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BLACK and BLOOM: variations in the albedo of the Greenland Ice Sheet as a result of interactions between microbes and particulates.

Lead Research Organisation: University of Leeds
Department Name: School of Earth and Environment

Abstract

Concerns are growing about how much melting occurs on the surface of the Greenland Ice Sheet (GrIS), and how much this melting will contribute to sea level rise (1). It seems that the amount of melting is accelerating and that the impact on sea level rise is over 1 mm each year (2). This information is of concern to governmental policy makers around the world because of the risk to viability of populated coastal and low-lying areas. There is currently a great scientific need to predict the amount of melting that will occur on the surface of the GrIS over the coming decades (3), since the uncertainties are high. The current models which are used to predict the amount of melting in a warmer climate rely heavily on determining the albedo, the ratio of how reflective the snow cover and the ice surface are to incoming solar energy. Surfaces which are whiter are said to have higher albedo, reflect more sunlight and melt less. Surfaces which are darker adsorb more sunlight and so melt more. Just how the albedo varies over time depends on a number of factors, including how wet the snow and ice is. One important factor that has been missed to date is bio-albedo. Each drop of water in wet snow and ice contains thousands of tiny microorganisms, mostly algae and cyanobacteria, which are pigmented - they have a built in sunblock - to protect them from sunlight. These algae and cyanobacteria have a large impact on the albedo, lowering it significantly. They also glue together dust particles that are swept out of the air by the falling snow. These dust particles also contain soot from industrial activity and forest fires, and so the mix of pigmented microbes and dark dust at the surface produces a darker ice sheet. We urgently need to know more about the factors that lead to and limit the growth of the pigmented microbes. Recent work by our group in the darkest zone of the ice sheet surface in the SW of Greenland shows that the darkest areas have the highest numbers of cells. Were these algae to grow equally well in other areas of the ice sheet surface, then the rate of melting of the whole ice sheet would increase very quickly. A major concern is that there will be more wet ice surfaces for these microorganisms to grow in, and for longer, during a period of climate warming, and so the microorganisms will grow in greater numbers and over a larger area, lowering the albedo and increasing the amount of melt that occurs each year. The nutrient - plant food - that the microorganisms need comes from the ice crystals and dust on the ice sheet surface, and there are fears that increased N levels in snow and ice may contribute to the growth of the microorganisms. This project aims to be the first to examine the growth and spread of the microorganisms in a warming climate, and to incorporate biological darkening into models that predict the future melting of the GrIS.

References

1. Sasgen I and 8 others. Timing and origin of recent regional ice-mass loss in Greenland. Earth and Planetary Science Letters, 333-334, 293-303(2012).
2. Rignot, E., Velicogna, I., van den Broeke, M. R., Monaghan, A. & Lenaerts, J. Acceleration of the contribution of the Greenland and Antarctic ice sheets to sea level rise. Geophys. Res. Lett. 38, L05503, doi:10.1029/2011gl046583 (2011).
3. Milne, G. A., Gehrels, W. R., Hughes, C. W. & Tamisiea, M. E. Identifying the causes of sea-level change. Nature Geosci 2, 471-478 (2009).

Planned Impact

BLACK and BLOOM aims to make a major impact on the state of the science for melt prediction from the Greenland Ice Sheet. We are committed to contributing our experiences during the course of our project to the international community via IASC (International Arctic Science Committee). We will be disseminating our research results to the academic community also via publication in the top rated peer reviewed literature and international, national and local conference presentations. We will use the auspices of the Cabot Institute at the University of Bristol to bring our improved predictions of the rate of melting of the Greenland Ice Sheet to the attention of governmental and other policy makers. The Dark Snow Project, run by Project Partner Jason Box (GEUS), is well known to the public, and we will link our project web site to that of Dark Snow to aid outreach of our work to the general public. We will contribute to blogs and question and answer sessions when we are in the field via web links from Kangerlussuaq International Science Support (KISS). Hence, we aim to outreach to a broad spectrum of scientists, policy makers and the general public.
 
Description please also see details in Key findings by main grant PI Prof. Martyn Tranter (University of Bristol);


in the work for work package 2 (Particulates), which is the target of the Leeds team we have made progress in both the aerosol and surface sample characterization. The data so far revealed a high degree of complexity, yet also a clear pathway to mineral and organic phosphate components in our surface samples and the TOC contents. One main paper has been published in Nature Communications in January 2021 (see McCutcheon et al 2021 entry.

The data that was acquired through in sit monitoring of particulate deposition and black carbon accumulation has been already in a large part evaluated.

