Selecting cost‐effective areas for restoration of ecosystem services

Selection of areas for restoration should be based on cost‐effectiveness analysis to attain the maximum benefit with a limited budget and overcome the traditional ad hoc allocation of funds for restoration projects. Restoration projects need to be planned on the basis of ecological knowledge and economic and social constraints. We devised a novel approach for selecting cost‐effective areas for restoration on the basis of biodiversity and potential provision of 3 ecosystem services: carbon storage, water depuration, and coastal protection. We used Marxan, a spatial prioritization tool, to balance the provision of ecosystem services against the cost of restoration. We tested this approach in a mangrove ecosystem in the Caribbean. Our approach efficiently selected restoration areas that at low cost were compatible with biodiversity targets and that maximized the provision of one or more ecosystem services. Choosing areas for restoration of mangroves on the basis carbon storage potential, largely guaranteed the restoration of biodiversity and other ecosystem services. Selección de Áreas Rentables para la Restauración de Servicios Ambientales     

Chronic dietary exposure of zebrafish to PAH mixtures results in carcinogenic but not genotoxic effects

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants that can be present at high levels as mixtures in polluted aquatic environments. Many PAHs are potent mutagens and several are well-known carcinogens. Despite numerous studies on individual compounds, little is known about the toxicity of PAHs mixtures that are encountered in environmental situations. In the present work, zebrafish were continuously fed from 5 days post-fertilisation to 14 months post-fertilisation (mpf) with a diet spiked with fractions of either pyrolytic (PY), petrogenic light oil (LO), or petrogenic heavy oil (HO) origin at three concentrations. A decrease in survival was identified after 3 mpf in fish fed with the highest concentration of HO or LO, but not for PY. All PAH fractions caused preneoplastic and neoplastic disorders in long-term-exposed animals. Target tissues were almost exclusively of epithelial origin, with the bile duct epithelium being the most susceptible to chronic exposure to all PAH fractions, and with germ cells being the second most responsive cells. Significantly higher incidences of neoplasms were observed with increasing PAH concentration and exposure duration. The most severe carcinogenic effects were induced by dietary exposure to HO compared to exposure to LO or PY (45, 30 and 7 %, respectively, after 9 to 10 months of exposure to an intermediate concentration of PAHs). In contrast, earliest carcinogenic effects were detected as soon as 3 mpf after exposure to LO, including the lowest concentration, or to PY. PAH bioactivation and genotoxicity in blood was assessed by ethoxyresorufin-O-deethylase activity quantification and comet and micronuclei assays, respectively, but none of these were positive. Chronic dietary exposure of zebrafish to PAH mixtures results in carcinogenotoxic events that impair survival and physiology of exposed fish.     

Improving Environmental and Social Targeting through Adaptive Management in Mexico's Payments for Hydrological Services Program

Natural resource managers are often expected to achieve both environmental protection and economic development even when there are fundamental trade‐offs between these goals. Adaptive management provides a theoretical structure for program administrators to balance social priorities in the presence of trade‐offs and to improve conservation targeting. We used the case of Mexico's federal Payments for Hydrological Services program (PSAH) to illustrate the importance of adaptive management for improving program targeting. We documented adaptive elements of PSAH and corresponding changes in program eligibility and selection criteria. To evaluate whether these changes resulted in enrollment of lands of high environmental and social priority, we compared the environmental and social characteristics of the areas enrolled in the program with the characteristics of all forested areas in Mexico, all areas eligible for the program, and all areas submitted for application to the program. The program successfully enrolled areas of both high ecological and social priority, and over time, adaptive changes in the program's criteria for eligibility and selection led to increased enrollment of land scoring high on both dimensions. Three factors facilitated adaptive management in Mexico and are likely to be generally important for conservation managers: a supportive political environment, including financial backing and encouragement to experiment from the federal government; availability of relatively good social and environmental data; and active participation in the review process by stakeholders and outside evaluators. Mejorando los Objetivos Ambiental y Social Mediante el Manejo Adaptativo en el Programa de Pagos por Servicios Hidrológicos en México     

