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Simple Summary: The Arctic is experiencing a significant temperature increase under the global warming trend. As a result, the Arctic permafrost is thawing, glacial meltwater is gathering, and the depressions are gradually forming lakes, affecting the composition and material cycles of the terrestrial ecosystems. Two meltwater lakes with different landscapes in the Ny-Ålesund region of the Arctic were taken as study objects. The structure of the archaeal community and the influence of soil physiochemical factors on the archaeal community were investigated. The differences in the archaeal community structure between the intertidal and subtidal zones of the two lakes were compared, and the reasons for the differences were analyzed and discussed. A redundancy analysis identified NH4+, SiO32−, MC, NO3−, and NO2− as key soil physicochemical factors that have significantly influenced the structure of the archaeal community. The hub archaea in the archaeal community were identified by weighted gene co-expression network analysis (WGCNA). The use of WGCNA in this study provides new ideas for future research on the microbial community structure. In the context of global warming, this study contributes to research on archaeal communities in Arctic meltwater lakes in response to climate change. Two typical lakes formed from meltwater in the Ny-Ålesund area were taken as the study subjects in 2018. To investigate the archaeal community compositions of the two lakes, 16S rRNA genes from soil samples from the intertidal and subtidal zones of the two lakes were sequenced with high throughput. At the phylum level, the intertidal zone was dominated by Crenarchaeota and the subtidal zone was dominated by Halobacter; at the genus level, the intertidal zone was dominated by Nitrososphaeraceae_unclassified and Candidatus_Nitrocosmicus, while the subtidal zone was dominated by Methanoregula. The soil physicochemical factors pH, moisture content (MC), total organic carbon (TOC), total organic nitrogen (TON), nitrite nitrogen (NO2−-N), and nitrate nitrogen (NO3−-N) were significantly different in the intertidal and subtidal zones of the lake. By redundancy analysis, the results indicated that NH4+-N, SiO32−-Si, MC, NO3−-N, and NO2−-N have had highly significant effects on the archaeal diversity and distribution. A weighted gene co-expression network analysis (WGCNA) was used to search for hub archaea associated with physicochemical factors. The results suggested that these physicochemical factors play important roles in the diversity and structure of the archaeal community at different sites by altering the abundance of certain hub archaea. In addition, Woesearchaeales was found to be the hub archaea genus at every site. [ABSTRACT FROM AUTHOR]

The distribution characteristics, sources, and risk levels of organochlorine pesticides (OCPs) in Ny-Ålesund of the Arctic region during China's 10th Arctic expedition were studied in this paper. Results showed that the concentration of OCPs in the surface soil of the Ny-Ålesund region ranged from 0.59 ng·g−1 to 3.87 ng·g−1, with an average concentration of 2.22 ng·g−1. Source analysis showed that the OCPs in the study area mainly originated from historical residues, and a certain degree of conversion between congeners of hexachlorocyclohexanes and dichlorodiphenyltrichloroethanes in the soil occurred due to environmental factors. Ecological risk assessment indicated that the study area was at a low ecological risk level, but the potential environmental impact of OCPs could not be neglected due to the specificity and sensitivity of the Arctic environment. • Six OCPs were detected in the topsoil of Ny-Ålesund, in the Arctic. • The OCPs mainly originated from historical residues. • OCPs in this region were at low ecological risk. [ABSTRACT FROM AUTHOR]

In this paper, the characteristics of persistent toxic substances (PTSs) in soil of Ny-Ålesund in the Arctic during the 10th Chinese Arctic (Arctic Ocean) scientific investigation were quantitatively analyzed. The sources and toxicity risks of polycyclic aromatic hydrocarbons (PAHs) in the soil was also analyzed. No obvious spatial distribution of PAHs was identified in the study area. LMW-PAHs are the main PAHs in this region, mainly tricyclic PAHs. The results of characteristic ratio method and PCA showed that the PAHs in soil mainly came from petroleum source and petroleum combustion source, and incomplete combustion of coal and wood, and atmospheric transport contributed to some extent. Ecological risk assessment results showed that the PAHs in soil did not bring toxicity risk, and the possibility of ecological risk was very low in Ny-Ålesund in the Arctic. [Display omitted] • Distribution characteristics of PTSs in soils of Ny-Ålesund in the Arctic. • Sources apportionment and Ecological risk assessment for PTSs in soils. • Risk levels of PTs and recommendations for prevention and control. [ABSTRACT FROM AUTHOR]