| 神农溪水体季节热分层特征及其对水华影响 |
| Characteristics of Seasonal thermal stratification in Shennong Stream and Its Influence on Algae Bloom |
| 投稿时间：2018-11-30 修订日期：2019-01-28 |
| DOI：10.15928/j.1674-3075.2020.04.003 |
| 中文关键词:水温 混合层 异重流 水华 神农溪 |
| 英文关键词:water temperature mixed layer density flow algae bloom Shennong Stream |
| 基金项目:国家自然科学基金重大计划(No. 91647207)；国家自然科学基金（No. 51779128、No. 51509086、No. 41501297、No. 51709096）；国家重点研究计划“面向江河湖库生态安全的水库群调度技术”。（No.2016YFC0402204） |
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| 中文摘要: |
| 水温对水生态系统中的物理、化学和生物过程有着重要影响。为分析神农溪水温季节分布特征，也为弄清神农溪水华与水温等环境因子之间的关系，于2015年分季节进行4次采样，并对水温、水动力、Chl-a以及环境因子等进行原位监测。研究发现神农溪不同季节存在不同形式的异重流，并影响着库湾水温垂向分布格局。春季水温分层开始发育，夏季水温受中上层异重流影响水温垂向分布呈现“双斜温”，秋、冬季主要受对流作用以及异重流的影响，上层水温呈等温状态。利用SPSS分析Chl-a与水华暴发因素之间的相关性发现，Chl-a与水温（R=0.752）、水体稳定系数（R=0.742）呈极显著正相关，而与混合层深度（R=-0.584）和溶解性氮（R=-0.609）、磷（R=-0.408）等营养盐呈极显著负相关。通过分析发现水温虽然与Chl-a呈显著的正相关关系，但并不能很好地解释神农溪水华暴发；神农溪藻类生长不受氮限制，但水华暴发消耗大量磷营养盐会对藻类继续增殖产生磷限制；春、夏季混合层深度骤减是神农溪水华暴发的主要原因。 |
| 英文摘要: |
| Water temperature strongly influences the physical, chemical and biological processes in aquatic ecosystems. Shennong Stream is a typical tributary of Three Gorges Reservoir (TGR) and the backwater, forming Shennong Bay (SNB), extends 20 km upstream from its confluence with TGR. In this study, we investigated the spatial-temporal distribution of water temperatures in Shennong Bay, characterized the mechanism of thermal stratification and analyzed the relationships between algae blooms and environment factors, particularly water temperature and mixing depth. The objective was to provide a theoretical basis for controlling algae blooms in Shennong Bay. In February, April, August and November of 2015, seasonal field monitoring was carried out across six sampling transects in Shennong Bay, including measurements of water depth, water temperature, flow velocity, transparency, dissolved total phosphorus (DTP), dissolved total nitrogen (DTN) and chlorophyll-a (Chl-a). Different density currents were observed in Shennong Bay that affected the water temperature pattern. In spring, thermal stratification began to develop and upper and middle density currents formed, resulting in a “double thermocline” during summer. In autumn and winter, the upper layers of TGR and Shennong Bay were isothermal and primarily affected by convection and density currents. Chl-a was positively correlated with the water temperature (R=0.752) and the water stability coefficient (R=0.742) and negatively correlated with mixing depth (R=-0.584), DTN (R=-0.609) and DTP (R=-0.408). However, the significant positive correlation between water temperature and Chl-a did not explain the algae blooms observed in Shennong Bay; algal growth was not limited by DTN, and the algae bloom consumed a large amount of DTP that then limited continued growth of algae. The outbreak of algae blooms in Shennong Bay during spring and summer was attributed to sudden decreases in mixing depth. The results of this study increase our understanding of TGR-Shennong Bay dynamics and can be used to help control algal blooms in Shennong Bay. |
| 王耀耀,徐涛,崔玉洁,纪道斌,黄佳维,方海涛,霍静,何金艳,张庆文,朱晓声.2020.神农溪水体季节热分层特征及其对水华影响[J].水生态学杂志,41(4):19-26. |
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