24-12 Tracking Anthropogenic Influence in Lake Wononscopomuc, Connecticut

Session: Lake Sedimentary Records of Past Climate and Environment (Posters)

Poster Booth No.: 40

Presenting Author:

Mia Sanchez

Authors:

Sanchez, Mia J.¹, Martini, Anna M.², Jones, David S.³, Ku, Timothy C. W.⁴, Chavez, Liam⁵, Collazo, Anthony⁶, Greaney, Molly⁷, Higgins, Riley⁸, Kaur, Divyanour⁹, Lebolt, Jesse¹⁰, McCully, Lillianne¹¹, Salas Romero, Oscar¹², Teske, Kathryn¹³, Linck, Mabel¹⁴, Weisgerber, Drew¹⁵

(1) Amherst College, Amherst, , (2) Amherst College, Geology and Environmental Studies, Amherst, , (3) Amherst College, Amherst, , (4) Wesleyan University Earth & Environmental Sciences, Middletown, , (5) University of Texas at El Paso, El Paso, , (6) University of Puerto Rico at Mayaguez, Mayaguez, , (7) Amherst College, Amherst, , (8) College of Wooster, Wooster, , (9) Rutgers University, New Brunswick, , (10) Amherst College, Amherst, , (11) Beloit College, Beloit, , (12) Highline College, Des Moines, , (13) Macalester College, St. Paul, , (14) Amherst College, Amherst, , (15) Amherst College, Amherst, ,

Abstract:

Lake sediments record local and regional environmental conditions, enabling the study of human-driven change. This study uses a multiproxy approach to identify and date anthropogenic influence in the sediments of Lake Wononscopomuc, a deep (30 m) temperate lake near Salisbury in northwestern Connecticut. Four sediment cores (1 freeze core, 2 gravity cores, 1 piston core) collected during the summer of 2025 were analyzed for organic matter content (% LOI), elemental composition (pXRF), Hg content (CV-AAS), C/N ratios (EA), and pore water ion concentrations (IC and ICP-OES). Modern lake conditions were characterized using temperature and conductivity measurements and water samples collected from multiple basins. Chronologies for all cores were developed by correlating Hg profiles to a previously collected core dated using ²¹⁰Pb and with supplementary ¹⁴C ages from plant macrofossils. Modeled ages support a continuous sedimentary record from ~1600 BCE to 2025 CE. 

Proxy analyses show three dominant phases of human activity in the watershed, interpreted as Pre-European Settlement, Pre-Industrial, and Post-Industrial. During the Pre-European period, organic matter (% LOI), nutrient (N, P, S), and clastic input proxies (Al, Ti) are relatively stable with several perturbations tentatively interpreted as storm or wildfire events. The Pre-Industrial is characterized by increased clastic input and reduced organic matter, consistent with enhanced erosion due to land clearing. The Post-Industrial period includes elevated trace metal concentrations (Hg, Pb, As, Zn) and high nutrient levels, indicating cultural eutrophication. 

These results indicate that anthropogenic activity has measurably altered Lake Wononscopomuc, leaving behind lasting geochemical signals preserved in the sedimentary record. Sources of geochemical changes are thought to reflect both regional activity, such as land use changes and industrial activity, as well as environmental trends measurable on a global scale, illustrating the complexity of determining a Holocene-Anthropocene geologic boundary. 

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