Large animals such as sea birds and marine mammals can transport limiting nutrients between different regions of the ocean, thereby stimulating and enhancing productivity. In Antarctica this process is influenced by formation and breakup of sea ice and its influence on the feeding behaviour of predators and their prey. We used analyses of bioactive metals (for example, Fe, Co, Mn), macronutrients (for example, N) and stable isotopes (δ¹³C and δ¹⁵N) in the excreta of Adélie (Pygoscelis adeliae) and emperor penguins (Aptenodytes forsteri) as well as Weddell seals (Leptonychotes weddellii) from multiple sites, among multiple years (2012–2014) to resolve how changes in sea ice dynamics, as indicated by MODIS satellite images, were coincident with prey switching and likely changes in nutrient fluxes between the offshore pelagic and coastal zones. We also sampled excreta of the south polar skua (Stercorarius maccormicki), which preys on penguins and scavenges the remains of both penguins and seals. We found strong coincidence of isotopic evidence for prey switching, between euphausiids (Euphausia superba and E. crystallorophias) and pelagic/cryopelagic fishes (for example, Pleuragramma antarcticum) in penguins, and between pelagic/cryopelagic fishes and Antarctic toothfish (Dissostichus mawsoni) in Weddell seals, with changes in sea ice cover among years. Further, prey switching was strongly linked to changes in the concentrations of nutrients (Fe and N) deposited in coastal environments by both penguins and seals. Our findings have important implications for understanding how the roles of large animals in supporting coastal productivity may shift with environmental conditions in polar ecosystems.

大型动物（例如海鸟和海洋哺乳动物）可以在海洋的不同区域之间运输有限的营养，从而刺激并提高生产力。在南极洲，这一过程受到海冰的形成和破裂及其对捕食者及其猎物摄食行为的影响。我们使用的生物活性金属的分析（例如，铁，钴，锰），常量营养素（例如，N）和稳定同位素（δ ¹³ C和δ ¹⁵在阿德利（的排泄物N）阿德利企鹅属企鹅）和帝企鹅（学名：Aptenodytes forsteri）以及Weddell海豹（Leptonychotes weddellii），以解决多年间（2012-2014年）海冰动力学变化（如MODIS卫星图像所示）如何与猎物转换以及近海中上层和沿海地区之间的养分通量变化同时发生的问题。我们还采样了南极贼鸥（Stercorarius maccormicki）的排泄物，它捕食企鹅，并清除企鹅和海豹的遗体。我们发现的猎物切换同位素证据强烈的巧合，磷虾（间磷虾和E. crystallorophias）和远洋/ cryopelagic鱼类（例如，Pleuragramma antarcticum）的企鹅，和远洋之间/ cryopelagic鱼和南极齿鱼（Dissostichus mawsoni）在Weddell海豹中，海冰盖数年间变化。此外，猎物转换与企鹅和海豹在沿海环境中沉积的营养物（铁和氮）浓度变化密切相关。我们的发现对理解大型动物在支持沿海生产力中的作用如何随极地生态系统的环境条件而发生变化具有重要意义。