Action spectra of microalgal photosynthesis and depth distribution of spectral scalar irradiance in a coastal marine sediment of Limfjorden, Denmark
Action spectra of microalgal photosynthesis and depth distribution of spectral scalar irradiance in a coastal marine sediment of Limfjorden, Denmark
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丹麦林峡湾沿岸海洋沉积物中微藻光合作用的作用光谱和光谱标量辐照度的深度分布
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发表时间：
1993
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通讯作者：
B. Jørgensen
中科院分区：
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作者：
H. Ploug;C. Lassen;B. Jørgensen
研究了光的互补光谱利用对沉积物中不同类型的含氧光营养生物进行分区的作用。海洋沉积物上覆盖着密集的硅藻种群和底层的蓝藻种群。利用氧和光微传感器，在0.1 mm的空间分辨率下直接测量了沉积物中光合作用的作用光谱和光谱标量辐照度E0。硅藻的作用光谱与含有Chl.a的硅藻层中标量辐照度K0的衰减光谱相似。类胡萝卜素是主要的光合色素。蓝藻的作用光谱在Chl.a的吸收区域出现光合作用的极大值。和藻蓝蛋白。利用测量的光谱标量辐照度深度分布和硅藻和蓝藻的作用光谱，计算了这两个种群暴露在400-700 nm光下的光合作用光谱质量。将这种光谱质量与入射到沉积物表面的光的光谱质量进行了比较。由于其光合作用活性色素具有最大吸收的波长优先消光，在类似的总量子通量下，硅藻的相对光质量降低到d入射光质量的85%。这种影响的部分原因是蓝藻底层沉积物的后向散射光的光谱变化。相比之下，位于真光区底部的蓝藻，由于被覆盖的硅藻吸收，光谱质量发生了有利的变化，达到了10%。结果表明，光谱光质的这些变化只是解释这两个光养种群分带的诸多因素中的一个，而总光强和化学微环境可能是更重要的因素。
The role of complementary spectral utilization of light for the zonation of different groups of oxygenic phototrophic organisms in sediments was studied. The marine sediment was covered by a dense population of diatoms with an underlying population of cyanobacteria. Action spectra for photosynthesis and spectral scalar irradiance, E0, were measured directly in the sediment at a spatial resolution of 0.1 mm by the use of oxygen and light microsensors. The action spectrum for the diatoms was similar to the attenuation spectrum of the scalar irradiance, K0, in the diatom layer with Chl.a. and carotenoids being the major photosynthetic pigments. The action spectrum of the cyanobacteria showed photosynthesis maxima at the absorption regions of Chl.a. and phycocyanin. The measured depth distribution of spectral scalar irradiance and the action spectra of diatoms and cyanobacteria were used to calculate the spectral quality for photosynthesis of the 400–700 nm light to which the two populations were exposed. This spectral quality was compared to that of the light incident on the sediment surface. Due to preferential extinction of wavelengths, at which their photosynthetically active pigments had maximal absorption, the relative light quality for diatoms was reduced to 85% of the quality of d incident light at a similar total quantum flux. This effect was partly due to spectral alterations of light backscattered from the underlying sediment with cyanobacteria. The cyanobacteria at the bottom of the euphotic zone, in contrast, experienced a light spectrum which was favorably altered, to 10% in quality, due to absorption by the overlying diatoms. It was concluded that these changes in spectral light quality can be considered as only one of more factors explaining the zonation of the two phototrophic populations, and that total light intensity and the chemical microenvironment are probably more important factors.