The relationship between Chironomus plumosus burrows and the spatial distribution of pore-water phosphate, iron and ammonium in lake sediments
The relationship between Chironomus plumosus burrows and the spatial distribution of pore-water phosphate, iron and ammonium in lake sediments
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DOI：
10.1111/j.1365-2427.2006.01702.x
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发表时间：
2007-02
影响因子：
2.7
通讯作者：
J. Lewandowski;Christine Laskov;M. Hupfer
中科院分区：
文献类型：
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作者：
J. Lewandowski;Christine Laskov;M. Hupfer
摘要 1. 为了研究摇蚊对孔隙水中磷酸盐、铁和铵浓度分布的影响，我们使用配备有二维孔隙水采样器、充满湖泊沉积物并栖息着不同密度的摇蚊的中生态系统进行了实验室实验。 2. 研究中使用了专门设计的中生态系统。前板和后板孔隙水采样器之间有 6 毫米深的空间，其厚度足以让摇蚊不受干扰地生活，但又足够薄，足以迫使所有洞穴进入一个二维平面。 3. 在实验过程中观察到洞穴的走向及其周围的氧化区域，并通过实验结束时拍摄的 X 射线图像进行识别。 4. 我们研究了C. plumosus 洞穴与孔隙水组成空间格局之间的关系。通风洞穴周围这三种离子的浓度显着降低（54％至24％），因为生物灌溉导致与上覆水相比富含溶解物质的孔隙水的对流交换，并且还因为氧气进入沉积物导致铵的硝化、铁（II）的氧化以及磷酸盐与Fe（III）羟基氧化物的共沉淀。 5. 在摇蚊的中生态系统中，新的（氧化还原）界面出现，扩散的孔隙水梯度垂直于洞穴的走向，并且主要磷酸盐、铵和铁（II）释放的位置从沉积物表面转移到洞穴壁。
Summary 1. To study the influence of chironomids on the distribution of pore-water concentrations of phosphate, iron and ammonium, we conducted a laboratory experiment using mesocosms equipped with two-dimensional pore-water samplers, filled with lake sediment and populated with different densities of Chironomus plumosus. 2. Specially designed mesocosms were used in the study. A 6-mm deep space between the front plate and the pore-water sampler at the back plate was just thick enough to allow the chironomids to live undisturbed, yet thin enough to force all the burrows into a two-dimensional plane. 3. The courses of the burrows were observed during the experiment as oxidised zones surrounding them, as well as being identified with an X-ray image taken at the end of the experiment. 4. We investigated the relationship between C. plumosus burrows and spatial patterns of pore-water composition. Concentrations of the three ions were significantly less around ventilated burrows (54% to 24%), as bioirrigation caused a convective exchange of pore-water enriched with dissolved species compared with the overlying water, and also because oxygen imported into the sediment resulting in nitrification of ammonium, oxidation of iron(II) and a co-precipitation of phosphate with Fe(III) oxyhydroxides. 5. In mesocosms with chironomids, new (redox) interfaces occurred with diffusive pore-water gradients perpendicular to the course of burrows and the site of major phosphate, ammonium and iron(II) release shifted from the sediment surface to the burrow walls.