Sharp contrasts between freshwater and marine microbial enzymatic capabilities, community composition, and DOM pools in a NE Greenland fjord
Increasing glacial discharge can lower salinity and alter organic matter (OM) supply in fjords, but assessing the biogeochemical effects of enhanced freshwater fluxes requires understanding of microbial interactions with OM across salinity gradients. Here, we examined microbial enzymatic capabilitie...
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Wiley Blackwell
2020
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ftcarolinadr:cdr.lib.unc.edu:g158bt37h 2023-06-11T04:09:18+02:00 Sharp contrasts between freshwater and marine microbial enzymatic capabilities, community composition, and DOM pools in a NE Greenland fjord Balmonte, J.P. Hasler-Sheetal, H. Glud, R.N. Andersen, T.J. Sejr, M.K. Middelboe, M. Teske, A. Arnosti, C. College of Arts and Sciences, Department of Marine Sciences 2020 https://doi.org/10.17615/5eq8-2018 https://cdr.lib.unc.edu/downloads/0p096h75t?file=thumbnail https://cdr.lib.unc.edu/downloads/0p096h75t English eng Wiley Blackwell https://doi.org/10.17615/5eq8-2018 https://cdr.lib.unc.edu/downloads/0p096h75t?file=thumbnail https://cdr.lib.unc.edu/downloads/0p096h75t http://rightsstatements.org/vocab/InC/1.0/ Limnology and Oceanography, 65(1) meltwater community composition dissolved organic matter fjord Young Sound marine environment seawater microbial community freshwater environment biogeochemical cycle Greenland Bacteria (microorganisms) microbial activity genetic analysis enzyme activity hydrolysis Arctic Article 2020 ftcarolinadr https://doi.org/10.17615/5eq8-2018 2023-05-28T21:02:54Z Increasing glacial discharge can lower salinity and alter organic matter (OM) supply in fjords, but assessing the biogeochemical effects of enhanced freshwater fluxes requires understanding of microbial interactions with OM across salinity gradients. Here, we examined microbial enzymatic capabilities—in bulk waters (nonsize-fractionated) and on particles (≥ 1.6 μm)—to hydrolyze common OM constituents (peptides, glucose, polysaccharides) along a freshwater–marine continuum within Tyrolerfjord-Young Sound. Bulk peptidase activities were up to 15-fold higher in the fjord than in glacial rivers, whereas bulk glucosidase activities in rivers were twofold greater, despite fourfold lower cell counts. Particle-associated glucosidase activities showed similar trends by salinity, but particle-associated peptidase activities were up to fivefold higher—or, for several peptidases, only detectable—in the fjord. Bulk polysaccharide hydrolase activities also exhibited freshwater–marine contrasts: xylan hydrolysis rates were fivefold higher in rivers, while chondroitin hydrolysis rates were 30-fold greater in the fjord. Contrasting enzymatic patterns paralleled variations in bacterial community structure, with most robust compositional shifts in river-to-fjord transitions, signifying a taxonomic and genetic basis for functional differences in freshwater and marine waters. However, distinct dissolved organic matter (DOM) pools across the salinity gradient, as well as a positive relationship between several enzymatic activities and DOM compounds, indicate that DOM supply exerts a more proximate control on microbial activities. Thus, differing microbial enzymatic capabilities, community structure, and DOM composition—interwoven with salinity and water mass origins—suggest that increased meltwater may alter OM retention and processing in fjords, changing the pool of OM supplied to coastal Arctic microbial communities. Article in Journal/Newspaper Arctic Greenland Carolina Digital Repository (UNC - University of North Carolina) Arctic Greenland Tyrolerfjord ENVELOPE(-21.883,-21.883,74.517,74.517) |
institution |
Open Polar |
collection |
Carolina Digital Repository (UNC - University of North Carolina) |
op_collection_id |
ftcarolinadr |
language |
English |
topic |
meltwater community composition dissolved organic matter fjord Young Sound marine environment seawater microbial community freshwater environment biogeochemical cycle Greenland Bacteria (microorganisms) microbial activity genetic analysis enzyme activity hydrolysis Arctic |
spellingShingle |
meltwater community composition dissolved organic matter fjord Young Sound marine environment seawater microbial community freshwater environment biogeochemical cycle Greenland Bacteria (microorganisms) microbial activity genetic analysis enzyme activity hydrolysis Arctic Balmonte, J.P. Hasler-Sheetal, H. Glud, R.N. Andersen, T.J. Sejr, M.K. Middelboe, M. Teske, A. Arnosti, C. Sharp contrasts between freshwater and marine microbial enzymatic capabilities, community composition, and DOM pools in a NE Greenland fjord |