Biological responses of wheat (Triticum aestivum) plants to the herbicide chlorotoluron in soils

Chlorotoluron is a phenylurea herbicide that is widely used for controlling grass weeds in the land of cereal, cotton and fruit production. However, extensive use of this herbicide may lead to its accumulation in ecosystems, thus inducing the toxicity to crops and vegetables. To assess chlorotoluron-induced toxicity in plants, we performed the experiment focusing on the metabolic adaptation of wheat plants (Triticum aestivum) to the chlorotoluron-induced oxidative stress. The wheat plants were cultured in the soils with chlorotoluron at concentrations of 0-25mg/kg. Chlorotoluron accumulation in plants was positively correlated with the external chlorotoluron concentrations, but negatively with the plant growth. Treatment with chlorotoluron induced the accumulation of O(2)(-) and H(2)O(2) in leaves and resulted in the peroxidation of plasma membrane lipids in the plant. We measured the endogenous proline level and found that it accumulated significantly in chlorotoluron-exposed roots and leaves. To understand the biochemical responses to the herbicide, activities of the antioxidant enzymes, such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) were assayed. Analysis of SOD activity by non-denaturing polyacrylamide gel electrophoresis (PAGE) revealed that there were three isoforms in the roots and leaves, but the isoforms in the tissues showed different patterns. Also, using the native PAGE, 6 isoforms of root POD and 10 in leaves were detected. The total activity of POD in roots was significantly enhanced. Activities of APX in roots and leaves showed a similar pattern. The CAT activities were generally suppressed under the chlorotoluron exposure.     

Contribution of a New PCR assay to the prenatal diagnosis of congenital toxoplasmosis

A polymerase chain reaction (PCR) assay has been developed for the detection of Toxoplasma gondii. The target sequence (88 bp) is part of a rDNA repetitive gene. A signal can be observed with only one parasite. It is directly and rapidly detected by electrophoresis and ethidium bromide staining. We report a prospective study of 80 documented cases of toxoplasmic seroconversions during pregnancy. The PCR assay of the amniotic fluids was compared with the current standard methods for diagnosis of fetal infection. Seventy specimens gave no PCR signal, and were negative according to prenatal tests and postnatal examinations. The presence of T. gondii was detected in ten specimens by PCR analysis. Four were confirmed by isolation of the parasite from the amniotic fluid; four by biological study of the fetal blood. For the remaining two, infection was diagnosed after birth. Together with ultrasonographic and biological data, this technique permits prenatal diagnosis within 1 day.     

New observations of the gills of Placopecten magellanicus (Mollusca: Bivalvia), and implications for nutrition

The internal anatomy and microanatomy of the gill of Placopecten magellanicus Gmelin collected in May and November 1985 from Chamcook Bay, New Brunswick, Canada, was studied using thin-section light microscopy and transmission electron microscopy. Most of the spurs show no evidence of organic union, and hence do not participate in vascular exchange. However, the dorsal bend shows both ciliary and organic interfilamentar union. The internal structure and the hemocytes of the dorsal respiratory expansion are presented. The epithelium consists of three distinct cell types, bounded by apical microvilli. All regions of the gill contain an epithelial basal membrane, which is greatly convoluted in the interconnecting vessels of the dorsal respiratory expansion. The significance of these observations is discussed in relation to possible roles in respiration, transmembrane transport and nutrition. The apical surface of all ciliated cells is covered with an acellular matrix composed of clear spherical vesicles, which may serve a mechanical function for which mucus would be unsuited. The significance of the abundance of mucocytes on the abfrontal surface of the principal filaments is discussed in terms of the escape response of pectinid bivalves.     

降低污水池外排含油量的有效措施

针对污水池外排含油量超标，加强污水池管理实施有效技术改造，降低外排水含油量，消除环境污染事故。