Sun Zhigao, Mou Xiaojie, Sun Wanlong
Institute of Geography, Fujian Normal University, Fuzhou 350007, PR China; Key Laboratory of Humid Subtropical Eco-geographical Process (Fujian Normal University), Ministry of Education, Fuzhou 350007, PR China.
Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130012, PR China.
Chemosphere. 2016 Mar;147:163-72. doi: 10.1016/j.chemosphere.2015.12.079. Epub 2016 Jan 6.
The concentrations of C, Pb, Cr, Cu, Zn, Ni and Mn were determined in decomposing litters of Phragmites australis, Suaeda salsa and Suaeda glauca in three plots of the Yellow River estuary to investigate the variations of metal stocks. Results showed that the decomposition rates significantly differed among species (p < 0.05), in the order of S. glauca (0.002010 d(-1)) > S. salsa (0.000814 d(-1)) > P. australis (0.000766 d(-1)). The concentrations of Cu and Zn in the three litters (particularly S. glauca) generally showed increasing tendency, while those of Pb, Cr, Ni and Mn exhibited different temporal variations. Compared to P. australis and S. salsa, the key mechanisms affecting the variation of metals in S. glauca might be more complex. In most periods, Pb stocks in P. australis, S. salsa and S. glauca, Zn stocks in S. salsa and S. glauca, and Cr, Ni and Mn stocks in P. australis and S. glauca were lower than the initial ones, implying that release exceeded incorporation. Comparatively, Zn stocks in P. australis, Cr, Ni and Mn stocks in S. salsa and in particular Cu stocks in the three litters were generally positive, evidencing incorporation of these metals in most sampling times. The three halophytes were particular efficient in binding Cu and releasing Pb, indicating that the potential eco-toxic risk of Pb exposure might be serious. This study emphasized the strong influences of key biotic (litter types, carbon/metal ratios and activities of microbial organisms) and abiotic variables (salinity, sediment resuspension induced by tidal inundation and passive sorption onto recalcitrant organic fractions) on metal cycling in coastal marshes of the Yellow River estuary.
为研究金属储量的变化情况，测定了黄河口三个样地中芦苇、碱蓬和盐地碱蓬分解凋落物中碳、铅、铬、铜、锌、镍和锰的浓度。结果表明，不同物种的分解速率存在显著差异（p < 0.05），顺序为盐地碱蓬（0.002010 d(-1)）>碱蓬（0.000814 d(-1)）>芦苇（0.000766 d(-1)）。三种凋落物中铜和锌的浓度（尤其是盐地碱蓬）总体呈上升趋势，而铅、铬、镍和锰的浓度则呈现出不同的时间变化。与芦苇和碱蓬相比，影响盐地碱蓬中金属变化的关键机制可能更为复杂。在大多数时期，芦苇、碱蓬和盐地碱蓬中的铅储量、碱蓬和盐地碱蓬中的锌储量以及芦苇和盐地碱蓬中的铬、镍和锰储量均低于初始值，这意味着释放量超过了吸收量。相比之下，芦苇中的锌储量、碱蓬中的铬、镍和锰储量，特别是三种凋落物中的铜储量总体呈正值，表明在大多数采样时间这些金属被吸收。这三种盐生植物在结合铜和释放铅方面特别有效，表明铅暴露的潜在生态毒性风险可能很严重。本研究强调了关键生物变量（凋落物类型、碳/金属比和微生物活性）和非生物变量（盐度、潮汐淹没引起的沉积物再悬浮以及对难降解有机组分的被动吸附）对黄河口滨海湿地金属循环的强烈影响。
