Ice algal bloom development on the surface of the Greenland Ice Sheet

• Published in: FEMS Microbiology Ecology
• Main Authors: Williamson, C J, Anesio, A M, Cook, J, Tedstone, A, Poniecka, E, Holland, A, Fagan, D, Tranter, M, Yallop, M L
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2018
• Subjects: cyanobacteria; cryosphere; polar; alpine; genomics; Greenland; Ice Sheet
• Online Access: https://hdl.handle.net/1983/5545becd-90a4-42fe-afc2-2f2eaa6dda34; https://research-information.bris.ac.uk/en/publications/5545becd-90a4-42fe-afc2-2f2eaa6dda34; https://doi.org/10.1093/femsec/fiy025; https://research-information.bris.ac.uk/ws/files/148343673/fiy025.pdf

It is fundamental to understand the development of Zygnematophycean (Streptophyte) micro-algal blooms within Greenland Ice Sheet (GrIS) supraglacial environments, given their potential to significantly impact both physical (melt) and chemical (carbon and nutrient cycling) surface characteristics. Here we report on a space-for-time assessment of a GrIS ice-algal bloom, achieved by sampling an ∼ 85 km transect spanning the south-western GrIS bare ice zone during the 2016 ablation season. Cell abundances ranged from 0 to 1.6 × 104 cells ml−1, with algal biomass demonstrated to increase in surface ice with time since snow line retreat (R2 = 0.73, P < 0.05). A suite of light harvesting and photo-protective pigments were quantified across transects (chlorophylls, carotenoids and phenols) and shown to increase in concert with algal biomass. Ice-algal communities drove net autotrophy of surface ice, with maximal rates of net production averaging 0.52 ± 0.04 mg C l−1 d−1, and a total accumulation of 1.306 Gg C (15.82 ± 8.14 kg C km−2) predicted for the 2016 ablation season across an 8.24 × 104 km2 region of the GrIS. By advancing our understanding of ice-algal bloom development, this study marks an important step toward projecting bloom occurrence and impacts into the future.