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, Robert
• 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: 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=755164
• 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.

冰盖给我们理解北温带生态系统带来了后勤障碍，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，但当前全球气候变暖的趋势正在加强关注的必要性。面对气候变暖，我们对这些环境中导致水华发展的因素的预测越来越有信心，但是，由于识别导致水华减少的因素并确定这种生物量的命运变得更加困难。挑战我们能力的后勤考虑与包括海岸警卫队在内的两国机构及其破冰资产的现有合作关系，再加上我离这个研究地点很近，研究这些盛开的过程提供了一种可行的方法来研究广泛的欠缺的兴起和衰落。这项以假设为驱动的提案的核心是解决伊利湖冬季硅藻华的发育、命运和食物网相互作用的问题。总体而言，该提案强调了寄生在营养供应和营养等传统控制之外的新兴作用。通过显微镜和转录组分析发现的潜在寄生虫包括壶菌和卵菌，它们是在农业和水产养殖中引起疾病​​的众所周知的病原体。寄生虫相互作用来自观察，从水华宏转录组中挖掘出的最丰富的病毒序列与自然宿主是真菌的 dsRNA Partitiviridae 家族对齐，并且鉴于壶菌是已知的硅藻寄生虫，人们很容易推测这些病毒可能有助于控制寄生在伊利湖冰下硅藻群落上的壶菌。这些初步发现的意义是多方面的，并提供了框架。依靠多种微生物相互作用在调节水华命运中的作用，寄生虫实现了分流，减少了直接输出到底栖生物的碳量。在此过程中，寄生虫改变了水华。将生物量放入池中，更容易被中上层食物网的不同成员消耗。