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41.
Florence Vouvé Leticia Cotrim da Cunha Léon Serve Jean Vigo Jean-Marie Salmon 《Chemistry and Ecology》2013,29(6):435-452
Fluorescence excitation-emission matrices showed the spectral signature of dissolved organic matter (DOM) downstream in the River Têt at all seasons corresponding to humic substances with maximum fluorescence emission λem=420–460 nm for excitations of λex=340–360 nm and the occasional presence of tryptophan, tracer of anthropogenic pressure, spectroscopically identified by λex/λem=310/350 nm. A factorial discriminant analysis, performed using the parameters selected (λex/λem pairs of wavelength), succeeded in a better discrimination of seasons than stations, and clearly showed the presence of two fluorophores. Fluorophore 1, with two absorption bands: λex=260–320 nm and 330–390 nm for λem=440–500 nm, and Fluorophore 2, with one absorption band: λex=300–360 nm for λem=410 nm, which are attributed to humic acid (HA) and fulvic acid (FA), respectively. Variations of DOM relative contents downstream in the River Têt, according to seasons and stations, showed high amounts of DOM (pedogenic character) along the river in the humid period, with the highest value obtained in the mountain section. In contrast, in summer, the DOM contents were low (aquagenic character). Moreover, DOM presents a relatively constant composition with a percentage of FA ranging from 40% at the mountain station to 48% at the mouth river, whatever the season. 相似文献
42.
Multiple techniques confirm elevational differences in insect size that may influence spider sociality 总被引:1,自引:0,他引:1
Social and subsocial spiders of the genus Anelosimus exhibit an altitudinal pattern in their geographic distribution at tropical latitudes in the Americas. Social species, which capture prey cooperatively, occur primarily in the lowland rain forest and are absent from higher elevations, whereas subsocial species are common at higher elevations but absent from the lowland rain forest. Previous studies have suggested that differences in the size of potential insect prey along altitudinal gradients may explain this pattern as insects were found to be, on average, larger in lowland rain forests than at higher elevations. These studies, however, may have under-sampled the insect size composition of each habitat because only one sampling technique was used. Using a number of collection methods we sampled the insect size composition in the environments of social and subsocial spiders in this genus. We found that the average insect size in lowland rain forest habitats was indeed larger than at high-elevation cloud forests in eastern Ecuador. We also found that, even though the various techniques differed in the size of the insects they captured (visual searching and blacklighting yielding larger insects than beating, sweeping, or malaise trapping), they all caught, on average, larger insects in the lowlands. Overall, spider colonies in the lowlands caught larger prey than did spider colonies at higher elevations, paralleling differences in insect size distribution obtained by the various techniques in their respective environments. 相似文献
43.
dos Santos Debora Regina Lopes Silva-Sales Marcelle Fumian Tulio Machado Maranhão Adriana Gonçalves Malta Fábio Correia Ferreira Fernando César Pimenta Marcia Maria Miagostovich Marize Pereira 《Food and environmental virology》2023,15(1):21-31
Food and Environmental Virology - This study assessed the sources of contamination of water matrices in a rural area using detection of a host-specific virus (human adenovirus [HAdV], porcine... 相似文献
44.
Leticia Burone Silvia Helena de Mello e Sousa Michel Michaelovitch de Mahiques Paulo Valente Aurea Ciotti Cíntia Yamashita 《Marine Biology》2011,158(1):159-179
Foraminiferal data were obtained from 66 samples of box cores on the southeastern Brazilian upper margin (between 23.8°–25.9°S
and 42.8°–46.13°W) to evaluate the benthic foraminiferal fauna distribution and its relation to some selected abiotic parameters.
We focused on areas with different primary production regimes on the southern Brazilian margin, which is generally considered
as an oligotrophic region. The total density (D), richness (R), mean diversity ([`(H¢ )] \overline{{H^{\prime } }} ), average living depth (ALD
X
) and percentages of specimens of different microhabitats (epifauna, shallow infauna, intermediate infauna and deep infauna)
were analyzed. The dominant species identified were Uvigerina spp., Globocassidulina subglobosa, Bulimina marginata, Adercotryma wrighti, Islandiella norcrossi, Rhizammina spp. and Brizalina sp.. We also established a set of mathematical functions for analyzing the vertical foraminiferal distribution patterns, providing
a quantitative tool that allows correlating the microfaunal density distributions with abiotic factors. In general, the cores
that fit with pure exponential decaying functions were related to the oligotrophic conditions prevalent on the Brazilian margin
and to the flow of the Brazilian Current (BC). Different foraminiferal responses were identified in cores located in higher
productivity zones, such as the northern and the southern region of the study area, where high percentages of infauna were
encountered in these cores, and the functions used to fit these profiles differ appreciably from a pure exponential function,
as a response of the significant living fauna in deeper layers of the sediment. One of the main factors supporting the different
foraminiferal assemblage responses may be related to the differences in primary productivity of the water column and, consequently,
in the estimated carbon flux to the sea floor. Nevertheless, also bottom water velocities, substrate type and water depth
need to be considered. 相似文献
45.
Environment, Development and Sustainability - The banking sector has a fundamental role in promoting sustainable development. Due to its performance as an intermediary, it can influence the pace... 相似文献