Biology Department, Western Washington University, Bellingham, WA 98225, United States.
Department of Plant and Microbial Biology and the BioTechnology Institute, University of Minnesota St. Paul, MN 55108, United States.
FEMS Microbiol Ecol. 2023 Oct 17;99(11). doi: 10.1093/femsec/fiad106.
Snow algal blooms frequently occur throughout alpine and polar environments during spring and summer months; however, our understanding of bloom dynamics is limited. We tracked a recurrent bloom of Chlainomonas sp. on Upper Bagley Lake in the North Cascade Mountains, USA, to assess the spatiotemporal dynamics in bloom color intensity, community photophysiology, and community composition over eight weeks. We found that the algae biomass had a dynamic patchy distribution over space and time, which was decoupled from changes in community composition and life-cycle progress averaged across the bloom. The proportional representation of Chlainomonas sp. remained consistent throughout the study while the overall community composition shows a progression through the bloom. We found that community photophysiology, measured by the maximum quantum yield of PSII (Fv/Fm), decreased on average throughout the bloom. These findings suggest that the Chlainomonas sp. community on Bagley Lake is not simply an algal bloom with rapid increase in biomass followed by a population crash, as is often seen in aquatic systems, though there is a physiological trajectory and sensitivity to environmental stress. These results contribute to our understanding of the biology of Chlainomonas sp. and its response to environmental stress, specifically an extreme warming event.
雪藻水华在春季和夏季经常出现在高山和极地环境中;然而，我们对水华动态的理解是有限的。我们跟踪了美国北喀斯喀特山脉上的巴格利湖上层的 Chlainomonas sp. 的周期性水华，以评估在八周内水华颜色强度、群落光生理和群落组成的时空动态。我们发现，藻类生物量在空间和时间上具有动态的斑块分布，与群落组成的变化和整个水华过程中的生命周期进展无关。Chlainomonas sp. 的比例代表在整个研究过程中保持一致，而整个群落组成则显示出随着水华的进行而逐渐发展。我们发现，群落光生理，由 PSII 的最大量子产量 (Fv/Fm) 衡量，在整个水华过程中平均下降。这些发现表明，Bagley 湖上的 Chlainomonas sp. 群落并不是简单的藻类水华，其生物量迅速增加，随后是种群崩溃，这在水生系统中很常见，尽管存在生理轨迹和对环境胁迫的敏感性。这些结果有助于我们了解 Chlainomonas sp. 的生物学及其对环境胁迫的反应，特别是对极端变暖事件的反应。
