Increasing Rates of Carbon Burial in Southwest Florida Coastal Wetlands

Authors

Joshua L. Breithaupt, University of Central Florida
Joseph M. Smoak, University of South FloridaFollow
Thomas S. Bianchi, University of Florida
Derrick R. Vaughn, University of Florida
Christian J. Sanders, Southern Cross University
Kara R. Radabaugh, Florida Fish and Wildlife Conservation Commission
Michael J. Osland, U.S. Geological Survey
Laura C. Feher, U.S. Geological Survey
James C. Lynch, U.S. National Park Service
Donald R. Cahoon, U.S. Geological Survey
Gordon H. Anderson, U.S. Geological Survey
Kevin R.T. Whelan, U.S. National Park Service
Brad E. Rosenheim, University of South FloridaFollow
Ryan P. Moyer, Florida Fish and Wildlife Conservation Commission
Lisa G. Chambers, University of Central Florida

Document Type

Article

Publication Date

2020

Keywords

carbon burial, blue carbon, lignin, Pb-210, Cs-137, surface marker horizons

Digital Object Identifier (DOI)

https://doi.org/10.1029/2019JG005349

Abstract

Rates of organic carbon (OC) burial in some coastal wetlands appear to be greater in recent years than they were in the past. Possible explanations include ongoing mineralization of older OC or the influence of an unaccounted-for artifact of the methods used to measure burial rates. Alternatively, the trend may represent real acceleration in OC burial. We quantified OC burial rates of mangrove and coastal freshwater marshes in southwest Florida through a comparison of rates derived from ²¹⁰Pb, ¹³⁷Cs, and surface marker horizons. Age/depth profiles of lignin: OC were used to assess whether down-core remineralization had depleted the OC pool relative to lignin, and lignin phenols were used to quantify the variability of lignin degradation. Over the past 120 years, OC burial rates at seven sites increased by factors ranging from 1.4 to 6.2. We propose that these increases represent net acceleration. Change in relative sea-level rise is the most likely large-scale driver of acceleration, and sediment deposition from large storms can contribute to periodic increases. Mangrove sites had higher OC and lignin burial rates than marsh sites, indicating inherent differences in OC burial factors between the two habitat types. The higher OC burial rates in mangrove soils mean that their encroachment into coastal freshwater marshes has the potential to increase burial rates in those locations even more than might be expected from the acceleration trends. Regionally, these findings suggest that burial represents a substantially growing proportion of the coastal wetland carbon budget.

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Terms of use for work posted in Scholar Commons.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

Journal of Geophysical Research: Biogeosciences, v. 125, issue 2, art. e2019JG005349

©2020. American Geophysical Union. All Rights Reserved.

Scholar Commons Citation

Breithaupt, Joshua L.; Smoak, Joseph M.; Bianchi, Thomas S.; Vaughn, Derrick R.; Sanders, Christian J.; Radabaugh, Kara R.; Osland, Michael J.; Feher, Laura C.; Lynch, James C.; Cahoon, Donald R.; Anderson, Gordon H.; Whelan, Kevin R.T.; Rosenheim, Brad E.; Moyer, Ryan P.; and Chambers, Lisa G., "Increasing Rates of Carbon Burial in Southwest Florida Coastal Wetlands" (2020). Marine Science Faculty Publications. 2417.
https://digitalcommons.usf.edu/msc_facpub/2417