Purpose

To study the effects of snail (Bellamya aeruginosa) bioturbation on phosphorus (P) mobility in sediment and the relevant mechanisms behind them.

Materials and method

A microcosm simulation experiment was carried out at millimeter resolution with an 89 days culture of homogeneous sediments. High-resolution dialysis (HR-Peeper) and diffusive gradient in thin films (DGT) techniques were utilized to simultaneously acquire the vertical distribution of soluble and labile P/iron (Fe) in bioturbation sediments.

Results and discussion

Snail bioturbation significantly enhanced soluble reactive P (SRP) and labile P concentrations, with the maximum increment to 306% and 1133% of the control sediments within the influence depths from 0 to − 30 mm and to − 20 mm, respectively. The P fluxes released from the sediment–water interfaces in snail treatments were correspondingly enhanced with the maximum increments to 218% of the control. Also, snail bioturbation significantly enhanced the soluble Fe(II) and labile Fe concentrations by maximum increment of 218% and 199% of the control within 0 to −24 mm and − 19 mm, respectively.

Conclusions

The high correlation between soluble/labile P and Fe suggested that P release from the sediment under snail bioturbation was due to the reduction and dissolution of Fe(III) oxyhydroxide.

中文翻译：

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富营养化湖泊中淡水蜗牛（Bellamya aeruginosa）生物扰动从沉积物中释放磷的实验研究

目的

研究蜗牛（Bellamya aeruginosa）生物扰动对沉积物中磷（P）迁移率的影响及其背后的相关机制。

材料与方法

在89天内培养出均质沉积物的情况下，以毫米级分辨率进行了微观模拟实验。利用高分辨率渗析（HR-Peeper）和薄膜扩散梯度（DGT）技术来同时获取生物扰动沉积物中可溶性和不稳定的P /铁（Fe）的垂直分布。

结果和讨论

蜗牛的生物扰动显着提高了可溶性反应性P（SRP）和不稳定P的浓度，在影响深度从0到-30 mm和到-20 mm的范围内，最大增加量分别为对照沉积物的306％和1133％。蜗牛处理过程中从沉积物-水界面释放的磷通量得到相应提高，最大增加量达到对照的218％。此外，蜗牛的生物扰动显着提高了可溶性Fe（II）和不稳定的Fe浓度，分别在0到-24 mm和-19 mm范围内最大增加了对照的218％和199％。

结论

可溶性/不稳定的磷与铁之间的高度相关性表明，在蜗牛生物扰动下磷从沉积物中的释放是由于羟基氢氧化铁（III）的还原和溶解所致。