Consequences of a Changing Cryosphere for Arctic Lake Biogeochemistry

The fate of heavy metals and nutrients melting out of the cryosphere into aquatic systems is not well understood. To address this, we measured heavy metals and nutrients in the water and sediment of four glacially fed (GF) and four snow and groundwater-fed (SF) lakes in West Greenland during the summer of 2023. GF lakes had significantly higher (133%) water concentrations of nutrients (TP, NO₃^-, NH₄⁺) and metals (Cd, Pb, Cr, Co, Ni, Al, Fe, Cu, Zn) compared to nearby SF lakes. This pattern was reflected in the sediments, where metal concentrations were generally higher in GF lakes compared to SF lakes. However, a few metals, notably Hg and Pb, were higher in SF compared to GF sediment. In all lakes, metals have generally increased over time. In one GF lake, we quantified inputs and outputs of metals and nutrients, and found that loads declined by an average of 69% from the lake inlet to outlet, suggesting the lake was a sink for these materials. Our results highlight that GF lakes in our study region are elevated in nutrients and metals compared to nearby SF lakes, indicating that the source of these materials is likely glacial meltwater. These results also show that GF lakes have the ability to sequester a high percent of the nutrients and metals flowing into the lakes; however, as meltwater fluxes increase due to climate change, the ability of these lakes to remain sinks is an open question.  

Primary Presenter: Ansley Grider, University of Maine (ansley.grider@maine.edu)

Authors:

Ansley Grider, University of Maine and Climate Change Institute  (ansley.grider@maine.edu)

Jasmine Saros, University of Maine and Climate Change Institute  (jasmine.saros@maine.edu)

Robert Northington, Elizabethtown College  (northingtonr@etown.edu)

Jacob Yde, Western Norway University of Applied Sciences  (Jacob.Yde@hvl.no)