DOI: 10.6073/pasta/c6db1ad516ef3688b0eec9ab9b0a35e3
title: Patterns of root biomass, productivity, turnover, and decomposition in riverine and scrub mangroves in the Everglades, Florida, USA, immediate-post-Irma, 2018-2019, and post-Irma, 2023-2024

description: Mangrove root biomass, productivity, and decomposition in the shallow (0-45 cm depth) root zone were estimated at Florida Coastal Everglades Long Term Ecological Research (FCE-LTER) Program Shark River (SRS4, SRS5, SRS6, SRS7) and Taylor River (TS/Ph6b, TS/Ph7b) mangrove sites during 2018-2019 and 2023-2024 following Hurricane Irma’s impacts in September 2017. Root biomass was estimated at all sites during both immediate-post-Irma (March 2018) and post-Irma (February-May 2023) periods with a PVC coring device (10.2 cm diameter x 45 cm length) using the same sampling protocol previously published for the study area (Castañeda-Moya et al. 2011). After collection, root cores were processed individually and initially rinsed with water through a 1-mm screen mesh to remove soil particles. Roots were separated manually based on their buoyancy, turgor, and color into biomass (live) and necromass (dead) components (Castañeda-Moya et al. 2011; Cormier et al. 2015; Medina-Calderon et al. 2021). Live roots were further sorted into three size diameter classes including fine (&lt;2 mm), small (2-5 mm), and coarse (5-20 mm). Roots greater than 20 mm in diameter were not included in this study due to sampling limitations (i.e., core area). All root samples were oven-dried at 60°C to a constant mass and weighed to estimate root biomass and necromass (g m-2). Root productivity was estimated with the ingrowth core technique (Vogt et al., 1998) during both the immediate-post-Irma and post-Irma periods using the same sampling protocol previously published for the study area (Castañeda-Moya et al. 2011). Ingrowth cores (10.2 cm diameter x 45 cm length) were made of synthetic material (3 mm mesh) and filled with root-free commercial sphagnum peat moss. This material has similar soil properties (i.e., bulk density, organic matter content, total C and N) as mangrove peat in our study sites. Ingrowth cores were installed in each of the cored holes formed during sampling of root biomass. At each site, ingrowth cores were deployed vertically into the soil to a depth of 45 cm and retrieved one year later (March 2019, and March-April 2024). Root growth within the ingrowth core was used to estimate annual root production (g m-2 yr-1) in the shallow root zone across all mangrove sites. After collection, ingrowth cores were processed individually using the same protocol as for root biomass. Turnover rate of fine roots in the shallow root zone was calculated as root productivity divided by root biomass at all sites. Root decomposition experiments were initiated in January 2018 at each site using the mesh bag (1-mm2; 10 x 40 cm) technique. Live roots were initially extracted by coring, rinsed with water to remove soil particles, air-dried for 24 hours, and then placed inside bags. Mesh bags were divided into two 20-cm depth sections (0-20 cm, 20-40 cm), each one containing 5-6 g of fresh root material from each site with an equal mixture of three root size classes: 1-4, 4-8, and 8-12 mm. A total of 18 bags were buried in the soil within two sampling points at each site. Bags were retrieved from sampling points after 190, 358, and 541 days of incubation, oven-dried at 60°C to a constant mass and weighed to estimate root mass loss. Decay rates of mangrove roots were calculated for all sites using the negative exponential model, Mt = M0 e-kt, where Mt = the percentage of dry root mass remaining at time t, M0 = original dry root mass, and k = decay constant (Nye 1961; Olson 1963). Data collection for this package is complete.
 
 See also related data packages:
 Data source for post-Irma period (2023-2024) root-production values (https://portal.edirepository.org/nis/mapbrowse?packageid=knb-lter-fce.1269.3)
 Pre-Wilma (i.e., pre-hurricane period) root data (https://portal.edirepository.org/nis/mapbrowse?scope=knb-lter-fce&identifier=1277).
 Post-Wilma root data (https://portal.edirepository.org/nis/mapbrowse?scope=knb-lter-fce&identifier=1286)
 
 
 
 References:
 Medina-Calderon, J.H., J.E. Mancera-Pineda, E. Castañeda-Moya, and V.H. Rivera-Monroy. 2021. Hydroperiod and salinity interactions control mangrove root dynamics in a karstic oceanic island in the Caribbean Sea (San Andres, Colombia). Frontiers in Marine Science 7: 598132. https://doi.org/10.3389/fmars.2020.598132.
 Cormier, N., R.R. Twilley, C.K. Ewel, and K.W. Krauss. 2015. Fine root productivity varies along nitrogen and phosphorus gradients in high-rainfall mangrove forests of Micronesia. Hydrobiologia 750, 69-87.
 Castañeda-Moya, E., R.R. Twilley, V.H. Rivera-Monroy, B.D. Marx, C. Coronado-Molina, and S.M.L. Ewe. 2011. Patterns of root dynamics in mangrove forests along environmental gradients in the Florida Coastal Everglades, USA. Ecosystems 14: 1178-1195. https://doi.org/10.1007/s10021-011-9473-3.
 Vogt, K.A., D.J. Vogt, J. Bloomfield. 1998. Analysis of some direct and indirect methods for estimating root biomass and production of forests at an ecosystem level. Plant Soil 200:71–89.
 Olson, J. S. 1963. Energy storage and the balance of producers and decomposers in ecological systems. Ecology 44: 322-331
 Nye, P. H. 1961. Organic matter and nutrient cycles under moist tropical forest. Plant and Soil 13: 333-346.