Canopy profiles of photosynthetic parameters under elevated CO2 and N fertilization in a poplar plantation

A poplar plantation has been exposed to an elevated CO2 concentration for 5 years using the free air CO2 enrichment (FACE) technique. Even after such a long period of exposure, leaves of Populus x euramericana have not shown clear signs of photosynthetic acclimation. Only at the end of the growing season for shade leaves was a decrease of maximum velocity of carboxylation (Vcmax) observed. Maximum electron transport rate (Jmax) was increased by FACE treatment in July. Assimilation rates at CO2 partial pressure of 400 (A400) and 600 (A600) micromol mol(-1) were not significantly different under FACE treatment. Most notably FACE significantly decreased stomatal conductance (g(s)) both on upper and lower canopy leaves. N fertilization increased N content in the leaves on mass basis (Nm) and specific leaf area (SLA) in both CO2 treatments but did not influence the photosynthetic parameters. These data show that in poplar plantations the long-term effects of elevated CO2 on photosynthesis do not differ considerably from the short-term ones even with N deposition.     

Long-term study of environmental levels of dioxins and furans in the vicinity of a municipal solid waste incinerator

From 1975 to 2004, a municipal solid waste incinerator (MSWI) was operating in Montcada (Barcelona, Catalonia, Spain). Because of the potential health risks derived from emission of pollutants by the facility, especially polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), a long-term monitoring program focused on measuring the environmental levels of PCDD/Fs near the facility, and to assess the health risks for the population living in the neighborhood, was established between 1996 and 2002. A total number of 111 soil and 121 herbage samples were analyzed for PCDD/Fs during this period. Human health risks for the individuals living near the MSWI (500 and 1,000 m) were also assessed before (1998) and after modernization (2000) of the facility. It included PCDD/F inhalation, dermal contact, soil and dust ingestion, and food intake. All these data are here summarized. The environmental levels of PCDD/Fs showed that the MSWI was not the main responsible of the atmospheric pollution by these compounds. In turn, human health risks for the population living in the vicinity of the facility after introduction of a modern technology were negligible in comparison with the dietary PCDD/F exposure.     

Searching for Networks: Ecological Connectivity for Amphibians Under Climate Change

Environmental Management - Ecological connectivity depends on key elements within the landscape, which can support ecological fluxes, species richness and long-term viability of a biological...     

Encounters between Antarctic limpets, <Emphasis Type="Italic">Nacella concinna</Emphasis>, and predatory sea stars, <Emphasis Type="Italic">Lysasterias</Emphasis> sp., in laboratory and field experiments

Antarctic limpets, Nacella concinna, from the Admiralty Bay (King George Island, South Shetlands) for at least part of the year (austral winter) co-exist with predatory sea stars Lysasterias sp. Our laboratory and field experiments established that the presence of Lysasterias sp. or its odour had considerable influence upon their behaviour. Limpets’ responses, consisting of shell mushrooming, shell rotation and flight, were distinctly different from their reaction to other stimuli, such as food and conspecific odours, or mechanical stimulation. Moreover, a significant impact of sea star presence on limpets’ activity was observed, with limpets fleeing to a distance of 60 cm from the predator. Such reactions allow limpets to lower the incidence of sea star predation, but at the cost of presumptive disrupting of foraging and an additional energy expended for locomotion. A visible difference was noted between two limpet populations, with the rockpool limpets responding only after physical contact with being touched by a sea star, and the subtidal ones responding at a distance of up to 20 cm.     

Estimating the complexity of bird song by using capture-recapture approaches from community ecology

Repertoire size, the number of unique song or syllable types in the repertoire, is a widely used measure of song complexity in birds, but it is difficult to calculate this exactly in species with large repertoires. A new method of repertoire size estimation applies species richness estimation procedures from community ecology, but such capture-recapture approaches have not been much tested. Here, we establish standardized sampling schemes and estimation procedures using capture-recapture models for syllable repertoires from 18 bird species, and suggest how these may be used to tackle problems of repertoire estimation. Different models, with different assumptions regarding the heterogeneity of the use of syllable types, performed best for different species with different song organizations. For most species, models assuming heterogeneous probability of occurrence of syllables (so-called detection probability) were selected due to the presence of both rare and frequent syllables. Capture-recapture estimates of syllable repertoire size from our small sample did not differ significantly from previous estimates using larger samples of count data. However, the enumeration of syllables in 15 songs yielded significantly lower estimates than previous reports. Hence, heterogeneity in detection probability of syllables should be addressed when estimating repertoire size. This is neglected using simple enumeration procedures, but is taken into account when repertoire size is estimated by appropriate capture-recapture models adjusted for species-specific song organization characteristics. We suggest that such approaches, in combination with standardized sampling, should be applied in species with potentially large repertoire size. On the other hand, in species with small repertoire size and homogenous syllable usage, enumerations may be satisfactory. Although researchers often use repertoire size as a measure of song complexity, listeners to songs are unlikely to count entire repertoires and they may rely on other cues, such as syllable detection probability.Communicated by A. Cockburn     

Virus Genome Quantification Does not Predict Norovirus Infectivity After Application of Food Inactivation Processing Technologies

When determining the effect of food processing on the infectivity of any contaminating virus, it is necessary to distinguish unambiguously between infectious and non-infectious viruses present. However, this can be difficult in the particular case of noroviruses (NoVs) because no reliable cell culture model is available. The aim of this study was to assess the use of molecular methods—RT real-time PCR (RT-qPCR) and enzymatic treatment (ET) coupled to RT-qPCR—to quantify the infectivity of NoV after application of various inactivating food-processing technologies. RT-qPCR and ET-RT-qPCR gave significantly different (P < 0.01) results concerning the reduction in viral genome counts by all inactivation procedures and conditions used, except for HHP treatment at 600 MPa for 5 min. These findings indicate that the ET prior to RT-qPCR has an effect on the estimation of the reduction of virus genome counts, and may eliminate genomes of affected virus particles. However, no correlation was found between the results obtained by ET-RT-qPCR and those obtained by cell culture. Therefore, the effect is presumably only partial, and not adequate to allow accurate estimation of virus inactivation. Consequently, our results indicate that the quantification of virus genomes by PCR, regardless of prior ET, is not adequate for establishing virus inactivation and/or infectivity. In addition, our results also illustrate that the general effect of virus inactivation is not directly correlated to effects on the integrity of virus genome and protein capsid. Presumably, inactivation by food processing is the consequence of effects on proteins involved in adhesion and invasion stages.     

Sulphurous air pollutants and exposure events of workers in thermal-mineral springs: a case study of Contursi Terme (Salerno,Italy)

Environmental Science and Pollution Research - Thermo-mineral springs are widely spread over the volcanic areas of Salerno, a city in southern Italy. Although the water of thermal structures...