Sandblom Erik, Gräns Albin, Axelsson Michael, Seth Henrik
Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.
Proc Biol Sci. 2014 Nov 7;281(1794):20141490. doi: 10.1098/rspb.2014.1490.
Temperature acclimation may offset the increased energy expenditure (standard metabolic rate, SMR) and reduced scope for activity (aerobic scope, AS) predicted to occur with local and global warming in fishes and other ectotherms. Yet, the time course and mechanisms of this process is little understood. Acclimation dynamics of SMR, maximum metabolic rate, AS and the specific dynamic action of feeding (SDA) were determined in shorthorn sculpin (Myoxocephalus scorpius) after transfer from 10°C to 16°C. SMR increased in the first week by 82% reducing AS to 55% of initial values, while peak postprandial metabolism was initially greater. This meant that the estimated AS during peak SDA approached zero, constraining digestion and leaving little room for additional aerobic processes. After eight weeks at 16°C, SMR was restored, while AS and the estimated AS during peak SDA recovered partly. Collectively, this demonstrated a considerable capacity for metabolic thermal compensation, which should be better incorporated into future models on organismal responses to climate change. A mathematical model based on the empirical data suggested that phenotypes with fast acclimation rates may be favoured by natural selection as the accumulated energetic cost of a slow acclimation rate increases in a warmer future with exacerbated thermal variations.
温度驯化可能会抵消鱼类和其他变温动物因局部和全球变暖预计会出现的能量消耗增加（标准代谢率，SMR）以及活动范围缩小（有氧范围，AS）的情况。然而，这个过程的时间进程和机制却鲜为人知。在短角杜父鱼（Myoxocephalus scorpius）从10°C转移到16°C后，测定了其标准代谢率、最大代谢率、有氧范围以及摄食的特殊动力作用（SDA）的驯化动态。标准代谢率在第一周增加了82%，使有氧范围降至初始值的55%，而餐后代谢峰值最初更大。这意味着在标准代谢率峰值期间估计的有氧范围接近零，限制了消化，几乎没有额外有氧过程的空间。在16°C下八周后，标准代谢率恢复，而有氧范围以及在标准代谢率峰值期间估计的有氧范围部分恢复。总体而言，这表明了相当大的代谢热补偿能力，应更好地纳入未来关于生物体对气候变化反应的模型中。基于经验数据的数学模型表明，随着未来气候变暖热变化加剧，慢驯化率累积的能量成本增加，具有快速驯化率的表型可能会受到自然选择的青睐。
