Anthropocene is a new geological concept, which indicates that human activity has become an active agent in changing the Earth’s systems. However, the Anthropocene still requires a great deal of stratigraphic evidence, including those of palaeontological records, to be formalized by the International Commission on Stratigraphy. 

The Sihailongwan Maar Lake has just been selected as a potential auxiliary site of Global boundary Stratotype Section and Point (GSSP) for demarcation of the Anthropocene by the Anthropocene Working Group (AWG). This site is located in a relatively remote area in Jilin Province in the northeastern China with little human disturbance. As a typical crater lake there is no inlet and outlet and thus it mainly receives atmospheric deposition, reflecting environmental change and human activities over large scales. 

To better understand how lake ecosystem responds to natural and anthropogenic environmental changes, researchers from the Institute of Earth Environment, Chinese Academy of Sciences and Umeå University, applied the sedDNA technology to reconstruct the micro-eukaryotic community structure changes over the past 160 years in this lake.  

They found that, the compositions of micro-eukaryotic community including photoautotrophs, mixotrophs, consumers, and parasites, exhibited a significant difference before and after the 1950s, which meant a re-arrangement of micro-eukaryotic at that time. Interestingly, the rearrangement of micro-eukaryotic at the 1950s was in good agreement with the rapid changes in other anthropogenic contaminants, such as, heavy metals, polycyclic aromatic hydrocarbon, and nutrients in this lake. These results indicated that human activities might have led to the irreversible effects on lake ecosystems.

The study provides biostratigraphy evidences of the impact of human activities on lake biota, and further supports the boundary of the Anthropocene occurring in the mid-20th century, as proposed by the Anthropocene Working Group. 

Contact: BAI Jie, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China. Email: baijie@ieecas.cn