光照和营养对亚热带浅水湖泊初级生产者的复合影响——基于微宇宙实验研究  

Combined effects of light and nutrient supply on primary producers in subtropical shallow lakes:a microcosm study

作　　者：罗东 李赠 赵苗苗 胡骞 周锐 戎俊 黎磊 LUO Dong;LI Zeng;ZHAO Miaomiao;HU Qian;ZHOU Rui;RONG Jun;LI Lei(Key Laboratory of Poyang Lake Environment and Resource Utilization,Ministry of Education,School of Life Sciences,Nanchang University,Nanchang 330031,China;Jiangxi Poyang Lake Wetland Conservation and Restoration National Permanent Scientific Research Base,National Ecosystem Research Station of Jiangxi Poyang Lake Wetland,Nanchang University,Nanchang 330031,China;Lushan Botanical Garden,Chinese Academy of Sciences,Jiujiang 332900,China)

机构地区：[1]南昌大学鄱阳湖环境与资源利用教育部重点实验室,南昌大学生命科学学院,南昌330031 [2]江西鄱阳湖湿地保护与恢复国家长期科研基地,江西鄱阳湖湿地生态系统国家定位观测研究站,南昌330031 [3]中国科学院庐山植物园,九江332900

出　　处：《生态学报》2024年第23期10639-10649,共11页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(31960248);南昌大学江西省财政科技专项“包干制”试点示范项目(ZBG20230418010)。

摘　　要：沉水植物、附着藻类和浮游植物作为浅水湖泊中的主要初级生产者,其竞争相互作用受到氮磷营养浓度升高和弱光胁迫的共同影响。探究营养盐和光照变化如何单独/共同影响这三种初级生产者及它们之间的相互作用关系,对于进一步理解全球气候变化背景下湖泊稳态的维持机制具有重要意义。选取长江流域冬春季节的优势种菹草(Potamogeton crispus)为植物材料,通过室内微宇宙模拟实验,设置不同营养(低营养:总氮0.8mg/L,总磷0.03mg/L,中营养:总氮1.8mg/L,总磷0.14mg/L)和遮荫处理(30%、60%和100%入射光强度),研究光照和营养水平对不同水体初级生产者的影响差异。结果表明:实验设置的营养范围内,营养增加促进菹草、附着藻类和浮游植物的生长,但是氮磷营养盐对附着藻类和浮游植物的促进作用远远大于对沉水植物的促进作用。遮荫增加显著抑制菹草的生长,但只有在中营养条件下,光照对生长的影响才明显,低营养条件下,光照对生长的影响不明显。相较于光强变化,浮游植物和附着藻类对水体营养的响应更为敏感,营养盐浓度不同造成的生物量差异远远大于光强不同造成的差异,表明实验过程中浮游植物和附着藻类的生长主要受营养盐的限制。因此,随着富营养化趋势加剧,由于弱光条件下菹草生长不佳,对藻类的抑制作用变弱,光强减弱和营养增加的联合作用会促进藻类的生长形成遮荫作用,引发植物种群衰退。水体富营养化过程中可溶性有机质输入增加、风浪增强和生物扰动等因素变化会降低湖泊下层光照强度,加剧富营养化对沉水植物的影响,从而对不同季节湖泊生态系统稳态维持产生不利影响。Submerged macrophytes,periphyton and phytoplankton are main primary producers in shallow lakes and their competitive interactions can be affected by increased nitrogen and phosphorus concentrations and low light stress.Exploring how changes in nutrients and light intensity separately/jointly affect these primary producers and their interactions is of great significance for our further understanding of the maintenance mechanisms of stable states in lakes under the context of global climate change.We selected Potamogeton crispus,a dominant species in winter and spring in the Yangtze River basin,as plant material.We conducted an indoor microcosm experiment simulating different conditions of nutrient concentrations(low nutrient:TN 0.8mg/L,TP 0.03mg/L,moderate nutrient:TN 1.8mg/L,TP 0.14mg/L)and shading(30%,60%,and 100%incident light)to study the effect of light and nutrient supply on different types of aquatic primary producers.The results showed that within the nutrient range that we had set up in the experiment,increased nutrient level promoted the growth of P.crispus,periphyton and phytoplankton,but the positive effect of nutrients on periphyton and phytoplankton was much greater than that on submerged macrophytes.An increase in shading significantly inhibited the growth of P.crispus,but the effect of light on macrophyte growth was only obvious under moderate nutrient,but not under low nutrient.Phytoplankton and periphyton were more responsive to different water nutrient levels than to changes in light intensities.The difference in phytoplankton and periphyton biomass caused by different nutrient concentrations was much greater than that caused by different light intensities,indicating that nutrient was the main factor that limiting phytoplankton and periphyton growth in the present experiment.These results suggested that as eutrophication intensifies,since P.crispus has a poor growth under low light conditions,its inhibitory effect on the algae can be weakened.Consequently,the combined effect of reduced light int

关 键 词：沉水植物 菹草 附着藻类 浮游植物 营养富集 光衰减 

分 类 号：Q948.8[生物学—植物学]