Plasticity in the temporal organization of behaviour in the limpet <Emphasis Type="Italic">Cellana grata</Emphasis>

The behaviour of intertidal consumers is often tightly constrained to tidal movements, although activity patterns can vary within these constraints. Spatio-temporal variability in behaviour of a limpet, Cellana grata, was analysed over different tidal conditions (spring and neap tides) and during different times of the year (one summer and one winter) at sites in Hong Kong. Activity was generally dictated by tidal movements, being concentrated when animals were awash. Plasticity in behaviour was observed, with some limpets anticipating activity during the summer period and delaying activity during winter time. Limpets were active for a time equal, or slightly less, than time awash. As the time awash exceeded ~14–16 h, however, activity duration decreased. Within this general pattern, tidal variation as well as variation among times of the year was noted, with the lowest dependence on time awash being recorded during winter neap tides. Limpets showed a slight preference for being active during nighttime, which was particularly evident when animals were emersed during the summer period. Although the basic activity in C. grata is constrained to a specific temporal window, this limpet is able to modulate its foraging strategies and resting height, according to local, daily changes in environmental conditions.     

Monitoring of Cr, Cu, Pb, V and Zn in polluted soils by laser induced breakdown spectroscopy (LIBS)

Laser Induced Breakdown Spectroscopy (LIBS) is a fast and multi-elemental analytical technique particularly suitable for the qualitative and quantitative analysis of heavy metals in solid samples, including environmental ones. Although LIBS is often recognised in the literature as a well-established analytical technique, results about quantitative analysis of elements in chemically complex matrices such as soils are quite contrasting. In this work, soil samples of various origins have been analyzed by LIBS and data compared to those obtained by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). The emission intensities of one selected line for each of the five analytes (i.e., Cr, Cu, Pb, V, and Zn) were normalized to the background signal, and plotted as a function of the concentration values previously determined by ICP-OES. Data showed a good linearity for all calibration lines drawn, and the correlation between ICP-OES and LIBS was confirmed by the satisfactory agreement obtained between the corresponding values. Consequently, LIBS method can be used at least for metal monitoring in soils. In this respect, a simple method for the estimation of the soil pollution degree by heavy metals, based on the determination of an anthropogenic index, was proposed and determined for Cr and Zn.     

Phylogeography and evolution of the triplefin <Emphasis Type="Italic">Tripterygion delaisi</Emphasis> (Pisces,Blennioidei)

The genus Tripterygion (Risso 1826) is restricted to the eastern Atlantic and the Mediterranean, and comprises only three species. T. melanuros and T. tripteronotus are essentially endemic to the Mediterranean, while Tripterygion delaisi occurs in the Atlantic and in the Mediterranean. Two subspecies of T. delaisi have been described (T. d. xanthosoma in the Mediterranean and T. d. delaisi in the Atlantic). Several scenarios have been proposed for the evolution of T. delaisi subspecies, but so far its subspeciation process is not clear. In this study we present a population survey of T. delaisi including specimens from the two recognized subspecies. We combined a phylogeographic approach with estimates of the direction of migration (between the Atlantic and the Mediterranean) and of the coalescence time of the two subspecies, using polymorphic mitochondrial and nuclear genes. The results of this study clearly support the existence of two Tripterygion delaisi clades, one in the eastern Atlantic islands and another in the Atlantic coasts of Europe and in the Mediterranean. Historical migration between the islands and Western Europe plus Mediterranean was restricted, and showed a westbound trend, with a higher number of migrants going from the Western Europe plus Mediterranean into the islands. We estimated the time of coalescence of both groups of T. delaisi to be more recent than the onset of Pleistocene glaciations (1.7 Mya). Our results are consistent with previous hypothesis that consider successive dispersal events of a Tripterygion ancestor from the western African coast colonizing the Atlantic islands and the Mediterranean, promoting the evolutionary divergence between these areas.     

Does the preferential microbial colonisation of ferromagnesian minerals affect mineral weathering in soil?

