Tate Heidi M, Studholme Katharine R, Domalik Alice D, Drever Mark C, Romero L Michael, Gormally Brenna M G, Hobson Keith A, Hipfner J Mark, Crossin Glenn T
Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada.
Wildlife Research Division, Environment and Climate Change Canada, Delta, British Columbia, Canada.
Conserv Physiol. 2021 Nov 25;9(1):coab090. doi: 10.1093/conphys/coab090. eCollection 2021.
'The Blob', a mass of anomalously warm water in the Northeast Pacific Ocean peaking from 2014 to 2016, caused a decrease in primary productivity with cascading effects on the marine ecosystem. Among the more obvious manifestations of the event were seabird breeding failures and mass mortality events. Here, we used corticosterone in breast feathers (fCort), grown in the winter period during migration, as an indicator of nutritional stress to investigate the impact of the Blob on two sentinel Pacific auk species (family Alcidae). Feathers were collected from breeding females over 8 years from 2010 to 2017, encompassing the Blob period. Since Pacific auks replace body feathers at sea during the migratory period, measures of fCort provide an accumulated measure of nutritional stress or allostatic load during this time. Changes in diet were also measured using δN and δC values from feathers. Relative to years prior to the Blob, the primarily zooplanktivorous Cassin's auklets () had elevated fCort in 2014-2017, which correlated with the occurrence of the Blob and a recovery period afterwards, with relatively stable feather isotope values. In contrast, generalist rhinoceros auklets () displayed stable fCort values across years and increased δN values during the Blob. As marine heatwaves increase in intensity and frequency due to climate change, this study provides insight into the variable response of Pacific auks to such phenomena and suggests a means for monitoring population-level responses to climatological variation.
“巨藻暖流”是指东北太平洋海域出现的一大片异常温暖的水体，在2014年至2016年达到峰值，它导致初级生产力下降，并对海洋生态系统产生连锁效应。该事件较为明显的表现包括海鸟繁殖失败和大规模死亡事件。在此，我们将在冬季迁徙期间生长的胸羽中的皮质酮（fCort）用作营养压力的指标，以研究“巨藻暖流”对两种太平洋海雀哨兵物种（海雀科）的影响。我们从2010年至2017年的8年时间里收集了繁殖期雌性海雀的羽毛，涵盖了“巨藻暖流”时期。由于太平洋海雀在迁徙期间在海上更换体羽，fCort的测量提供了这段时间内营养压力或应激负荷的累积测量值。我们还利用羽毛中的δN和δC值来测量饮食变化。相对于“巨藻暖流”出现之前的年份，主要以浮游动物为食的卡辛氏小海雀在2014年至2017年期间fCort升高，这与“巨藻暖流”的出现及其后的恢复期相关，羽毛同位素值相对稳定。相比之下，食性广泛的角嘴海雀多年来fCort值稳定，在“巨藻暖流”期间δN值增加。随着气候变化导致海洋热浪强度和频率增加，本研究深入了解了太平洋海雀对这类现象的不同反应，并提出了一种监测种群水平对气候变异反应的方法。
