Microbial cell budgets of an Arctic glacier surface quantified using flow cytometry
Summary Uncertainty surrounds estimates of microbial cell and organic detritus fluxes from glacier surfaces. Here, we present the first enumeration of biological particles draining from a supraglacial catchment, on Midtre Lovénbreen (Svalbard) over 36 days. A stream cell flux of 1.08 × 107 cells m−2...
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Published in | Environmental microbiology Vol. 14; no. 11; pp. 2998 - 3012 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
England
Blackwell Publishing Ltd
01.11.2012
Wiley Subscription Services, Inc |
Subjects | |
Online Access | Get full text |
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Summary: | Summary
Uncertainty surrounds estimates of microbial cell and organic detritus fluxes from glacier surfaces. Here, we present the first enumeration of biological particles draining from a supraglacial catchment, on Midtre Lovénbreen (Svalbard) over 36 days. A stream cell flux of 1.08 × 107 cells m−2 h−1 was found, with strong inverse, non‐linear associations between water discharge and biological particle concentrations. Over the study period, a significant decrease in cell‐like particles exhibiting 530 nm autofluorescence was noted. The observed total fluvial export of ∼ 7.5 × 1014 cells equates to 15.1–72.7 g C, and a large proportion of these cells were small (< 0.5 μm in diameter). Differences between the observed fluvial export and inputs from ice‐melt and aeolian deposition were marked: results indicate an apparent storage rate of 8.83 × 107 cells m−2 h−1. Analysis of surface ice cores revealed cell concentrations comparable to previous studies (6 × 104 cells ml−1) but, critically, showed no variation with depth in the uppermost 1 m. The physical retention and growth of particulates at glacier surfaces has two implications: to contribute to ice mass thinning through feedbacks altering surface albedo, and to potentially seed recently deglaciated terrain with cells, genes and labile organic matter. This highlights the merit of further study into glacier surface hydraulics and biological processes. |
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Bibliography: | istex:DEDF2E1E3AA94AC2315FF0919F1FC2C6F628BF20 NERC Standard Grants - No. NE/G00496X/1; No. NE/G006253/1 Aberystwyth University Research Fund Fig. S1. Example scatter plots from FCM showing contrast between (a) unstained and (b) stained response to blue (488 nm) laser excitation, highlighting the SGII shift in green fluorescence and a threshold (∼ 102 DN) for separating biological and non-biological particulates for a stream sample taken on DOY196. The threshold was defined from samples in which autofluorescent particles appeared absent. Panel c illustrates the SSC vs. FSC scatter plot for biological particles in a supraglacial stream sample and the size classification boundaries derived independently from the use of a pseudo-blank sample containing beads. ArticleID:EMI2876 Climate Change Consortium of Wales (C3W) ark:/67375/WNG-HCX86B23-1 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1462-2912 1462-2920 |
DOI: | 10.1111/j.1462-2920.2012.02876.x |