Institute of Hydrobiology, Biology Centre of the Czech Academy of Sciences, Na Sádkách 7, České Budějovice 37005, Czech Republic; Soil and Water Research Infrastructure, Biology Centre of the Czech Academy of Sciences, Na Sádkách 7, České Budějovice 37005, Czech Republic.
Institute of Hydrobiology, Biology Centre of the Czech Academy of Sciences, Na Sádkách 7, České Budějovice 37005, Czech Republic.
Sci Total Environ. 2021 Feb 10;755(Pt 2):142550. doi: 10.1016/j.scitotenv.2020.142550. Epub 2020 Oct 1.
Using archived fish scale samples together with long-term monitoring data, this study investigates the potential of fish scales to record historical changes in the aquatic environment. We analysed stable carbon (δC) and nitrogen (δN) isotopes in the scales of two planktivorous cyprinid species collected from the meso-eutrophic Římov Reservoir, Czechia, over its entire four-decade history (1979-2016). The δC of the fish scales varied greatly throughout the reservoir history. The lowest δC values were observed immediately after the reservoir was filled in 1979, indicating that fish production at that time was likely partially supported by C-depleted CO released from the inundated soil. During the 1980s, due to the high levels of phytoplankton production stimulated by high phosphorus inputs from the catchment, the δC values substantially increased. However, since 1990, the δC values have generally decreased, reflecting a gradual reduction in reservoir primary production caused by the decreasing input of phosphorus and increasing input of dissolved organic carbon from the catchment. The δC of fish scales was also used to reconstruct the CO concentration of the surface water. The reconstructed CO varied significantly during the four-decade history, but it was always below the air-equilibrium concentration, suggesting that the surface water of the reservoir has consistently absorbed atmospheric carbon. The fish-scale δN values remained relatively stable, while slightly increasing within three years after impoundment, likely because the nitrogen supply was high throughout the studied period. Our study contributes to the growing body of literature demonstrating that stable isotope analysis of archived biological samples is a promising approach for understanding historical trends in the biogeochemistry of aquatic environments. In particular, our results highlight the potential of δC in archived fish scales in reconstructing carbon cycle changes and evaluating human impacts on aquatic ecosystems.
利用存档的鱼鳞样本和长期监测数据，本研究调查了鱼鳞记录水生环境历史变化的潜力。我们分析了捷克中营养型里姆诺水库两种滤食性鲤科鱼类鱼鳞中的稳定碳（δC）和氮（δN）同位素，这些样本采集自水库 40 年的历史（1979-2016 年）。鱼鳞中的 δC 在整个水库历史中变化很大。1979 年水库蓄水后立即观察到最低的 δC 值，表明当时鱼类的产量可能部分依赖于淹没土壤中释放的耗尽 C 的 CO。20 世纪 80 年代，由于集水区高磷输入刺激了浮游植物的大量生产，δC 值大幅增加。然而，自 1990 年以来，δC 值普遍下降，反映了集水区磷输入减少和溶解有机碳输入增加导致水库初级生产力逐渐下降。鱼鳞的 δC 还被用于重建地表水的 CO 浓度。在 40 年的历史中，重建的 CO 变化显著，但始终低于空气平衡浓度，表明水库的地表水一直在吸收大气中的碳。鱼鳞的 δN 值相对稳定，在蓄水后三年内略有增加，可能是因为整个研究期间氮供应都很高。我们的研究为越来越多的文献做出了贡献，这些文献证明了对存档生物样本进行稳定同位素分析是了解水生环境生物地球化学历史趋势的一种很有前途的方法。特别是，我们的结果强调了存档鱼鳞中 δC 重建碳循环变化和评估人类对水生生态系统影响的潜力。
