Data from: Ecophysiological limits to aerobic metabolism in hypoxia determine epibenthic distributions and energy sequestration in the northeast Pacific ocean

Expansion of oxygen deficient waters (hypoxia) in the northeast Pacific Ocean (NEP) will have marked impacts on marine life. The response of the resident communities will be a function of their ecophysiological constraints in low oxygen, although this remains untested in the NEP due to a lack of integrative studies. Here, we combine in situ surveys and lab-based respirometry experiments were conducted on three indicator species (spot prawn Pandalus platyceros, slender sole Lyopsetta exilis, squat lobster Munida quadrispina) of seasonally hypoxic systems in the NEP to test if metabolic constraints determine distributions and energy sequestration in a hypoxic setting. These experiments were integrated with a global review of critical oxygen levels ( math formula; lower threshold of aerobic metabolism) for crustaceans to determine if math formula-based hypoxia thresholds are different among ocean basins. Our results show that species-specific differences in math formula and standard metabolic rates (1) determine the lowest environmental oxygen ([O2]env) at which in situ populations occur, (2) result in disproportionate shifts in distributions among co-occurring species during summer hypoxia expansion events, and (3) characterize shifts in megafaunal community respiration rates due to marked spatio-temporal variability in [O2]env. Our results show that math formula-based hypoxia thresholds are significantly lower in the East Pacific Ocean relative to other major ocean basins, which suggests that the physiological response of local fauna to deoxygenation can be determined by the natural variability and oxygen exposure in a region. In order to establish realistic predictions on the biological consequences of marine deoxygenation, we suggest integrating metabolism-based traits to calculate hypoxia thresholds for marine ecosystems.东北太平洋（NEP）的低氧（hypoxia）水域扩张将对海洋生物产生显著影响。本地群落的响应将取决于其在低氧环境下的生理生态限制，但由于缺乏整合性研究，这一科学问题在东北太平洋尚未得到验证。本研究结合原位调查（in situ surveys）与针对东北太平洋季节性低氧系统的三种指示物种（indicator species）——斑虾*Pandalus platyceros*、细鳎*Lyopsetta exilis*、四刺铠甲虾*Munida quadrispina*——开展的实验室呼吸代谢实验（respirometry experiments），以检验代谢限制是否决定了低氧环境下物种的分布与能量固存。本研究还整合了全球甲壳类临界氧水平（critical oxygen levels，即有氧代谢（aerobic metabolism）的下限阈值）的综述数据，以探究基于临界氧水平的低氧阈值在不同大洋盆地间是否存在差异。研究结果表明：（1）物种特异性的临界氧水平与标准代谢率（standard metabolic rates）决定了原位种群所能存活的最低环境氧浓度([O₂]env)；（2）在夏季低氧扩张事件中，共存物种的分布会出现不均衡位移；（3）由于环境氧浓度存在显著的时空变异性，大型生物群落（megafaunal community）的呼吸速率会发生改变。本研究同时发现，相较于其他主要大洋盆地，东太平洋基于临界氧水平的低氧阈值显著更低，这表明本地动物群对海洋脱氧（marine deoxygenation）的生理响应可由区域内的自然变异与氧暴露水平决定。为了对海洋脱氧的生物学效应作出切合实际的预测，我们建议整合基于代谢的性状参数，以计算海洋生态系统的低氧阈值。