珠江三角洲滨海小流域人工景观湖富营养化评价

Eutrophication Status of Artificial Lakes in a Small Coastal Watershed in Pearl River Delta

在2009年3~7月间,通过对中山大学珠海校区滨海小流域上游河流、下游人工景观湖不同监测样点进行取样分析,根据营养盐、藻类与叶绿素a等指标评价该流域水体的富养化状态,结果表明:1) 上游河流采样点的综合营养状态指数(TLI)均小于40,水体仅处于中营养状态,富营养化的风险小,下游人工景观湖的TLI在50~96之间,均已进入轻度富营养状态甚至重度富营养状态;2) 下游人工景观湖中总氮(TN)浓度在2.96~11.51 mg/L之间,总磷(TP)浓度在0.13~0.67 mg/L之间,均超过湖泊富营养化发生的初始值(TN为0.7 mg/L,TP为0.05 mg/L);3) 人工景观湖浮游藻类丰度介于1.09 ×106~4.58 ×106个/L之间,大于湖库富营养化发生时的阈值106个/L,且浮游藻类以蓝藻、绿藻为主;4) 人工景观湖中叶绿素a浓度在65~505.23 μg/L之间。Water samples were analyzed for a small coastal watershed in Sun Yat-sen University (Zhuhai) from March to July. Based on the results of total nitrogen (TN), total phosphor (TP), phytoplankton and chlorophyll a, eutrophication status were evaluated. The results showed that: 1) the comprehensive trophic level indexes of upper watershed were less than 40, which suggested the water was meso-eutrophic. The indexes of lower watershed were more than 50, which suggested the water was eutrophic;2) TN concentration was 2.96 - 11.51 mg/L and TP concentration was 0.13 - 0.67 mg/L in artificial lakes in the lower watershed, which exceeded 0.7 mg/L and 0.05 mg/L respectively, the thresholds of lake eutrophication;3) the abundance of phytoplankton in the artificial lakes was 1.09 ×106 - 4.58 ×106 cells/L, which is higher than 106 cells/L, the threshold of eutrophication occurring;4) the chlorophyll a concentration in the artificial lakes was 65 - 505.23 μg/L.