標題: Response of bottom sediment stability after carp removal in a small lake
作者: Lin, Ying-Tien
Wu, Chin H.
防災與水環境研究中心
Disaster Prevention and Water Environment Research Center
關鍵字: Acoustic and electromagnetic signals;carp;sediment sublayer;sediment stability;suspended sediment concentration
公開日期: 2013
摘要: This study combined several features of acoustic and electromagnetic (EM) waves-based devices including sub-bottom profiler (SBP), side-scan sonar (SSS) and ground penetrating radar (GPR), and in situ sediment data to study responses of bottom sediments after carp removal in Lake Wingra. In 2007, i.e., before carp removal, macrophytes only grew to a water depth of 2 m. Meanwhile, GPR data showed no visible sublayer in vegetated regions, while SBP data revealed a loose and fluffy sediment layer in unvegetated regions, easily affected by wave or current motions. The field data showed that suspended sediment concentrations (SSC) were much greater in unvegetated regions than those in vegetated regions during a one-day wind event, and the resuspended sediments could remain suspended in the water column for two days. In 2009, i.e., after more than half (51%) of carp were removed, the fluffy sediment layer recognized by SBP became thinner or even disappeared, and both SBP and SSS results showed that submerged macrophytes started growing in deeper water. In situ sediment data presented that bulk sediment density and critical shear stress became greater, and bottom sediments consolidated and were harder to be resuspended. Secchi depth collected between 2008 and 2010 was greater than that in the previous 10 years, indicated clearer water state. In short, the fluffy sediment layer because of carp activities may be the main source for suspended sediments to deteriorate water quality. Removal of carp is crucial for stabilizing bottom sediment and improving water clarity in this small lake.
URI: http://hdl.handle.net/11536/22909
http://dx.doi.org/10.1051/limn/2013049
ISSN: 0003-4088
DOI: 10.1051/limn/2013049
期刊: ANNALES DE LIMNOLOGIE-INTERNATIONAL JOURNAL OF LIMNOLOGY
Volume: 49
Issue: 3
起始頁: 157
結束頁: 168
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