Furthermore, the detailed mineralogy and particle size distribution in the aerosol and surface samples were analysed using newly developed and implemented methods (CPS, TGA/DSC, SEM/EDAX etc). This data was urgently needed as a crucial input for the modelling and linking to the albedo measurements for the research in work package 3. Analysing the spectral composition of the accumulated black carbon in our aerosol filters required us to apply (and be awarded) for synchrotron beamtime both at the UK Diamond Light Source as well as at the French Soleil Light Source. During the two allocated times we assessed the speciation and chemical environments for black carbon nanoparticles in our air samples in order to be able to say something about the nature and delivery mechanisms of black carbon to the Greenland ice surface.

As detailed in the original proposal we have worked closely with our project partner Paola Formenti (Paris) to determine on our filter samples and surface samples the contributions of elemental carbon (EC) vs organic carbon (OC) as a proxy for black carbon vs. biological inputs to the surface of the Greenland Ice Sheet and to assess what happens with this EC/OC delivered to the surface during processing.

Various talks and posters (i.e., VM Goldschmidt meeting 2017, 2018, and various national and international seminars in university departments have been given to disseminate our findings to the wider academic audience). In addition, various outreach activities (e., Pint of Science, Gren Great Britain Week) were used to disseminate our findings also to the general public.
Exploitation Route the detailed mineralogical, particle size and particle mass loading was quantified by the research in workpackage 2 as it was urgently needed as input into the bio-albedo modelling of workpackage 3 (this work is currently in review);

Two main papers have been published and several manuscripts resulting form the research in workpackage 2 are in progress. These are led by the Leeds PDRA and extended through a collaboration with a postdoc funded through a separate grant at the German Research Centre for Geosciences, GFZ.

The in progress manuscripts are: (1) Atmospheric processes affecting algal blooms on the Greenland Ice Sheet (2) Metabolic profiling of ice algal communities on the Greenland Ice Sheet (3) Carbon dynamics in airborne and surface environments on the Greenland Ice Sheet.
Sectors Environment

URL https://blackandbloom.org/
 
Description see details for main award - in Narrative Impact by main grant PI Prof. Martyn Tranter (University of Bristol); the Leeds PDRA has worked on non-academic impact via outreach activities (i.e., Pint of Science, Green Great Britain Week) McQuaid has given two outreach talks in past 12 months, including Pint of Science (Leeds) and Francis Holland Girls School (London)
First Year Of Impact 2018
Sector Education,Environment
Impact Types Societal

 
Title Complementary Geochemical, mineralogical and microbiological analyses of materials collected on the Greenland Ice Sheet 
Description This data publication is supplementary material to McCutcheon et al. (2021): "Melting of the Greenland Ice Sheet is a leading cause of land-ice mass loss and cryosphere-attributed sea level rise. Blooms of pigmented glacier ice algae lower ice albedo and accelerate surface melting in the ice sheet's southwest sector. Although glacier ice algae cause up to 13% of the surface melting in this region, the controls on bloom development remain poorly understood. Here we show a direct link between mineral phosphorus in surface ice and glacier ice algae biomass through the quantification of solid and fluid phase phosphorus reservoirs in surface habitats across the southwest ablation zone of the ice sheet. We demonstrate that nutrients from mineral dust likely drive glacier ice algal growth, and thereby identify mineral dust as a secondary control on ice sheet melting." Tables included in this data publication: Supplementary Table 1. Locations, dates and sample types collected for particulate analyses. Sites 4a and 4b were the base camp locations for 2016 and 2017, respectively. Supplementary Table 2. Results of a Tukey HSD test with a 95% family-wise confidence interval for Fv/Fm measurements made at 24 h and 120 h in the nutrient addition experiment. Supplementary Table 3. Results of a Tukey HSD test with a 95% family-wise confidence interval for rETRmax measurements made at 24 h and 120 h in the nutrient addition experiment. Supplementary Table 4. Glacier algal cell concentrations (cells·mL-1) at the end of the 120 h nutrient incubation experiment. Glacier algae assemblage used for the incubations had an initial mean cell concentration of 8.0 ± 2.1 ? 103 cells·mL-1. Supplementary Table 5. Carbon, nitrogen, and phosphorus content of solid LAPs collected from melted surface ice. TC: total carbon. TOC: total organic carbon, IC: inorganic carbon, Pexch: exchangeable/loosely bound phosphorus, Pmin: mineral phosphorus, Porg: organic phosphorus. Supplementary Table 6. Mineral phase abundances in 2016 and 2017 particulate samples as determined by Rietveld refinement with powder X-ray diffraction data. Abundances given as weight percent of total mineral dust (n=20). Supplementary Table 7. Mineral class abundances in high algal biomass (Hbio) ice sampled across the ablation zone in 2016. Values listed in weight percent of total mineral dust % (+/- standard error where applicable). Two-sided t-test comparing of mineral class abundances between site 3 and 4a. Supplementary Table 8. Major cation and anion concentrations in the fluid phase and pH, conductivity and total dissolved solids (TDS) of supraglacial stream water and melted ice and snow samples. LOD: level of detection, LOQ: level of quantification, ND: no data. Supplementary Table 9. Number of raw and processed sequences after each quality filtering step for 16S, ITS2 and 18S. Supplementary Table 10. Table shows the full bacterial community composition with the taxonomic assignments of each ASV on the lowest possible level. Values represent the relative abundances of the 16S ASVs in percentage of the total number of sequences and collapsed on the species level. Values are rounded to one decimal place, thus " 0. Supplementary Table 11. Table shows the full eukaryotic community composition collapsed into higher eukaryotic taxonomic groups. Values represent the relative abundance of the 18S ASVs in percentage of the total number of sequences and collapsed on the species level. Values are rounded to one decimal place, thus " 0. Supplementary Table 12. Table shows the fungal community composition with the taxonomic assignments of the ten most abundant ASV on the lowest possible level. The representative sequences were blasted against NCBI and the closest accession number with the respective similarity were recorded. If several hits shared the similarity one hit was chosen as an example ("e.g."). Values represent the relative abundance of the ITS2 ASVs in percentage of the total number of sequences. Values are rounded to one decimal place, thus " 0. Supplementary Table 13. Table shows the full algal community composition with the taxonomic assignments of each ASV on the lowest possible level. Values represent the relative abundance of the 18S ASVs in percentage of the total number of sequences. All ASVs were blasted against NCBI and the closest accession number with the respective similarity were recorded. If several hits shared the similarity one hit was chosen as an example ("e.g."). Values are rounded to one decimal place, hence " 0. *Based on light microscopic identifications in Lutz et al. (2018), this ASV likely represents Mesotaenium sp. (99.4% similarity with M. berggrenii var. alaskana) and not Ancylonema nordenskioeldii despite the slightly higher similarity (99.6%). Supplementary Table 14. Rare Earth Element (REE) analysis concentrations (µg·g-1) for the mineral dust in particulate samples. 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
URL https://dataservices.gfz-potsdam.de/panmetaworks/showshort.php?id=314f3458-5c3b-11ec-958d-ed2b0fcbcc...
 
