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971.
Reproductive activity and production of the calanoid copepods Calanus helgolandicus and Calanoides carinatus were measured during a summer upwelling event off the coast of NW Spain. The upwelling pattern affected the distribution and fecundity of both species in the study area. The demographic composition of both populations and the stage of gonad maturation (e.g. the high abundance of fertilised females with mature ova) indicated active reproduction. C.
carinatus, a highly fecund species associated with the African upwelling zones and considered as an upwelling specialist, showed low production rates (overall means of 15 eggs female–1
day–1 and 3% body C day–1), despite the fact that the food conditions (high phytoplankton biomass dominated by diatoms) seemed to be optimal for this species. By contrast, C. helgolandicus, a temperate species that shows a strong link between spring phytoplankton blooms and reproduction time, seems to be flexible enough to take full advantage of shorter-term, enhanced feeding conditions associated with the pulsed nature of the summer coastal upwelling. Both the egg and carbon-specific production rates attained by this species (overall means of 26 eggs female–1
day–1 and 12% body C day–1) were similar to values reported for a spring bloom situation. This high production would imply a long spring–summer recruitment event of C. helgolandicus in these waters. For both species the stage of gonad maturation was significantly correlated with their egg production rates and likely influenced by the food conditions; a species-specific nutritional requirement for final oogenesis is suggested. The carbon condition factor (carbon weight/prosome volume) of C. carinatus
females was higher than that of C. helgolandicus, suggesting differential use of the carbon ingested; C.
helgolandicus seems to use all ingested carbon to produce eggs at a high rates, whereas C. carinatus seems to store part of the ingested carbon as lipid reserves to ensure female survival and to support production during subsequent unfavourable food conditions.Communicated by S.A. Poulet, Roscoff 相似文献
972.
Ammonia emissions from the composting of different organic wastes. Dependency on process temperature 总被引:20,自引:0,他引:20
Ammonia emissions were quantified for the laboratory-scale composting of three typical organic wastes with medium nitrogen content: organic fraction of municipal solid wastes, raw sludge and anaerobically digested sludge; and the composting of two wastes with high nitrogen content: animal by-products from slaughterhouses and partially hydrolysed hair from the leather industry. All the wastes were mixed with the proper amount of bulking agent. Ammonia emitted in the composting of the five wastes investigated revealed a strong dependence on temperature, with a distinct pattern found in ammonia emissions for each waste in the thermophilic first stage of composting (exponential increase of ammonia emitted when increasing temperature) than that of the mesophilic final stage (linear increase of ammonia emissions when increasing temperature). As composting needs high temperatures to ensure the sanitisation of compost and ammonia emissions are one of the main environmental impacts associated to composting and responsible for obtaining compost with a low agronomical quality, it is proposed that sanitisation is conducted after the first stage in large-scale composting facilities by a proper temperature control. CAPSULE: Ammonia emission pattern and correlation with process temperature are presented for the composting process of different organic wastes. 相似文献
973.
Ortea PM Allis O Healy BM Lehane M Ní Shuilleabháin A Furey A James KJ 《Chemosphere》2004,55(10):1395-1402
Microcystins, toxic cyclic heptapeptides and nodularin-R, a toxic cyclic pentapeptide, were determined using liquid chromatography (LC) with detection using photo-diode array ultra-violet (PDA-UV) and protein phosphatase (PP) assay. Positive fractions were analysed for toxins using collision-induced dissociation (CID) and tandem MS/MS experiments which were carried out simultaneously using electrospray ion-trap instrumentation. Reversed-phase liquid chromatography (LC) using an acetonitrile/water gradient was used for the LC-MS(2) determination of six microcystins standards and nodularin. The molecular related ion species, [M+H](+)([M+2H](2+) in the case of MC-RR), were used as the precursor ions for MS(2) experiments. Optimum calibration and reproducibility data were obtained for MC-LR using LC-MS(2); 0.1-5.0 microg/ml, r2 = 0.992 (n = 3); % RSD < or =7.3 at 0.25 microg MC-LR/ml (n = 3). The detection limit (S/N = 3) was better than 0.1 ng. Water samples for microcystin analysis were first screened using protein phosphatase (PP) assays and positives were concentrated using C-18 solid-phase extraction. The developed method was applied to examine a lake in Ireland contaminated by Microcystis sp. and MC-LR and MC-LA were identified. 相似文献
974.
Immobilization of heavy metals in polluted soils by the addition of zeolitic material synthesized from coal fly ash 总被引:9,自引:0,他引:9
Querol X Alastuey A Moreno N Alvarez-Ayuso E García-Sánchez A Cama J Ayora C Simón M 《Chemosphere》2006,62(2):171-180
The use of zeolitic material synthesized from coal fly ash for the immobilization of pollutants in contaminated soils was investigated in experimental plots in the Guadiamar Valley (SW Spain). This area was affected by a pyrite slurry spill in April 1998. Although reclamation activities were completed in a few months, residual pyrite slurry mixed with soil accounted for relatively high leachable levels of trace elements such as Zn, Pb, As, Cu, Sb, Co, Tl and Cd. Phytoremediation strategies were adopted for the final recovery of the polluted soils. The immobilization of metals had previously been undertaken to avoid leaching processes and the consequent groundwater pollution. To this end, 1100 kg of high NaP1 (Na6[(AlO2)6(SiO2)10] .15H2O) zeolitic material was synthesized using fly ash from the Teruel power plant (NE Spain), in a 10 m3 reactor. This zeolitic material was manually applied using different doses (10000-25000 kg per hectare), into the 25 cm topsoil. Another plot (control) was maintained without zeolite. Sampling was carried out 1 and 2 years after the zeolite addition. The results show that the zeolitic material considerably decreases the leaching of Cd, Co, Cu, Ni, and Zn. The sorption of metals in soil clay minerals (illite) proved to be the main cause contributing to the immobilization of these pollutants. This sorption could be a consequence of the rise in pH from 3.3 to 7.6 owing to the alkalinity of the zeolitic material added (caused by traces of free lime in the fly ash, or residual NaOH from synthesis). 相似文献
975.
