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71.
Low Genetic Variability in the Hawaiian Monk Seal 总被引:1,自引:0,他引:1
Maria B. Kretzmann William G. Gilmartin Axel Meyer Gerard P. Zegers Steven R. Fain Bruce F. Taylor & Daniel P. Costa 《Conservation biology》1997,11(2):482-490
The Hawaiian monk seal ( Monachus schauinslandi) is a critically endangered species that has failed to recover from human exploitation despite decades of protection and ongoing management efforts designed to increase population growth. The seals breed at five principal locations in the northwestern Hawaiian islands, and inter-island migration is limited. Genetic variation in this species is expected to be low due to a recent population bottleneck and probable inbreeding within small subpopulations. To test the hypothesis that small population size and strong site fidelity has led to low within-island genetic variability and significant between-island differentiation, we used two independent approaches to quantify genetic variation both within and among the principal subpopulations. Mitochondrial control region and tRNA gene sequences (359 base pairs) were obtained from 50 seals and revealed very low genetic diversity (0.6% variable sites), with no evidence of subpopulation differentiation. Multilocus DNA fingerprints from 22 individuals also indicated low genetic variation in at least some subpopulations (band-sharing values for "unrelated" seals from the same island ranged from 49 to 73%). This method also provided preliminary evidence of population subdivision ( F'st estimates of 0.20 and 0.13 for two adjacent island pairs). Translocations of seals among islands may therefore have the potential to relieve local inbreeding and possibly to reduce the total amount of variation preserved in the population. Genetic variation is only one of many factors that determine the ability of an endangered species to recover. Maintenance of existing genetic diversity, however, remains an important priority for conservation programs because of the possibility of increased disease resistance in more variable populations and the chance that inbreeding depression may only be manifest under adverse environmental conditions. 相似文献
72.
Mobility of heavy metals as related to soil chemical and mineralogical characteristics of Brazilian soils 总被引:5,自引:0,他引:5
de Matos AT Fontes MP da Costa LM Martinez MA 《Environmental pollution (Barking, Essex : 1987)》2001,111(3):429-435
In order to better understand the relationship between soil characteristics and mobility of some heavy metals, correlation studies were conducted in samples of unlimed and limed A, B and C horizons of three Brazilian soils, representative of the majority of the tropical soils. A number of chemical and mineralogical characteristics of one Oxisol and two Ultisols were related to the retardation factors (Rf) for zinc (Zn), cadmium (Cd), copper (Cu) and lead (Pb). The retardation factors, obtained in leaching column experiments, were used as an estimate of solute movement in the profile. Soil types and soil horizons were found to influence metal retardation factors which, in turn, correlated better with the chemical than the mineralogical soil characteristics. For the unlimed soil samples, the soil characteristics that significantly correlated with Zn-Rf and Cd-Rf were the sum of exchangeable bases (SB), and soil exchangeable (Ca-KCl) and non-exchangeable (Ca-HCl) calcium contents. These results showed the strong influence of the cation exchange phenomenon on the retention and mobility of these two metals. For Cu and Pb, not only SB, cation exchange capacity (CEC) and Ca-KCl and Ca-HCl but also the organic matter correlated well with the Rf, showing that complex or chelate formation may play an important role in the movement of these elements. The important soil chemical characteristics related to the retardation factors in the limed soil samples were SB for Cd, and Ca-HCl for Cu and Pb, suggesting that precipitation may also influence the mobility and retention of the latter two heavy metals in these soil samples. Soil pH influenced the heavy metals adsorption and movement as shown by the significant correlation with the retardation factors when the combined data for the unlimed and limed soil samples was considered. 相似文献
73.
Mrcia Gabriel Genesio Mario da Rosa Arci Dirceu Wastowski Jefferson Alves da Costa Fernanda Volpatto 《环境质量管理》2019,29(2):149-154
Separation of water for reuse is essential in an effluent treatment system, especially in activities with high water consumption, such as a pig production system. The objective of this work was to evaluate the efficiency of Tanfloc SG® coagulant tannin/organic flocculant used to treat effluent generated during the intensive rearing of swine. For the evaluation, laboratory and in situ tests (field test) were performed. The laboratory tests were performed to define the concentration (1 and 16%), dosage (0, 0.1, 0.2, 0.3, 0.4, 0.5, 1.0, 2.0, 4.0, 8.0, and 16.0 milliliters of the solution), and time (24, 48, 72, and 96 hours) of coagulation/flocculation treatment of the solid portion of the effluent. The parameters pH, turbidity, oxidation reduction potential, dissolved oxygen, and electroconductivity (in microsiemens per centimeter) were evaluated using a multiparameter probe and the parameters ammonia (NH3), nitrate (NO3), and nitrite (NO2) in the laboratory, in relation to the coagulation/flocculation time of the solid part of the effluent. The use of tannin as a coagulant/flocculant of plant origin in the treatment of swine effluents was effective in reducing turbidity and concentrations of ammonia, nitrite, and nitrate, and it allowed separation of the solid–liquid phase in approximately 68% as liquid phase. 相似文献
74.
