Distribution and composition of redox-active species and dissolved organic carbon in Arctic lacustrine porewaters

Abstract
The interaction between redox-active species and dissolved organic carbon (DOC) is crucial in driving lacustrine benthic microbial processes. In lacustrine porewaters, many redox-active species exist in their reduced form, while DOC acts as a substrate and an electron acceptor. Understanding the types and abundance of redox-active species in porewaters along with their complementary DOC substrate is pivotal for gaining insights into benthic processes, particularly in regions susceptible to climate change. We report the in-situ measurement of redox-active species in sediment porewaters, alongside the ex-situ measurement of DOC extracted from cores collected from two Arctic lakes (Toolik and Fog 1). Fe2+ was abundantly detected below 4 cm of the sediment-water interface in all cores and was inversely related to dissolved O2. Additionally, two distinct Fe(III)-complexes were identified. DOC ranged in the order of 10s of mg/L and either remained stable or increased with depth. A comparison between Toolik and Fog 1 lakes revealed a higher accumulation of Fe2+ and DOC in the latter. This study marks the first of its kind to assess spatial distributions of redox-active species and DOC as a function of depth from multiple sites in Arctic lacustrine porewaters.
Description
This article was originally published in Arctic, Antarctic, and Alpine Research. The version of record is available at: https://doi.org/10.1080/15230430.2024.2371534 © 2024 The Author(s). Published with license by Taylor & Francis Group, LLC. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. The terms on which this article has been published allow the posting of the Accepted Manuscript in a repository by the author(s) or with their consent.
Keywords
Arctic, porewater, dissolved organic carbon (DOC), iron, microelectrode, climate action, life on land
Citation
Xin, Danhui, Jeffrey M. Hudson, Anthony Sigman-Lowery, and Yu-Ping Chin. 2024. “Distribution and Composition of Redox-Active Species and Dissolved Organic Carbon in Arctic Lacustrine Porewaters.” Arctic, Antarctic, and Alpine Research 56 (1). doi:10.1080/15230430.2024.2371534.