Grodzińska K Godzik B Fraczek W Badea O Oszlányi J Postelnicu D Shparyk Y 《Environmental pollution (Barking, Essex : 1987)》2004,130(1):17-32
Within the framework of the project "Effects of forest health on biodiversity with emphasis on air pollution in the Carpathian Mountains" 26 permanent study sites were established in the vicinity of the ozone monitoring sites. The study sites were located on the NW-SE transect through the Western (12 sites), Eastern (11 sites) and Southern (3 sites) Carpathians in forest ecosystems typical of each area. Some of the forest monitoring sites were located in national parks, biosphere reserves and areas of protected landscape. Each permanent site of 0.7 ha area consisted of 5 small 500m(2) circular plots, arranged in the form of a cross, i.e. four placed on the cardinal points (N, E, S, W) and one in the center. Phytosociological records were done twice during the 1998 growing season using the Braun-Blanquet's method. The study sites represented various types of forest: Picea abies stands (8), beech (Fagus sylvatica) stands (10), fir (Abies alba) stands (2) and mixed beech-fir, spruce-fir and beech-spruce stands (6). Age of most stands was 80-100 years. Degree of crown damage varied greatly between sites, a percentage of damaged trees decrease in Carpathians from West to East. It corresponds well with the O(3) level in these areas. Typical damage by O(3) in herb layer species in several Carpathian sites were found. Land-use map for the entire Carpathian Mountains and two detailed land use maps for Tatras (Western Carpathians) and Retezat (Southern Carpathians) are presented. A little more than half of the Carpathian territory is forested. The most densely forested are Eastern Carpathians, while the most sparsely Western Carpathians. Arable lands occupy 22.6% of the Carpathians, pastures and meadows 6.2%, water bodies 1.9%, and build up areas several percent. In the highest elevation of the Carpathians alpine meadows (11.3%) and rocks (3.5%) are distributed. 相似文献
976.
Isabel Díaz-Reviriego Álvaro Fernández-Llamazares Matthieu Salpeteur Patricia L. Howard Victoria Reyes-García 《Ambio》2016,45(3):263-275
Local medical systems are key elements of social-ecological systems as they provide culturally appropriate and locally accessible health care options, especially for populations with scarce access to biomedicine. The adaptive capacity of local medical systems generally rests on two pillars: species diversity and a robust local knowledge system, both threatened by local and global environmental change. We first present a conceptual framework to guide the assessment of knowledge diversity and redundancy in local medicinal knowledge systems through a gender lens. Then, we apply this conceptual framework to our research on the local medicinal plant knowledge of the Tsimane’ Amerindians. Our results suggest that Tsimane’ medicinal plant knowledge is gendered and that the frequency of reported ailments and the redundancy of knowledge used to treat them are positively associated. We discuss the implications of knowledge diversity and redundancy for local knowledge systems’ adaptive capacity, resilience, and health sovereignty. 相似文献
977.
978.
Irene Iniesta-Arandia Federica Ravera Stephanie Buechler Isabel Díaz-Reviriego María E. Fernández-Giménez Maureen G. Reed Mary Thompson-Hall Hailey Wilmer Lemlem Aregu Philippa Cohen Houria Djoudi Sarah Lawless Berta Martín-López Thomas Smucker Grace B. Villamor Elizabeth Edna Wangui 《Ambio》2016,45(3):383-393
This synthesis article joins the authors of the special issue “Gender perspectives in resilience, vulnerability and adaptation to global environmental change” in a common reflective dialogue about the main contributions of their papers. In sum, here we reflect on links between gender and feminist approaches to research in adaptation and resilience in global environmental change (GEC). The main theoretical contributions of this special issue are threefold: emphasizing the relevance of power relations in feminist political ecology, bringing the livelihood and intersectionality approaches into GEC, and linking resilience theories and critical feminist research. Empirical insights on key debates in GEC studies are also highlighted from the nine cases analysed, from Europe, the Americas, Asia, Africa and the Pacific. Further, the special issue also contributes to broaden the gender approach in adaptation to GEC by incorporating research sites in the Global North alongside sites from the Global South. This paper examines and compares the main approaches adopted (e.g. qualitative or mixed methods) and the methodological challenges that derive from intersectional perspectives. Finally, key messages for policy agendas and further research are drawn from the common reflection. 相似文献
979.
980.
Improvement in electrokinetic remediation of heavy metal spiked kaolin with the polarity exchange technique 总被引:8,自引:0,他引:8
In the electrokinetic treatment of heavy metal polluted soil, an alkaline environment is generated at the cathode side. It provokes the precipitation of metal ions as hydroxides into the soil and diminishes the capability of the electroremediation to clean the polluted site. In this work the "polarity exchange" technique is presented as a simple way to avoid the negative effect of OH(-) on metal transportation. This technique lies in the operation during short time intervals at inverted polarity, so that the generation of H+ ions from the oxidation of water neutralize in the alkaline zone where the metal is precipitated, favouring its dissolution. Once the metals are redissolved, the polarity is set to the original position to transport them to the desired direction. Kaolin clay contaminated with Mn was used to test the feasibility of the polarity exchange technique. The application of the "conventional technique" dealt with a removal of 14% of the initial Mn in 7.6d. For a similar treatment time the polarity exchange technique resulted in 72% of removed Mn. Successive polarity exchanges will yield with a complete decontamination of the soil with a moderate increment in the electric power consumption. 相似文献