34 research outputs found
Aerobic and anaerobic energy expenditure during rest and activity in montane Bufo b. boreas and Rana pipiens
The relations of standard and active aerobic and anaerobic metabolism and heart rate to body temperature ( T b ) were measured in montane groups of Bufo b. boreas and Rana pipiens maintained under field conditions. These amphibians experience daily variation of T b over 30°C and 23°C, respectively (Carey, 1978). Standard and active aerobic and anaerobic metabolism, heart rate, aerobic and anaerobic scope are markedly temperature-dependent with no broad plateaus of thermal independence. Heart rate increments provide little augmentation of oxygen transport during activity; increased extraction of oxygen from the blood probably contributes importantly to oxygen supply during activity. Development of extensive aerobic capacities in Bufo may be related to aggressive behavior of males during breeding. Standard metabolic rates of both species are more thermally dependent than comparable values for lowland relatives. Thermal sensitivity of physiological functions may have distinct advantages over thermally compensated rates in the short growing season and daily thermal fluctuations of the montane environment.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47726/1/442_2004_Article_BF00348070.pd
Characterization of polysaccharidase activity optima in the anaerobic digestion of municipal solid waste
Body size miniaturization in a lineage of colubrid snakes: Implications for cranial anatomy
As body size strongly determines the biology of an organism at all levels, it can be expected that miniaturization comes with substantial structural and functional constraints. Dwarf snakes of the genus Eirenis are derived from big, surfaceâdwelling ancestors, considered to be similar to those of the sister genus Dolichophis. To better understand the structural implications of miniaturization on the feeding apparatus in Eirenis, the morphology of the cranial musculoskeletal system of Dolichophis schmidti was compared with that of the miniature Eirenis punctatolineatus and E. persicus using highâresolution ”CT data. The gape index was compared between D. schmidti and 14 Eirenis species. Our results show a relatively increased neurocranium size and decreased maximal jaw muscle force in E. persicus, compared with the D. schmidti, and an intermediate situation in E. punctatolineatus. A significant negative allometry in gape index relative to body size is observed across the transition from the Dolichophis to Pediophis and Eirenis subgenera. However, the gape index relative to head size showed a significant negative allometry only across the transition from the Dolichophis to Pseudocyclophis subgenus. In DolichophisâEirenis dwarfing lineages, different structural patterns are observed through miniaturization, indicating that overcoming the challenge of miniaturization has achieved via different adaptations
A simple method for assessing the vulnerability of wetland ecosystem services
Wetlands can provide many ecosystem services, but throughout the world are exposed to a range of
pressures. In some locations these are well documented and are being successfully addressed. However at other
locations, lack of data, resources and methods are hindering thorough assessment. This is particularly the case
in remote wetlands such as those in the Himalayan region. This paper presents a methodology developed and
tested on three wetland sites in Nepal. The method gives a structure to data collection and analysis and leads
the user through to producing a vulnerability assessment of wetlands. We found that in each case the method
provided a prioritised table of values and threats and this helped to make the development of a site management
plan straightforward. The action plan highlights data gaps and identifies priority areas for attention. The results
from our assessment of Rupa Lake are also presented in this paper