| 基于分位数回归的洱海藻类对氮、磷及水温的响应特征 |
| 摘要点击 2899 全文点击 1292 投稿时间：2016-07-06 修订日期：2016-08-10 |
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| 中文关键词 营养物 水温 分位数回归 藻类叶绿素a 洱海 |
| 英文关键词 nutrients water temperature quantile regression algae chlorophyll a Lake Erhai |
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| 中文摘要 |
| 基于云南洱海长时间尺度水质观测数据，运用分位数回归方法分析浮游藻类叶绿素a（Chl-a）对氮（N）、磷（P）、水温的定量响应关系.结果表明过去20余年洱海藻类生物量受水温、N、P共同影响，随着洱海富营养化程度的加剧，水温对藻类生物量的相对重要度在持续下降，斜率平均值从2.70下降至0.44.而营养物对藻类的促进效应明显在提升，尤其是TP对藻类的相对重要度持续在攀升，斜率平均值从-0.3增长至0.8.TN对藻类生物量整体表现为较稳定的正效应，但近些年（2008~2013年）TN对藻类正效应达到最低.2002之后，P已逐渐取代N成为最重要的营养物限制因子.在季节方面，春季和秋季以水温和N的共同限制为主导，但春季当Chl-a>8 mg·m-3时，N和水温对藻类的正效应逐渐被P取代.夏季完全以N、P共同限制效应占主导，当Chl-a>3 mg·m-3时，TP的正效应逐渐超过TN，冬季则以P和水温的共同限制效应为主导.在气候变暖的大背景下，洱海富营养化控制应以“控P”为主和N、P协同削减的策略.当前富营养化控制过程中，应着重监控春、秋两季温度短期快速上升可能引发的全湖藻华风险. |
| 英文摘要 |
| Based on water quality monitoring data of Lake Erhai from 1990 to 2013,the yearly and seasonally response characteristics of algal chlorophyll-a to total nitrogen (TN),total phosphorus (TP) and water temperature was investigated using quantile regression method.It indicated that water temperature was always the primary limiting factor of algal biomass indicated by chlorophyll a (Chl-a) across recent 24 years,but its limiting effect on algal Chl-a content was kept descending sharply and replaced much by nutrients (e.g.P,N) with the increasing eutrophic level.Especially the slope values of TP on Chl-a were kept ascending from -0.3 to 0.8.Since 2002,the positive effect of TN on Chl-a presented slow descending tendency,and P became the most important limiting nutrient factor of algal growth.According to the seasonal variation analysis,water temperature and N had dominant effects on algal Chl-a in spring and autumn,but they were replaced by P in the case of Chl-a>8 mg·m-3 in spring.In summer,N and P had strong interactive impacts on the algal growth,and the positive effect of P was stronger than that of N in the case of Chl-a>3 mg·m-3.In winter,algal biomass was co-limited by temperature and P.It suggested that P reduction is the prior choice of eutrophication control of Lake Erhai,and simultaneously reducing N load is necessary in the background of global warming.In addition,so far a emergency controlling measure should be taken to monitor algal blooming due to sharp ascending of water temperature within a few days in spring and autumn. |
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