topic_facet |
meltwater community composition dissolved organic matter fjord Young Sound marine environment seawater microbial community freshwater environment biogeochemical cycle Greenland Bacteria (microorganisms) microbial activity genetic analysis enzyme activity hydrolysis Arctic |
description |
Increasing glacial discharge can lower salinity and alter organic matter (OM) supply in fjords, but assessing the biogeochemical effects of enhanced freshwater fluxes requires understanding of microbial interactions with OM across salinity gradients. Here, we examined microbial enzymatic capabilities—in bulk waters (nonsize-fractionated) and on particles (≥ 1.6 μm)—to hydrolyze common OM constituents (peptides, glucose, polysaccharides) along a freshwater–marine continuum within Tyrolerfjord-Young Sound. Bulk peptidase activities were up to 15-fold higher in the fjord than in glacial rivers, whereas bulk glucosidase activities in rivers were twofold greater, despite fourfold lower cell counts. Particle-associated glucosidase activities showed similar trends by salinity, but particle-associated peptidase activities were up to fivefold higher—or, for several peptidases, only detectable—in the fjord. Bulk polysaccharide hydrolase activities also exhibited freshwater–marine contrasts: xylan hydrolysis rates were fivefold higher in rivers, while chondroitin hydrolysis rates were 30-fold greater in the fjord. Contrasting enzymatic patterns paralleled variations in bacterial community structure, with most robust compositional shifts in river-to-fjord transitions, signifying a taxonomic and genetic basis for functional differences in freshwater and marine waters. However, distinct dissolved organic matter (DOM) pools across the salinity gradient, as well as a positive relationship between several enzymatic activities and DOM compounds, indicate that DOM supply exerts a more proximate control on microbial activities. Thus, differing microbial enzymatic capabilities, community structure, and DOM composition—interwoven with salinity and water mass origins—suggest that increased meltwater may alter OM retention and processing in fjords, changing the pool of OM supplied to coastal Arctic microbial communities. |
author2 |
College of Arts and Sciences, Department of Marine Sciences |
format |
Article in Journal/Newspaper |
author |
Balmonte, J.P. Hasler-Sheetal, H. Glud, R.N. Andersen, T.J. Sejr, M.K. Middelboe, M. Teske, A. Arnosti, C. |
author_facet |
Balmonte, J.P. Hasler-Sheetal, H. Glud, R.N. Andersen, T.J. Sejr, M.K. Middelboe, M. Teske, A. Arnosti, C. |
author_sort |
Balmonte, J.P. |
title |
Sharp contrasts between freshwater and marine microbial enzymatic capabilities, community composition, and DOM pools in a NE Greenland fjord |
title_short |
Sharp contrasts between freshwater and marine microbial enzymatic capabilities, community composition, and DOM pools in a NE Greenland fjord |
title_full |
Sharp contrasts between freshwater and marine microbial enzymatic capabilities, community composition, and DOM pools in a NE Greenland fjord |
title_fullStr |
Sharp contrasts between freshwater and marine microbial enzymatic capabilities, community composition, and DOM pools in a NE Greenland fjord |
title_full_unstemmed |
Sharp contrasts between freshwater and marine microbial enzymatic capabilities, community composition, and DOM pools in a NE Greenland fjord |
title_sort |
sharp contrasts between freshwater and marine microbial enzymatic capabilities, community composition, and dom pools in a ne greenland fjord |
publisher |
Wiley Blackwell |
publishDate |
2020 |
url |
https://doi.org/10.17615/5eq8-2018 https://cdr.lib.unc.edu/downloads/0p096h75t?file=thumbnail https://cdr.lib.unc.edu/downloads/0p096h75t |
long_lat |
ENVELOPE(-21.883,-21.883,74.517,74.517) |
geographic |
Arctic Greenland Tyrolerfjord |
geographic_facet |
Arctic Greenland Tyrolerfjord |
genre |
Arctic Greenland |
genre_facet |
Arctic Greenland |
op_source |
Limnology and Oceanography, 65(1) |
op_relation |
https://doi.org/10.17615/5eq8-2018 https://cdr.lib.unc.edu/downloads/0p096h75t?file=thumbnail https://cdr.lib.unc.edu/downloads/0p096h75t |
op_rights |
http://rightsstatements.org/vocab/InC/1.0/ |
op_doi |
https://doi.org/10.17615/5eq8-2018 |
_version_ |
1768383089508089856 |