Dark survival strategies in benthic diatoms from polar waters

极地浅水区高生产力的微型底栖动物主要是硅藻，它们必须在秋末和初春之间应对长时间的黑暗。由于这些生物的黑暗生存策略几乎没有人研究，将在实验室受控条件下对潜在机制进行全面和准确的评估，北极Kongsfjorden和南极波特湾有大量的代表性物种。要研究的机制包括最长存活期，这将使用各种细胞生物标记(大分子组成、超微结构、活力、活性)和遗传标记(参与金龙藻多糖和脂类降解的功能基因的表达)来确定。此外，还将通过测量生长和光合作用来评估重新照射后恢复的能力，以及温度对暗生存潜力的影响。将对北极和南极底栖硅藻进行比较，以勾勒出具体的反应模式，这可能与两个区域不同的冷水历史有关，因此与各自分类群对极端低温的适应程度不同有关。如果观测到的北极变暖等环境变化对底栖硅藻的黑暗生存潜力产生负面影响，它们作为极地地区重要初级生产者的生态功能可能会严重减弱，从而对所有较高的营养水平造成影响。

The highly productive microphytobenthos of polar shallow water zones is dominated by diatoms which have to cope with long periods of darkness between late autumn and early spring. Since the dark survival strategies of these organisms are almost unstudied, a comprehensive and precise evaluation of the underlying mechanisms will be carried out under controlled conditions in the laboratory with representative species abundant in the Arctic Kongsfjorden and the Antarctic Potter Cove. The mechanisms to be studied include the maximum survival period which will be determined using various cell biological markers (macromolecular composition, ultrastructure, viability, activity) as well as genetic markers (expression of functional genes involved in the degradation of chrysolaminaran and lipids). In addition, the capability to recover after re-irradiation by measuring growth and photosynthesis, and the effect of temperature on the dark survival potential will be evaluated. Arctic and Antarctic benthic diatoms will be compared to outline specific response patterns which are probably related to the different cold water history of both regions and hence to a different degree of adaptation to extreme low temperatures in the respective taxa. If environmental changes such as the observed Arctic warming are negatively affecting the dark survival potential of benthic diatoms, their ecological function as important primary producers in polar regions may be strongly reduced with consequences for all higher trophic levels.