Root biomass and productivity in subtropical arid mangroves from the Gulf of California

Root biomass and productivity research provide valuable information for understanding the ecological processes that occur within mangroves. The data reported by different studies on belowground biomass suggest a high spatial variability, which local factors can control. In this study, the productivity and biomass of belowground roots and pneumatophores of arid mangroves were measured along with sediment and water physical-chemical characteristics in three mangrove zones of the arid region of the Gulf of California, Mexico. Core extraction was performed to measure belowground biomass; in addition, the root productivity was determined using the ingrowth core technique, and pneumatophores were sampled at the soil level. Sediment samples were collected monthly to determine texture, pH, bulk density, moisture content, and organic matter. The flood pattern was estimated using piezometers. The study ran from June 2018 to May 2019. An average root productivity was 213.7 g m(-2).year(-1), with belowground biomass (74.05 +/- 15.2 ton.ha(-1)) and pneumatophores of 5.69 +/- 0.92 ton.ha(-1). We conclude that the amount of root biomass in arid regions is inverse to the scrub-type mangrove's structural development, which stores up to 70% more than the mangroves in tropical regions. Thus mangroves in arid regions play a role in belowground carbon storage, which depends on multiple variables simultaneously (i.e.: salinity, flood pattern, soil depth, interstitial ORP).