Unraveling novel microbial community interactions involved in the decline and fate of an under-ice diatom bloom

揭示与冰下硅藻华衰落和命运相关的新型微生物群落相互作用

• 批准号: RGPIN-2019-03943
• 负责人: McKay, RMichael
• 金额: $ 3.42万
• 依托单位: University of Windsor
• 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=713863
• 关键词: Unraveling; novel; microbial; community; interactions

Ice cover presents a logistical obstacle to our understanding of north temperate ecosystems. Reflecting this, ecosystem models frequently neglect or underestimate biological parameters associated with ice cover including potentially high rates of primary productivity. Yet current warming trends in global climate are reinforcing the need to focus attention on ice covered environments. We are growing more confident in our predictions of factors contributing to bloom development in these environments in the face of climate warming. However, identifying factors that lead to bloom decline and determining the fate of this biomass is more difficult owing to logistical considerations that challenge our abilities to study these blooms from 'rise to fall'. Existing collaborative relationships with binational agencies including Coast Guards and their ice-breaking assets combined with my close proximity to this study site offer a feasible approach to study the rise and decline of an expansive under-ice diatom bloom in Lake Erie. Central to this hypothesis-driven proposal are questions addressing the development, fate and foodweb interactions of Lake Erie's winter diatom bloom. Broadly, the proposal highlights the emerging role of parasitism beyond conventional controls such as nutrient supply and grazing, in regulating plankton dynamics during a poorly studied season. Amongst potential parasites identified by microscopy and transcriptomic analysis were chytrid fungi and oomycetes, fungal-like protists that are well-known pathogens causing disease in agriculture and aquaculture. Additional insights into novel host-parasite interactions came from the observation that the most abundant viral sequences mined from a bloom metatranscriptome aligned with the dsRNA Partitiviridae family whose natural hosts are fungi and plants. Given that chytrids are known parasites of diatoms, it is tempting to speculate that these viruses may help control chytrids which in turn are parasitic on the under-ice Lake Erie diatom community. The implications of these preliminary findings are manifold and provide the framework to hypothesize roles for diverse microbial interactions in regulating bloom fate whereby parasites effectuate a shunt reducing the amount of carbon that is directly exported to the benthos. In doing so, parasites transform bloom biomass into pools more readily consumed by diverse members of the pelagic food web.

冰盖是我们理解北温带生态系统的一个后勤障碍。反映这一点，生态系统模型经常忽视或低估与冰盖相关的生物参数，包括潜在的高初级生产力。然而，目前全球气候变暖的趋势正在加强关注冰雪覆盖环境的必要性。面对气候变暖，我们对这些环境中促成水华发展的因素的预测越来越有信心。然而，确定导致开花下降的因素，并确定这种生物量的命运是比较困难的，由于后勤方面的考虑，挑战我们的能力，研究这些开花从“上升到下降”。现有的合作关系与两国机构，包括海岸警卫队和他们的破冰资产结合我的密切接近这个研究地点提供了一个可行的方法来研究的兴起和衰落的一个广阔的冰下硅藻水华伊利湖。这个假设驱动的建议的核心是解决伊利湖冬季硅藻水华的发展，命运和食物网相互作用的问题。总的来说，该提案强调了寄生虫在营养供应和放牧等传统控制之外的新兴作用，在研究不足的季节调节浮游生物动态。通过显微镜和转录组学分析鉴定的潜在寄生虫包括壶菌和卵菌，真菌样原生生物是农业和水产养殖中引起疾病的已知病原体。对新的宿主-寄生虫相互作用的额外见解来自于以下观察：从Bloom元转录组中挖掘的最丰富的病毒序列与dsRNA Partitiviridae家族对齐，该家族的天然宿主是真菌和植物。鉴于壶菌是已知的硅藻寄生虫，很容易推测这些病毒可能有助于控制壶菌，而壶菌又寄生在冰下的伊利湖硅藻群落中。这些初步研究结果的影响是多方面的，并提供了一个框架来假设不同的微生物在调节水华命运的相互作用，从而寄生虫实现分流，减少直接出口到底栖生物的碳量。在这样做的过程中，寄生虫将水华生物量转化为更容易被浮游食物网的不同成员消耗的水池。