北京師范大學(xué)水科學(xué)研究院王圣瑞教授團(tuán)隊(duì)探討了沉積物中的磷對(duì)內(nèi)源磷儲(chǔ)存的相對(duì)重要性以及生物可利用性磷在洱海藻類(lèi)生長(zhǎng)中的作用。結(jié)果發(fā)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(jié)合態(tài)有機(jī)磷（Po）作為額外的營(yíng)養(yǎng)源，是湖泊系統(tǒng)內(nèi)部磷平衡的一個(gè)組成部分，但常被忽視。本文探討了沉積物中的磷對(duì)內(nèi)源磷儲(chǔ)存的相對(duì)重要性以及生物可利用性磷在中國(guó)洱海藻類(lèi)生長(zhǎng)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?jī)?chǔ)存是有效磷的一種重要形式，對(duì)內(nèi)源磷儲(chǔ)存至關(guān)重要。生物可利用性Po主要包括不穩(wěn)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(wěn)定的單酯和二酯P，表明Po的生物可利用性順序?yàn)? HClPo >NaOHPo >H2OPo >NaHCO3Po。這意味著傳統(tǒng)的連續(xù)分餾方法可能高估了沉積物中不穩(wěn)定Po的有效性。此外，對(duì)生物有效態(tài)有機(jī)質(zhì)(Po)的環(huán)境過(guò)程分析表明，降解有機(jī)質(zhì)（DOM）結(jié)構(gòu)的穩(wěn)定減輕了二酯P的降解和釋放，而藻類(lèi)生物量的增加所產(chǎn)生的豐富的堿性磷酸酶促進(jìn)了二酯P的降解。DOM結(jié)構(gòu)的穩(wěn)定性和雙酯P的降解可能是造成不穩(wěn)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(xué)循環(huán)補(bǔ)充了上覆水體中的有效磷，并在藻華期間進(jìn)一步促進(jìn)了藻類(lèi)的生長(zhǎng)。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(duì)藻類(lèi)生長(zhǎng)的供給循環(huán)。

本文轉(zhuǎn)自：農(nóng)業(yè)環(huán)境科學(xué)