Original Research ARTICLE
Does stream water composition at Sleepers River in Vermont reflect dynamic changes in soils during recovery from acidification?
- 1University of Vermont, United States
- 2United States Geological Survey, United States
- 3Middlebury College, United States
Stream water pH and composition are widely used to monitor ongoing recovery from the deposition of strong anthropogenic acids in many forested headwater catchments in the northeastern US. However, stream water composition is a function of highly complex and coupled processes, flowpaths, and variations in soil and bedrock composition. Spatial heterogeneity is especially pronounced in headwater catchments with steep topography, potentially limiting stream water composition as an indicator of changes in critical zone (CZ) dynamics during system recovery. To investigate the link between catchment characteristics, landscape position, and stream water composition we used long-term data (1991-2015) from the Sleepers River Research Watershed (SRRW) in northeastern Vermont. We investigated trends with time in stream water and trends with time, depth, and landscape position (upslope, midslope, and riparian zone) in groundwater (GW) and soil solution. We further determined soil elemental composition and mineralogy on archived (1996) and modern (2017) soil samples to assess changes in composition with time. SRRW is inherently well-buffered by calcite in bedrock and till, but soils had become acidified and are now recovering from acidification. Although base cations, especially Ca, decrease progressively with time in GW, riparian soils have become more enriched in Ca, due to a mixture of lateral and vertical transfers. At the same time stream water Ca fluxes increased over the past two decades, likely due to the leaching of (transient) legacy Ca from riparian zones and increased water fluxes. The stream water response therefore reflects the dynamic changes in soil chemistry, flow routing and water inputs.
Keywords: Weathering, Recovery, acid impact, Sleepers River, Carbonate
Received: 27 Jul 2018;
Accepted: 18 Dec 2018.
Edited by:Samuel Abiven, University of Zurich, Switzerland
Reviewed by:Patrick Durand, INRA Centre Bretagne-Normandie, France
Lei Duan, Tsinghua University, China
Copyright: © 2018 Armfield, Perdrial, Gagnon, Ehrenkranz, Perdrial, Cincotta, Ross, Shanley, Underwood and Ryan. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Julia Perdrial, University of Vermont, Burlington, United States, Julia.Perdrial@uvm.edu