Exploring Variability of Trichodesmium Photophysiology Using Multi-Excitation Wavelength Fast Repetition Rate Fluorometry
Fast repetition rate fluorometry (FRRf) allows for rapid non-destructive assessment of phytoplankton photophysiology in situ yet has rarely been applied to Trichodesmium. This gap reflects long-standing concerns that Trichodesmium (and other cyanobacteria) contain pigments that are less effective at...
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Frontiers Media S.A.
2022-04-01
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| Series: | Frontiers in Microbiology |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmicb.2022.813573/full |
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| author | Yuanli Zhu Yuanli Zhu Yuanyuan Feng Thomas J. Browning Zuozhu Wen David J. Hughes Qiang Hao Qiang Hao Ruifeng Zhang Qicheng Meng Mark L. Wells Mark L. Wells Zhibing Jiang P. A. K. N. Dissanayake W. N. C. Priyadarshani Lu Shou Jiangning Zeng Fei Chai |
| author_facet | Yuanli Zhu Yuanli Zhu Yuanyuan Feng Thomas J. Browning Zuozhu Wen David J. Hughes Qiang Hao Qiang Hao Ruifeng Zhang Qicheng Meng Mark L. Wells Mark L. Wells Zhibing Jiang P. A. K. N. Dissanayake W. N. C. Priyadarshani Lu Shou Jiangning Zeng Fei Chai |
| author_sort | Yuanli Zhu |
| collection | DOAJ |
| description | Fast repetition rate fluorometry (FRRf) allows for rapid non-destructive assessment of phytoplankton photophysiology in situ yet has rarely been applied to Trichodesmium. This gap reflects long-standing concerns that Trichodesmium (and other cyanobacteria) contain pigments that are less effective at absorbing blue light which is often used as the sole excitation source in FRR fluorometers—potentially leading to underestimation of key fluorescence parameters. In this study, we use a multi-excitation FRR fluorometer (equipped with blue, green, and orange LEDs) to investigate photophysiological variability in Trichodesmium assemblages from two sites. Using a multi-LED measurement protocol (447+519+634 nm combined), we assessed maximum photochemical efficiency (Fv/Fm), functional absorption cross section of PSII (σPSII), and electron transport rates (ETRs) for Trichodesmium assemblages in both the Northwest Pacific (NWP) and North Indian Ocean in the vicinity of Sri Lanka (NIO-SL). Evaluating fluorometer performance, we showed that use of a multi-LED measuring protocol yields a significant increase of Fv/Fm for Trichodesmium compared to blue-only excitation. We found distinct photophysiological differences for Trichodesmium at both locations with higher average Fv/Fm as well as lower σPSII and non-photochemical quenching (NPQNSV) observed in the NWP compared to the NIO-SL (Kruskal–Wallis t-test df = 1, p < 0.05). Fluorescence light response curves (FLCs) further revealed differences in ETR response with a lower initial slope (αETR) and higher maximum electron turnover rate (ETRPSIImax) observed for Trichodesmium in the NWP compared to the NIO-SL, translating to a higher averaged light saturation EK (= ETRPSIImax/αETR) for cells at this location. Spatial variations in physiological parameters were both observed between and within regions, likely linked to nutrient supply and physiological stress. Finally, we applied an algorithm to estimate primary productivity of Trichodesmium using FRRf-derived fluorescence parameters, yielding an estimated carbon-fixation rate ranging from 7.8 to 21.1 mgC mg Chl-a–1 h–1 across this dataset. Overall, our findings demonstrate that capacity of multi-excitation FRRf to advance the application of Chl-a fluorescence techniques in phytoplankton assemblages dominated by cyanobacteria and reveals novel insight into environmental regulation of photoacclimation in natural Trichodesmium populations. |
| first_indexed | 2024-12-13T22:38:14Z |
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| issn | 1664-302X |
| language | English |
| last_indexed | 2024-12-13T22:38:14Z |
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| series | Frontiers in Microbiology |
| spelling | doaj.art-e4343821b2004866b92f3827313e5d442022-12-21T23:28:56ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2022-04-011310.3389/fmicb.2022.813573813573Exploring Variability of Trichodesmium Photophysiology Using Multi-Excitation Wavelength Fast Repetition Rate FluorometryYuanli Zhu0Yuanli Zhu1Yuanyuan Feng2Thomas J. Browning3Zuozhu Wen4David J. Hughes5Qiang Hao6Qiang Hao7Ruifeng Zhang8Qicheng Meng9Mark L. Wells10Mark L. Wells11Zhibing Jiang12P. A. K. N. Dissanayake13W. N. C. Priyadarshani14Lu Shou15Jiangning Zeng16Fei Chai17State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, ChinaKey Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, ChinaSchool of Oceanography, Shanghai Jiao Tong University, Shanghai, ChinaMarine Biogeochemistry Division, GEOMAR Helmholtz Centre for Ocean Research, Kiel, GermanyState Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, ChinaClimate Change Cluster, Faculty of Science, University of Technology Sydney, Ultimo, NSW, AustraliaState Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, ChinaKey Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, ChinaSchool