The productivity of aquatic ecosystems depends on the supply of limiting nutrients. The invasion of the Laurentian Great Lakes, the world’s largest freshwater ecosystem, by dreissenid (zebra and quagga) mussels has dramatically altered the ecology of these lakes. A key open question is how dreissenids affect the cycling of phosphorus (P), the nutrient that limits productivity in the Great Lakes. We show that a single species, the quagga mussel, is now the primary regulator of P cycling in the lower four Great Lakes. By virtue of their enormous biomass, quagga mussels sequester large quantities of P in their tissues and dramatically intensify benthic P exchanges. Mass balance analysis reveals a previously unrecognized sensitivity of the Great Lakes ecosystem, where P availability is now regulated by the dynamics of mussel populations while the role of the external inputs of phosphorus is suppressed. Our results show that a single invasive species can have dramatic consequences for geochemical cycles even in the world’s largest aquatic ecosystems. The ongoing spread of dreissenids across a multitude of lakes in North America and Europe is likely to affect carbon and nutrient cycling in these systems for many decades, with important implications for water quality management.

水生生态系统的生产力取决于有限养分的供应。Dreissenid（斑马和斑马）贻贝入侵世界最大的淡水生态系统Laurentian大湖，极大地改变了这些湖的生态。一个悬而未决的关键问题是，地衣藻类化合物如何影响磷（P）的循环，磷是限制五大湖生产力的养分。我们表明，单一种类的斑贝贻贝现在是下四个大湖中磷循环的主要调节剂。斑马贻贝凭借其巨大的生物量，在其组织中螯合了大量的P，并大大增强了底栖P交换。质量平衡分析揭示了大湖区生态系统以前无法识别的敏感性，磷的有效性现在受到贻贝种群动态的调节，而磷的外部输入的作用受到抑制。我们的结果表明，即使在世界上最大的水生生态系统中，单一入侵物种也可能对地球化学循环产生重大影响。地衣藻类在北美和欧洲众多湖泊中的持续传播可能会影响这些系统中数十年来的碳和养分循环，这对水质管理具有重要意义。