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71.
Diet induced differences in carbon isotope fractionation between sirenians and terrestrial ungulates
Carbon isotope differences (Δ13C) between bioapatite and diet, collagen and diet, and bioapatite and collagen were calculated for four species of sirenians,
Dugong dugon (Müller), Trichechus manatus (Linnaeus), Trichechus inunguis (Natterer), and the extinct Hydrodamalis gigas (Zimmerman). Bone and tooth samples were taken from archived materials collected from populations during the mid eighteenth
century (H. gigas), between 1978 and 1984 (T. manatus, T. inunguis), and between 1997 and 1999 (D. dugon). Mean Δ13C values were compared with those for terrestrial ungulates, carnivores, and six species of carnivorous marine mammals (cetaceans = 1;
pinnipeds = 4; mustelids = 1). Significant differences in mean δ13C values among species for all tissue types were detected that separated species or populations foraging on freshwater plants
or attached marine macroalgae (δ13C values < −6‰; Δ13Cbioapatite–diet ∼14‰) from those feeding on marine seagrasses (δ13C values > −4‰; Δ13Cbioapatite–diet ∼11‰). Likewise, Δ13Cbioapatite–collagen values for freshwater and algal-foraging species (∼7‰) were greater than those for seagrass-foraging species (∼5‰). Variation
in Δ13C values calculated between tissues and between tissues and diet among species may relate to the nutritional composition of
a species’ diet and the extent and type of microbial fermentation that occurs during digestion of different types of plants.
These results highlight the complications that can arise when making dietary interpretations without having first determined
species-specific Δ13Ctissue–diet values.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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Dr. Albert Koch 《Die Naturwissenschaften》1916,4(9):109-114
76.
Dr. Albert Koch 《Die Naturwissenschaften》1916,4(29):417-419
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79.
Numerous power plants in Europe had to be throttled in summer months of the years 2003 and 2006 due to water shortages and
high water temperatures caused by a hot and dry summer. Therefore, the effects of higher temperatures on power plants have
received much attention in the last years. One article published in Regional Environmental Change presents a study about ‘Modeling thermoelectric power generation in view of climate change’. In this article, the statement
is given that other studies do not include aspects as environmental legislation or cots of water shortages. This comment will
show that in at least one article cited these aspects are considered. 相似文献
80.
Erik R. Hagen K. John. Holmes Julie E. Kiang Roland C. Steiner 《Journal of the American Water Resources Association》2005,41(6):1417-1430
The three largest water utilities in the Washington, D.C., metropolitan area (WMA) rely on the Potomac River and its reservoirs for water supply. These utilities have committed to a periodic review of the system's adequacy to meet future demands. In 1990, 1995, 2000, and again in 2004 (for publication in 2005) the utilities requested that the Interstate Commission on the Potomac River Basin (ICPRB) conduct a 20‐year water demand and resource adequacy study to fulfill this need. The selection of the five‐year interval provides multiple benefits. It allows regular updates and incorporation of recent demographic forecasts, and it increases visibility and understanding of the adequacy of the region's water resources. It also provides adequate time to conduct research on the physical system and to incorporate modifications based on this research into subsequent studies. The studies and lessons learned are presented in this case study of the WMA. The work has been a natural outgrowth of a long history of cooperative water supply planning and management among the main WMA water utilities and ICPRB. 相似文献