Abstract
Salt marshes are hotspots of nutrient processing and carbon sequestration. So far, studies addressing spatiotemporal variability in and drivers of salt marsh biogeochemical function, carbon storage and resilience have focused on ocean-driven surface hydrologic influences, neglecting effects of terrestrial hydrology through subsurface connections. Here we evaluate drivers of salt marsh redox potential, a proxy for biogeochemical state, through wavelet analyses and information theory using data from seven marshes. The results point to terrestrial groundwater level as a dominant control on redox variability across all sites. Because redox is a key driver of biogeochemical processes, and specifically oxidation of organic matter that sequesters carbon and maintains marsh elevation, these terrestrial influences are critical to understanding marsh function and evolution. The newly identified links between onshore groundwater levels and marsh redox conditions shift the traditional paradigm and suggest that terrestrial hydrology is a primary control on salt marsh carbon sequestration potential and resilience.
| Original language | English |
|---|---|
| Pages (from-to) | 157-166 |
| Number of pages | 10 |
| Journal | Nature Water |
| Volume | 3 |
| Issue number | 2 |
| DOIs | |
| State | Published - Feb 2025 |
Funding
J.A.G. was supported by WHOI’s Ocean Vision Program. E.G. received support from funds through CDFW Climate Change Impacts on Wildlife and from a COAST Grant Development Program. B.A. was supported by the Watershed Function Science Focus Area project at Lawrence Berkeley National Laboratory funded by the US Department of Energy (DOE), Office of Science, Biological and Environmental Research under contract no. DE-AC02-05CH11231. H.A.M., D.P. and the CZN data collection were supported by the National Science Foundation Coastal Critical Zone Collaborative Network (EAR 2012484). Funding for SMARTX was provided by the US Department of Energy, Office of Science, Office of Biological and Environmental Research, Environmental System Science program under awards DE-SC0014413, DE-SC0019110 and DE-SC0021112, and the Smithsonian Institution. The SMARTX automated redox system was designed by R. Rich. TEMPEST monitoring data were supported through the Field, Measurements, and Experiments (FME) component of the Coastal Observations, Mechanisms, and Predictions Across Systems and Scales (COMPASS) programme (https://compass.pnnl.gov/). COMPASS-FME is a multiinstitutional project supported by the US Department of Energy, Office of Science, Biological and Environmental Research as part of the Environmental System Science Program. E.H., M.J.B. and data collection at Wax Lake Delta were supported by a grant to E.H. through the Early Career Research Program through the DOE Office of Science Biological and Environmental Research programme. I.F. and data collection at PIE LTER were supported by DOE award DE-SC0022108. Notice: This paper has been authored in part by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US DOE. The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this paper, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (https://www.energy.gov/doe-public-access-plan).