Determination of metal partitioning in porewater extracted from the Seine River Estuary sediment (France)

Total dissolved trace and major metals and their partitioning in porewater sediment have been investigated at two sites in the Seine River estuary (France). For this purpose, solid phase extraction (SPE) has been employed using specific chelating resins for the separation and preconcentration of organic and inorganic forms of studied metals under controlled (N2) inert atmosphere. In fact, the study is focused on the development of a method for sample collection and handling under inert atmosphere in order to avoid some potential artefacts of the extracted porewater, to preserve the samples from possible chemical oxidation changes and to determine metals partitioning between organic and inorganic forms. For this point, a separation and preconcentration method using two columns in series (chelamine and C18 columns) was used. The trace and major metals fixed on the two resins for all determinations were stripped by nitric acid (2 M) and analyzed by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) and Zeeman Graphite Furnace Atomic Absorption Spectroscopy (ZGF-AAS). The relationship between the distribution of metals and physico-chemical parameters such as pH and Eh (redox potential) as a function of depth was discussed. Some tendency in the distributions and seasonal variability of these traces and major metals are improved. The concentrations for all studied metals decreased as a function of depth where iron and manganese were found at mg L(-1) levels and other metals were found at [micro sign]g L(-1) levels, as well as there were significant fractions of all metals (except of manganese) which were complexed by organic matter. The comparison of data for the major elements (Fe and Mn), obtained by direct determination (without preconcentration) and preconcentration, show a very good recovery.     

Effects of access to preen gland secretions on mallard plumage

Preen glands exist in almost every bird species and several non-exclusive functions have been proposed for this gland and the oils that it produces. One function generally admitted is that the oily secretions of the preen gland would provide a waterproofing layer when spread over feathers. Alternatively, several authors have proposed that plumage waterproofness is mostly due to the spatial micro-structure of feathers. The purpose of this study was to examine, by manipulating the access to the preen gland, the effect of the preen oil on the plumage waterproofness and condition. To explore this question, we carried out two independent experiments where we temporarily blocked access to the preen gland secretions with a removable mechanism in one group of captive mallards (Anas platyrhynchos), whilst a second group of birds had access to gland secretions. In a long-term experiment (3 months of treatment) and a short-term experiment (10 days), we measured plumage water retention and condition. After 3 months without access to preen glands, we found a significant decrease of plumage condition and an associated increase in plumage water retention. Moreover, we found a significant correlation between plumage condition and water retention ability. In contrast, after 10 days of treatment, no significant effect was found on plumage condition and water retention. Our study shows that preen oil acts to maintain plumage condition and suggests that feather microstructure is essential to maintain plumage waterproofness.     

Perfluorooctane sulfonic acid and organohalogen pollutants in liver of three freshwater fish species in Flanders (Belgium): relationships with biochemical and organismal effects

A perfluorooctane sulfonic acid (PFOS) assessment was conducted on gibel carp (Carassius auratus gibelio), carp (Cyprinus carpio), and eel (Anguilla anguilla) in Flanders (Belgium). The liver PFOS concentrations in fish from the Ieperlee canal (Boezinge, 250-9031 ng/g wet weight, respectively) and the Blokkersdijk pond (Antwerp, 633-1822 ng/g wet weight) were higher than at the Zuun basin (Sint-Pieters-Leeuw, 11.2-162 ng/g wet weight) and among the highest in feral fish worldwide. Eel from the Oude Maas pond (Dilsen-Stokkem) and Watersportbaan basin (Ghent) had PFOS concentrations ranging between 212 and 857 ng/g wet weight. The hepatic PFOS concentration was significantly and positively related with the serum alanine aminotransferase activity, and negatively with the serum protein content in eel and carp. The hepatic PFOS concentration in carp correlated significantly and negatively with the serum electrolyte concentrations whereas a significant positive relation was found with the hematocrit in eel. Although 13 organochlorine pesticides, 22 polychlorinated biphenyl (PCB) congeners and 7 polybrominated diphenyl ethers (PBDEs) were also measured in the liver tissue, only PCB 28, PCB 74, gamma-hexachlorocyclohexane (gamma-HCH) and hexachlorobenzene (HCB) were suggested to contribute to the observed serological alterations in eel.     

Modelling forest succession in two southeastern Canadian mixedwood ecosystem types using the ZELIG model

The gap model ZELIG was validated for red spruce–balsam fir–yellow birch and yellow birch–sugar maple–balsam fir forest types in southern Quebec, Canada. Long-term historical data originating from the Lake Edward Experimental Forest, La Mauricie National Park, were used. The effect of the variation in plot size, representing the space within which trees uptake site resources, was also examined. Several species were included in both forest types: red spruce (Picea rubens Sarg.), balsam fir (Abies balsamea (L.) Mill.), yellow birch (Betula alleghaniensis Britton), white birch (Betula papyrifera Marsh.), red maple (Acer rubrum L.), sugar maple (Acer saccharum Marsh.), American beech (Fagus grandifolia Ehrh.), eastern hemlock (Tsuga canadensis (L.) Carr.) and northern white cedar (Thuja occidentalis L.). The pattern of change in basal area growth varied among species, ranging from a steady increase to a more or less rapid decline. There was a good agreement between observations and predictions for yellow birch, red spruce, red maple, sugar maple, balsam fir and northern white cedar. Plot size had a significant impact on the dynamics of the different species. Depending on the species, the decline was accelerated, the amplitude of the fluctuations varied, or the maximum basal area reached changed. Predicted regeneration varied among species and the number of seedlings generally increased with increase in plot size. The pattern of development for most species was related to their life characteristics. The results highlighted the fact that there is a critical lack of knowledge and data on the dynamics of regeneration from the seedling to the sapling stages for the two forest types studied, which resulted in poor predictions for some species. As the life characteristics varied among species, the use of only one plot size for all species may not be realistic.     

