Complete DATASET_Contrasting nonphotochemical quenching patterns under high light and darkness aligns with light niche occupancy in Arctic diatoms

Over the seasons, Arctic diatom species occupy shifting habitats defined by contrasting light climates, constrainedby snow and ice cover dynamics interacting with extreme photoperiod and solar angle variations. HowArctic diatom photoadaptation strategies differ across their heterogeneous light niches remains a poorly documentedbut crucial missing link to anticipate Arctic Ocean responses to shrinking sea-ice and increasing light. Toaddress this question, we selected five Arctic diatom species with diverse life traits, representative of distinct lightniches across the seasonal light environment continuum: from snow-covered dimly lit bottom ice to summerstratified waters. We studied their photoacclimation plasticity to two growth light levels and the subsequentresponses of their nonphotochemical quenching (NPQ) and xanthophyll cycle to both dark incubations and lightshifts. We deciphered NPQ and xanthophyll cycle tuning in darkness and their light-dependent induction kinetics,which aligned with species’ light niche occupancy. In ice-related species, NPQ was sustained in darkness andits induction was more reactive to moderate light shifts. Open-water species triggered strong NPQ induction indarkness and reached higher maximal NPQ under high light. Marginal ice zone species showed strong adaptationto light fluctuations with a dark response fine-tuned depending upon light history. We argue these traits areanchored in diverging photoadaption strategies fostering Arctic diatom success in their respective light niches.

历经四季更迭，北极硅藻物种栖息于随光照气候差异动态变化的生境中，此类生境的分布受积雪与冰盖动态变化调控，并与极端光周期、太阳角度变异相互作用。目前，关于北极硅藻的光适应策略在其异质性光生态位间的差异机制，相关研究鲜有记载，但这一环节却是预测北冰洋应对海冰缩减与光照增强响应的关键缺失点。为解答该问题，我们选取了5种具有不同生活特征的北极硅藻，它们分别代表了季节光照环境梯度（从积雪覆盖的昏暗冰底生境至夏季层化水体）中的不同光生态位。我们研究了它们对两种生长光照水平的光适应可塑性，以及非光化学淬灭（nonphotochemical quenching, NPQ）和叶黄素循环（xanthophyll cycle）在黑暗培养与光照转换条件下的后续响应。我们解析了黑暗环境中NPQ与叶黄素循环的调控机制，及其光照依赖的诱导动力学特征，上述特征与各物种的光生态位占据情况高度匹配。与冰栖息相关的物种，其NPQ在黑暗中持续存在，且对中等光照转换的响应更为敏锐；开阔水体物种则会在黑暗中诱导产生强烈的NPQ，并在高光条件下达到更高的最大NPQ值；冰缘带物种对光照波动具有极强的适应性，其黑暗响应会根据光照历史进行精细调控。我们认为，这些特征根植于差异化的光适应策略，正是这些策略助力北极硅藻在各自的光生态位中成功存续。