Environmental Biophysics and Molecular Ecology Program, Department of Marine and Coastal Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA.
Photosynth Res. 2024 Mar;159(2-3):253-259. doi: 10.1007/s11120-023-01060-8. Epub 2023 Nov 29.
Phytoplankton in the ocean account for less than 1% of the global photosynthetic biomass, but contribute about 45% of the photosynthetically fixed carbon on Earth. This amazing production/biomass ratio implies a very high photosynthetic efficiency. But, how efficiently is the absorbed light used in marine photosynthesis? The introduction of picosecond and then femtosecond lasers for kinetic measurements in mid 1970s to 90 s was a revolution in basic photosynthesis research that vastly improved our understanding of the energy conversion processes in photosynthetic reactions. Until recently, the use of this technology in the ocean was not feasible due to the complexity of related instrumentation and the lack of picosecond lasers suitable for routine operation in the field. However, recent advances in solid-state laser technology and the development of compact data acquisition electronics led to the application of picosecond fluorescence lifetime analyses in the field. Here, we review the development of operational ultrasensitive picosecond fluorescence instruments to infer photosynthetic energy conversion processes in ocean ecosystems. This analysis revealed that, in spite of the high production/biomass ratio in marine phytoplankton, the photosynthetic energy conversion efficiency is exceptionally low-on average, ca. 50% of its maximum potential, suggesting that most of the contemporary open ocean surface waters are extremely nutrient deficient.
海洋中的浮游植物仅占全球光合作用生物量的不到 1%，但却贡献了地球上约 45%的光合作用固定碳。这种惊人的生产力/生物量比意味着非常高的光合作用效率。但是，海洋光合作用中吸收的光的利用效率有多高呢？在 20 世纪 70 年代中期到 90 年代，皮秒和飞秒激光被引入用于动力学测量，这是基础光合作用研究的一场革命，极大地提高了我们对光合作用反应中能量转换过程的理解。直到最近，由于相关仪器的复杂性以及缺乏适合现场常规操作的皮秒激光器，该技术在海洋中的应用还不可行。然而，固态激光技术的最新进展和紧凑数据采集电子设备的发展，使得皮秒荧光寿命分析在现场得到了应用。在这里，我们回顾了可操作的超灵敏皮秒荧光仪器的发展，以推断海洋生态系统中的光合作用能量转换过程。该分析表明，尽管海洋浮游植物的生产力/生物量比很高，但光合作用的能量转换效率却非常低——平均约为其最大潜力的 50%，这表明当今大部分开阔海洋表面水域都极度缺乏营养物质。
