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: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=711287
• 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.

在高山雪地的表面上，一个未开发的迷人细胞生物学的金矿正在生长。热爱的单细胞藻类在雪中定居，并支持在融化季节盛开的丰富的微观社区。绿藻会产生一种保护性的红色颜料，将雪绿，橙色或红色变成。因为它反映出太阳辐射少于白雪，所以彩色雪会导致局部温度升高，熔化更多和藻类的生长更多。 随着全球变暖的雪和冰的程度和季节性持续时间，有据迹象表明，剩余的雪地越来越多。我们对这些基于藻类的社区一无所知，这些社区在极端环境中蓬勃发展，这会受到气候变化和可能增强全球变暖的影响。 最终，该研究计划将发现新鲜的雪是如何定植的，以及物种之间的细胞相互作用如何在营养贫困，寒冷的栖息地中支持生命。我们将学习藻类如何使用其纤毛（鞭子样细胞附属物），是否遵循光线上游的融雪的铆钉；将细胞连接到基于粘液的社区；或识别并紧紧抓住伴侣。我们将学习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。同样在长期的视野中，我们将检验以下假设：在雪表面捕获和合成的固定碳，复杂的代谢物以及营养物质为高山环境的土壤提供了重要的输入。 我们的第一个目标是确定生活在当地高山雪地上的藻类，真菌和其他微生物的物种。使用荧光激活的细胞分选（FACS），DNA测序和微观观察，3名MSC学生和我将在当地高山雪地上建立微生物群落的多样性。我们将了解这些社区在一个赛季的过程中如何发展以及它们如何变化。基因表达研究将为学习各种生物如何一起工作提供基础。第二个目标是在我们设备齐全的细胞生物学实验室中使用现场实验和实验室研究来确定雪藻的神秘生活历史。最后，我们的第三个目标是发现藻类在每年春天的雪表面如何重新到达。有些人会在风中或下雪时到达，还是从下面的土壤中游泳？该研究计划内置的是为6名新研究生的培训机会，以及每年3名本科生和几位公民科学家。 该研究计划将帮助我们了解这些藻类在全球变暖的背景下加速高山雪地融化的作用。我们将为全球重要的微生物群落提供基础细胞生物学。正如发现科学中发生的那样，我们也可能会发现不可预见的价值的新型细胞机制。