Polar marine ecosystems are particularly vulnerable to the effects of climate change. Warming temperatures, freshening seawater, and disruption to sea-ice formation potentially all have cascading effects on food webs. New approaches are needed to better understand spatiotemporal interactions among biogeochemical processes at the base of Southern Ocean food webs. In marine systems, isoscapes (models of the spatial variation in the stable isotopic composition) of carbon and nitrogen have proven useful in identifying spatial variation in a range of biogeochemical processes, such as nutrient utilization by phytoplankton. Isoscapes provide a baseline for interpreting stable isotope compositions of higher trophic level animals in movement, migration, and diet research. Here, we produce carbon and nitrogen isoscapes across the entire Southern Ocean (>40°S) using surface particulate organic matter isotope data, collected over the past 50 years. We use Integrated Nested Laplace Approximation-based approaches to predict mean annual isoscapes and four seasonal isoscapes using a suite of environmental data as predictor variables. Clear spatial gradients in δ¹³C and δ¹⁵N values were predicted across the Southern Ocean, consistent with previous statistical and mechanistic views of isotopic variability in this region. We identify strong seasonal variability in both carbon and nitrogen isoscapes, with key implications for the use of static or annual average isoscape baselines in animal studies attempting to document seasonal migratory or foraging behaviors.

中文翻译：

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南大洋等景模式：预测颗粒有机物的碳和氮同位素组成的时空变异性

极地海洋生态系统特别容易受到气候变化的影响。气温升高、海水变淡水和海冰形成的破坏都可能对食物网产生连锁效应。需要新的方法来更好地了解南大洋食物网底部生物地球化学过程之间的时空相互作用。在海洋系统中，碳和氮的等值线图（稳定同位素组成的空间变化模型）已被证明可用于识别一系列生物地球化学过程中的空间变化，例如浮游植物对养分的利用。Isoscapes 为解释运动、迁移和饮食研究中较高营养级动物的稳定同位素组成提供了基线。在这里，我们生成了整个南大洋 (> 40°S) 使用过去 50 年收集的表面颗粒有机物同位素数据。我们使用基于集成嵌套拉普拉斯近似的方法来使用一组环境数据作为预测变量来预测平均年度等景和四个季节性等景。δ 中的清晰空间梯度预测了整个南大洋的¹³ C 和 δ ¹⁵ N 值，这与先前对该地区同位素变异性的统计和机械观点一致。我们确定了碳和氮等值景的强烈季节性变化，这对在试图记录季节性迁徙或觅食行为的动物研究中使用静态或年平均等景基线具有重要意义。