Belowground decomposition of mangrove roots in Florida coastal everglades

Authors

Nicole Poret, Department of Biology, University of Louisiana at LafayetteFollow
Robert R. Twilley, Wetland Biogeochemistry Institute, Department of Oceanography and Coastal Sciences, Louisiana State UniversityFollow
Victor H. Rivera-Monroy, Wetland Biogeochemistry Institute, Department of Oceanography and Coastal Sciences, Louisiana State UniversityFollow
Carlos Coronado-Molina, South Florida Water Management DistrictFollow

Abstract

Mangrove root decomposition rates were measured by distributing mesh bags containing fine root material across six sites with different soil fertility and hydroperiod to compare ambient differences to substrate quality. Roots from a site with lower soil phosphorus concentration were used as a reference and compared to ambient roots at five other sites with increased phosphorus concentration. Four mesh bags of each root type (ambient versus reference), separated into four 10-cm replicate intervals, were buried up to 42 cm depth at each site and incubated for 250 d (initiation in May 2004). Mass loss of ambient mangrove roots was significant at all study sites and ranged from 17% to 54%; there was no significant difference with depth at any one site. Reference decomposition constants (−k) ranged from 0.0012 to 0.0018 d⁻¹ among Taylor Slough sites compared to 0.0023–0.0028 d⁻¹ among Shark River sites, indicating slower decomposition rates associated with lower soil phosphorous and longer flood duration. Reference roots had similar decomposition rates as ambient roots in four of the six sites, and there were no significant correlations between indices of root substrate quality and decomposition rates. Among these distinct landscape gradients of south Florida mangroves, soil environmental conditions have a greater effect on belowground root decomposition than root substrate quality.

Comments

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Recommended Citation

Poret, N., R.R. Twilley, V.H. Rivera-Monroy, C. Coronado-Molina. 2007. Belowground Decomposition of Mangrove Roots in Florida Coastal Everglades. Estuaries and Coasts. 30(3): 491-496.