Microbial diversity and water column measurements from sea ice, Chukchi Sea, 2013-2018

This work explores the hypothesis that parasitic chytrids (fungi) may change the seasonal cycle of ice algal abundances and diversity by targeting specific ice algal taxa, mainly certain diatom species. In addressing this hypothesis, this grant aims at providing information on the spatial and temporal patterns of abundance, and diversity of marine fungi in arctic sea ice in comparison to water column information and relate this information to various environmental data which will include salinity, temperature, and as well as ice thickness and snow cover. Field work will be conducted between 2014 and 2015 on the fast ice in Barrow and in spring of 2015 on RV (Research Vessel) Sikulaq in the Bering sea. The combined data set will allow for a refined interpretation of the relevance of the parasitic fungi for the food web structure in arctic seas. This study is the first to explore these ecological processes in polar sea ice and can potentially lead to a paradigm change on carbon processing similar to one seen recently in freshwater science. Detailed studies on marine chytrids are rare in any ice covered marine region and these observations might stimulate new research in both Arctic and Antarctic regions. Biological community composition information will contribute to diversity research on fungi in general and the understanding of global patterns in microbial biodiversity linked. The research will have broader impacts in its engagement in teaching activities through training of two participating UAF (University of Alaska Fairbanks) students and through high school seminars as well as meeting with teachers in Barrow, and their potential participation in expeditions. A broad public audience including minorities will be kept informed through media coverage and project-specific web pages documenting the field and lab work. This data has been published in the following peer-reviewed journal articles BT Hassett, R Gradinger (2017) Eukaryotic microbial richness increases with latitude and decreasing temperature in the Pacific Subarctic domain in late winter Polar Biology 40 (11), 2161-2169 BT Hassett, ALL Ducluzeau, RE Collins, R Gradinger (2017) Spatial distribution of aquatic marine fungi across the western Arctic and sub‐arctic. Environmental Microbiology 19 (2), 475-484 BT Hassett, R Gradinger (2016) Chytrids dominate arctic marine fungal communities. Environmental Microbiology 18 (6), 2001-2009.

本研究旨在验证如下假说：寄生性壶菌（parasitic chytrids，一类真菌）可通过靶向特定冰藻类群（主要为部分硅藻物种），改变冰藻丰度与多样性的季节周期。为验证该假说，本资助项目将获取北极海冰中海洋真菌丰度的时空分布模式与多样性信息，并与水柱相关数据进行对比，同时将上述数据与盐度、温度、海冰厚度及积雪覆盖等各类环境数据建立关联。野外调查工作将于2014至2015年间在巴罗（Barrow）的固定冰（fast ice）区开展，并于2015年春季在白令海的「西库拉克号」研究船（RV Sikulaq，Research Vessel）上进行。整合后的数据集将支持对寄生真菌在北极海域食物网结构中相关作用的精细化阐释。本研究是首个在极地海冰中探索此类生态过程的工作，或可推动碳循环处理研究的范式革新，类似近期淡水科学领域取得的范式突破。在所有覆冰海洋区域中，针对海洋壶菌的详细研究均较为匮乏，本研究的观测结果或可激发北极与南极地区的相关新研究。海洋真菌群落组成信息将为通用真菌多样性研究提供参考，并助力理解与全球微生物生物多样性模式相关的机制。本研究将通过培训两名参与项目的阿拉斯加费尔班克斯大学（University of Alaska Fairbanks, UAF）学生、开展高中研讨会以及与巴罗当地教师交流等活动推进教学工作，并支持学生参与科考活动，以此产生更广泛的社会影响。研究团队将通过媒体报道及专属项目官网记录野外与实验室工作进展，向包括少数族裔在内的广大公众普及相关研究内容。本数据集已发表于以下同行评审期刊论文：BT Hassett、R Gradinger (2017) 太平洋亚北极区域晚冬时期真核微生物丰富度随纬度升高与温度降低而增加，《极地生物学》（Polar Biology）40(11): 2161-2169；BT Hassett、ALL Ducluzeau、RE Collins、R Gradinger (2017) 西北极与亚北极海域水生真菌的空间分布，《环境微生物学》（Environmental Microbiology）19(2): 475-484；BT Hassett、R Gradinger (2016) 壶菌主导北极海洋真菌群落，《环境微生物学》（Environmental Microbiology）18(6): 2001-2009。