大冶湖水体光学特性的季节变化及其影响因子  

Seasonal Variation in Daye Lake Optical Properties and Influencing Factors

作　　者：任伟祥 吴晓东 葛绪广 罗楚玉 龙紫洁 廖泽勇 REN Wei-xiang;WU Xiao-dong;GE Xu-guang;LUO Chu-yu;LONG Zi-jie;LIAO Ze-yong(College of Urban and Environmental Sciences,Hubei Normal University,Huangshi 435002,P.R.China)

机构地区：[1]湖北师范大学城市与环境学院,湖北黄石435002

出　　处：《水生态学杂志》2021年第3期79-85,共7页Journal of Hydroecology

基　　金：湖北省教育厅项目(Q20182502,D20152503);湖北师范大学湖泊流域重金属污染机理与生态修复创新团队项目。

摘　　要：基于2018年对大冶湖全湖四季的野外调查与水质监测,结合大冶湖的形态,将研究范围划分为西区和东区两大部分,均匀设置15个采样点,在1、4、8、10月对各点位进行水样采集;通过分析水体光学衰减系数(K_(d))、真光层深度(Z_(eu))及其他水体光学特性重要参数,得到大冶湖周年的光合有效辐射(PAR)衰减特性,可为大冶湖流域生态管理及沉水植物恢复提供参考。结果显示:(1)大冶湖的K_(d)在季节上以冬季最低,夏季最高,平均值为3.17/m,由春至秋的季节变化不明显;(2)大冶湖水体光学特性最主要的影响因子为叶绿素a(Chl-a)、悬浮物(SS)和溶解性有机物(DOM),相关系数最高分别达到0.606、0.445和0.419,是限制水体K_(d)的主要因子,关系式为:K_(d)=0.019Chl-a+0.011SS-0.029DOM+2.364,降低水体Chl-a、SS和DOM浓度成为改善大冶湖水体光学特性的重要内容;(3)大冶湖适宜进行沉水植物恢复的季节为春季,全湖其他季节的光学阈值(真光层深度/水深,Z_(eu)/D_(w))均小于1,不利于沉水植物的萌发生长,恢复区域以磊山、蚌壳岭以东湖区、南部湖区沿岸浅水地带以及湖西侧的河道浅滩为宜。The photosynthetically active radiation(PAR)available in water bodies is the most important factor for the growth of submerged plants.In this study,we characterized the annual fluctuation of PAR in Daye Lake by determining the light attenuation coefficient(K_(d)),euphotic depth(Z_(eu))and other important optical parameters.The factors influencing seasonal variation in optical properties were also identified.The objectives were to provide basic information for the ecological management of Daye Lake basin and a reference for restoring submerged macrophytes.The study was based on a seasonal(January,April,August,October)field investigation and water quality monitoring at 15 sampling sites in Daye Lake during 2018.The K_(d) of Daye Lake was lowest in winter(2.47/m)and highest in summer(3.69/m),with an average of 3.17/m.The seasonal variation from spring to autumn was not significant.Spatially,K_(d) decreased from west to east.The water of Daye Lake was moderately eutrophic,with an annual average Secchi depth(SD)of 40 cm,and the chlorophyll a(Chl-a),dissolved organic matter(DOM)and suspended solids(SS)in summer were significantly higher than in other seasons.Chl-a,DOM and SS were the primary factors affecting the optical properties,with respective correlation coefficients up to 0.606,0.445 and 0.419.The primary factors were related to K_(d) according to the following equation:K_(d)=0.019 Chl-a+0.011 SS-0.029 DOM+2.364.Thus,decreasing Chl-a,SS and DOM is important for improving water transparency in Daye Lake.The appropriate season for restoring submerged macrophytes in Daye Lake is spring,because the light threshold(the ratio of euphotic depth to water depth,Z_(eu)/D_(w))of the lake in other seasons is less than 1,and is not sufficient for germination and growth of submerged macrophytes.Restoration of macrophytes is suitable in lake areas east of Leishan Mountain and Bangkeling Mountain,the coastal shallow water on the southern margin and the river shoal in western Daye Lake.

关 键 词：大冶湖 光合有效辐射 透明度 沉水植物 真光层深度 

分 类 号：X171.4[环境科学与工程—环境科学]