Cooper C E, Withers P C
Centre for Ecosystem Diversity and Dynamics in the Department of Environmental and Aquatic Sciences, Curtin University of Technology, P.O. Box U1987, Perth, Western Australia 6845, Australia.
Physiol Biochem Zool. 2010 Mar-Apr;83(2):385-93. doi: 10.1086/605612.
Strict criteria have been established for measurement of basal metabolic rate and standard evaporative water loss to ensure that data can be compared intra- and interspecifically. However, data-sampling regimes vary, from essentially continuous sampling to interrupted (switching) systems with data recorded periodically at more widely spaced intervals. Here we compare one continuous and three interrupted sampling regimes to determine whether sampling regime has a significant effect on estimation of basal metabolic rate or standard evaporative water loss. Compared to continuous 20-s sampling averaged over 20 min, sampling every 6 min and averaging over 60 min overestimated basal metabolic rate and evaporative water loss, sampling every 3 min and averaging over 21 min underestimated basal metabolic rate, and sampling every 12 min and averaging over 36 min showed no difference in estimates. Increasing the period over which the minimum mean was calculated significantly increased estimates of physiological variables. Reducing the frequency of sampling from 20 s to a longer interval of 3, 6, or 12 min underestimated basal metabolic rate but not evaporative water loss. This indicates that sampling frequency per se influences estimates of basal metabolic rate and that differences are not just an artifact of differences in the period over which the mean is calculated. Sampling regime can have a highly significant influence on estimation of standard physiological variables, although the actual differences between sampling regimes were generally small (usually <5%). Although continuous sampling is the preferred sampling regime for open-flow respirometry studies, if time and cost are prohibitive, then use of an appropriate switching system will result in smaller errors than measuring individuals continuously for shorter periods.
已制定了严格的标准来测量基础代谢率和标准蒸发失水量，以确保数据能够在种内和种间进行比较。然而，数据采样方式各不相同，从基本的连续采样到间断（切换）系统，数据以更宽的间隔定期记录。在这里，我们比较了一种连续采样方式和三种间断采样方式，以确定采样方式是否对基础代谢率或标准蒸发失水量的估计有显著影响。与连续20秒采样并在20分钟内求平均值相比，每6分钟采样并在60分钟内求平均值高估了基础代谢率和蒸发失水量，每3分钟采样并在21分钟内求平均值低估了基础代谢率，而每12分钟采样并在36分钟内求平均值在估计值上没有差异。计算最小平均值的时间段增加显著提高了生理变量的估计值。将采样频率从20秒降低到3、6或12分钟的较长间隔会低估基础代谢率，但不会低估蒸发失水量。这表明采样频率本身会影响基础代谢率的估计，且差异不仅仅是计算平均值的时间段不同所造成的假象。采样方式对标准生理变量的估计可能有非常显著的影响，尽管采样方式之间的实际差异通常较小（通常<5%）。虽然连续采样是开放流呼吸测定研究的首选采样方式，但如果时间和成本过高，那么使用合适的切换系统将比短时间连续测量个体产生更小的误差。
