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

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 (<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