• 关键词：盐分  淹水  磷形态  磷酸酶活性  潮汐淡水沼泽湿地  闽江河口

• 基金项目：国家自然科学基金面上项目（No.32071598，41877335）；福建省自然科学基金（No.2019J02008，2020J01503）；福建省林业科技项目（No.201935，2021FKJ31）

• 孙一萍
• 1. 福建师范大学地理科学学院, 福州 350007;2. 福建师范大学, 湿润亚热带生态地理过程教育部重点实验室, 福州 350007

• 罗敏
• 3. 福州大学环境与安全工程学院, 福州 350116

• 刘育秀
• 1. 福建师范大学地理科学学院, 福州 350007;2. 福建师范大学, 湿润亚热带生态地理过程教育部重点实验室, 福州 350007

• 谭季
• 1. 福建师范大学地理科学学院, 福州 350007;2. 福建师范大学, 湿润亚热带生态地理过程教育部重点实验室, 福州 350007

• 黄佳芳
• 1. 福建师范大学地理科学学院, 福州 350007;2. 福建师范大学, 湿润亚热带生态地理过程教育部重点实验室, 福州 350007

• 摘要：选取中国东南沿海闽江河口潮汐淡水沼泽湿地土壤作为研究对象,研究不同盐分(淡水对照、低盐处理、高盐处理)和不同淹水(CK、CK+15 cm、CK+30 cm)交互处理对土壤磷形态和磷酸酶活性的影响.结果表明,在闽江河口潮汐淡水沼泽湿地土壤中,无机磷是土壤总磷的主要赋存形态,约占总磷含量的68%~82%,有机磷含量约占总磷的18%~32%.无机磷以铁铝结合态磷为主(60%~66%),其次为钙结合态磷和闭蓄态磷.淹水处理对磷的总量和形态的影响有限,盐分变化对磷的总量和形态影响显著.低盐处理可增加铁铝结合态磷、闭蓄态磷含量及碱性磷酸酶活性,而高盐处理则对它们表现出抑制作用.随着盐分的增加,土壤总磷含量逐渐降低,土壤中钙结合态磷含量和磷酸盐含量将逐渐升高.相关分析表明,有机磷含量与土壤碱性磷酸酶活性呈负相关,无机磷含量与土壤碱性磷酸酶活性呈正相关.当盐分由淡水变化至低盐时,土壤磷的形态主要由有机磷向无机磷转化;而当盐分由低盐变化至高盐时,无机磷占比降低,有机磷占比增加.研究结果表明,碱性磷酸酶活性在磷形态对盐分和淹水的响应中发挥着重要作用.

• Abstract：In the present study, we established mesocosms loaded with soil from a tidal freshwater wetland of the Min River Estuary, southeast China, and subjected them to three salinity treatments (fresh control, oligohaline, mesohaline) and three flooding treatments (control, control+15 cm, control+30 cm) treatments. Thereafter, we simultaneously assessed the abundance and speciation of phosphorus (P) and P-acquiring enzyme activities. In general, the contents of organic P accounted for approximately 68%~82% of total P, whereas those of inorganic P accounted for approximately 18%~32% of total P. Moreover, iron/aluminum bound P (Fe/Al-P) was the main component (approximately 60%~66%) of inorganic P, followed by calcium bound P and occluded P. Salinity had remarkable impact on the abundance and speciation of P, whereas flooding treatments revealed limited effect. Oligohaline treatment increased the contents of Fe/Al-P and occluded P and alkaline phosphatase activities, whereas mesohaline treatment decreased these contents. As salinity increased, the total P contents and acid phosphatase activities decreased; however, the calcium bound P contents and porewater phosphate concentrations increased. This study revealed that organic and inorganic P contents exhibited negative and positive correlation with alkaline phosphatase activities, respectively. When the salinity changed from freshwater to oligohaline, few parts of organic P transformed into inorganic P. Furthermore, when the salinity changed from oligohaline to mesohaline, the importance of inorganic P decreased, whereas that of organic P increased. Thus, this study highlighted the importance of phosphorus-acquiring enzyme activities on the feedbacks of abundance and speciation of P toward increasing salinity and flooding in tidal freshwater wetland soils.

• Key words：salinity  flooding  phosphorus speciation  phosphatase activity  tidal freshwater wetland  Min River Estuary

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