Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bentho-Pelagic Processes, Am Alten Hafen 26, 27568 Bremerhaven, Germany.
Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Am Handelshafen 12, 27570 Bremerhaven, Germany.
J Exp Biol. 2018 Oct 31;221(Pt 21):jeb184473. doi: 10.1242/jeb.184473.
Polar cod () is an important prey species in the Arctic ecosystem, yet its habitat is changing rapidly: climate change, through rising seawater temperatures and CO concentrations, is projected to be most pronounced in Arctic waters. This study aimed to investigate the influence of ocean acidification and warming on maximum performance parameters of as indicators for the species' acclimation capacities under environmental conditions projected for the end of this century. After 4 months at four acclimation temperatures (0, 3, 6, 8°C) each combined with two levels (390 and 1170 µatm), aerobic capacities and swimming performance of were recorded following a protocol. At both CO levels, standard metabolic rate (SMR) was elevated at the highest acclimation temperature indicating thermal limitations. Maximum metabolic rate (MMR) increased continuously with temperature, suggesting an optimum temperature for aerobic scope for exercise (AS) at 6°C. Aerobic swimming performance () increased with acclimation temperature irrespective of CO levels, while critical swimming speed () did not reveal any clear trend with temperature. Hypercapnia evoked an increase in MMR (and thereby AS). However, swimming performance (both and ) was impaired under elevated near-future conditions, indicating reduced efficiencies of oxygen turnover. The contribution of anaerobic metabolism to swimming performance was very low overall, and further reduced under hypercapnia. Our results revealed high sensitivities of maximum performance parameters (MMR, , ) of to ocean acidification. Impaired swimming capacity under ocean acidification may reflect reduced future competitive strength of .
北极鳕鱼（ ）是北极生态系统中的一种重要猎物物种，但它的栖息地正在迅速变化：预计气候变化将通过海水升温以及 CO2 浓度的升高，对北极水域产生最显著的影响。本研究旨在调查海洋酸化和变暖对北极鳕鱼最大性能参数的影响，这些参数可作为该物种在本世纪末预计环境条件下适应能力的指标。在四个适应温度（0、3、6 和 8°C）下分别进行 4 个月的实验，并结合两种 CO2 水平（390 和 1170 µatm），采用 protocol 记录了北极鳕鱼的有氧能力和游泳性能。在两种 CO2 水平下，标准代谢率（SMR）在最高适应温度下升高，表明存在热限制。最大代谢率（MMR）随温度连续增加，表明有氧范围（AS）的最佳温度为 6°C。有氧游泳性能（ ）随适应温度的升高而升高，而临界游泳速度（ ）与温度没有明显的趋势。高 CO2 水平会引起 MMR（进而 AS）的增加。然而，在高浓度 CO2 条件下，游泳性能（ 和 ）均受到损害，表明氧气利用率降低。整体而言，无氧代谢对游泳性能的贡献非常低，在高 CO2 条件下进一步降低。研究结果表明，北极鳕鱼的最大性能参数（MMR、 、 ）对海洋酸化非常敏感。海洋酸化导致的游泳能力受损可能反映出北极鳕鱼未来竞争能力的降低。
