【作者】 王翔；

【导师】 赵南京； 殷高方；

【作者基本信息】 中国科学技术大学 ， 光学， 2021， 博士

【摘要】 浮游植物初级生产力是浮游植物通过光合作用吸收CO2合成有机物的能力,是水生生态系统物质和能量的基础。浮游植物初级生产力的测量常采取采样、培养和实验室分析的模式,测量周期长,成本高,实现浮游植物初级生产力的快速准确测量对水体承载能力评估、水体质量评价、海洋气候变迁研究等有着重要的科学意义与应用价值。叶绿素荧光动力学法可实现浮游植物初级生产力的快速测量,然而仪器状态、环境条件以及模型参数设定将影响测量结果准确性。本文以不同门类藻种为测量对象,研究了基于荧光动力学法的浮游植物初级生产力准确测量校正方法,设计了浮游植物初级生产力快速原位监测仪辅助功能模块,并开展了外场测量应用验证。取得主要研究成果如下:(1)研究了荧光动力学法藻类光合荧光参数准确测量方法。研究了基底信号对光合荧光参数测量结果的影响和校正方法,结果表明校正后Fv/Fm值约为0.60,相对误差为1.2%,准确度提高23%;研究了激发光强自适应调控方法,通过筛选荧光参数Eσ,实现不同门类藻的快速精确激发光强调控,结果表明,在不同光强初始条件下,自适应调整后均可获得稳定的激发光强且光强RSD小于2.5%,Fv/Fm测量值和Fast-Ocean测定结果一致;研究了水体浊度对光合荧光参数测量准确性影响及校正方法,校正后Fo和Fm相对标准偏差分别为0.52%和0.69%。(2)研究了浮游植物初级生产力测量中光合尺寸单元校正方法。基于激发光谱法实现了混合藻各组分占比的准确获取,以此为基础计算了混合藻光合尺寸单元并对混合藻初级生产力进行校正,与光合放氧法完成了实验比测验证。结果表明,纯种蓝藻、绿藻和甲藻初级生产力测量误差由校正前的38.8%、14.3%和13.2%下降至3.9%、4.1%和5.2%;混合样品初级生产力最大和平均测量误差由校正前的20.4%和15.2%下降至4.5%和5.2%。该方法解决了光合尺寸单元使用固定值带来的水体浮游植物初级生产力测量偏差问题。(3)研究了浮游植物初级生产力测量中藻类光吸收系数校正方法。基于吸收模型,并以荧光激发光谱表征其吸收系数,解决了单一波段吸收系数代替光合有效辐射波段总吸收效率问题。结果表明,与光合放氧法测定结果相比,纯种藻校正前后初级生产力测量相对误差分别为3.17%和1.83%,蓝、绿藻混合样品校正前后测量相对误差分别为28.43%和5.33%,校正后浮游植物初级生产力测量准确性得到提升。(4)设计研制了浮游植物初级生产力快速原位监测仪功能模块,提高了外场应用测量准确性。结合PAR光量子传感器设计了环境光模拟调节电路,实现了不同环境光强的自由调控模拟;设计了光电倍增管自动增益调整模块,实现了不同浓度藻类样品荧光信号的高灵敏获取;设计了多波段LED诱导激发荧光光谱获取模块,实现了藻类激发荧光光谱的快速获取。经测试,仪器响应时间为1.56分钟,准确度≤±9.69%,精密度4.86%,检测限为0.138 nmol(e)/m3/s,测量范围为0～1013 nmol(e)/m3/s,重现性为3.04%。在黄海、渤海、南海、北极等海域开展了浮游植物初级生产力原位监测仪外场测量验证实验,快速获取了浮游植物初级生产力时空分布数据,验证了仪器长期运行稳定性与可靠性。更多还原

