Changes in total sulfur of lake sediments from central-eastern China linked to volcanic aerosol and human activity

Abstract

Investigations into the repercussions of human activities on global climate and the ecological environment have received widespread attention. Over the past century, research has primarily focused on the impact of heavy metals and nutrients on lake ecosystems, along with their links to human activities. However, there is a noticeable dearth in explorations of historical variations in sulfur (S), an element that also has complex adverse effects on the environment and ecosystems. Here, we present an approximately 1800-year record of the total S (TS) content of sediments in Lake Nvshan, central-eastern China. The results provide evidence to indicate that high (low) TS contents in Lake Nvshan sediments are associated with strong (weak) volcanism in the Northern Hemisphere on multi-century scales. We also observed significant enhancement of TS content at 1750 and 1900 CE, which corresponded to a significant increase in the regional population at these times. We thus infer that elevations in TS levels prior to the increase in human activities likely resulted from increased volcanisms that led to greater inputs of sulfate from the stratosphere into the lake. Subsequently, the increases in TS contents could be attributed to intensified human industrial activities. Our findings revealed that volcanically derived sulfates have been supplanted by anthropogenically driven increases in the levels of sulfides as the primary factor influencing sediment TS contents in Lake Nvshan. These findings could elucidate how human activities have steered lake systems away from their natural baseline, thereby augmenting our understanding of their broader environmental impact.