Snow algae: life cycles, motility & community structure

雪藻：生命周期、运动性

• 批准号: RGPIN-2017-04904
• 负责人: Quarmby, Lynne
• 金额: $ 1.89万
• 依托单位: Simon Fraser University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=761199
• 关键词: Snow; algae; life; cycles; motility

An untapped gold mine of fascinating cell biology is growing on the surfaces of alpine snowfields. Cold-loving unicellular algae colonize the snow and support a rich microscopic community that blooms during the melt season. The green algae produce a protective red pigment, turning the snow green, orange or red. Because it reflects less solar radiation than white snow, coloured snow causes an increase in local temperature, more melting and more algal growth. As the extent and seasonal duration of snow and ice diminishes with global warming, there are indications of algal blooms on an increasing fraction of remaining snowfields. We know little about these algal-based communities that thrive in an extreme environment dramatically impacted by climate change and possibly amplifying global warming. Ultimately, this research program will discover how fresh snow is colonized and how cellular interactions between species support life in a nutrient poor, cold habitat. We will learn how the algae use their cilia (whip-like cellular appendages), whether to follow the rivulets of snowmelt upstream to the light; to attach the cell to a mucilage-based community; or to recognize and hold tight to mates. We will learn how sexual and asexual cell division and the formation of spores produce blooms on the snow. Also on the long-term horizon, we will test the hypothesis that the fixed carbon, complex metabolites, and nutrients captured and synthesized on the surface of the snow provide important inputs to the soil of alpine environments. Our first objective will be to determine the species of algae, fungi & other microbes that live on local alpine snowfields. Using fluorescence-activated cell sorting (FACS), DNA sequencing, and microscopic observations, 3 MSc students and I will establish the diversity of microbial communities on local alpine snowfields. We will learn how those communities develop over the course of a season and how they vary year to year. Gene expression studies will provide a foundation for learning how the various organisms work together. The second objective is to work out the enigmatic life histories of snow algae, using both field experiments and lab studies in our well-equipped cell biology laboratory. Finally, our third objective is to discover how algae arrive afresh on the surface of the snow each spring. Do some arrive on the wind, or with the snow or do they all swim up from the soil below? Built into the research program are training opportunities for 6 new graduate students, along with 3 undergraduate students and several citizen-scientists every year. The research program will help us understand the role played by these algae in accelerating the melting of alpine snowfields in the context of global warming. We will provide the foundational cell biology for a globally significant microbial community. As happens in discovery science, we may also uncover novel cellular mechanisms of unforeseen value.

一座尚未开发的金矿，迷人的细胞生物学正在高山雪原的表面生长。喜欢寒冷的单细胞藻类在雪中定居，并在融化季节支持丰富的微观群落。这些绿色藻类产生一种保护性的红色色素，使雪变成绿色、橙子或红色。因为它反射的太阳辐射比白色雪少，彩色雪会导致当地温度升高，更多的融化和更多的藻类生长。 随着冰雪的范围和季节性持续时间随着全球变暖而减少，有迹象表明，在剩余的雪原上，藻类大量繁殖的比例越来越大。我们对这些以藻类为基础的社区知之甚少，这些社区在极端环境中蓬勃发展，受到气候变化的严重影响，并可能加剧全球变暖。 最终，这项研究计划将发现新鲜的雪是如何被殖民的，以及物种之间的细胞相互作用如何在营养不良的寒冷栖息地支持生命。我们将学习藻类如何使用它们的纤毛（鞭子一样的细胞附属物），是否跟随融雪的溪流逆流而上，以获得光明;将细胞附着在基于粘液的社区;或者识别并紧紧抓住配偶。我们将学习有性和无性细胞分裂以及孢子的形成如何在雪地上产生花朵。此外，在长期的视野中，我们将测试的假设，固定碳，复杂的代谢产物，并在雪的表面上捕获和合成的营养物质提供了重要的输入到高山环境的土壤。 我们的第一个目标是确定生活在当地高山雪原上的藻类、真菌和其他微生物的种类。使用荧光激活细胞分选（FACS），DNA测序和显微镜观察，3个硕士学生和我将建立当地高山雪原上微生物群落的多样性。我们将了解这些社区如何在一个季节的过程中发展，以及它们每年如何变化。基因表达研究将为了解各种生物体如何协同工作提供基础。第二个目标是在我们设备齐全的细胞生物学实验室中进行实地实验和实验室研究，以了解雪藻神秘的生活史。最后，我们的第三个目标是发现藻类是如何在每年春天重新到达雪表面的。有些是乘着风来的，还是随着雪来的，还是它们都是从下面的土壤里游上来的？该研究计划每年为6名新研究生、沿着3名本科生和几名公民科学家提供培训机会。该研究计划将帮助我们了解在全球变暖的背景下，这些藻类在加速高山雪原融化方面所发挥的作用。我们将为全球重要的微生物群落提供基础细胞生物学。就像发现科学中发生的那样，我们也可能发现具有不可预见价值的新细胞机制。