【Abstract】 The primary productivity of phytoplankton is the ability of phytoplankton to absorb CO2 to synthesize organic matter through photosynthesis,and it is the basis of material and energy in aquatic ecosystems.The measurement of the primary productivity of phytoplankton mostly adopts,culture,and laboratory analysis modes.The measurement cycle is long and the cost is high.The rapid and accurate measurement of the primary productivity of phytoplankton is important for the evaluation of aquatic ecosystem carrying capacity,aquatic ecosystem quality evaluation,and research on ocean climate change.The scientific significance and application value.The chlorophyll fluorescence kinetics method can realize the rapid measurement of the primary productivity of phytoplankton,but the instrument status,environmental conditions and model parameter settings will affect the accuracy of the measurement results.In this paper,different phylum algae species are used as the measurement objects,the method for accurate measurement and correction of phytoplankton primary productivity based on fluorescence kinetics is studied,the auxiliary function module of the rapid in-situ monitor for phytoplankton primary productivity is designed,and the field measurement application verification is carried out.The main research results obtained are as follows:(1)The accurate measurement method of algae photosynthetic fluorescence parameters by fluorescence kinetics method was studied.The effect of instrument noise on the measurement of photosynthetic fluorescence parameters was studied.The results showed that the corrected Fv/Fm value was about 0.60,the relative error was 1.2%,and the accuracy was improved by 23%.The adaptive control method of excitation light intensity was studied,and the photo synthetic fluorescence parameters were screened.Eσ,to achieve rapid and accurate excitation light emphasis control for different species of algae.The results show that under different initial conditions of light intensity,stable excitation light intensity can be obtained after adaptive adjustment and the light intensity RSD is less than 2.5%,Fv/Fm measurement value The results are consistent with those of Fast-Ocean;the influence of water turbidity on the measurement accuracy of photo synthetic fluorescence parameters and the correction method are studied.After correction,the relative standard deviations of Fo and Fm are 0.52%and 0.69%,respectively.(2)The correction method of photosynthetic size unit in the measurement of phytoplankton primary productivity is studied.Based on the excitation spectroscopy,the accurate acquisition of the proportions of the components of the mixed algae was achieved.Based on this,the photo synthetic size unit of the mixed algae was calculated and the primary productivity of the mixed algae was corrected.The experimental comparison and verification with the photosynthetic oxygen evolution method was completed.The results showed that the measurement error of primary productivity of pure cyanobacteria,green algae and dinoflagellate decreased from 38.8%,14.3%and 13.2%before correction to 3.9%,4.1%and 5.2%;the maximum and average measurement errors of primary productivity of mixed samples were corrected by correction.The former 20.4%and 15.2%dropped to 4.5%and 5.2%.This method solves the problem of the measurement deviation of the primary productivity of algae in the aquatic ecosystem caused by the fixed value of the photosynthetic size unit.(3)The correction method of algae light absorption coefficient in the measurement of phytoplankton primary productivity is studied.Based on the absorption model and the fluorescence excitation spectrum to characterize its absorption coefficient,it solves the problem of single-band absorption coefficient instead of the total absorption efficiency of photosynthetically active radiation.The results showed that,compared with the results of photosynthetic oxygen evolution method,the relative errors of purebred algae before and after calibration were 3.17%and 1.83%,and the relative errors of blue and green algae mixed samples before and after calibration were 28.43%and 5.33%,respectively.After calibration,the accuracy of phytoplankton primary productivity measurement has been improved.(4)The auxiliary application function module of the rapid in-situ monitor for phytoplankton primary productivity is designed to improve the measurement accuracy of the field application.Combined with the PAR light quantum sensor,the ambient light analog adjustment circuit is designed to realize the free adjustment and simulation of different ambient light intensities;the photomultiplier tube automatic gain adjustment module is designed to realize the highly sensitive acquisition of the fluorescence signal of the algae samples with different concentrations;the multi-band is designed The LED excitation fluorescence spectrum acquisition module realizes the rapid acquisition of the algae excitation fluorescence spectrum.After testing,The response time of the instrument is 1.56 minutes,the accuracy is ≤±9.69%,the precision is 4.86%,the detection limit is 0.138 nmol(e)/m3/s,and the measurement range is 0 nmol(e)/m3/s～1013 nmol(e)/m3/s,reproducible The reproducibility is 3.04%.In the Yellow Sea,the Bohai Sea,the South China Sea,the Arctic and other waters,the phytoplankton primary productivity in-situ monitor field measurement verification experiment was carried out,and the time and spatial distribution data of the phytoplankton primary productivity were quickly obtained,which verified the long-term stability and reliability of the instrument.更多还原