Bacterial use of choline to tolerate salinity shifts in sea-ice brines
Abstract Bacteria within the brine network of sea ice experience temperature-driven fluctuations in salinity on both short and long temporal scales, yet their means of osmoprotection against such fluctuations is poorly understood. One mechanism used to withstand the ion fluxes caused by salinity shi...
Published in: | Elementa: Science of the Anthropocene |
---|---|
Main Authors: | , , , , |
Other Authors: | |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
University of California Press
2016
|
Subjects: | |
Online Access: | http://dx.doi.org/10.12952/journal.elementa.000120 http://online.ucpress.edu/elementa/article-pdf/doi/10.12952/journal.elementa.000120/473697/156-1627-1-ce.pdf |
id |
crunicaliforniap:10.12952/journal.elementa.000120 |
---|---|
record_format |
openpolar |
spelling |
crunicaliforniap:10.12952/journal.elementa.000120 2023-12-10T09:49:14+01:00 Bacterial use of choline to tolerate salinity shifts in sea-ice brines Firth, E. Carpenter, S.D. Sørensen, H.L. Collins, R.E. Deming, J.W. Blum, Joel D. 2016 http://dx.doi.org/10.12952/journal.elementa.000120 http://online.ucpress.edu/elementa/article-pdf/doi/10.12952/journal.elementa.000120/473697/156-1627-1-ce.pdf en eng University of California Press Elementa: Science of the Anthropocene volume 4 ISSN 2325-1026 Atmospheric Science Geology Geotechnical Engineering and Engineering Geology Ecology Environmental Engineering Oceanography journal-article 2016 crunicaliforniap https://doi.org/10.12952/journal.elementa.000120 2023-11-16T18:34:00Z Abstract Bacteria within the brine network of sea ice experience temperature-driven fluctuations in salinity on both short and long temporal scales, yet their means of osmoprotection against such fluctuations is poorly understood. One mechanism used to withstand the ion fluxes caused by salinity shifts, well-known in mesophilic bacteria, is the import and export of low molecular weight organic solutes that are compatible with intracellular functions. Working with the marine psychrophilic gammaproteobacterium, Colwellia psychrerythraea 34H, and with natural microbial assemblages present in sackhole brines drained from sea ice in Kanajorsuit Bay (2013) and Kobbefjord (2014), Greenland, we measured the utilization of 14C-choline (precursor to glycine betaine, a common compatible solute) at −1°C upon salinity shifts to double and to half the starting salinity. In all cases and across a range of starting salinities, when salinity was increased, 14C-solute (choline or derivatives) was preferentially retained as an intracellular osmolyte; when salinity was decreased, 14C-choline was preferentially respired to 14CO2. Additional experiments with cold-adapted bacteria in culture indicated that an abrupt downshift in salinity prompted rapid (subsecond) expulsion of retained 14C-solute, but that uptake of 14C-choline and solute retention resumed when salinity was returned to starting value. Overall, the results indicate that bacteria in sea-ice brines use compatible solutes for osmoprotection, transporting, storing and cycling these molecules as needed to withstand naturally occurring salinity shifts and persist through the seasons. Because choline and many commonly used compatible solutes contain nitrogen, we suggest that when brines freshen and bacteria respire such compatible solutes, the corresponding regeneration of ammonium may enhance specific biogeochemical processes in the ice, possibly algal productivity but particularly nitrification. Measurements of potential nitrification rates in parallel sea-ice samples are ... Article in Journal/Newspaper Greenland Sea ice University of California Press (via Crossref) Greenland Kobbefjord ENVELOPE(-51.527,-51.527,64.177,64.177) Elementa: Science of the Anthropocene 4 |
institution |
Open Polar |
collection |
University of California Press (via Crossref) |
op_collection_id |
crunicaliforniap |
language |
English |
topic |