Fungal activity is thought to play a direct and effective role in the breakdown and dissolution of primary minerals and in the synthesis of clay minerals in soil environments, with important consequences for plant growth and ecosystem functioning. We have studied primary mineral weathering in volcanic soils developed on trachydacite in southern Tuscany using a combination of qualitative and quantitative mineralogical and microbiological techniques. Specifically, we characterized the weathering and microbiological colonization of the magnetically separated ferromagnesian minerals (biotite and orthopyroxene) and non-ferromagnesian constituents (K-feldspar and volcanic glass) of the coarse sand fraction (250-1,000 microm). Our results show that in the basal horizons of the soils, the ferromagnesian minerals are much more intensively colonized by microorganisms than K-feldspar and glass, but that the composition of the microbial communities living on the two mineral fractions is similar. Moreover, X-ray diffraction, optical and scanning electron microscope observations show that although the ferromagnesian minerals are preferentially associated with an embryonic form of the clay mineral halloysite, they are still relatively fresh. We interpret our results as indicating that in this instance microbial activity, and particularly fungal activity, has not been an effective agent of mineral weathering, that the association with clay minerals is indirect, and that fungal weathering of primary minerals may not be as important a source of plant nutrients as previously claimed.     

Temperature effects on fecundity,development and survival of the benthopelagic calanoid copepod, <Emphasis Type="Italic">Pseudocyclops xiphophorus</Emphasis>

The shallow-living, benthopelagic copepod species Pseudocyclops xiphophorus Wells (R Soc Edimburg 67:1967), collected over a yearly cycle from the fouling material in the brackish water Lake Faro (North-eastern Sicily), showed marked seasonal fluctuations in population abundances, with maximum numbers recorded in autumn. Highest in situ egg production rates coincided with periods of low adult and juvenile densities and vice versa, except in autumn when peaks in egg production and adult population densities were coincident. In this period, mean daily egg production rates reached a maximum of 4–5 eggs per female, when surface water temperature was 17–18°C. Egg production rates declined drastically in winter and were completely arrested when surface temperatures dropped to 10–12°C. In March, daily egg production rates began to increase again with an increase in ambient temperatures, reaching a maximum at the end of August. In the laboratory, as in the field, mean daily egg production rates were positively correlated with temperature, with values ranging from 2.2 ± 0.3 (16°C) to 8.9 ± 2.6 (30°C) (mean ± S.D.) eggs per female per day. At 32°C, P. xiphophorus females survived but did not reproduce. At 34°C, all specimens died after a few days. In terms of total egg production for the entire female lifespan, maximum values occurred at 16°C and minimum at 24°C. Temperature also dramatically affected female life span, which was shorter at higher temperatures. Development time of eggs decreased with increasing temperature, as also development time from egg to adulthood. Remating was necessary for the continued production of fertile eggs at 16°C because female life span was longer. The unique egg-laying behaviour in this species may ensure higher survival rates of egg stages compared to free-spawning and egg-carrying calanoid species. After releasing the egg pair, the female swims over the eggs with a rotatory motion, secreting a substance which facilitates the adhesion of the eggs to the bottom; she then continues to swim over the eggs until they are attached. Although egg production rates in this species are low compared to other pelagic copepods, they are within the range of values reported for egg-carrying species. The greater fecundity at higher temperatures compared to other subtemperate species indicates that the species is well adapted to the higher temperatures of coastal lagoons and brackish water lakes where it contributes to the biofouling community.     

Utilization of a new host in the screaming cowbird <Emphasis Type="Italic">Molothrus rufoaxillaris</Emphasis>, a host specialist brood parasite: host switch or host acquisition?

The screaming cowbird Molothrus rufoaxillaris has been long known as a host specialist brood parasite. However, in the past years, the utilization of two new hosts has been documented. We examined the variation in mitochondrial control region sequences from screaming cowbird chicks found in the nests of two hosts, the bay-winged cowbird (Agelaioides badius), which is its regular host, and the chopi blackbird (Gnorimopsar chopi), which is a new host, in Formosa Province, Argentina. If a group of females switched to this new host, we expected to find an association between host use and haplotype frequency distribution, indicating the presence of host-specific female lineages, whereas we expected no such association if the cowbird population incorporated this new host and females use both hosts simultaneously. Haplotype frequency distributions differed between cowbird chicks from the nests of both hosts. This indicates that nest choice by females of this brood parasite is not random and that they preferentially parasitize the nests of the same host species.     

