DATA for “Warming winters in lakes: Later ice onset promotes consumer overwintering and shapes springtime planktonic food webs” DOI: org/10.1073/pnas.2114840118

NOTE: <br>-Please use the latest version of the dataset (now V6), which includes info re. units and better corresponds to the code. Additional updates may be made over time. <br>-Details re. calculations and conversions are provided in the Methods/Appendix of the paper.-Contact info: [e-mail] <br><br>ABSTRACT:<br>Global climate warming is causing the loss of freshwater ice around the Northern Hemisphere. Although the timing and duration of ice covers are known to regulate ecological processes in seasonally ice-covered ecosystems, the consequences of shortening winters for freshwater biota are poorly understood owing to the scarcity of under-ice research. Here, we present one of the first in-lake experiments to postpone ice-cover onset (by ≤21 d), thereby extending light availability (by ≤40 d) in early winter, and explicitly demonstrate cascading effects on pelagic food web processes and phenologies. Delaying ice-on elicited a sequence of events from winter to spring: 1) relatively greater densities of algal resources and primary consumers in early winter; 2) an enhanced prevalence of winter-active (overwintering) consumers throughout the ice-covered period, associated with augmented storage of high-quality fats likely due to a longer access to algal resources in early winter; and 3) an altered trophic structure after ice-off, with greater initial springtime densities of overwintering consumers driving stronger, earlier top-down regulation, effectively reducing the spring algal bloom. Increasingly later ice onset may thus promote consumer overwintering, which can confer a competitive advantage on taxa capable of surviving winters upon ice-off; a process that may diminish spring food availability for other consumers, potentially disrupting trophic linkages and energy flow pathways over the subsequent open-water season. In considering a future with warmer winters, these results provide empirical evidence that may help anticipate phenological responses to freshwater ice loss and, more broadly, constitute a case of climate-induced cross-seasonal cascade on realized food web processes.

注意事项：<br>- 请使用该数据集的最新版本（当前为V6），该版本包含单位相关信息，且与代码的适配性更佳。后续或持续推出更新。<br>- 计算与转换的详细说明已在论文的「方法/附录」章节中提供。<br>- 联系方式：[e-mail]<br><br>摘要：<br>全球气候变暖正导致北半球周边的淡水冰逐渐消融。尽管学界已知冰盖的形成时间与持续时长会调控季节性冰封生态系统中的生态过程，但由于冰下研究的匮乏，冬季时长缩短对淡水生物群落的影响仍未得到充分阐释。本研究开展了首批针对推迟冰封起始时间的湖内原位实验之一，将冰封起始时间推迟≤21天，从而将初冬的光照可利用时长延长≤40天，并明确证实了其对浮游食物网过程与物候的级联效应。推迟冰封起始引发了从冬季到春季的一系列连锁反应：1）初冬时节藻类资源与初级消费者的密度相对更高；2）整个冰封期内冬季活跃（overwintering）消费者的占比上升，这一现象或与初冬更长时间的藻类资源获取期带来的优质脂肪积累提升有关；3）冰融后营养结构发生改变，越冬消费者的春季初始密度更高，由此驱动了更强且更早的下行调控，最终有效抑制了春季藻华。因此，冰封起始时间愈发延后可能会促进消费者的越冬行为，这将为能够在冰融后顺利越冬的类群赋予竞争优势；该过程可能会削弱其他消费者的春季食物可获得性，进而在后续的敞水期内破坏营养联系与能量流动路径。针对冬季变暖的未来场景，本研究结果提供了可用于预测淡水冰消失带来的物候响应的实证证据；更广泛地说，本研究揭示了气候诱导的跨季节级联效应对实际食物网过程的影响案例。