Title Complementary Geochemical, mineralogical and microbiological analyses of materials collected on the Greenland Ice Sheet 
Description This dataset comprises of geochemical, mineralogical and microbiological analyses of material collected on the southwestern margin of the Greenland Ice Sheet in 2016 and 2017. Stream water, melted ice and snow samples were collected and analysed for carbon, nitrogen, phosphorus, cation and anion concentrations, pH, conductivity, total dissolved solids (TDS), mineral phase and class abundances and Rare Earth Elements (REE). Microbial community composition was also analysed. In addition, the results of a nutrient incubation experiment are also presented.The data were collected as part of a project investigating drivers of glacial ice algal growth on the Greenland Ice Sheet. We acknowledge funding from UK Natural Environment Research Council Consortium Grant, Black and Bloom (NE/M020770/1, NE/M021025/1 and NE/S001670/1). LGB and SL acknowledge funding from the German Helmholtz Recruiting Initiative (award number: I-044-16-01). LGB, AMA, and MT were also supported through an ERC Synergy Grant (?Deep Purple' grant # 856416) from the European Research Council (ERC) 
Type Of Material Database/Collection of data 
Year Produced 2023 
Provided To Others? Yes  
URL https://data.bas.ac.uk/full-record.php?id=GB/NERC/BAS/PDC/01707
 
Description Goechemical and microbiological pathways on the Greenland Ice sheet 
Organisation Helmholtz Association of German Research Centres
Department German Research Centre for Geosciences
Country Germany 
Sector Private 
PI Contribution Through a separately non-NERC funded 3 postdoctoral position to the PI from the Helmholtz Recruiting Initiative at at the German Research Center for Geosciences in Potsdam Germany we expanded the objectives of this NERC funded Black and Bloom project to include aspects that address the microbial ecological characterization of microbial community diversity and functions from the samples collected at the various field sites.
Collaborator Contribution So far, from this collaborative work and using samples collected by the common teams during the field season in the summer of 2016, a GFZ lead paper is in press in Microbial Genomics (Stefanie Lutz, Jenine McCutcheon, James B. McQuaid and Liane G. Benning (2018) The diversity of ice algal communities on the Greenland Ice Sheet as revealed by oligotyping; Microbial Genomics in press). Progress on the characterizations of all particulates in both aerosols and surface sample that relate to the outputs of Work package two are in progress and manuscripts are forthcoming.
Impact Stefanie Lutz, Jenine McCutcheon, James B. McQuaid and Liane G. Benning (2018) The diversity of ice algal communities on the Greenland Ice Sheet as revealed by oligotyping; Microbial Genomics in press.
Start Year 2016