植物学报 ›› 2020, Vol. 55 ›› Issue (6): 666-676.DOI: 10.11983/CBB20085

• 研究论文 • 上一篇    下一篇

再生水补给河道内芦苇的光谱特征及其对水体氮和磷含量的响应

赵睿1,2, 卜红梅1,*(), 宋献方1,2, 高融瑾3   

  1. 1中国科学院地理科学与资源研究所, 陆地水循环及地表过程院重点实验室, 北京 100101
    2中国科学院大学, 资源与环境学院, 北京 100049
    3立命馆亚洲太平洋大学, 亚洲太平洋学院, 大分県別府市, 日本
  • 收稿日期:2020-05-15 接受日期:2020-07-29 出版日期:2020-11-01 发布日期:2020-11-11
  • 通讯作者: 卜红梅
  • 作者简介:*E-mail: buhm@igsnrr.ac.cn
  • 基金资助:
    国家自然科学基金重点项目(41730749);北京市自然科学基金(8172044)

Spectral Characteristics of Phragmites australis and Its Response to Riverine Nitrogen and Phosphorus Contents in River Reaches Restored by Reclaimed Water

Rui Zhao1,2, Hongmei Bu1,*(), Xianfang Song1,2, Rongjin Gao3   

  1. 1Key Laboratory of Water Cycle and Related Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
    2College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
    3College of Asia Pacific Studies, Ritsumeikan Asia Pacific University, Oita Beppu, Japan
  • Received:2020-05-15 Accepted:2020-07-29 Online:2020-11-01 Published:2020-11-11
  • Contact: Hongmei Bu

摘要: 再生水是城市景观河湖的重要补给水源, 然而再生水中含量较高的氮和磷营养盐会引起水体富营养化, 破坏水生态平衡。以再生水补给的潮白河为研究区, 运用高光谱技术分析了挺水植物芦苇(Phragmites australis)叶片的光谱特征, 并结合水质数据, 通过拟合模型, 探究了芦苇对再生水中氮和磷的响应关系。结果表明, 各采样点水体的总氮(TN)和总磷(TP)含量分别介于1.85-18.16 mg·L-1及0.01-0.36 mg·L-1之间, 叶绿素a (Chl a)和溶解氧(DO)含量的范围分别为0.60-47.45 μg·L-1与4.24-11.4 mg·L-1。水体富营养化较为严重, 但仍处于富氧环境。多重方差分析表明, 不同采样点之间水体的TN、TP和Chl a含量差异显著(P<0.05)。由光谱反射率及反射率一阶导数曲线可知, 水体TN含量越高, 叶片光谱在可见光区的反射率越小, 红边位置也越向波长长的方向移动(即红移)。相关分析表明, 水体TN和TP含量与吸光度值log(1/R)在可见光区的相关性较强, 且TN与log(1/R)的相关系数高于TP。芦苇叶片光谱可在一定程度上区分水体TN含量差异, 但TP对光谱特征的影响模式不明显。光谱指数与水体TN含量之间的拟合模型中, 基于光化学指数(PRI)、修正叶绿素吸收指数(MCARI)和导数叶绿素指数(DCI)的模型能够解释水体TN含量变化的62.4%-70.9% (P<0.05), 可用于再生水氮含量的定量监测。该研究证明了植物光谱技术在水体富营养化监测上的可行性, 为保障再生水修复河道水质和生态安全提供了科学依据。

关键词: 再生水, 光谱反射率, 光谱指数, 氮和磷含量, 芦苇

Abstract: Reclaimed water is an important water source replenishing rivers and lakes for urban landscape. Higher contents of nitrogen and phosphorus in reclaimed water will cause eutrophication, disrupting the balance of hydro-ecology. Hyperspectral technology was applied to analyze the spectral characteristics of the emergent plant Phragmites australis, and the spectral characteristics response of P. australis leaf to nitrogen and phosphorus contents were explored in the Chaobai River restored by reclaimed water. Results showed that concentrations of total nitrogen (TN), total phosphorus (TP), chlorophyll a (Chl a), and dissolved oxygen (DO) were 1.85-18.16 mg·L -1, 0.01-0.36 mg·L-1, 0.60-47.45 μg·L -1, and 4.24-11.4 mg·L-1, respectively. Although the river water eutrophication was serious, it was still in an oxygen-rich environment. The results showed that there were significant differences in the concentrations of TN, TP, and Chl a among sampling sites (P<0.05) in multiple analysis of variance. With the increasing of riverine TN concentrations, the reflectance of leaf spectrum in the visible band lowered and the position of red edge also moved towards higher wavelength (i.e., redshift). The riverine TN and TP contents had significant correlations with the absorbance value log(1/R) in the visible band in correlation analysis, and the correlation coefficients between TN and log(1/R) were higher than that of TP. The difference of TN concentrations could be inferred by the spectrum of P. australis leaf to a certain extent, while the effect of TP on spectral characteristics was weaker than TN. TN was selected to establish fitting models with different spectral indices. Based on the photochemical reflectance index (PRI), the modified chlorophyll absorption ratio index (MCARI) and the derivative chlorophyll index (DCI), the exponential equations explained 62.4%-70.9% of TN (P<0.05), which could be useful for quantitatively monitoring of nitrogen contents in reclaimed water. This research proved practicability of plant spectrum technology in water eutrophication monitoring, providing a scientific basis for ensuring water quality safety and ecological security in rivers and lakes restored by reclaimed water.

Key words: reclaimed water, spectral reflectance, spectral index, nitrogen and phosphorus contents, Phragmites australis