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排序方式: 共有980条查询结果,搜索用时 734 毫秒
491.
Marie Vagner José-Luis Zambonino-Infante David Mazurais Nathalie Imbert-Auvray Natascha Ouillon Emmanuel Dubillot Hervé Le Delliou David Akbar Christel Lefrançois 《Marine Biology》2014,161(11):2547-2562
In this study, we hypothesised that a reduction in n-3 HUFA availability for higher consumers, as expected with global change, would negatively impact the physiological performances of fish. The aim was to experimentally evaluate the effect of n-3 HUFA dietary content on cardio-respiratory performances of the golden grey mullet (Liza aurata), a microalgae grazer of high ecological importance in European coastal areas. These performances were evaluated in terms of critical swimming speed U crit, associated oxygen consumption MO2, post-exercise oxygen consumption and calcium fluxes in cardiomyocytes. Two replicated groups of fish were fed on a rich (standard diet, SD diet: 1.2 % n-3 HUFA on dry matter basis, DMB) or a poor n-3 HUFA (low n-3 HUFA diet, LD diet: 0.2 % n-3 HUFA on DMB) diet during 5 months and were called SD and LD groups, respectively. The results showed that the LD diet reduced growth rate as well as the aerobic capacity of L. aurata at 20 °C, suggesting that fish may have to save energy by modifying the proportion of energy allocated to energy-demanding activities, such as digestion or feeding. In addition, this LD diet induced higher levels of haematocrit and plasma osmolality, indicating a stress response at the second and third levels in that group. However, the LD diet caused a massive increase in swimming efficiency. This should improve the capacity of L. aurata to migrate and to forage over a wide area. In turn, these could then compensate for the reduction in growth rate and aerobic metabolism. 相似文献
492.
493.
Lebrun Manhattan Nandillon Romain Miard Florie Le Forestier Lydie Morabito Domenico Bourgerie Sylvain 《Environmental geochemistry and health》2021,43(4):1491-1505
Environmental Geochemistry and Health - Metal(loid) soil pollution is a major environmental and health issue, requiring these areas to be remediated, for example through phytoremediation processes.... 相似文献
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495.
Mating reef white-tip sharks, Triaenodon obesus, were observed and photographed in shallow waters of the Hawaiian Islands. The sharks copulated in a stationary parallel orientation with their heads on the bottom and bodies angled upwards approximately 45° into the water column. Pair contact during copulation was maintained by the male's left clasper anchored in the female's vent and by his tight oral grasp of the female's left pectoral fin. Results show that reposed sedentary modes of copulation are not limited to small species. In a reproductive context, biting behavior by male sharks functions as a premating releaser for female cooperation and for pair-contact maintenance during copulation. 相似文献
496.
Chemical interactions among marine microalgae were studied in cultures of pennate diatoms on agar plates. Nine marine and freshwater pennate diatoms were surveyed as potential bioassay organisms; Cylindrotheca fusiformis was most favourable for assays because of its rapid and even growth on agar. Diatom and bacterial bioassays were used to screen cell and filtrate extracts of 14 microalgal cultures. A number of these algal species, which were grown axenically, produced extractable, intracellular and/or extracellular substances that inhibited the growth of C. fusiformis. Our results suggest that the culturing of pennate diatoms on a solid medium can provide a simple bioassay for screening algal extracts which potentially contain growth inhibitors involved in microalgal allelopathy. 相似文献
497.
Vintró LL McMahon CA Mitchell PI Josefsson D Holm E Roos P 《Journal of environmental radioactivity》2002,60(1-2):73-89
New data on the levels and long-range transport of plutonium in the Arctic Ocean, recorded in the course of two expeditions to this zone in 1994 and 1996, are discussed in this paper. Specifically, approximately 100 plutonium measurements in surface and sub-surface water sampled at 58 separate stations throughout the Kara, Laptev and East Siberian Seas, as well as along latitudinal transects across the Lomonosov Ridge, are reported and interpreted in terms of the circulation pathways responsible for the transport of this element from the North Atlantic to the Arctic Shelf and into the Arctic interior. In addition, the behaviour of plutonium in its transit through the vast Arctic shelf seas to open waters under extreme environmental conditions is discussed in terms of the partitioning of plutonium between filtered (<0.45 microm) seawater and suspended particulate, and its association with colloidal matter. Finally, limited evidence of the presence of a colloidal plutonium component in Arctic waters subject to direct riverine input is adduced. 相似文献
498.
A 'livelihoods gap' has become evident in international aid delivery to Somalia. Existing aid interventions do not address the economic dynamics of vulnerability resulting from Somalia's long history of predatory development and asset stripping. To prevent poor households' regular return to sub-subsistence income levels after a brief period of plenty, this paper argues that aid agencies should reorient and expand existing interventions to assist poor households to capitalise on temporary improvements in environmental and security conditions. As a corollary to emergency relief and efforts to construct state institutions, it is necessary to devise country-wide interventions that will rebuild household asset bases by protecting savings during times of stress and ensuring that markets benefit poor producers. 相似文献
499.
500.
Karine Vallée-Rehel Valérie Langlois Philippe Guérin Alain Le Borgne 《Journal of Polymers and the Environment》1999,7(1):27-34
Environmental concerns result in a progressive withdrawal of antifouling paints containing organotin derivatives. The nature of the binders is critical with regard to the erosion of the protecting film through factors such as bond cleavage, dissolution, and diffusion of the degradation products. The versatility of acrylic polymers, due to the possibility of varying their chemical structure had conducted, in the first stage, to combine different types of repeating units in the macromolecular backbone. Formulation and evaluation, in natural sites, of these binders, with a well-defined hydrophobic/hydrophilic balance and with hydrolyzable pendant groups, have shown the possibility to prepare new organotin free resins which can be formulated and which are erodible in seawater over a long period (more than 2 years). A further step has been engaged with the development of graft copolymers containing biocompatible and hydrolyzable oligomers of -hydroxyacids. Their preparation requires the synthesis of -methacryloyloxyoligo--hydroxyacid macromonomers. Copolymers prepared from a mixture of the macromonomer and of an alkyl ester of acrylic acid were formulated with a biocide and deposited on a plate. Their ability to release cuprous oxide, as a model molecule, has been checked and quantified by the inductively coupled plasma analytical method. The uptake of water in the paint, which is enhanced by the hydrolysis of -hydroxyacid oligomers, as determined by the enzymatic measurement of liberated L-lactic acid, conducts to the polymer erosion and to a protecting bioactive surface. 相似文献