State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Science, Nanjing, 210008, China.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Science, Nanjing, 210008, China.
Environ Pollut. 2016 Dec;219:656-662. doi: 10.1016/j.envpol.2016.06.044. Epub 2016 Jul 1.
In aquatic ecosystems, ecological processes such as organic matter mineralization and nutrient cycling are regulated by benthic O in sediments, and application of in situ techniques in field environments has the potential to better define the links between O dynamics and the unique biogeochemical phenomena occurring in these regions. The effects of benthic O on sediment nutrients release were identified on the basis of field specific observations conducted over one and a half years at Taihu Lake. Sediment dredging (SD) practices have sharply reworked the benthic boundary oxidation layer, and the oxygen penetration depth (OPD) in the SD responded as expected to the new-born surface, increasing immediately (7.5 ± 0.8 - 10.5 ± 0.6 mm) after dredging, then further increasing with an unusually high heterogeneity when a significant submersed macrophytes (SM) coverage of about 40% was implemented. Multiple correlation analysis revealed that OPD was responsible for PO and NH release. A lower benthic oxygen flux was immediately observed in dredging-related sediments in the case of dredging compared to SM or the control (CK), which suggested that oxygen demand is low in the uppermost sediments because of the degradable fresh organic carbon removal. SD and SDSM implementation was most successful at continuously reducing the size of PO released from sediments over one and a half years, and a significant seasonal-dependent release was also observed. The direction of flux was consistent among SD and SDSM, suggesting the potential to reduce internal PO release even further with the invasion of SM communities. Our results indicated that ecological engineering practices could alleviate internal nutrient loads from the contaminated bottom sediment, which was probably in positive response to benthic oxygen changes.
在水生生态系统中，有机物质矿化和养分循环等生态过程受到沉积物中底栖 O 的调节，原位技术在野外环境中的应用有可能更好地定义 O 动态与这些区域发生的独特生物地球化学现象之间的联系。根据在太湖进行的为期一年半的现场特定观测，确定了底栖 O 对沉积物养分释放的影响。底泥疏浚 (SD) 实践剧烈地重塑了底边界氧化层，SD 中的氧渗透深度 (OPD) 如预期的那样对新形成的表面做出反应，疏浚后立即增加（7.5±0.8-10.5±0.6 毫米），然后当实施约 40%的大量沉水植物 (SM) 覆盖时，进一步增加且具有异常高的异质性。多元相关分析表明，OPD 是 PO 和 NH 释放的原因。与 SM 或对照 (CK) 相比，疏浚相关沉积物中的底栖氧气通量立即降低，这表明由于可降解新鲜有机碳的去除，最上层沉积物中的氧气需求较低。与 SM 或对照 (CK) 相比，SD 和 SDSM 的实施在过去一年半的时间里持续降低了从沉积物中释放的 PO 的大小，并且还观察到了显著的季节性释放。SD 和 SDSM 之间的通量方向一致，这表明随着 SM 群落的入侵，有潜力进一步减少 PO 的内部释放。我们的结果表明，生态工程实践可以减轻受污染底泥的内部养分负荷，这可能是对底栖氧变化的积极响应。
