Polyphosphate (polyP) is important to phytoplankton ecology, but a unified view of its variability and roles in ecosystem‐scale phosphorus (P) cycling is lacking. We study polyP in the world's largest freshwater ecosystem, the Laurentian Great Lakes, covering pelagic to nearshore areas across a wide nutrient gradient. We show that polyP (average 10.99 ± 3.90 nmol L−1) constitutes 3.8–30.2% (average 18.1 ± 7.2%) of total particulate P (TPP). PolyP accumulation is higher in low‐P pelagic waters compared with more productive nearshore areas. PolyP is preferentially degraded in the water column of the Great Lakes, enhancing P recycling and relieving the nitrogen (N) : P imbalance. Our data enables a coherent large‐scale freshwater‐to‐oceanic comparison. We show that while different plankton groups accumulate different levels of polyP with smaller plankton accumulating more, P availability is the key driver of polyP variability within and across systems.

中文翻译：

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五大湖中的聚磷酸盐

多磷酸盐（polyP）对浮游植物生态学很重要，但对其变异性和在生态系统规模磷（P）循环中的作用缺乏统一的看法。我们研究了世界上最大的淡水生态系统劳伦森五大湖中的多聚磷，该生态系统覆盖了从远洋到近岸区域的广泛营养梯度。我们表明，polyP（平均 10.99 ± 3.90 nmol L−1) 占总颗粒物 P (TPP) 的 3.8–30.2%（平均 18.1 ± 7.2%）。与生产力较高的近岸地区相比，低磷中上层水域的多磷积累量更高。 PolyP优先在五大湖的水体中降解，增强磷的循环利用并缓解氮（N）：磷的不平衡。我们的数据可以进行连贯的大规模淡水与海洋比较。我们表明，虽然不同的浮游生物群体积累了不同水平的多聚磷，较小的浮游生物积累更多，但磷的可用性是系统内和跨系统的多磷变异性的关键驱动因素。