泉州湾河口湿地不同植被恢复下沉积物磷形态和酶活性特征

Changes of phosphorus speciation and enzyme activities in sediments of the Quanzhou Bay estuarine wetland under different vegetation restoration patterns

基于定位观测,研究了泉州湾河口湿地秋茄(Kandelia obovate,KO)、桐花树(Aegiceras corniculatum,AC)、以及秋茄+桐花树(KA)混交等3种植被恢复下沉积物磷形态、酶活性以及环境因子变化特征,并与养蛏滩涂(恢复前,SC)进行了比较,以评估不同植被恢复模式对沉积物磷库及酶活性的影响.结果表明:(1)植被恢复19年后,3种恢复模式下沉积物全磷(TP)和无机磷(IP)含量相较恢复前均呈上升趋势,其中KA最高,SC最低;而沉积物有机磷(OP)含量在不同恢复模式间差异不显著;不同恢复模式下,IP均是沉积物磷的主要形态,占TP的60%~73%;其中,沉积物氢氧化钠提取磷(NaOH-P)和盐酸提取磷(HCl-P)在KA处理下明显高于恢复前(SC).(2)与恢复前相比,不同恢复模式下沉积物碱性磷酸酶、脲酶、蔗糖酶活性明显增加,总体表现为AC>KA>KO>SC,但过氧化氢酶在不同植被恢复模式下并无明显差异.(3)冗余分析结果显示,不同恢复模式下沉积物磷含量变化主要受酶活性(特别是碱性磷酸酶)及环境因子(pH、有机质、全氮等)的综合影响.泉州湾河口湿地植被恢复显著提高了沉积物磷库和微生物酶活性,从而调控了湿地养分动态;并且相较恢复前而言,秋茄+桐花树混交模式对沉积物营养状态及酶活性的影响要优于单一秋茄或桐花树种植.

Estuarine wetlands play a key role in phosphorus(P)retention and cycling. however,there is few research performed to determine how different vegetation restoration patterns in estuarine wetlands affects P contents and enzyme activities. Here,we investigated sediment P speciation,enzyme activities,and environmental variables under three different vegetation restoration patterns(i. e. Kandelia obovate(KO),Aegiceras corniculatum(AC),and Kandelia obovate+Aegiceras corniculatum(KA))in the Quanzhou Bay estuarine wetland. In addition,tidal flats(before restoration;SC)were treated as a control. Results showed that(1) After 19 years of vegetation restoration,the contents of total P(TP)and inorganic P(IP)in sediments under all three patterns increased compared to SC,with the highest found in KA. However,there was no significant difference in the organic P contents among different patterns. IP was the main form of P for all three patterns,because it accounted for 60%~73% of TP. NaOH-P and HCl-P contents in sediments under KA pattern were significantly higher than those in SC.(2) Compared to SC,the activities of alkaline phosphatase,urease and sucrase enhanced significantly under different patterns,with the order of AC>KA>KO>SC,but there was no significant difference in catalase activities.(3) Redundancy analysis results showed that the changes of P in sediments under different patterns were mainly affected by enzyme activities(mainly alkaline phosphatase)and environmental factors(pH,organic matter,total nitrogen). Our findings indicated that the P pools and microbial enzyme activities in sediments were significantly improved by vegetation restoration patterns in estuarine wetlands,and the beneficial effect of the mixed of K. obovate and A. corniculatum on the nutrient status and enzyme activity of sediments was better than that of single K. obovate or A. corniculatum pattern.