Reference : Patterns and Drivers of Extracellular Enzyme Activity in New Zealand Glacier-Fed Streams
Scientific journals : Article
Life sciences : Environmental sciences & ecology
http://hdl.handle.net/10993/48977
Patterns and Drivers of Extracellular Enzyme Activity in New Zealand Glacier-Fed Streams
English
Kohler, Tyler J. [Ecole Polytechnique Fédérale de Lausanne - EPFL]
Peter, Hannes [Ecole Polytechnique Fédérale de Lausanne - EPFL]
Fodelianakis, Stilianos [Ecole Polytechnique Fédérale de Lausanne - EPFL]
Pramateftaki, Paraskevi [Ecole Polytechnique Fédérale de Lausanne - EPFL]
Styllas, Michail [Ecole Polytechnique Fédérale de Lausanne - EPFL]
Tolosano, Matteo [Ecole Polytechnique Fédérale de Lausanne - EPFL]
de Staercke, Vincent [Ecole Polytechnique Fédérale de Lausanne - EPFL]
Schön, Martina [Ecole Polytechnique Fédérale de Lausanne - EPFL]
Busi, Susheel Bhanu mailto [University of Luxembourg > Luxembourg Centre for Systems Biomedicine (LCSB) > Systems Ecology]
Wilmes, Paul mailto [University of Luxembourg > Luxembourg Centre for Systems Biomedicine (LCSB) > Systems Ecology]
Washburne, Alex [> >]
Battin, Tom J. [Ecole Polytechnique Fédérale de Lausanne - EPFL]
19-Nov-2020
Frontiers in Microbiology
11
2922
Yes
International
1664-302X
[en] Glacier-fed streams (GFSs) exhibit near-freezing temperatures, variable flows, and often high turbidities. Currently, the rapid shrinkage of mountain glaciers is altering the delivery of meltwater, solutes, and particulate matter to GFSs, with unknown consequences for their ecology. Benthic biofilms dominate microbial life in GFSs, and play a major role in their biogeochemical cycling. Mineralization is likely an important process for microbes to meet elemental budgets in these systems due to commonly oligotrophic conditions, and extracellular enzymes retained within the biofilm enable the degradation of organic matter and acquisition of carbon (C), nitrogen (N), and phosphorus (P). The measurement and comparison of these extracellular enzyme activities (EEA) can in turn provide insight into microbial elemental acquisition effort relative to environmental availability. To better understand how benthic biofilm communities meet resource demands, and how this might shift as glaciers vanish under climate change, we investigated biofilm EEA in 20 GFSs varying in glacier influence from New Zealand’s Southern Alps. Using turbidity and distance to the glacier snout normalized for glacier size as proxies for glacier influence, we found that bacterial abundance (BA), chlorophyll a (Chl a), extracellular polymeric substances (EPS), and total EEA per gram of sediment increased with decreasing glacier influence. Yet, when normalized by BA, EPS decreased with decreasing glacier influence, Chl a still increased, and there was no relationship with total EEA. Based on EEA ratios, we found that the majority of GFS microbial communities were N-limited, with a few streams of different underlying bedrock geology exhibiting P-limitation. Cell-specific C-acquiring EEA was positively related to the ratio of Chl a to BA, presumably reflecting the utilization of algal exudates. Meanwhile, cell-specific N-acquiring EEA were positively correlated with the concentration of dissolved inorganic nitrogen (DIN), and both N- and P-acquiring EEA increased with greater cell-specific EPS. Overall, our results reveal greater glacier influence to be negatively related to GFS biofilm biomass parameters, and generally associated with greater microbial N demand. These results help to illuminate the ecology of GFS biofilms, along with their biogeochemical response to a shifting habitat template with ongoing climate change.
Stream Biology and Ecosystems Research group
The NOMIS Foundation
Vanishing Glaciers
Researchers ; Professionals ; Students ; General public
http://hdl.handle.net/10993/48977
10.3389/fmicb.2020.591465
https://www.frontiersin.org/article/10.3389/fmicb.2020.591465
Copyright © 2020 Kohler, Peter, Fodelianakis, Pramateftaki, Styllas, Tolosano, de Staercke, Schön, Busi, Wilmes, Washburne and Battin. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

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