摘要
近年来贵州草海呈现出以水生植物为主的草型清水稳态向以浮游植物为主的藻型浊水稳态转变的趋势,生态功能降低。叶绿素a(Chl a)浓度是衡量浮游植物生物量的重要指标,探究Chl a浓度变化对全面掌握草海生态状况及制定相应的恢复措施具有重要意义。该研究于2020–2021年夏秋季对草海水体进行采样,分析草海草-藻型稳态转换过程中Chl a浓度的变化;运用广义可加模型(GAM)分析各环境因子与Chl a浓度的关系。结果表明:稳态转换后(2021年调查期间)草海水体Chl a浓度显著升高,Chl a浓度均值为(17.96±10.62)μg·L^(–1),较稳态转换前(2020年调查期间)高出2.5倍;草海营养状态由中营养状态发展为富营养状态,水质恶化趋势明显;单因素GAM模型结果显示,高锰酸盐指数(COD_(Mn))、总氮(TN)浓度和水温(WT)对Chl a浓度影响显著,解释率较高(26.70%–33.30%);环境因子影响程度为WT>COD_(Mn)>TN浓度。该研究认为COD_(Mn)、TN浓度是驱动湖区Chla浓度变化的重要因子,WT则为诱导因子。草海沉水植被的大面积消亡和Chla浓度显著升高,表明草海正处于草型向藻型转换的关键节点,须及时采取干预措施促进沉水植被恢复,进一步深入研究草海稳态转换的成因及恢复对策。
Aims In recent years,the aquatic ecosystem of Caohai Lake,in Guizhou Province in southwest China,has shown a trend of phase shift from macrophyte-to phytoplankton-dominated states,which indicates the weakening ecological functioning of the lake.The chlorophyll a(Chl a)concentration is an important indicator of phytoplankton biomass.It is of great significance to clarify the variation of Chl a concentration in comprehensively understanding the ecological status and developing feasible restoration measures for the Lake.Methods Surface water samples were collected from the Lake in summers and autumns of 2020–2021 to analyze the variation of Chl a concentration.The generalized additive model(GAM)was applied to explore the relationship between each environmental factor and Chl a concentration.Important findings The results showed that,the Chl a concentration in surface water of Caohai Lake increased during phase shift,with an average up to(17.96±10.62)μg·L^(–1)(during the monitoring period in 2021),which was 2.5 times greater than that before the phase shift(during monitoring period in 2020).The comprehensive trophic state of the Lake changed from mesotrophic state to eutrophic state,and the water quality presented an obvious trend of deterioration.Results from the single-factor GAM analysis showed that permanganate index(COD_(Mn)),total nitrogen(TN)concentration and water temperature(WT)had significant effects on Chl a concentration,which among all investigated environmental factors,account for 26.70%–33.30%of the concentration variation of Chl a,with WT,COD_(Mn),TN concentration exhibiting the largest,intermediate,and smallest impact respectively.Based on the present study,it is concluded that COD_(Mn)and TN concentration were important factors driving the variation of Chl a concentration in Caohai Lake,and WT was an inducing factor.The massive extinction of submerged macrophyte and the significant increase of Chl a concentration indicated that the Lake is in phase shift from macrophyte-to phytoplankton-dominated state.Feasible measures should be developed timely to promote the restoration of submerged macrophyte,and further studies on phase shift mechanisms and restoration measures for the Lake should be carried out.
作者
李安艳
黄先飞
田源斌
董继兴
郑菲菲
夏品华
LI An-Yan;HUANG Xian-Fei;TIAN Yuan-Bin;DONG Ji-Xing;ZHENG Fei-Fei;XIA Pin-Hua(Key Laboratory for Information System of Mountainous Areas and Protection of Ecological Environment of Guizhou Province,Guizhou Normal University,Guiyang 550001,China;and Guizhou Caohai Wetland Ecosystem National Observation and Research Station,Bijie,Guizhou 553199,China)
出处
《植物生态学报》
CAS
CSCD
北大核心
2023年第8期1171-1181,共11页
Chinese Journal of Plant Ecology
基金
贵州省科技计划项目(2021470)
国家自然科学基金(41867056)。
关键词
贵州草海
Chl
a浓度
稳态转换
环境因子
GAM模型
Caohai Lake,Guizhou
chlorophyll a concentration
regime shift
environmental factor
GAM model
