Sediment accumulation and mineralization in mangrove forests, Jiulongjiang Estuary, China

Rates of sediment accumulation and microbial mineralisation were examined at 3 Kandelia candel forests.Within each forest, measurements for species (6)identification, basal area, and diameter at breast height were taken. All sediment samples were taken within the same 100-200m2 plots. Root (live and dead) biomass was estimated. Triplicate surface samples were taken for percent sand, silt and clay, and water content. Soild-phase concentrations of TOC, TN, Fe and S (all % dry weights), Mn and TP (ug g-1), and C:N (molar) were determined from 2-3 cores from each site. Salinity was measured on filtered water.Mass sediment accumulation rates were determined from gamma spectrometric measurements of 210Pb, 226Ra and 137Cs.Sediment samples were taken in summer (July 2002) and autumn (September 2003).Gas fluxes (CO2 and O2) were measured across the sediment-air interface. Rates of net dissolved Fe, Mn and ammonium releases from sediments and denitrification, nitrogen fixation, methane and nitrous oxide fluxes were also measured. To measure rates of sediment accumulation and microbial mineralisation in Kandeli candel mangrove forests of southern China

本研究针对3处秋茄（Kandelia candel）红树林的沉积物沉积速率与微生物矿化速率开展了测定分析。在每处红树林样地内，均针对6个物种开展了鉴定、基盖度及胸径的测定工作。所有沉积物样品均采集自统一的100-200m²样方内。研究人员对活根与死根的生物量进行了估算。采集三份平行表层沉积物样品，用于测定砂粒、粉粒、黏粒占比及含水率。从每个样地的2-3根沉积物岩芯中，测定了总有机碳（Total Organic Carbon，TOC）、总氮（Total Nitrogen，TN）、铁（Fe）、硫（S）（均以干重百分比计）、锰（Mn）、总磷（Total Phosphorus，TP）（单位为μg g⁻¹）的固相浓度，以及碳氮摩尔比（C:N，摩尔比）。对过滤后的水体测定了盐度。通过对²¹⁰Pb、²²⁶Ra及¹³⁷Cs的γ能谱测量，计算得到沉积物的质量沉积速率。沉积物样品分别于2002年夏季（7月）与2003年秋季（9月）采集。测定了沉积物-空气界面的CO₂与O₂气体通量。同时还测定了沉积物溶解性铁、锰与铵态氮的净释放速率，以及反硝化作用、固氮作用、甲烷与一氧化二氮的通量。本研究旨在测定中国南部秋茄红树林的沉积物沉积速率与微生物矿化速率。