Medwed Cynthia, Karsten Ulf, Romahn Juliane, Kaiser Jérôme, Dellwig Olaf, Arz Helge, Kremp Anke
Leibniz Institute for Baltic Sea Research Warnemuende, Department of Biological Oceanography, Rostock, 18119, Germany.
Applied Ecology and Phycology, Institute of Biological Sciences, University of Rostock, Rostock, 18059, Germany.
ISME Commun. 2024 Nov 13;4(1):ycae140. doi: 10.1093/ismeco/ycae140. eCollection 2024 Jan.
Cyanobacterial blooms in the Baltic Sea proliferated in recent decades due to rising sea surface temperatures, resulting in significant ecological impacts. To elucidate their current success, we examined ecophysiological, biochemical, and morphological traits of recent and ~33-year-old strains of using a resurrection approach. The ability of many cyanobacteria to form dormant stages that can persist in anoxic sediments for decades provides a unique opportunity to study adaptive traits to past environmental conditions. A short sediment core from the Eastern Gotland Basin was processed to isolate strains of buried in 1987 ± 2 and 2020 ± 0.5 Common Era. Sequencing was used for species identification, followed by characterization of cell morphometry, carbon, nitrogen, and chlorophyll content. Photosynthetic performance was evaluated by using pulse-amplitude modulated fluorimetry and oxygen optodes to assess light and temperature requirements. Our results revealed trait changes in over the past 3 decades: Temperature optimum for photosynthesis shifted from 15.3-21.1°C, which is consistent with the past and present local SST. Recent strains exhibited increased carbon, nitrogen, and chlorophyll content despite decreased cell volume. The demonstrated adaptability of to increasing temperature suggests that this species will thrive in a warmer climate in the future. These insights will aid modeling efforts aimed at understanding and managing consequences of future cyanobacterial blooms in the Baltic Sea ecosystem.
近几十年来，由于海面温度上升，波罗的海蓝藻水华迅速扩散，造成了重大的生态影响。为了阐明它们当前成功的原因，我们采用复苏法研究了近期和大约33年前菌株的生态生理、生化和形态特征。许多蓝藻形成休眠阶段并能在缺氧沉积物中持续数十年的能力，为研究对过去环境条件的适应特性提供了独特的机会。对来自东哥特兰盆地的一个短沉积岩芯进行处理，以分离出公元1987±2年和2020±0.5年埋藏的菌株。测序用于物种鉴定，随后对细胞形态学、碳、氮和叶绿素含量进行表征。通过使用脉冲幅度调制荧光法和氧电极来评估光合性能，以评估对光照和温度的需求。我们的结果揭示了过去30年里该物种的特征变化：光合作用的最适温度从15.3-21.1°C转变，这与过去和现在当地的海表温度一致。尽管细胞体积减小，但近期菌株的碳、氮和叶绿素含量增加。该物种对温度升高表现出的适应性表明，它将在未来更温暖的气候中茁壮成长。这些见解将有助于开展建模工作，以理解和管理波罗的海生态系统中未来蓝藻水华的后果。
