Are glacier surfaces the last refuge of an evolutionarily ancient lineage of unknown fungi?

冰川表面是未知真菌进化古老谱系的最后避难所吗？

• 批准号: NE/K000942/1
• 负责人: Arwyn Edwards
• 金额: $ 8.01万
• 依托单位: Aberystwyth University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FK000942%2F1
• 关键词: glacier; surfaces; last; refuge; evolutionarily

Glaciers and ice-sheets are increasingly recognized as the homes of surprisingly diverse and active microbial ecosystems. Even the mere prospect of life in Antarctic subglacial lakes, isolated for many millennia, attracts major international attention and investment. However since life certainly flourishes in unusual habitats on glacier surfaces. these should not be overlooked in our attempts to explore microbial biodiversity. Cryoconite holes are one such habitat, formed when rocky dusts are colonized by a diverse and highly active microbial consortium, forming a darkened microbe-mineral aggregate which increases the transfer of the sun's energy to ice and thus accelerates surface melt. My doctoral studies centred on the diversity and functioning of the bacterial community of cryoconite, which is dominated by organisms closely related to taxa in a broad range of habitats world-wide. In stark contrast, of the eukaryotes inhabiting cryoconite on High Arctic glaciers, the most abundant group by biomass, Fungi, appears strongly dominated by two related groups of fungi hitherto unknown to science. These fungi account for 75% of the sequences in collections of fungal DNA extracted from Svalbard cryoconite, and according to microscopy using genetic stains specific to the group, are derived from small ovoid cells attached to debris. Sequenced genes from specific DNA tests for the fungi demonstrate their presence in cryoconite worldwide suggesting a broad geographic range while the absence of affiliated sequences from DNA databases and the failure to detect the group in periglacial habitats imply their restriction to the cryoconite group near the root of the fungal tree of life and provide a crudely estimated divergence during the Neoproterozoic era, which consisted of major world-wide glaciations, including a hypothesized "Snowball Earth". Little else is known about these fungi, tentatively named the "cryomycetes". Therefore, I seek support to detail their evolutionary history, population structure, ecological functions and interactions. Doing so will permit the testing of the hypotheses that i)"cryomycetes" assume a significant role in the functioning of the extant cryoconite ecosystem ii)they form a major new branch on the fungal tree of life iii)cryoconite holes have formed a stable refuge for these fungi over glacial cycles. As a consequence, I anticipate insights into the interactions between cryoconite biodiversity and melting glaciers, both in the present day, and potentially in the postulated transition from a Neoproterozoic "Snowball" to a "Mudball" Earth.

冰川和冰盖越来越被认为是令人惊讶的多样性和活跃的微生物生态系统的家园。即使仅仅是南极冰下湖泊中生命的前景，也吸引了国际上的大量关注和投资。然而，由于生命肯定会在冰川表面的不寻常栖息地栖息。在我们探索微生物生物多样性的尝试中，这些都不应被忽视。冰尘洞就是这样一个栖息地，当岩石尘埃被多样化和高度活跃的微生物群落殖民时，形成了一个黑暗的微生物-矿物聚集体，增加了太阳能向冰的转移，从而加速了表面融化。我的博士研究集中在cryoconite细菌群落的多样性和功能，这是占主导地位的生物密切相关的类群在广泛的栖息地世界各地。与此形成鲜明对比的是，在北极冰川上的真核生物中，生物量最丰富的真菌类似乎被科学界迄今未知的两种相关真菌类所主导。这些真菌占75%的序列在收集的真菌DNA提取自斯瓦尔巴群岛cryoconite，并根据显微镜下使用遗传染料特定的组，是来自小卵形细胞附着在碎片。来自真菌的特定DNA测试的测序基因表明它们存在于世界范围内的冰尘中，这表明了广泛的地理范围，而DNA数据库中没有附属序列，并且未能在冰缘生境中检测到该组，这意味着它们局限于靠近真菌生命树根部的冰尘组，并提供了新元古代期间的粗略估计分歧，其中包括世界范围内的主要冰川，包括假设的“雪球地球”。关于这些暂时被命名为“cryomycetes”的真菌，我们所知甚少。因此，我寻求支持，详细介绍它们的进化历史，种群结构，生态功能和相互作用。这样做将允许测试以下假设：i）“冰菌”在现存冰尘生态系统的功能中发挥重要作用ii）它们形成真菌生命树上的一个主要新分支iii）冰尘洞已经形成了这些真菌在冰川循环中的稳定避难所。因此，我预计到cryoconite生物多样性和冰川融化之间的相互作用的见解，无论是在今天，并可能在假设的过渡从新元古代的“雪球”到“泥球”地球。

项目成果

A metagenomic snapshot of taxonomic and functional diversity in an alpine glacier cryoconite ecosystem

• DOI: 10.1088/1748-9326/8/3/035003
• 发表时间: 2013-07-01
• 期刊: ENVIRONMENTAL RESEARCH LETTERS
• 影响因子: 6.7
• 作者: Edwards, Arwyn;Pachebat, Justin A.;Sattler, Birgit
• 通讯作者: Sattler, Birgit

Microbial dynamics in glacier forefield soils show succession is not just skin deep.

冰川前田土壤中的微生物动态表明，演替不仅仅是表面现象。

• DOI: 10.1111/mec.13098
• 发表时间: 2015
• 期刊: Molecular ecology
• 影响因子: 4.9
• 作者: Edwards A

A germ theory for glacial systems?

• DOI: 10.1002/wat2.1029
• 发表时间: 2014-07-01
• 期刊: WILEY INTERDISCIPLINARY REVIEWS-WATER
• 影响因子: 8.2
• 作者: Edwards, Arwyn;Irvine-Fynn, Tristram;Rassner, Sara M. E.
• 通讯作者: Rassner, Sara M. E.

Contrasts between the cryoconite and ice-marginal bacterial communities of Svalbard glaciers

• DOI: 10.3402/polar.v32i0.19468
• 发表时间: 2013-01-01
• 期刊: POLAR RESEARCH
• 影响因子: 1.9
• 作者: Edwards, Arwyn;Rassner, Sara M. E.;Griffith, Gareth Wyn
• 通讯作者: Griffith, Gareth Wyn