植被演替对杭州湾南岸盐沼物质循环的影响

本研究选择杭州湾庵东浅滩作为研究区,选取盐沼区三个不同植被带进行柱状样的采集,通过测量沉积物的粒度、沉积速率、碳氮含量(有机碳、总碳、总氮、碳氮比)等参数,系统分析研究区盐沼湿地植被演替对盐沼物质循环产生的影响。研究结果发现,不同植被覆盖下沉积物粒径差异显著,沿海向陆逐渐变细;沉积速率从海三棱藨草滩、互花米草滩、植被交错区依次递减;总碳、总氮、有机碳含量特征为互花米草滩植被交错区海三棱藨草滩,碳氮比介于6～9,有机碳以海源物质为主;通过计算,发现有机碳埋藏速率为互花米草159 g/(m2·a)]海三棱藨草140 g/(m2·a)]植被交错区119 g/(m2·a)]。从整体上来看,杭州湾南岸盐沼从海三棱藨草群落向互花米草群落演替时,沉积物颗粒发生细化,沉积速率有所变化,而总碳、有机碳、总氮含量增加,盐沼有机碳埋藏速率增加。

Impact of vegetation succession on salt marsh material circu-lation in Southern Hangzhou Bay

Andong Shoal, Southern Hangzhou Bay was selected as the study area for collecting sediment cores along three saltmarsh vegetation zones. Based on the measurements of particle size, deposition rate, carbon and nitrogen contentstotal organic carbon (TOC), total carbon (TC), total nitrogen (TN), carbon to nitrogen ratio (C/N)], the impact of vegetation succession on salt marsh material circulation was systematically analyzed. Results show that the particle size within different vegetation zones was significantly different, gradually becoming finer from seaward to landward. The deposition rate decreased from the Scripus mariqueter zone and Spantina alterniflora zone to the ecotone zone. The TC, TN, and TOC contents decreased from the S. alterniflora zone to the ecotone zone and then to the S. mariqueter zone. The carbon to nitrogen ratio ranged between 6 and 9; thus, the organic carbon was mainly sea sourced. The burial rate of TOC was estimated to decrease from the S. alterniflora zone (159 g/(m²·a) to the S. mariqueter zone (140 g/(m²·a)) and then to the ecotone zone (119 g/(m²·a)). Overall, when the saltmarsh on the south bank of the Hangzhou Bay succeeded from the S. mariqueter zone to the S. alterniflora zone, the sediment particles were refined and the deposition rate changed. The TC, TOC, and TC contents and the rate of organic carbon burial increased.