Gabriel L. Castiglioni Jorge Cuellar Raúl Rodrigo Jorge A. V. Costa Ranulfo Monte-Alegre 《Journal of Polymers and the Environment》2016,24(3):264-273
Macroporous poly(styrene-co-divinylbenzene) microparticles, with three different structural characteristics, have been synthesized and used as supports in the immobilization of lipase from Burkholderia cepacia. The best immobilization yield was found upon using microparticles with 35 % of divinylbenzene and the immobilized lipase on this type of particles was used as a catalyst to obtain biodiesel from soybean oil and ethanol. From the experimental results of the transesterification reaction, an empirical model quantitatively relating the temperature, the concentration of the enzyme and the transesterification yield was obtained. Statistical analysis of this model indicated that within the range of values of the variables studied (35–47 °C and 231–788 U/mg respectively) only the enzyme concentration exerted a significant influence on the reaction yield. Additionally, the good fit of a Michaelis–Menten-type model to the experimental results suggests that the limiting step of the reaction was the formation of the enzyme-substrate complex. 相似文献
75.
Maria João Cruz Elisabeth Maria Rogier Robert Tiago Costa David Avelar Rui Rebelo Mário Pulquério 《Regional Environmental Change》2016,16(5):1293-1304
Assessing biodiversity vulnerability to future climate change is essential for developing robust adaptation strategies. A number of vulnerability assessment methodologies have been developed, from bioclimatic envelop models to more complex approaches that also consider biological traits and population status. However, the lack of comparative studies leaves the user to choose among the different methodologies without much guidance. This study applied three vulnerability assessment approaches to the Portuguese herpetofauna: (I) impact assessment approach based on bioclimatic models; (II) integrated vulnerability assessment approach, adding the evaluation of adaptive capacity to approach I; and (III) integrated vulnerability assessment and validation based on expert consultation. Results showed disagreement between the different approaches for 19 % of the species studied. Most differences were found between approach III and the two other approaches. All approaches showed advantages and limitations, the choice of a methodology being ultimately dependent on the study goals. Approach I has proven efficient to capture general vulnerability patterns. Approach II, although presenting results similar to approach I, allows for the identification of key factors affecting the species adaptive capacity and may be useful in tailoring adaptation measures. Approach III further allows us to identify knowledge gaps and to evaluate vulnerability when data availability or quality is reduced. Further, because this approach is based on an expert workshop, it has proven a perfect means to build on the vulnerability assessment results to identify indicator species and prioritize specific adaptation options. 相似文献
76.
77.
Hanane Bouchghoul Chloé Quelin Philippe Loget Féréchté Encha-Razavi Marie-Victoire Senat Lorraine Maheut Julie Galimand Sophie Collardeau-Frachon Lydie Da Costa Jelena Martinovic 《黑龙江环境通报》2018,38(10):772-778
We report a multiplex family with a GATA1 gene mutation responsible for a massive fetal cerebral hemorrhage occurring at 36 weeks. Two other stillbirth cousins presented with fetal hydrops and congenital hemochromatosis' phenotype at 37 and 12 weeks of gestation. Molecular screening revealed the presence of a c.613G>A pathogenic allelic variation in exon 4 of GATA1 gene in the 3 male siblings and their carrier mothers. The diagnosis of a GATA1 gene mutation may be suspected in cases of male fetuses with intracerebral bleeding, particularly if a history of prior fetal loss(es) and mild maternal thrombocytopenia are also present. 相似文献
78.
Pinheiro Samara Lima Marcelo Carneiro Bruno Costa Tavares Vanessa Câmara Volney 《Environmental science and pollution research international》2019,26(6):5738-5750
Environmental Science and Pollution Research - The port regions of the Amazon are subject to environmental impacts high shipping traffic. In October 2015, a cargo ship containing 5000 oxen sank in... 相似文献
79.
Costa Henrique Santana Tejerina-Garro Francisco Leonardo Rocha Cleonice 《Environmental science and pollution research international》2017,24(27):22018-22025
Environmental Science and Pollution Research - This research aimed to determine the water-sediment interaction (partition coefficient Kd) of trace element (Cd, Cu, total Cr, Pb, and Zn) in tropical... 相似文献
80.