Short-Term Groundwater Level Fluctuations Drive Subsurface Redox Variability

• DOI: 10.1021/acs.est.4c01115
• Publication Date: 2024-08-08T16:17:56Z
• Authors: Fausto Machado-Silva; Michael N. Weintraub; Nicholas D. Ward; Kennedy O. Doro; Peter J. Regier; Solomon Ehosioke; Shan Pushpajom Th...; Roberta B. Peixoto; Leticia Sandoval; Inke Forbrich; Kenneth M. Kemner; Edward J. O’Loughlin; Lucie Stetten; Trisha Spanbauer; Thomas B. Bridgeman; Teri O’Meara; Kenton A. Rod; Kaizad Patel; Nate G. McDowell; J. Patrick Megonigal; Roy L. Rich; Vanessa L Bailey
• Keywords: Biogeochemical Cycle; Biogeochemistry

As global change processes modify the extent and functions of terrestrial–aquatic interfaces, variability critical dynamic transitional zones between wetlands uplands increases. However, it is still unclear how fluctuating water levels at these boundaries alter groundwater biogeochemical cycling. Here, we used high-temporal resolution data along gradients from to during freshwater coastal areas capture spatiotemporal patterns redox potential (Eh). We observed that topography influences Eh higher in than wetlands; however, high within TAI challenged establishment distinct zonation. Declining generally decreased Eh, but most locations exhibited significant variability, which associated with rare instances short-term level fluctuations, introducing oxygen. The Eh-oxygen relationship showed hysteresis patterns, reflecting poising capacity maintaining more oxidizing states longer dissolved oxygen presence. Surprisingly, frequent uplands. infer occasional entering specific wetland–upland acts as control points. High-resolution can such yet instances, supporting redox-informed models advancing predictability climate feedback.