Root productivity of riverine and scrub mangroves from the Shark River Slough and Taylor Slough, Everglades National Park (FCE LTER), Florida, USA, March 2024 - ongoing

Root productivity of riverine and scrub mangroves in the Florida Everglades: Mangrove root productivity in the shallow root zone (0-45 cm depth) was estimated at all Shark River (SRS-4, SRS-5, SRS-6, SRS-7) and Taylor River (TS/Ph-6, TS/Ph-7) sites in March-April 2024. Root productivity was estimated with the ingrowth core technique 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 as previously reported by Castañeda-Moya et al. (2011). Ingrowth cores were installed in holes made out with a PVC coring device (10.2 cm diameter x 45 cm length). At each site, 8 ingrowth cores were deployed vertically into the soil to a depth of 45 cm and retrieved one year later (March-April 2024). After collection, ingrowth cores were processed individually and initially rinsed with water through a 1-mm screen mesh to remove soil particles and peat moss material. Live roots were separated manually based on their buoyancy, turgor, and color (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. Root growth within each ingrowth core following one year of incubation was used to estimate annual root productivity (g m⁻² yr⁻¹) in the shallow root zone across all mangrove sites. This is an ongoing project with data collection occurring every 2-3 years after 2024. All data collection and processing were funded by FCE-LTER.

References:
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.
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.
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.

佛罗里达大沼泽地河流型与灌丛型红树林的根系生产力

2024年3—4月，针对鲨鱼河（SRS-4、SRS-5、SRS-6、SRS-7）与泰勒河（TS/Ph-6、TS/Ph-7）的全部样点，估算了其浅根区（0~45cm深度）的红树林根系生产力。
本次研究采用内生长芯法（ingrowth core technique），并沿用了此前针对该研究区发布的采样方案（Castañeda-Moya等，2011）。内生长芯（直径10.2cm×长度45cm）由合成材料（孔径3mm网布）制成，内部填充无根系的商用泥炭藓泥炭。如Castañeda-Moya等（2011）此前报道，该材料的土壤特性（容重、有机质含量、总碳与总氮含量）与本研究样地的红树林泥炭基本一致。
内生长芯被植入PVC取芯器（直径10.2cm×长度45cm）打出的孔洞中。每个样点垂直布设8个内生长芯至45cm深度，并于一年后（2024年3—4月）取回。
样品采集完成后，对每个内生长芯分别进行处理：首先用1mm筛网水洗以去除土壤颗粒与泥炭藓基质；随后依据浮力、膨压及颜色手工分离活根（Castañeda-Moya等，2011；Cormier等，2015；Medina-Calderon等，2021）。将分离得到的活根按直径划分为3个等级：细根（<2mm）、小根（2~5mm）与粗根（5~20mm）。由于采样限制（即芯样面积），直径大于20mm的根系未纳入本研究。
所有根系样品均置于60℃烘箱中烘干至恒重后称重。以一年培育期内每个内生长芯中的根系生长量为基础，估算得到所有红树林样点浅根区的年根系生产力（单位：g·m⁻²·yr⁻¹）。
本项目为长期监测研究，2024年后将每2~3年开展一次数据采集。全部数据采集与处理工作由FCE-LTER资助。

参考文献：
1. Castañeda-Moya, E., R.R. Twilley, V.H. Rivera-Monroy, B.D. Marx, C. Coronado-Molina, 及S.M.L. Ewe. 2011. 美国佛罗里达海岸大沼泽地环境梯度下红树林森林根系动态格局. 《生态系统》（Ecosystems）14: 1178-1195. https://doi.org/10.1007/s10021-011-9473-3.
2. Cormier, N., R.R. Twilley, C.K. Ewel, 及K.W. Krauss. 2015. 密克罗尼西亚高降雨区红树林森林沿氮磷梯度的细根生产力变化. 《水生生物学》（Hydrobiologia）750: 69-87.
3. Medina-Calderon, J.H., J.E. Mancera-Pineda, E. Castañeda-Moya, 及V.H. Rivera-Monroy. 2021. 淹水时长与盐度的交互作用调控加勒比海喀斯特海洋岛（哥伦比亚圣安德烈斯岛）的红树林根系动态. 《海洋科学前沿》（Frontiers in Marine Science）7: 598132. https://doi.org/10.3389/fmars.2020.598132.