Isotopic evidence for soil water sources and reciprocal movement in a semi-arid degraded wetland:Implications for wetland restoration  

作　　者：Yuanchun Zou Sijian Zhang Xiaofei Yu Guobin Fu Xianguo Lu 

机构地区：[1]Heilongjiang Xingkai Lake Wetland Ecosystem National Observation and Research Station&Key Laboratory of Wetland Ecology and Environment&Jilin Provincial Joint Key Laboratory of Changbai Mountain Wetland and Ecology,Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences,Changchun 130102,China [2]State Environmental Protection Key Laboratory for Wetland Conservation and Vegetation Restoration&Jilin Provincial Key Laboratory of Ecological Restoration and Ecosystem Management&Key Laboratory of Vegetation Ecology of Ministry of Education,School of Environment,Northeast Normal University,Changchun 130117,China [3]CSIRO Land and Water,Private Bag 5,Wembley,WA 6913,Australia

出　　处：《Fundamental Research》2023年第6期861-867,共7页自然科学基础研究（英文版）

基　　金：the National Natural Science Foundation of China(42222102,41971136,42171107,42230516);the Department of Science and Technology of Jilin Province(20230508089RC);the Professional Association of the Alliance of International Science Organizations(ANSO-PA-2020-14).

摘　　要：Understanding water dynamics is a prerequisite for the restoration of degraded ecosystems in arid and semiarid regions.In this study,we carried out δD and δ^(18)O analyses of precipitation,unsaturated soil water,overland flow,surface runoff,and groundwater samples from a seasonally flooded wetland in the Momoge National Nature Reserve of the Songnen Plain,Northeast China,to identify the water sources and understand the mechanisms of unsaturated soil water movement.Unsaturated soil water content(W/W%)at every 20 cm along with a soil profile(0–100 cm)was collected during the growing season,and the HYDRUS-1D model was used to simulate temporal-spatial variations.The results showed that the local meteoric water line(δD=5.90δ18O-7.34,R2=0.95)had a smaller slope and intercept than the global meteoric water line because of strong evaporation at our study site under semi-arid climate.The groundwater was partly recharged by local precipitation via overland flow and unsaturated soil water infiltration.Unsaturated soil water was sourced from both precipitation and groundwater with variations at different depths.The upper soil layer at 0–15 cm was mainly sourced from limited precipitation,while the groundwater could move up to a 25 cm layer during the dry period.The unsaturated soil water content increased with soil depth in the top 40 cm,decreased at depths of 40 to 80 cm,and increased again at depths of 80 to 100 cm.The HYDRUS-1D model could simulate the unsaturated soil water dynamics well in the upper(0–40 cm)and lower(80–100 cm)sections,but poorly for depths of 40–80 cm due to the upward and downward flow.The bidirectional unsaturated soil water movement highlights the importance of capillary groundwater for wetland plants with similar climatic or hydrogeological conditions.

关 键 词：Water stable isotopes Unsaturated soil water sourcing HYDRUS-1D Degraded wetland restoration Songnen Plain 

分 类 号：P64[天文地球—地质矿产勘探]