State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
J Environ Sci (China). 2010;22(11):1674-82. doi: 10.1016/s1001-0742(09)60305-3.
As a diagenetic progress, bioturbation influences solute exchange across the sediment-water interface (SWI). Different benthic animals have various mechanical activities in sediment, thereby they may have different effects on solute exchange across the SWI. This laboratory study examined the impacts of different benthic animals on phosphorus dynamics across the SWI. Tubificid worms and Chironomidae larvae were introduced as model organisms which, based on their mechanical activities, belong to upward-conveyors and gallery-diffusers, respectively. The microcosm simulation study was carried out with a continuous flow culture system, and all sediment, water, and worms and larvae specimens were sampled from Taihu Lake, China. To compare their bioturbation effects, the same biomass (17.1 g wet weight (ww)/m2) was adopted for worms and larvae. Worms altered no oxygen penetration depth in sediment, while larvae increased the O2 penetration depth, compared to the control treatment. Their emergence also enhanced sediment O2 uptake. The oxidation of ferrous iron in pore water produced ferric iron oxyhydroxides that adsorbed soluble reactive phosphorus (SRP) from the overlying water and pore water. Larvae built obviously oxidized tubes with about 2 mm diameter and the maximum length of 6 cm in sediment, and significantly decreased ferrous iron and SRP in the pore water compared to the control and worms treatments. Worms constructed no visually-oxidized galleries in the sediment in contrast to larvae, and they did not significantly alter SRP in the pore water relative to the control treatment. The adsorption of ferric iron oxyhydroxides to SRP caused by worms and larvae inhibited SRP release from sediment. Comparatively, worms inhibited more SRP release than larvae based on the same biomass, as they successively renewed the ferric iron oxyhydroxides rich oxidation layer through their deposition.
作为成岩作用的一个进展，生物扰动影响着溶质在沉积物-水界面（SWI）的交换。不同的底栖动物在沉积物中有不同的机械活动，因此它们可能对 SWI 上的溶质交换有不同的影响。本实验室研究了不同底栖动物对磷在 SWI 上的动态的影响。引入多毛类环节动物和摇蚊幼虫作为模型生物，它们的机械活动分别属于上运移者和通道扩散者。微宇宙模拟研究采用连续流动培养系统进行，所有沉积物、水和蠕虫和幼虫标本均取自中国太湖。为了比较它们的生物扰动效应，采用相同的生物量（17.1 g 湿重（ww）/m2）用于蠕虫和幼虫。与对照处理相比，蠕虫没有改变沉积物中的氧气穿透深度，而幼虫增加了氧气穿透深度。它们的出现也增强了沉积物对氧气的吸收。孔隙水中亚铁的氧化产生了铁的氢氧化物，它从上层水和孔隙水中吸附了可溶解性反应磷（SRP）。幼虫在沉积物中建造了明显氧化的管，直径约 2 毫米，最长可达 6 厘米，与对照和蠕虫处理相比，显著降低了孔隙水中的亚铁和 SRP。与幼虫相比，蠕虫在沉积物中没有构建明显的氧化通道，与对照处理相比，它们没有显著改变孔隙水中的 SRP。蠕虫和幼虫产生的铁的氢氧化物对 SRP 的吸附抑制了 SRP 从沉积物中的释放。相对而言，基于相同的生物量，蠕虫比幼虫抑制了更多的 SRP 释放，因为它们通过沉积连续更新富含铁的氧化层。
