School of Life Science, Anhui Key Laboratory of Resource and Plant Biology, Huaibei Normal University, Huaibei, 235000, China.
Environ Sci Pollut Res Int. 2020 Feb;27(5):4737-4745. doi: 10.1007/s11356-019-07157-9. Epub 2019 Dec 16.
Cladoceran remains (e.g., Daphnia ephippia) in sediments are usually able to accurately reflect the historical succession of cladoceran in lakes. However, mechanisms describing the interaction between density changes of empty ephippia and ephippia containing resting eggs in lake sediments and environmental factors remain unclear. The diversity and vertical changes of Daphnia ephippia in the 30-cm sedimentary layer (equivalent to about 90 years) were investigated in a subtropical Chinese lake, Lake Chaohu. The ephippia of D. similoides sinensis, D. pulex, and D. galeata were identified in the lake sediments. The densities and accumulation rates of both empty ephippia and ephippia containing resting eggs of three Daphnia species showed similar patterns. The values in the surface sedimentary layers (after the 1970s) were notably higher than in the bottom sedimentary layers (before the 1970s). The densities and accumulation rates of both empty ephippia and ephippia containing resting eggs of D. similoides sinensis were higher than those of D. pulex and D. galeata. Highly significant relationships (P < 0.001) between the TN contents and the ephippial densities and accumulation rates of D. similoides sinensis and D. galeata. TP contents had also significant correlations with the ephippial densities and accumulation rates of D. similoides sinensis and D. galeata, whereas it was not significant correlations with those of D. pulex (P > 0.05). Our results suggested that long-term eutrophication and cyanobacterial blooms might significantly affect the production of Daphnia ephippia and their vertical distribution in the sediments in eutrophic lakes.
枝角类遗骸（如溞类休眠卵）在沉积物中的存在通常能够准确反映湖泊中枝角类的历史演替。然而，描述空的休眠卵和含有休眠卵的休眠卵在湖泊沉积物中密度变化与环境因素之间相互作用的机制尚不清楚。在中国亚热带湖泊巢湖的 30 厘米沉积层（相当于约 90 年）中，研究了枝角类休眠卵的多样性和垂直变化。在湖泊沉积物中鉴定出中华象鼻溞、裸腹溞和隆线溞的休眠卵。三种枝角类的空休眠卵和含有休眠卵的休眠卵的密度和积累率表现出相似的模式。表层沉积物（20 世纪 70 年代以后）的数值明显高于底层沉积物（20 世纪 70 年代以前）。中华象鼻溞的空休眠卵和含有休眠卵的休眠卵的密度和积累率均高于裸腹溞和隆线溞。中华象鼻溞和隆线溞的总氮含量与休眠卵密度和积累率之间存在高度显著关系（P<0.001）。总磷含量与中华象鼻溞和隆线溞的休眠卵密度和积累率也有显著相关性，而与裸腹溞的休眠卵密度和积累率无显著相关性（P>0.05）。我们的研究结果表明，长期富营养化和蓝藻水华可能会显著影响富营养化湖泊中枝角类休眠卵的产生及其在沉积物中的垂直分布。
