Evaluating drivers of environmental change in a lake sediment core: Insights from spectroscopic metrics of water-extractable organic matter and stable carbon isotopes

Applied Geochemistry
By: , and 

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Abstract

Freshwater lakes play a critical role in the global carbon cycle by storing and transforming organic matter (OM) from both terrestrial and aquatic sources. Small lakes in northern temperate regions, despite their limited surface area, disproportionately influence regional carbon budgets. Buried sediments integrate OM inputs over time and archive ecosystem responses to natural and anthropogenic disturbances. However, the direction and magnitude of recent environmental changes on sediment carbon (C) dynamics remain poorly understood. A 23-cm core was collected from a small temperate lake in northeastern USA to evaluate sediment OM content and composition over timescales relevant to historical land-use change, damming, and recovery from acid deposition. Patterns in OM burial and source contributions were revealed via elemental and isotopic analyses of bulk OM and ultraviolet-visible spectrophotometry of water-extractable organic matter (WEOM). The optical metrics expanded observations of likely OM sources beyond the information gained from bulk carbon metrics (total carbon, δ13C). The aromaticity of WEOM increased downcore, which is consistent with a shift from increased terrestrial inputs during early logging and damming activity (pre ∼1920) to more microbial-derived OM in recent surficial sediments. Future applications of WEOM optical properties as complements to traditional geochemical metrics can enhance interpretations of lake ecosystem responses recorded in lake sediments to environmental perturbations in temperate lakes.

Suggested Citation

Collins, A., Gifford, S.R., Schaller, M., Stubbins, A., Wagner, S., and Ryan, K.A., 2026, Evaluating drivers of environmental change in a lake sediment core: Insights from spectroscopic metrics of water-extractable organic matter and stable carbon isotopes: Applied Geochemistry, v. 202, 106768, 14 p., https://doi.org/10.1016/j.apgeochem.2026.106768.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Evaluating drivers of environmental change in a lake sediment core: Insights from spectroscopic metrics of water-extractable organic matter and stable carbon isotopes
Series title Applied Geochemistry
DOI 10.1016/j.apgeochem.2026.106768
Volume 202
Publication Date March 13, 2026
Year Published 2026
Language English
Publisher Elsevier
Contributing office(s) New York Water Science Center
Description 106768, 14 p.
Country United States
State New York
Other Geospatial Brant Lake
Additional publication details