Leunert, Franziska and Eckert, Werner and Paul, Andrea and Gerhardt, Volkmar and Grossart, Hans-Peter (2014) Phytoplankton response to UV-generated hydrogen peroxide from natural organic matter. JOURNAL OF PLANKTON RESEARCH, 36 (1). pp. 185-197. ISSN 0142-7873, 1464-3774
Full text not available from this repository. (Request a copy)Abstract
In aquatic systems, natural organic matter (NOM) and in particular humic substances effectively absorb the ultraviolet (UV)/visible light spectrum of solar radiation and act as a photoprotective filter for organisms. Simultaneously, UV contributes to the generation of potentially harmful reactive oxygen species (ROS). Dose-response experiments were conducted on cyanobacteria and green algae with hydrogen peroxide (H2O2) as a long-lived representative of ROS. Delayed fluorescence (DF) decay kinetics was used as a non-invasive tool to follow changes of phytoplankton activity in real time. In order to investigate phototoxicity and photoprotection by NOM on phytoplankton, we exposed algae to UV-pre-irradiated NOM and direct UV excitation. Cyanobacteria responded to H2O2 concentrations as low as 10(-7) M, while green algae were 2 orders of magnitude less sensitive. UV irradiation of medium with NOM generated H2O2 concentrations of 1.5 x 10(-7) to 3.6 x 10(-7) M. When exposed to these concentrations, only the DF of cyanobacteria led to a measurable effect while that of green algae did not change. The addition of NOM protected all phytoplankton from direct UV irradiation, but cyanobacteria benefitted less. From this we conclude that UV-irradiated water enriched with NOM can adversely affect the physiology of cyanobacteria, but not of green algae, which might control phytoplankton composition and species-specific activities.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SINGLET OXYGEN; HUMIC SUBSTANCES; MICROCYSTIS-AERUGINOSA; ULTRAVIOLET-RADIATION; DELAYED FLUORESCENCE; PHOTOCHEMICAL FORMATION; ASCORBATE PEROXIDASE; COASTAL WATERS; SURFACE WATERS; GREEN-ALGAE; reactive oxygen species; Microcystis aeruginosa; green algae; delayed fluorescence; phycocyanin |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Alumni or Retired Professors |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 29 Nov 2019 12:17 |
| Last Modified: | 29 Nov 2019 12:17 |
| URI: | https://pred.uni-regensburg.de/id/eprint/11077 |
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