Darkening of the Greenland Ice Sheet: Fungal Abundance and Diversity Are Associated With Algal Bloom

Abstract

Recent studies have highlighted the importance of ice-algal blooms in driving darkening and therefore surface melt of the Greenland Ice Sheet (GrIS). However, the contribution of fungal and bacterial communities to this microbially driven albedo reduction remains unconstrained. To address this significant knowledge gap, fungi were isolated from key GrIS surface habitats (surface ice containing varying abundance of ice algae, supraglacial water, cryoconite holes, and snow), and a combination of cultivation and sequencing methods utilized to characterize the algal-associated fungal and bacterial diversity and abundance. Six hundred and ninety-seven taxa of fungi were obtained by amplicon sequencing and more than 200 fungal cultures belonging to 46 different species were isolated through cultivation approaches. Basidiomycota dominated in surface ice and water samples, and Ascomycota in snow samples. Amplicon sequencing revealed that bacteria were characterized by a higher diversity (883 taxa detected). Results from cultivation as well as ergosterol analyses suggested that surface ice dominated by ice algae and cryoconite holes supported the highest fungal biomass (10 4 –10 5 CFU/100 ml) and that many fungal taxa recognized as endophytes and plant pathogens were associated with dark ice characterized by a high abundance of ice algae. This paper significantly advances this field of research by investigating for the first time the fungal abundance and diversity associated with algal blooms causing the darkening of the GrIS. There is a strong association between the abundance and diversity of fungal species and the blooming of algae on the surface ice of the Greenland Ice Sheet.

Prevalence of Antimicrobial Resistance and Hemolytic Phenotypes in Culturable Arctic Bacteria

“…The plates were incubated at the initial isolation temperature of each isolate and, in addition, at 37 • C. DNA was extracted using PrepMan Ultra reagent (Applied Biosystems) according to the manufacturer instructions. 16S rRNA gene was amplified with 27f-lane, 1492R, 8F, and 1541R primers (Tam et al, 2015;Perini et al, 2019a;Mogrovejo-Arias et al, 2020). The 16S nucleotide amplicons were Sanger-sequenced by Microsynth AG (Switzerland).…”

Phenotypes Associated with Pathogenicity: Their Expression in Arctic Fungal Isolates

“…Fungi were transferred onto fresh MEA (malt extract agar) or PDA (potato dextrose agar, Biolife) media for a week to obtain pure cultures. Filamentous fungi DNA was extracted following the protocol described in [4], while yeast DNA was extracted using the PrepMan Ultra reagent (Applied Biosystems, Foster City, CA, USA) according to the manufacturer instructions.…”

“…In addition to bacteria, a great diversity of psychrophilic, as well as psychrotolerant fungi inhabit the cryosphere, where they play important roles in the ecosystem [3]. For example, a strong association between the abundance and diversity of fungi and the blooming of algae on the dark surface ice of the Greenland Ice Sheet has been described [4]. Particularly common are species of the genera Penicillium, Thelebolus, Alternaria, Rhodotorula, Vishniacozyma, Aspergillus, and Cladosporium [3][4][5][6].…”

Water bears dominated cryoconite hole ecosystems: densities, habitat preferences and physiological adaptations of Tardigrada on an alpine glacier

“…Therefore, we investigated habitat preferences, densities and desiccation tolerance of tardigrades on the Forni Glacier in the Alps during the middle of summer 2018. Despite the fact that the understanding of cryoconite holes and glacial ecosystems is increasing (Cook et al 2015;Pittino et al 2018;Perini et al 2019;Takeuchi et al 2018), the knowledge on tardigrades inhabiting them is still far from satisfactory and may limit our understanding of the functions, dynamics and trophic relations in supraglacial ecosystems. Therefore, all knowledge on organism's dynamics, dispersal and interactions with ice must be acquired in order to understand biological aspects of the glacial biome (Hodson et al 2015;Cook et al 2015Cook et al , 2016.…”