Effects of historical dust-mediated atmospheric phosphorus deposition on phosphorus fractions in sediments and primary productivity of Dalongwan Maar Lake, Northeast China

Atmospheric phosphorus (P) deposition has a significant impact on sensitive aquatic ecosystems in remote areas. However, its effect on the P fractions of lake sediments and the development of lake ecosystems are poorly understood, especially for P-limited lakes. This study investigates this issue via analyzing trap and core sediments of Dalongwan Maar Lake (DML), a P-limited lake in Northeast China. The provenance analysis indicates that the sediments in DML are mainly derived from the aeolian input from northern China deserts, which brings P-containing particles. Then, the relationships between atmospheric P deposition and the P fractions of the DML lake sediment and its ecosystems over the past 180 years were explored. The results show that: 1) The P fractions in trap sediments exhibit significant seasonal variation, with calcium-bound P (HCl-Pi) being the predominant fractions during spring and winter, while aluminum-bound P (NaOH-Pi) and iron and manganese (hydroxide)oxy-bound P (NaBD-Pi) are more prevalent in summer and autumn. The ranking order of P fractions in the core sediments was HCl-Pi > NaOH-Pi > NaBD-Pi > Res.-P (residual P). 2) The HCl-Pi content in the sediments of DML appears to be influenced by variations in northern China dust activity, while the Fe/Al-Pi (the sum of NaOH-Pi and NaBD-Pi contents) is associated with industrial and residential emission activities. 3) A gradual increase in atmospheric P deposition activity in northern China over the past century was observed. It may hinder the development of primary productivity in DML by increasing the water hardness, which is conducive to the formation of HCl-Pi. Furthermore, deeper water depth limits nutrient recycling from the lakebed, impeding algal growth. These findings enhance our understanding of how atmospheric P deposition influences lake sediment P fractions and ecosystems and provide guidance for the long-term health of DML. •The main source of the Dalongwan Maar Lake (DML) sediments is explored.•The effects of atmospheric phosphorus deposition on the P fractions of lake sediments and the development of lake ecosystems are discussed.•The enhancement of regional atmospheric P deposition activities may have a negative effect on the development of primary productivity in DML.