The Antarctic seasonal sea-ice zone (SIZ) is one of the most extensive and dynamic habitats on Earth. In summer, increased insolation and ice melt cause primary production to peak, sustaining large populations of locally-breeding seabirds. Due to their hypermobility, large Procellariiformes, including albatrosses, breeding in the subantarctic also have the potential to access the SIZ and track macroscale resource waves over the Sothern Ocean but the extent to which they do this is poorly known. Here, we analysed the foraging movements of breeding albatrosses and large petrels (seven species, 1298 individuals) recorded using GPS loggers and satellite-transmitters to quantify their use of sea-ice habitats and test whether they tracked seasonal drivers of primary production. Foraging latitudes of white-chinned petrels Procellaria aequinoctialis and black-browed Thalassarche melanophris, grey-headed T. chrysostoma and wandering albatrosses Diomedea exulans varied sinusoidally over the breeding season, presumably in response to lagged effects of solar irradiance on primary production. Foraging latitudes of northern and southern giant petrels (Macronectes halli and M. giganteus), and light-mantled albatrosses Phoebetria palpebrata, exhibited no strong seasonal trend, but the latter two species spent ≥ 20 % of their time in the SIZ during incubation and post-brood, prior to or at the time of the spring ice breakup. Southern giant petrels travelled hundreds of km into the pack ice, encountering sea-ice concentrations up to 100 %, whereas light-mantled albatrosses remained almost exclusively in open water near the Marginal Ice Zone (MIZ). The remaining species spent up to 15 % of their time in the SIZ, typically from 5-7 weeks after breakup, and avoided the MIZ. This supports hypotheses that sea ice presents albatrosses but not giant petrels with physical barriers to flight or foraging, and that open-water-affiliated species use the SIZ only after primary production stimulated by ice melt transfers to intermediate trophic levels. Given that all seven species used the SIZ, it is likely that the phenology and demography of these and many other subantarctic-breeding seabirds are mechanistically linked to sea-ice dynamics. Declines in Antarctic sea ice predicted under climate change could therefore modulate and exacerbate the already unsustainable anthropogenic impacts being experienced by these populations.

中文翻译：

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信天翁和大型海燕对海冰觅食栖息地的季节性资源跟踪和利用


南极季节性海冰区 （SIZ） 是地球上最广泛、最具活力的栖息地之一。在夏季，日照增加和冰融化导致初级生产达到顶峰，维持了大量当地繁殖的海鸟种群。由于它们的过度活动，在亚南极繁殖的大型 Procellariiformes，包括信天翁，也有可能进入 SIZ 并跟踪 Sothern Ocean 上的宏观资源波，但它们这样做的程度知之甚少。在这里，我们分析了使用 GPS 记录器和卫星发射器记录的繁殖信天翁和大型海燕（7 个物种，1298 只）的觅食运动，以量化它们对海冰栖息地的利用，并测试它们是否跟踪初级生产的季节性驱动因素。白颌海燕 Procellaria aequinoctialis 和黑眉 Thalassarche melanophris、灰头 T. chrysostoma 和流浪信天翁 Diomedea exulans 的觅食纬度在繁殖季节呈正弦曲线变化，可能是为了响应太阳辐照度对初级生产的滞后影响。在纬度地区觅食北部和南部的巨型海燕 （Macronectes halli 和 M. giganteus） 以及轻披风信天翁 Phoebetria palpebrata 没有表现出强烈的季节性趋势，但后两个物种在孵化期间和育雏后、春季冰雪破裂之前或之时，在 SIZ 中度过了 ≥20% 的时间。南方巨型海燕进入浮冰数百公里，遇到海冰浓度高达 100%，而轻披信天翁几乎完全停留在边缘冰区 （MIZ） 附近的开阔水域。其余物种在 SIZ 中度过了高达 15% 的时间，通常在解体后 5-7 周，并避开了 MIZ。 这支持了以下假设：海冰呈现信天翁而不是巨型海燕，对飞行或觅食有物理障碍，并且开放水域附属物种只有在冰融化转移到中等营养级刺激初级生产后才使用 SIZ。鉴于所有七个物种都使用了 SIZ，这些海鸟和许多其他亚南极繁殖海鸟的物候和人口学很可能在机械上与海冰动力学有关。因此，在气候变化下预测的南极海冰减少可能会调节和加剧这些种群正在经历的已经不可持续的人为影响。