Peck Lloyd Samuel, Morley Simon Anthony, Pörtner Hans-Otto, Clark Melody Susan
Natural Environment Research Council British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK.
Oecologia. 2007 Dec;154(3):479-84. doi: 10.1007/s00442-007-0858-0. Epub 2007 Sep 26.
Animal responses to changing environments are most commonly studied in relation to temperature change. The current paradigm for marine ectotherms is that temperature limits are set through oxygen limitation. Oxygen limitation leads to progressive reductions in capacity to perform work or activity, and these are more important and proximate measures of a population's ability to survive. Here we measured the ability of a large Antarctic clam to rebury when removed from sediment at temperatures between -1.5 and 7.5 degrees C and at three oxygen concentrations, 10.2, 20.5 and 27.7%. The proportion of the population capable of reburying declined rapidly and linearly with temperature from around 65% at 0 degrees C to 0% at 6 degrees C in normoxia (20.5% O2). Decreasing oxygen to 10.2% reduced temperature limits for successful burial by around 2 degrees C, and increasing oxygen to 27.7% raised the limits by 1-1.5 degrees C. There was an interactive effect of body size and temperature on burying: the temperature limits of larger individuals were lower than smaller animals. Similarly, these size limits were increased by increasing oxygen availability. Considering data for all temperatures and oxygen levels, the fastest burying rates occurred at 3 degrees C, which is 2 degrees C above the maximum summer temperature at this site.
动物对环境变化的反应通常是在与温度变化相关的研究中进行的。目前关于海洋变温动物的范式是，温度限制是通过氧气限制来设定的。氧气限制会导致执行工作或活动的能力逐渐下降，而这些是衡量种群生存能力更重要且更直接的指标。在此，我们测量了一种大型南极蛤蜊在温度介于-1.5至7.5摄氏度之间且处于三种氧气浓度（10.2%、20.5%和27.7%）时从沉积物中取出后重新埋入的能力。在常氧（20.5% O₂）条件下，能够重新埋入的种群比例随温度从0摄氏度时的约65%迅速且呈线性下降至6摄氏度时的0%。将氧气浓度降至10.2%会使成功埋入的温度限制降低约2摄氏度，而将氧气浓度增至27.7%则会使温度限制提高1至1.5摄氏度。体型和温度对埋入行为存在交互作用：较大个体的温度限制低于较小个体。同样，通过增加氧气供应，这些体型限制会提高。综合所有温度和氧气水平的数据来看，最快的埋入速率出现在3摄氏度时，这比该地点夏季最高温度高出2摄氏度。
