Liu Xia, Liu Bao-Gui, Chen Yu-Wei, Gao Jun-Feng
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Huan Jing Ke Xue. 2016 Jun 8;37(6):2141-2148. doi: 10.13227/j.hjkx.2016.06.017.
As one of the few remaining lakes that are freely connected with the Yangtze River, Poyang Lake exhibits a unique aquatic ecology which is different from the disconnected lakes. In order to study the mechanism of limnological responses to water level fluctuations (WLFs), samples were collected weekly over 10 months from September 2011 to December 2012 in Xingzi and Duchang, and the effect of fluctuations in water level on nutrients and phytoplankton chlorophyll a (Chla) concentrations was investigated in Poyang Lake. Chla concentrations were strongly related to WLFs, with higher Chla concentrations in the higher water phase. The regression analysis indicated that Chla concentrations were significantly and positively correlated with water temperature (<0.0001) and secchi depth (SD) (<0.0001) but negatively correlated with total and inorganic nitrogen concentrations (TN,<0.01; NO-N,<0.01; NH-N:<0.05). SD and total and inorganic nitrogen concentrations were all significantly correlated with WLFs of Poyang Lake (SD,<0.01; TN,<0.0001; NO-N:<0.01; NH-N,<0.0001). Two different water levels were identified in the lake by principal components analysis:the low water level with high nutrient values and the high water level with high water temperature, SD, and Chla values. These results supported the hypothesis that WLFs clearly exerted an overall impact on the growth of phytoplankton in Poyang Lake of the Yangtze River floodplain. WLFs affected the water transparency (expressed by SD), nutrients, and Chla concentrations of Poyang Lake, likely due to flush flood pulse, re-suspension of suspended matter, dilution effects, and human activities.
作为仅存的少数几个与长江自由连通的湖泊之一，鄱阳湖呈现出一种不同于那些与长江隔绝的湖泊的独特水生生态。为了研究湖泊学对水位波动（WLFs）的响应机制，于2011年9月至2012年12月的10个月内，每周在星子和都昌采集样本，研究了鄱阳湖水位波动对营养物质和浮游植物叶绿素a（Chla）浓度的影响。Chla浓度与水位波动密切相关，在高水位阶段Chla浓度更高。回归分析表明，Chla浓度与水温（<0.0001）和透明度（SD）（<0.0001）呈显著正相关，但与总氮和无机氮浓度呈负相关（TN，<0.01；NO-N，<0.01；NH-N：<0.05）。SD以及总氮和无机氮浓度均与鄱阳湖的水位波动显著相关（SD，<0.01；TN，<0.0001；NO-N：<0.01；NH-N，<0.0001）。通过主成分分析在该湖泊中识别出两种不同的水位：营养值高的低水位和水温、SD及Chla值高的高水位。这些结果支持了以下假设，即水位波动对长江泛滥平原鄱阳湖浮游植物的生长产生了明显的总体影响。水位波动影响了鄱阳湖的水体透明度（用SD表示）、营养物质和Chla浓度，这可能是由于洪水脉冲、悬浮物再悬浮、稀释效应以及人类活动所致。
