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Photoacclimation in freshwater diatoms: interspecific and inter-habitat comparisons

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journal contribution
posted on 29.10.2020, 23:50 authored by Pengling Shi, Ping Xie, Lanhai Liu, Jingzhen Cui, Xiaoqing Wang, Pinhong Yang

Diatoms are a type of photosynthetic phytoplankton that can acclimate to the light level of their environment. Diatoms from different habitats exhibit different photoacclimation characteristics; those from relatively low-light intensity habitats present relatively high photosynthetic activity, high light-harvesting pigment (Chla) content, and low xanthophyll content. Conversely, diatoms from high-light intensity environments have lower photosynthetic activity, less Chla content, and efficient xanthophyll cycling. Hence, diatoms can maintain high growth and photosynthetic activity within a wide range of light intensities. Whether the mechanisms of such adaptability are a consequence of biological photoacclimation to different light intensities or interspecific differences is unknown. Here, we show that differences in photoacclimation ability are more significant than species differences. We found similar species compositions in low- and high-light habitats of the Hanjiang River, China; however, there were remarkable differences in rapid light-response curve parameters. The photoacclimation of algae and trends in their photosynthetic activity can be estimated by rapid detection techniques. We isolated three diatom species common to both habitats and grew them under various light intensities, finding that they have an excellent ability to acclimate to local light conditions. Diatoms can use physiological strategies to handle light fluctuations, but only for short periods. Our results provide a theoretical basis for controlling algal blooms through light management. With knowledge of the photoacclimation characteristics of diatoms and according to the availability of local water conservancy facilities, it is possible to use light management to control diatom blooms more efficiently than with conventional techniques, thereby reducing water usage.

Funding

This work was supported by the National Natural Science Foundation of China (no. 31600315), the Postdoctoral Research Foundation of China (nos. 2017M612559, 2017M611939), the Opening Fund of the State Key Laboratory of Freshwater Ecology and Biotechnology (grant no. 2018FB08), the Science and Technology Plan of Changde City: Research on Light Stress of Freshwater Diatoms, and the Doctoral Start-up project of Hunan University of Arts and Science (no. 16BSQD30).

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