Data from: Anemic streams: Iron and essential trace metals frequently limit primary producer biomass

Metals are essential for microbial metabolism, yet their role as limiting nutrients in freshwater streams remains poorly understood. We quantified the prevalence of metal and nutrient (co-)limitation of primary producers in 41 streams. Metal limitation was widespread with Fe limitation eliciting the strongest and most consistent biomass responses (50% of streams). Zn limitation was also common (33% of streams), marking the first evidence of Zn-limited stream biofilms at this spatial scale. Metals were often co-limiting with N and P, highlighting interactions between macro- and micronutrients. Diatoms were more responsive to Zn and cyanobacteria reached higher biomass with N and P enrichment, emphasizing divergent nutrient responses among taxa. Predictive modeling indicated that Fe and Zn limitation could be forecasted from environmental variables related to macronutrient supply. These findings challenge the long-standing assumption that stream primary producers are rarely metal-limited and suggest that trace metals may play an underappreciated role in regulating stream productivity, community composition, and nutrient cycling. v1.0 first data release includes all code for models, analyses, and figures.金属元素对微生物代谢至关重要，但其作为淡水溪流中限制性营养因子的作用迄今仍未得到充分阐释。本研究针对41条溪流，量化了初级生产者（primary producers）受金属与营养物质（共同）限制的普遍程度。金属限制现象分布广泛，其中铁（Fe）限制所引发的生物量响应最为强烈且稳定，覆盖50%的受试溪流；锌（Zn）限制同样常见（占受试溪流的33%），这为本研究在该空间尺度下首次观测到溪流生物膜（biofilms）受锌限制的现象提供了实证支持。金属元素常与氮（N）、磷（P）共同构成限制因子，凸显了常量营养元素与微量营养元素间的交互调控关系。硅藻（diatoms）对锌的响应更为显著，而蓝细菌（cyanobacteria）在氮、磷富集条件下可获得更高生物量，这体现了不同类群（taxa）对营养物质的响应模式存在显著分化。预测模型显示，可通过与常量营养元素供给相关的环境变量，对铁、锌限制现象进行预测。本研究结果挑战了"溪流初级生产者极少受金属限制"这一长期存在的学术假设，并表明痕量金属（trace metals）在调控溪流生产力、群落组成及营养循环中所发挥的作用，此前未得到足够重视。 本数据集v1.0首次公开版本包含模型构建、数据分析及图表绘制的全部代码。