Abstract:
Glaciers host ecosystems comprised of biodiverse and active microbiota.
Among glacial ecosystems, less is known about the ecology of ice caps
since most studies focus on valley glaciers or ice sheet margins. Previously
we detailed the microbiota of one such high Arctic ice cap, focusing on cryoconite
as a microbe-mineral aggregate formed by cyanobacteria. Here, we
employ metabolomics at the scale of an entire ice cap to reveal the major
metabolic pathways prevailing in the cryoconite of Foxfonna, central Svalbard.
We reveal how geophysical and biotic processes influence the metabolomes
of its resident cryoconite microbiota. We observed differences in
amino acid, fatty acid, and nucleotide synthesis across the cap reflecting
the influence of ice topography and the cyanobacteria within cryoconite. Ice
topography influences central carbohydrate metabolism and nitrogen assimilation,
whereas bacterial community structure governs lipid, nucleotide, and
carotenoid biosynthesis processes. The prominence of polyamine metabolism
and nitrogen assimilation highlights the importance of recycling nitrogenous
nutrients. To our knowledge, this study represents the first application
of metabolomics across an entire ice mass, demonstrating its utility as a tool
for revealing the fundamental metabolic processes essential for sustaining
life in supraglacial ecosystems experiencing profound change due to Arctic
climate change-driven mass loss.