Sprawl matters: the evolution of fringe land,natural amenities and disposable income in a Mediterranean urban area

We investigate the relationship between land-use changes (1987–2007) and the spatial distribution of the average declared income of resident population in a southern European metropolitan region (Athens, Greece) as a contribution to the analysis of suburbanization processes in the Mediterranean region. To demonstrate that urban expansion is accompanied with multiple modifications in the use of the surrounding non-urban land, we developed a computational approach based on spatial indexes of landscape configuration and proximity as a result of changes in the local socio-spatial structure. Diversity in the use of land surrounding built-up parcels in the Athens’ metropolitan region increased significantly between 1987 and 2007, reflecting a progressive fragmentation of the exurban landscape. The percentage of forests and (high-quality) natural land surrounding built-up parcels increased from 8.1 to 9.4 % between 1987 and 2007. The reverse pattern was observed for (low-quality) sparsely vegetated areas, declining from 65 to 47 %. Large built-up parcels were surrounded by a higher percentage of natural land than small parcels. The largest increase over time in forest and natural land surrounding built-up parcels was observed in municipalities with high per capita declared income, and the reverse pattern was observed for sparse vegetation. Our results demonstrate that scattered urban expansion determines a polarization in suburban areas with high-quality and low-quality natural amenities. Sprawl increases economic inequality and socio-spatial disparities contributing to a spatially unbalanced distribution of natural amenities with higher consumption of high-quality land.     

Chemical recycling of poly(ethylene terephthalate) (pet) by hydrolysis and glycolysis

In this paper we review an interesting method of PET recycling, i.e. chemical recycling; it is based on the concept of depolymerizing the condensation polymer through solvolytic chain cleavage into low molecular products which can be purified and reused as raw materials for the production of high-quality chemical products. In this work our attention is confined to the hydrolysis (neutral, acid and alkaline) and glycolysis processes of PET chemical recycling; operating conditions and mechanism of each method are reported and described. The neutral hydrolysis has an auto accelerating character; two kinetic models have been proposed: an half-order and a second order kinetic model. The acid hydrolysis could be explained by a modified shrinking core model under chemical reaction control and the alkaline hydrolysis by a first-order model with respect to hydroxide ion concentration. To describe glycolysis, two different kinetic models have been proposed where EG can act or not as internal catalyst. Further experimental and theoretical investigations are required to shed light on the promising processes of PET chemical recycling reviewed in this work.     

Tensile Behavior of Thermoplastic Films from Wheat Flours as Function of Raw Material Baking Properties

The production of bioplastics directly from wheat flour has been demonstrated to be reliable, but scarce knowledge is available on how flour characteristics may affect the performance of thermoplastic films. In this work, we first established the most suitable recipe and process for the production of extruded films and then we used eight single-cultivar wheat flours with different baking technological properties to assess how they affect the mechanical properties of thermoplastic films. The results have shown that flours from soft grain cultivars offered more rigid and deformable films than flours from hard grain cultivars. For similar hardness, the alveographic P/L ratio of the dough was inversely related to rigidity and directly related to deformability of plastic films, while the deformation energy of the dough (W) played a role only for great differences of it. The subsequent fabrication of blends between each of the flours that yielded the best film properties and polycaprolactone (PCL) at different proportions indicated that a wheat flour/PCL ratio (TWF/PCL) of 75/25 offered the most suitable films for further application. Our results are likely to be useful for improving the plasticization of flour, in that selection of wheat flours could be tailored on the properties desired for the bioplastic films.     

Ozone sensitivity of currant tomato (Lycopersicon pimpinellifolium), a potential bioindicator species

The wild tomato species Lycopersicon pimpinellifolium (currant tomato) was exposed to different O3 concentration, both in controlled environment fumigation facilities and in open-top chambers, to assess its sensitivity and to verify its potential as a bioindicator plant. Plants appeared particularly sensitive to O3 at an early stage of growth, responding with typical chlorotic spots within 24 h after exposure to a single pulse of 50 ppb for 3 h, and differentiating peculiar symptoms, such as reddish necrotic stipples, bronzing and extensive necrosis, depending on O3 concentration. Histo-cytochemical investigations with 3,3'-diaminobenzidine, to localize H2O2, and Evans blue, to detect dead cells, suggested that currant tomato sensitivity to O3 could be due to a deficiency in the anti-oxidant pools. The combination of these stainings proved to be useful, either to predict visible symptoms, early before their appearance, and to validate leaf ozone injury.