Mooney Benjamin Paul, Gårdmark Anna, Faithfull Carolyn, van Dorst Renee Mina, Huss Magnus
Department of Aquatic Resources, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences, Umeå, Sweden.
Glob Chang Biol. 2025 Jun;31(6):e70288. doi: 10.1111/gcb.70288.
Climate warming reshapes biomass distributions across trophic levels in aquatic systems, with implications for ecosystem functioning and service provisioning. Using a space-for-time approach across temperate and boreal lakes, we analyse a dataset spanning wide gradients in temperature and nutrient availability, including species and biomass data for phytoplankton, fish, and, in some cases, zooplankton. We hypothesise that (1) warmer lakes have higher fish-to-phytoplankton biomass ratios than colder lakes, and (2) this relationship weakens at high phosphorus levels due to proliferation of inedible phytoplankton. Contrary to expectations, our results show that warmer lakes exhibit lower fish-to-phytoplankton biomass ratios, regardless of phosphorus concentrations or the contribution of benthic relative to whole lake primary production. This suggests reduced energy transfer efficiency from producers to consumers in warming waters. Changes in phytoplankton and fish community composition are likely part of the explanation for why increased phytoplankton biomass in warmer lakes does not translate into higher fish biomass. Our findings highlight a critical shift in biomass distribution from fish to phytoplankton with rising temperatures in northern lakes, potentially signalling future declines in food web efficiency and predator biomass under continued climate warming.
气候变暖重塑了水生系统中各营养级的生物量分布，对生态系统功能和服务供应产生影响。我们采用时空替代法，对温带和寒带湖泊进行研究，分析了一个涵盖温度和养分可利用性广泛梯度的数据集，包括浮游植物、鱼类以及某些情况下浮游动物的物种和生物量数据。我们假设：（1）较温暖湖泊的鱼类与浮游植物生物量之比高于较寒冷湖泊；（2）由于不可食用浮游植物的增殖，这种关系在高磷水平下会减弱。与预期相反，我们的结果表明，无论磷浓度如何，也无论底栖生物相对于整个湖泊初级生产的贡献如何，较温暖湖泊的鱼类与浮游植物生物量之比都较低。这表明在水温升高的水域中，生产者向消费者的能量转移效率降低。浮游植物和鱼类群落组成的变化可能是较温暖湖泊中浮游植物生物量增加却未转化为更高鱼类生物量的部分原因。我们的研究结果突出了随着北方湖泊温度升高，生物量分布从鱼类向浮游植物的关键转变，这可能预示着在持续的气候变暖下，未来食物网效率和捕食者生物量将下降。