Atmospheric Science Geology Geotechnical Engineering and Engineering Geology Ecology Environmental Engineering Oceanography |
spellingShingle |
Atmospheric Science Geology Geotechnical Engineering and Engineering Geology Ecology Environmental Engineering Oceanography Firth, E. Carpenter, S.D. Sørensen, H.L. Collins, R.E. Deming, J.W. Bacterial use of choline to tolerate salinity shifts in sea-ice brines |
topic_facet |
Atmospheric Science Geology Geotechnical Engineering and Engineering Geology Ecology Environmental Engineering Oceanography |
description |
Abstract Bacteria within the brine network of sea ice experience temperature-driven fluctuations in salinity on both short and long temporal scales, yet their means of osmoprotection against such fluctuations is poorly understood. One mechanism used to withstand the ion fluxes caused by salinity shifts, well-known in mesophilic bacteria, is the import and export of low molecular weight organic solutes that are compatible with intracellular functions. Working with the marine psychrophilic gammaproteobacterium, Colwellia psychrerythraea 34H, and with natural microbial assemblages present in sackhole brines drained from sea ice in Kanajorsuit Bay (2013) and Kobbefjord (2014), Greenland, we measured the utilization of 14C-choline (precursor to glycine betaine, a common compatible solute) at −1°C upon salinity shifts to double and to half the starting salinity. In all cases and across a range of starting salinities, when salinity was increased, 14C-solute (choline or derivatives) was preferentially retained as an intracellular osmolyte; when salinity was decreased, 14C-choline was preferentially respired to 14CO2. Additional experiments with cold-adapted bacteria in culture indicated that an abrupt downshift in salinity prompted rapid (subsecond) expulsion of retained 14C-solute, but that uptake of 14C-choline and solute retention resumed when salinity was returned to starting value. Overall, the results indicate that bacteria in sea-ice brines use compatible solutes for osmoprotection, transporting, storing and cycling these molecules as needed to withstand naturally occurring salinity shifts and persist through the seasons. Because choline and many commonly used compatible solutes contain nitrogen, we suggest that when brines freshen and bacteria respire such compatible solutes, the corresponding regeneration of ammonium may enhance specific biogeochemical processes in the ice, possibly algal productivity but particularly nitrification. Measurements of potential nitrification rates in parallel sea-ice samples are ... |
author2 |
Blum, Joel D. |
format |
Article in Journal/Newspaper |
author |
Firth, E. Carpenter, S.D. Sørensen, H.L. Collins, R.E. Deming, J.W. |
author_facet |
Firth, E. Carpenter, S.D. Sørensen, H.L. Collins, R.E. Deming, J.W. |
author_sort |
Firth, E. |
title |
Bacterial use of choline to tolerate salinity shifts in sea-ice brines |
title_short |
Bacterial use of choline to tolerate salinity shifts in sea-ice brines |
title_full |
Bacterial use of choline to tolerate salinity shifts in sea-ice brines |
title_fullStr |
Bacterial use of choline to tolerate salinity shifts in sea-ice brines |
title_full_unstemmed |
Bacterial use of choline to tolerate salinity shifts in sea-ice brines |
title_sort |
bacterial use of choline to tolerate salinity shifts in sea-ice brines |
publisher |
University of California Press |
publishDate |
2016 |
url |
http://dx.doi.org/10.12952/journal.elementa.000120 http://online.ucpress.edu/elementa/article-pdf/doi/10.12952/journal.elementa.000120/473697/156-1627-1-ce.pdf |
long_lat |
ENVELOPE(-51.527,-51.527,64.177,64.177) |
geographic |
Greenland Kobbefjord |
geographic_facet |
Greenland Kobbefjord |
genre |
Greenland Sea ice |
genre_facet |
Greenland Sea ice |
op_source |
Elementa: Science of the Anthropocene volume 4 ISSN 2325-1026 |
op_doi |
https://doi.org/10.12952/journal.elementa.000120 |
container_title |
Elementa: Science of the Anthropocene |
container_volume |
4 |
_version_ |
1784893576517255168 |