湿地要素中碳氮同位素特征与水文连通的关系

为探究湿地三要素中碳氮稳定同位素分布特征与湿地水文连通的关系,选取黄河三角洲恢复区和潮汐区湿地典型样点,分析样点水文连通度、植物/土壤/水体悬浮颗粒物中碳氮稳定同位素分布特征及水文连通度与碳氮稳定同位素间的关系。结果表明：恢复区芦苇（Phragmite australis）、香蒲（Typha orientalis）和盐地碱蓬（Suaeda salsa）三种植物地上及地下部分δ¹³C值存在显著差异。恢复区芦苇湿地水体悬浮颗粒物中的δ¹³C值比潮汐区芦苇湿地的更低。潮汐区三个芦苇样点土壤中δ¹³C值和δ¹⁵N值无显著差异,但与恢复区芦苇土壤存在显著差异;恢复区和潮汐区湿地区域水文连通度分别为0.0520和0.0484,不同样点间水文连通度差异较大;湿地水文连通度与植物地上部分及水体悬浮颗粒物中δ¹³C值呈显著负相关关系,说明水文连通对水体悬浮颗粒物的来源及植物的碳代谢和生长可能存在影响。

Distribution characteristics of carbon and nitrogen stable isotopes in wetland components and their relationship with wetland hydrological connectivity

To explore the relationship between hydrological connectivity of wetlands and the characteristics of stable carbon and nitrogen isotopes in wetland components (plant, soil and water), hydrological connectivity of typical sites and stable carbon and nitrogen isotopes of plant, soil and water suspended particulate (TSS) samples from the Yellow River Delta were analyzed by field investigation and laboratory analysis. There were significant differences of δ¹³C between the aboveground and underground parts of the studied three plants (Phragmite australis, Typha orientalis and Suaeda salsa) in restored wetlands. The δ¹³C in TSS of restored wetlands was lower than that in tidal wetlands. The hydrological connectivity degree of restored wetlands and tidal wetlands was 0.0520 and 0.0484, respectively. The hydrological connectivity degree among sites was quite different. There was a significant negative correlation between the hydrological connectivity degree and the content of δ¹³C in TSS and aboveground part of plants, which indicated the probable effect of hydrological connectivity on the source of suspended particulate matter in water bodies, as well as the carbon metabolism in plant and plant growth.