水盐环境对黄河口淡水湿地土壤碳、氮、磷生态化学计量特征的影响

碳(C)、氮(N)、磷(P)是土壤重要的营养元素，其生态化学计量特征可以反映土壤供肥能力和质量状况，在揭示生态系统稳态机制中具有重要作用.水盐环境对河口湿地生态化学计量特征具有重要影响，但土壤C、 N、 P生态化学计量特征对水盐环境变化的响应仍不清楚.以黄河口湿地为研究对象，采用土柱移位培养法，将淡水湿地土壤分别移位至不同潮滩部位(高潮滩、中潮滩和低潮滩)的盐沼湿地，研究水盐环境对C、 N、 P生态化学计量特征的影响.结果表明，移位23个月后，淡水湿地土壤含水量(SWC)和电导率(EC)与C、 N、 P生态化学计量特征均发生了不同程度的变化.土壤SWC在高潮滩和中潮滩降低(P<0.05),在低潮滩升高(P<0.05); EC在3种潮滩上均有不同程度的升高(P<0.05).土壤有机碳(TOC)和全氮(TN)在高潮滩显著降低(P<0.05),全磷(TP)则在中潮滩和高潮滩显著降低(P<0.05); C∶N在高潮滩和中潮滩及C∶P和N∶P在高潮滩显著降低(P<0.05); C、 N、 P生态化学计量比在低潮滩变化均不显著(P>0.05).水盐环境主要...

Effects of Water-salt Environment on Freshwater Wetland Soil C, N, and P Ecological Stoichiometric Characteristics in the Yellow River Estuary Wetland

Carbon (C), nitrogen (N), and phosphorus (P) are important nutrients, and their ecological stoichiometric characteristics can reflect the quality and fertility capacity of soil, which is critical to understanding the stable mechanisms of estuarine wetland ecosystems. Under global changes, the increase in salinity and flooding caused by sea level rise will lead to changes in biogeochemical processes in estuarine wetlands, which is expected to affect the ecological stoichiometric characteristics of soil C, N, and P and ultimately interfere with the stability of wetland ecosystems. However, it remains unclear how the C, N, and P ecological stoichiometric characteristics respond to the water-salt environment in estuarine wetlands. We differentiated changes in the C, N, and P ecological stoichiometric characteristics through an ex-situ culture experiment for 23 months in the Yellow River Estuary Wetland. The five sites with distinct tidal hydrology were selected to manipulate translocation of soil cores from the freshwater marsh to high-, middle-, and low-tidal flats in June 2019. The results showed that soil water content (SWC); electrical conductivity (EC); and C, N, and P ecological stoichiometric characteristics of freshwater marsh soil significantly changed after translocation for 23 months. SWC decreased on the high- and middle-tidal flats (P<0.05) and increased on the low-tidal flat (P<0.05). EC increased to different degrees on all three tidal flats (P<0.05). Soil total organic carbon (TOC) and total nitrogen (TN) were significantly lower on the high-tidal flat (P<0.05), whereas total phosphorus (TP) was significantly lower on the middle- and high-tidal flats (P<0.05). C:N was decreased on the high- and middle-tidal flats (P<0.05); C:P and N:P were lower on the high-tidal flat; and all C, N, and P ecological stoichiometric characteristics showed no change on the low-tidal flat (P>0.05). Pearson''s analysis showed that the ecological stoichiometric characteristics of C, N, and P were related to some properties of soil over the culture sites. The PLS-SEM model showed that the water-salt environment had different effects on soil C:N, C:P, and N:P through the main pathways of negative effects on soil TOC and TP. The results suggest that sea level rise may impact the C, N, and P ecological stoichiometric characteristics in freshwater marsh soil, resulting in some possible changes in the nutrient cycles of estuarine wetlands.