Study of the effects of suspended marine clay on the reflectance spectra of phytoplankton
Study of the effects of suspended marine clay on the reflectance spectra of phytoplankton
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DOI：
10.1080/01431160110059918
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发表时间：
2002-01
影响因子：
3.4
通讯作者：
K. Gin;S. T. Koh;I. Lin
中科院分区：
文献类型：
--
作者：
K. Gin;S. T. Koh;I. Lin
建立了对照实验，研究了从新加坡海水和淡水中分离的浮游植物的反射光谱。叶绿素的典型反射在绿波段（540 ~ 570 nm），而吸收主要在蓝波段（400 ~ 500 nm）和红波段（~ 650 nm）。在近红外（NIR）区域687 nm、719 nm和760 nm处观察到额外的反射率峰。高、低叶绿素浓度下的光谱曲线对比表明，近红外波段的总反射率明显大于可见光波段。所选反射峰的色比和一阶导数与叶绿素a含量相关。红-近红外比和一阶导数在687nm处与叶绿素a的相关性最好。在纯藻培养物中加入海相粘土，观察到某些波段的光反射率优先增加。与近红外波段相比，添加天然海洋粘土时，可见光波段，特别是绿色波段的增加幅度更大。相比之下，当添加燃烧的海洋粘土（有机物含量去除）时，近红外波段的反射率增加相对较大。实验结果能够部分解释在新加坡沿海水域光谱反射率测量中观察到的趋势。
A controlled experiment was set up to study the reflectance spectra of phytoplankton cultures isolated from marine and fresh waters in Singapore. Typical reflectance of chlorophyll was observed in the green band (540-570 nm), whereas absorption was mainly in the blue band (400-500 nm) and red band (∼650 nm). Additional reflectance peaks were observed in the near-infrared (NIR) region at 687 nm, 719 nm and 760 nm. A comparison of the spectral profiles at high and low chlorophyll concentrations indicates that there is a significantly greater increase in the overall reflectance in the (NIR) band compared to that in the visible band. Colour ratios and first derivatives at selected reflectance peaks were correlated with chlorophyll a content. The red-NIR ratio and first derivative at 687 nm (NIR) give the best correlations with chlorophyll a . When marine clays were added to the pure algal culture, a preferential increase in reflectance of light at certain wavebands was observed. When natural marine clay was added, there was a greater increase in the visible band, especially the green wavelengths, compared to that in the NIR band. In contrast, when combusted marine clay (organic content removed) was added, a relatively greater increase in reflectance in the NIR band was seen. The experimental results were able to partially explain the trends observed in spectral reflectance measurements of the coastal waters of Singapore.