease in its ecotoxicity, is considered absolutely essential. At the same time, a direct relationship was observed between the lead content and the ecotoxicity value.     

Sexual and natural selection in a continuous time model

We call sexual selection the selection attributable only to the mating system, to distinguish it from other forms of selection (i.e. viability or fertility) which we call natural selection. We introduce a new continuous time model of sexual selection and we explore its relationship with natural selection. This model is an extension of the model proposed by Hoppensteadt [Hoppensteadt, F., 1977. Mathematical Theories of Populations: Demographics, Genetics and Epidemics. SIAM] and considers the three genotypes determined by two alleles in a locus, each with its own mortality and fertility rates, and the respective mating preferences.     

Extractable atrazine and its metabolites in agricultural soils from the temperate humid zone

Extractable atrazine and its metabolites (hydroxyatrazine, deethylatrazine and deisopropylatrazine) were evaluated in agricultural soils from the temperate humid zone (Galicia, NW Spain) under laboratory conditions. The experiment was performed with five soils with different properties (organic C, soil texture and atrazine application history), both unamended and treated with atrazine at field application rate. Measurements of the atrazine compounds were made at different time intervals (1, 3, 6, 9 and 12 weeks) during a 3-month incubation period. Results showed that only hydroxyatrazine was detected in the extractable fraction of the unamended soils, with values remaining relatively constant throughout the incubation period. Atrazine addition notably increased the concentration of the parent compound and its degradation products; deisopropylatrazine and hydroxyatrazine were the main metabolites detected in the extractable fraction of the treated soils, whereas deethylatrazine was not detected. After 7 days incubation, values of total extractable residues, expressed as percentage of initially added atrazine, ranged from 75 to 86% (25–68% of atrazine, 7–11% of hydroxyatrazine and 9–57% of deisopropylatrazine). The values decreased rapidly during the first 3 weeks of incubation, showing values of 2–8% in soils with higher atrazine application and from 28 to 30% in soils with lower application history. At the end of the incubation, 2–8% of total extractable residues were still detected (0–4% of atrazine, 2–3% of hydroxyatrazine and 0–2% of deisopropylatrazine), indicating a residual effect of atrazine addition. These variations in the extractable fraction indicated that most added atrazine was rapidly degraded, especially in soils with higher application history.