The role of the upper tidal estuary in wetland blue carbon storage and flux

Ken W. Krauss*, Gregory B. Noe, Jamie A. Duberstein, William H. Conner, Camille L. Stagg, Nicole Cormier, Miriam C. Jones, Christopher E. Bernhardt, B. Graeme Lockaby, Andrew S. From, Thomas W. Doyle, Richard H. Day, Scott H. Ensign, Katherine N. Pierfelice, Cliff R. Hupp, Alex T. Chow, Julie L. Whitbeck

*Corresponding author for this work

    Research output: Contribution to journalArticle

    25 Citations (Scopus)

    Abstract

    Carbon (C) standing stocks, C mass balance, and soil C burial in tidal freshwater forested wetlands (TFFW) and TFFW transitioning to low-salinity marshes along the upper estuary are not typically included in “blue carbon” accounting, but may represent a significant C sink. Results from two salinity transects along the tidal Waccamaw and Savannah rivers of the U.S. Atlantic Coast show that total C standing stocks were 322–1,264 Mg C/ha among all sites, generally shifting to greater soil storage as salinity increased. Carbon mass balance inputs (litterfall, woody growth, herbaceous growth, root growth, and surface accumulation) minus C outputs (surface litter and root decomposition, gaseous C) over a period of up to 11 years were 340–900 g C · m −2 · year −1. Soil C burial was variable (7–337 g C · m −2 · year −1), and lateral C export was estimated as C mass balance minus soil C burial as 267–849 g C · m −2 · year −1. This represents a large amount of C export to support aquatic biogeochemical transformations. Despite reduced C persistence within emergent vegetation, decomposition of organic matter, and higher lateral C export, total C storage increased as forests converted to marsh with salinization. These tidal river wetlands exhibited high N mineralization in salinity-stressed forested sites and considerable P mineralization in low-salinity marshes. Large C standing stocks and rates of C sequestration suggest that TFFW and oligohaline marshes are considerably important globally to coastal C dynamics and in facilitating energy transformations in areas of the world in which they occur.

    Original languageEnglish
    Pages (from-to)817-839
    Number of pages23
    JournalGlobal Biogeochemical Cycles
    Volume32
    Issue number5
    DOIs
    Publication statusPublished - May 2018

    Keywords

    • Wetland
    • Swamp forest
    • Tide
    • Carbon budget
    • Marsh

    Cite this