Taxon interactions control the distributions of cryoconite bacteria colonizing a High Arctic ice cap.
Microbial colonization of glacial ice surfaces incurs feedbacks which affect the melting rate of the ice surface. Ecosystems formed as microbe-mineral aggregates termed cryoconite locally reduce ice surface albedo and represent foci of biodiversity and biogeochemical cycling. Consequently, greater understanding the ecological processes in the formation of functional cryoconite ecosystems upon glacier surfaces is sought. Here, we present the first bacterial biogeography of an ice cap, evaluating the respective roles of dispersal, environmental and biotic filtration occurring at local scales in the assembly of cryoconite microbiota. 16S rRNA gene amplicon semiconductor sequencing of cryoconite colonizing a Svalbard ice cap coupled with digital elevation modelling of physical parameters reveals the bacterial community is dominated by a ubiquitous core of generalist taxa, with evidence for a moderate pairwise distance-decay relationship. While geographic position and melt season duration are prominent among environmental predictors of community structure, the core population of taxa appears highly influential in structuring the bacterial community. Taxon co-occurrence network analysis reveals a highly modular community structured by positive interactions with bottleneck taxa, predominantly Actinobacteria affiliated to isolates from soil humus. In contrast, the filamentous cyanobacterial taxon (assigned to Leptolyngbya/Phormidesmis pristleyi) which dominates the community and binds together granular cryoconite are poorly connected to other taxa. While our study targeted one ice cap, the prominent role of generalist core taxa with close environmental relatives across the global cryosphere indicate discrete roles for cosmopolitan Actinobacteria and Cyanobacteria as respective keystone taxa and ecosystem engineers of cryoconite ecosystems colonizing ice caps.
Institute of Biological, Rural and Environmental Sciences, Aberystwyth University, Cledwyn Building, Aberystwyth, SY23 3DD, UK.
Jarishma K
JK
Gokul
Department of Geography, University of Sheffield, Sheffield, S10 2TN, UK.|Department of Arctic Geology, University Centre in Svalbard (UNIS), Longyearbyen, N-9171, Svalbard, UK.
Andrew J
AJ
Hodson
Institute of Biological, Rural and Environmental Sciences, Aberystwyth University, Cledwyn Building, Aberystwyth, SY23 3DD, UK.
Eli R
ER
Saetnan
Department of Geography and Earth Sciences, Aberystwyth University, Llandinam Building, Aberystwyth, SY23 3DB, UK.
Tristram D L
TD
Irvine-Fynn
Institute of Biological, Rural and Environmental Sciences, Aberystwyth University, Cledwyn Building, Aberystwyth, SY23 3DD, UK.
Philippa J
PJ
Westall
Institute of Biological, Rural and Environmental Sciences, Aberystwyth University, Cledwyn Building, Aberystwyth, SY23 3DD, UK.
Andrew P
AP
Detheridge
Department of Earth Sciences, Graduate School of Science, Chiba University, 1-33, Yayoicho, Inage-ku, Chiba, 263-8522, Japan.
Nozomu
N
Takeuchi
Institute of Biological, Rural and Environmental Sciences, Aberystwyth University, Cledwyn Building, Aberystwyth, SY23 3DD, UK.|University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire, LE12 5RD, UK.
Jennifer
J
Bussell
Institute of Biological, Rural and Environmental Sciences, Aberystwyth University, Cledwyn Building, Aberystwyth, SY23 3DD, UK.
Luis A J
LA
Mur
Institute of Biological, Rural and Environmental Sciences, Aberystwyth University, Cledwyn Building, Aberystwyth, SY23 3DD, UK.
Arwyn
A
Edwards
D001419:Bacteria / Q000145:classification* / Q000235:genetics; D044822:Biodiversity; D046448:Ice Cover / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013538:Svalbard
D012336:RNA, Ribosomal, 16S
Svalbard; bacteria; biogeography; cryoconite; ecosystem engineering; keystone species