Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Centre for Limnology, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu County, Estonia.
Sci Rep. 2019 Nov 19;9(1):17087. doi: 10.1038/s41598-019-53541-3.
Reconstructions of past food web dynamics are necessary for better understanding long-term impacts of climate change on subarctic lakes. We studied elemental and stable isotopic composition of sedimentary organic matter, photosynthetic pigments and carbon stable isotopic composition of Daphnia (Cladocera; Crustacea) resting eggs (δC) in a sediment record from a small subarctic lake. We examined how regional climate and landscape changes over the last 5800 years affected the relative importance of allochthonous and autochthonous carbon transfer to zooplankton. Overall, δC values were well in line with the range of theoretical values of aquatic primary producers, confirming that zooplankton consumers in subarctic lakes, even in the long-term perspective, are mainly fuelled by autochthonous primary production. Results also revealed greater incorporations of benthic algae into zooplankton biomass in periods that had a warmer and drier climate and clearer water, whereas a colder and wetter climate and lower water transparency induced higher contributions of planktonic algae to Daphnia biomass. This study thus emphasizes long-term influence of terrestrial-aquatic linkages and in-lake processes on the functioning of subarctic lake food webs.
重建过去的食物网动态对于更好地理解气候变化对亚北极湖泊的长期影响是必要的。我们研究了一个小亚北极湖泊沉积物记录中的沉积有机质、浮游植物色素和大型溞（甲壳纲；节肢动物）休眠卵的碳稳定同位素组成（δC）的元素和稳定同位素组成。我们研究了过去 5800 年来区域气候和景观变化如何影响异养和自养碳向浮游动物转移的相对重要性。总体而言，δC 值与水生初级生产者的理论值范围非常吻合，这证实了即使从长期来看，亚北极湖泊中的浮游动物消费者主要以自养初级生产为食。研究结果还表明，在气候温暖干燥、水质清澈的时期，底栖藻类更多地被纳入浮游动物生物量，而在寒冷潮湿、水透明度较低的时期，浮游藻类对大型溞生物量的贡献更高。因此，本研究强调了陆地-水域联系和湖泊内过程对亚北极湖泊食物网功能的长期影响。