of Oceanography, Shanghai Jiao Tong University, Shanghai, ChinaState Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, ChinaState Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, ChinaDarling Marine Center, University of Maine, Walpole, ME, United StatesKey Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, ChinaDepartment of Oceanography and Marine Geology, Faculty of Fisheries and Marine Sciences and Technology, University of Ruhuna, Matara, Sri LankaNational Institute of Oceanography and Marine Sciences, National Aquatic Resources Research and Development Agency, Colombo, Sri LankaKey Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, ChinaKey Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, ChinaState Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, ChinaFast repetition rate fluorometry (FRRf) allows for rapid non-destructive assessment of phytoplankton photophysiology in situ yet has rarely been applied to Trichodesmium. This gap reflects long-standing concerns that Trichodesmium (and other cyanobacteria) contain pigments that are less effective at absorbing blue light which is often used as the sole excitation source in FRR fluorometers—potentially leading to underestimation of key fluorescence parameters. In this study, we use a multi-excitation FRR fluorometer (equipped with blue, green, and orange LEDs) to investigate photophysiological variability in Trichodesmium assemblages from two sites. Using a multi-LED measurement protocol (447+519+634 nm combined), we assessed maximum photochemical efficiency (Fv/Fm), functional absorption cross section of PSII (σPSII), and electron transport rates (ETRs) for Trichodesmium assemblages in both the Northwest Pacific (NWP) and North Indian Ocean in the vicinity of Sri Lanka (NIO-SL). Evaluating fluorometer performance, we showed that use of a multi-LED measuring protocol yields a significant increase of Fv/Fm for Trichodesmium compared to blue-only excitation. We found distinct photophysiological differences for Trichodesmium at both locations with higher average Fv/Fm as well as lower σPSII and non-photochemical quenching (NPQNSV) observed in the NWP compared to the NIO-SL (Kruskal–Wallis t-test df = 1, p < 0.05). Fluorescence light response curves (FLCs) further revealed differences in ETR response with a lower initial slope (αETR) and higher maximum electron turnover rate (ETRPSIImax) observed for Trichodesmium in the NWP compared to the NIO-SL, translating to a higher averaged light saturation EK (= ETRPSIImax/αETR) for cells at this location. Spatial variations in physiological parameters were both observed between and within regions, likely linked to nutrient supply and physiological stress. Finally, we applied an algorithm to estimate primary productivity of Trichodesmium using FRRf-derived fluorescence parameters, yielding an estimated carbon-fixation rate ranging from 7.8 to 21.1 mgC mg Chl-a–1 h–1 across this dataset. Overall, our findings demonstrate that capacity of multi-excitation FRRf to advance the application of Chl-a fluorescence techniques in phytoplankton assemblages dominated by cyanobacteria and reveals novel insight into environmental regulation of photoacclimation in natural Trichodesmium populations.https://www.frontiersin.org/articles/10.3389/fmicb.2022.813573/fullTrichodesmiumfast repetition rate fluorometerphotophysiologyphotobiologyphotoacclimatiioniron stress |
| spellingShingle | Yuanli Zhu Yuanli Zhu Yuanyuan Feng Thomas J. Browning Zuozhu Wen David J. Hughes Qiang Hao Qiang Hao Ruifeng Zhang Qicheng Meng Mark L. Wells Mark L. Wells Zhibing Jiang P. A. K. N. Dissanayake W. N. C. Priyadarshani Lu Shou Jiangning Zeng Fei Chai Exploring Variability of Trichodesmium Photophysiology Using Multi-Excitation Wavelength Fast Repetition Rate Fluorometry Frontiers in Microbiology Trichodesmium fast repetition rate fluorometer photophysiology photobiology photoacclimatiion iron stress |
| title | Exploring Variability of Trichodesmium Photophysiology Using Multi-Excitation Wavelength Fast Repetition Rate Fluorometry |
| title_full | Exploring Variability of Trichodesmium Photophysiology Using Multi-Excitation Wavelength Fast Repetition Rate Fluorometry |
| title_fullStr | Exploring Variability of Trichodesmium Photophysiology Using Multi-Excitation Wavelength Fast Repetition Rate Fluorometry |
| title_full_unstemmed | Exploring Variability of Trichodesmium Photophysiology Using Multi-Excitation Wavelength Fast Repetition Rate Fluorometry |
| title_short | Exploring Variability of Trichodesmium Photophysiology Using Multi-Excitation Wavelength Fast Repetition Rate Fluorometry |
| title_sort | exploring variability of trichodesmium photophysiology using multi excitation wavelength fast repetition rate fluorometry |
| topic | Trichodesmium fast repetition rate fluorometer photophysiology photobiology photoacclimatiion iron stress |
| url | https://www.frontiersin.org/articles/10.3389/fmicb.2022.813573/full |
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