Decrease in macrofauna density increases the sediment phosphorus release and maintains the high phosphorus level of water column in Lake Taihu: A case study on Grandidierella taihuensis
Decrease in macrofauna density increases the sediment phosphorus release and maintains the high phosphorus level of water column in Lake Taihu: A case study on Grandidierella taihuensis
复制标题
大型动物密度的降低增加了沉积物磷的释放并维持了太湖水体的高磷水平：以太湖大水藻为例
DOI：
10.1016/j.watres.2022.119193
复制
发表时间：
2022
期刊：
影响因子：
12.8
通讯作者：
Yan Wang
中科院分区：
文献类型：
--
作者：
Cai Li;Shiming Ding;Yongjiu Cai;Musong Chen;Zhilin Zhong;Xianfang Fan;Yan Wang
Internal phosphorus (P) loading can increase the P level in the water column and further sustains cyanobacterial blooms. This study focused on the role of benthic fauna bioturbation in affecting the sediment P release and the P level of water column in a eutrophic lake, Lake Taihu. The macrofauna density decreased from 4766.56 ± 10541.80 ind/m2in 2007 to 345 ± 447.63 ind/m2in 2020 due to the frequent bottom-water hypoxia in Lake Taihu. The reduced macrofauna density majorly resulted fromGrandidierella taihuensis, Limnodrilus hoffmeisteri, andTanypus chinensislarvae, and their total density decreased by approximately 97% in 2020 compared to 2007. G. taihuensis, one of the major benthic faunas, was further used as a representative to investigate the effects of bioturbation on sediment P release using high-resolution sampling and imaging techniques. The results show thatG. taihuensiscan increase the O2penetration depth by more than 20 mm through bio-irrigation, and causes the redox conditions in burrows and surrounding sediments to change dramatically within a few minutes due to the intermittent ventilation. Subsequent oxidation of the soluble Fe(II) led to the formation of Fe-oxide bound P in the surface sediments, thereby increasing the P retention in the sediments. When theG. taihuensisdensity was 1563 ind/m2at the sampling site, approximately 0.12 g m−2yr−1P can be retained in sediments. As previous studies have shown thatL. hoffmeisteriandT. chinensisplayed a similar role in increasing the P retention in sediments through their bioturbation activities, the sharp decline in benthic fauna density and burrowing activities in Lake Taihu should be an important reason for maintaining the high P level in the water column by decreasing the P retention in sediments.