Nutrient transfer by runoff from sewage sludge amended soil under simulated rainfall

Wastewater sludges are used in agriculture as soil amendment and fertilizer, with regard to their organic matter and nutrient content. However, availability of nitrogen and phosphorus from sludge-amended soils and their transfer in runoff may lead to eutrophication of downstream surface water. The aim of this study is to establish and compare the effect of two different sludges on these transfers: an anaerobically digested and thermically stabilised sludge (Seine-Aval treatment plant, sludge no. 1), and a limed sludge (Saint-Quentin treatment plant, sludge no. 2). Experiments were performed on 12 sloping micro-plots (1 m × 1 m) submitted to sludge spreading and controlled rainfall simulation. Runoff water was sampled and analysed for concentrations in nitrogen species and phosphorus. Results show that spreading of sludge no. 1 increased both ammonium nitrogen (mean of 1.1 mg L^–1 N-NH₄ vs. 0.2 mg L^–1 N-NH₄ for control micro-plots) and particulate phosphorus concentrations (mean of 2 mg L^–1 P vs. 1.1 mg L^–1 P for control micro-plots) in runoff water. On the other hand, sludge no. 2 did not induce any significant effect on nutrient concentrations in runoff. These results are related to chemical composition and physical treatment of sludges. This study underlines the existence of a short-term risk of nutrient mobilisation by runoff after sludge spreading on soil, and the need to check precisely the impact of this practice on water quality.     

Are rapid population estimates accurate? A field trial of two different assessment methods

Emergencies resulting in large-scale displacement often lead to populations resettling in areas where basic health services and sanitation are unavailable. To plan relief-related activities quickly, rapid population size estimates are needed. The currently recommended Quadrat method estimates total population by extrapolating the average population size living in square blocks of known area to the total site surface. An alternative approach, the T-Square, provides a population estimate based on analysis of the spatial distribution of housing units taken throughout a site. We field tested both methods and validated the results against a census in Esturro Bairro, Beira, Mozambique. Compared to the census (population: 9,479), the T-Square yielded a better population estimate (9,523) than the Quadrat method (7,681; 95% confidence interval: 6,160-9,201), but was more difficult for field survey teams to implement. Although applicable only to similar sites, several general conclusions can be drawn for emergency planning.     

Compost, manure, and gypsum application to timothy/red clover forage

Some of the most fertile agricultural land in Atlantic Canada includes dykelands, which were developed from rich salt marshes along the Bay of Fundy through the construction of dykes. A 2-yr field experiment was conducted on dykeland soil to evaluate the effect of fertility treatments: source-separated municipal solid waste (SS-MSW) compost, solid manure, commercial fertilizer, and gypsum on (1) timothy/red clover forage productivity, (2) N, S, and other nutrients uptake, and (3) residual NO(3)-N and NH(4)-N in the soil profile. All fertility treatments increased dry matter yields from the two cuts each year relative to the control. Residual soil NO(3)-N and NH(4)-N concentrations in the fall of the second year decreased with depth, and beyond 20-cm depth were lower than 1 mg kg(-1). Gypsum application equivalent to 40 kg S ha(-1) increased dry matter yields and N uptake by forage, and increased soil Mehlich 3-extractable S, tissue S, and uptake of S, Ca, P, Cu, Fe, and Mn relative to the control. High rates of compost can provide sufficient N, S, and perhaps other nutrients to a perennial forage system under the cool wet climate of Atlantic Canada with no heavy metal enrichment of forage. However, the chemical N provided greater total N uptake than organic sources, except the high rate of compost, suggesting that the N availability from organic sources was not well synchronized with forage N demand. Municipal solid waste compost may also increase soil and forage tissue Na, which might be of concern.     

Habitat Matrix Effects on Pond Occupancy in Newts

Abstract: In farmlands, the population viability of many amphibians is suspected to depend on the resistance the matrix of crop fields presents to movements between ponds and terrestrial sites and movements among ponds. Over recent decades the increase in cereal growing at the expense of cattle breeding has caused a drastic change in habitat matrix in many European regions. We investigated the effect of such change on populations of three newt species (   Triturus helveticus , T. alpestris , and T. cristatus ) by comparing their abundances in sites that varied in amount of cultivated ground. A multivariate regression analysis of the relationship of newt abundance to both pond and landscape variables demonstrated the negative influence of cultivated ground on abundance. The width of the uncultivated sector linking the pond to the forest was a good predictor of abundance after the influences of both pond area and fish presence were removed. Moreover, newt presence was positively related to the number of ponds within that 50-ha surrounding area, highlighting the role of metapopulation functioning in newt occupancy of ponds. The relationship between newt abundance and width of uncultivated sectors agrees with present knowledge of the orientation mechanisms that underlie migration movements in urodeles. Such a relationship between connectedness and sector width shows that narrow, linear corridors such as hedgerows may not be useful in newt conservation. Our study also highlights the need to incorporate a behavioral component of habitat use into models of connectivity in conservation biology.