6场半全场第18105期:Environmental Pollution:沉積物結合態有機磷對內源磷儲存及藻類生長的作用

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北京師范大學水科學研究院王圣瑞教授團隊探討了沉積物中的磷對內源磷儲存的相對重要性以及生物可利用性磷在洱海藻類生長中的作用。結果發表于Environmental Pollution(IF=5.714)。

Highlights

Role and supply model of sediment bioavailable Po in algal growth was studied.

The potential releasing risk of Erhai sediment bioavailable Po is great.

DOM structure, microorganism activity and algae biomass are responsible for bioavailable Po environmental processes.

Bioavailable Po replenishes available P pools in overlying water to facilitate algal growth.

Abstract

The role of sediment–bound organic phosphorus (Po) as an additional nutrient source is a component of internal P budgets in lake system that is usually neglected. Here we examined the relative importance of sediment Po to internal P load and the role of bioavailable Po in algal growth in Lake Erhai, China. Lake Erhai sediment extractable Po accounted for 11–43% (27% average) of extractable total P, and bioavailable Po accounted for 21–66% (40%) of Po. The massive storage of bioavailable Po represents an important form of available P, essential to internal loads. The bioavailable Po includes mainnly labile monoester P and diester P was identified in the sequential extractions by H2O, NaHCO3, NaOH, and HCl. 40% of H2OPo, 39% of NaHCO3Po, 43% of NaOHPo, and 56% of HClPo can be hydrolyzed to labile monoester and diester P, suggesting that the bioavailability of Po fractions was in decreasing order as follows: HClPo>NaOHPo>H2OPo>NaHCO3Po. It is implied that traditional sequential fractionation of Po might overestimate the availability of labile Po in sediments. Furthermore, analysis of the environmental processes of bioavailable Po showed that the stabler structure of dissloved organic matter (DOM) alleviated the degradation and release of diester P, abundant alkaline phosphatase due to higher algal biomass promoted the degradation of diester P. The stability of DOM structure and the degradation of diester P might responsible for the spatial differences of labile monoester P. The biogeochemical cycle of bioavailable Po replenishs available P pools in overlying water and further facilitate algal growth during the algal blooms. Therefore, to control the algal blooms in Lake Erhai, an effective action is urgently required to reduce the accumulation of Po in sediments and interrupt the supply cycle of bioavailable Po to algal growth.

 

沉積物結合態有機磷(Po)作為額外的營養源,是湖泊系統內部磷平衡的一個組成部分,但常被忽視。本文探討了沉積物中的磷對內源磷儲存的相對重要性以及生物可利用性磷在中國洱海藻類生長中的作用。洱海沉積物可提取的Po占可提取總P的11%-43%(平均值為27%),生物可利用性Po占可提取總P的21%-66%(平均值為40%)。生物可利用性Po的大量儲存是有效磷的一種重要形式,對內源磷儲存至關重要。生物可利用性Po主要包括不穩定單酯P和二酯P,由H2O、NaHCO3、NaOH和HCl依次提取。40%的H2OPo、39%的NaHCO3Po、43%的NaOHPo和56%的HClPo可以水解為不穩定的單酯和二酯P,表明Po的生物可利用性順序為: HClPo >NaOHPo >H2OPo >NaHCO3Po。這意味著傳統的連續分餾方法可能高估了沉積物中不穩定Po的有效性。此外,對生物有效態有機質(Po)的環境過程分析表明,降解有機質(DOM)結構的穩定減輕了二酯P的降解和釋放,而藻類生物量的增加所產生的豐富的堿性磷酸酶促進了二酯P的降解。DOM結構的穩定性和雙酯P的降解可能是造成不穩定單酯P空間分布差異性的原因。生物有效磷的生物地球化學循環補充了上覆水體中的有效磷,并在藻華期間進一步促進了藻類的生長。因此,控制洱海藻華,迫切需要采取有效措施減少沉積物中Po的積累,阻斷生物可利用性Po對藻類生長的供給循環。

本文轉自:農業環境科學

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