158-5 Trophic Status and Redox Dynamics Drive Arsenic Enrichment: Insights from a 4500-Year Lake Record

Session: Redox-Driven Nutrient and Contaminant Dynamics in Terrestrial Systems

Presenting Author:

Authors:

Abstract:

Rising arsenic (As) concentrations in freshwater ecosystems pose significant risks to human health and natural environments. While recent studies have documented spatial and seasonal variations in As concentration and speciation across global lacustrine systems, the underlying mechanisms controlling these variations—particularly potential linkages between climate change and As geochemistry—remain poorly understood. To address this knowledge gap, we analyzed a 4,500-year sedimentary record of As from Lake Kulun-nuur in Inner Mongolia, north-central China, situated within the East Asian monsoon domain. Our multi-proxy analysis reveals that As bioaccumulation was primarily driven by fluctuating redox conditions and changes in lake trophic status. Importantly, our findings demonstrate a significant influence of the East Asian monsoon system on As enrichment patterns within Lake Kulun-nuur sediments, providing new insights into the climate-biogeochemical coupling of As dynamics in lacustrine environments over millennial timescales.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-10100

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