Summers Natalie, Fragoso Glaucia M, Johnsen Geir
Centre for Autonomous Marine Operations and Systems (AMOS), Trondheim Biological Station, Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
University Centre in Svalbard (UNIS), Longyearbyen, Norway.
Sci Rep. 2023 Oct 20;13(1):17971. doi: 10.1038/s41598-023-44026-5.
Arctic macroalgae species have developed different growth strategies to survive extreme seasonal changes in irradiance in polar regions. We compared photophysiological parameters such as the light saturation parameter (E) and pigment composition of green, red, and brown macroalgae collected in January (Polar Night) and October 2020 (end of the light season). Macroalgae in January appeared healthier (morphologically) and had longer lamina (new growth) than those in October. E values for red, and brown algae were higher with lower maximum quantum yield of PS II fluorescence (F/F) in January versus October. Furthermore, in January, new tissues in kelp species had higher E than the older tissue. Higher E and lower F/F during the Polar Night indicates that the photosynthetic apparatus is active but slow. Furthermore, we discuss Chlorophyll (Chl) a emission spectra under blue and green excitation light to determine the ratio of Chl a in photosystem II (PS II) vs photosystem I (PS I). Absorbance spectra of P. palmata was used to interpret the emission spectra. The observed spectral shifts in the absorbance and reflectance spectra of different macroalgae is discussed. Photophysiological methods provide health information complementary to future mapping and monitoring of macroalgae. These results reveal that macroalgae grow new tissue in darkness.
北极大型藻类物种已经形成了不同的生长策略，以在极地地区光照强度极端的季节性变化中生存。我们比较了2020年1月（极夜）和10月（光照季节结束时）采集的绿藻、红藻和褐藻的光生理参数，如光饱和参数（E）和色素组成。1月的大型藻类在形态上看起来更健康，叶片（新生长部分）也比10月的更长。与10月相比，1月红藻和褐藻的E值更高，而PS II荧光的最大量子产率（F/F）更低。此外，1月海带物种的新组织比老组织具有更高的E值。极夜期间较高的E值和较低的F/F表明光合机构活跃但速度较慢。此外，我们讨论了叶绿素（Chl）a在蓝光和绿光激发下的发射光谱，以确定光系统II（PS II）和光系统I（PS I）中Chl a的比例。利用掌状红皮藻的吸收光谱来解释发射光谱。讨论了不同大型藻类吸收光谱和反射光谱中观察到的光谱变化。光生理方法为未来大型藻类的测绘和监测提供了补充健康信息。这些结果表明，大型藻类在黑暗中生长新组织。
