Stable carbon and nitrogen isotopic composition of benthic and pelagic organic matter in lakes of the McMurdo Dry Valleys, Antarctica
The perennially ice-covered lakes in the McMurdo Dry Valleys, Antarctica, are part of the coldest and driest ecosystem on earth. To understand lacustrine carbon and nitrogen cycling in this end-member ecosystem, and to define paleolimnological proxies for ice-covered lakes, we measured the stable ca...
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2004
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Online Access: | https://digitalcommons.lsu.edu/geo_pubs/662 https://doi.org/10.1007/s10498-004-2262-2 |
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ftlouisianastuir:oai:digitalcommons.lsu.edu:geo_pubs-1661 2023-06-11T04:07:14+02:00 Stable carbon and nitrogen isotopic composition of benthic and pelagic organic matter in lakes of the McMurdo Dry Valleys, Antarctica Lawson, Jennifer Doran, Peter T. Kenig, Fabien Des Marais, David J. Priscu, John C. 2004-09-01T07:00:00Z https://digitalcommons.lsu.edu/geo_pubs/662 https://doi.org/10.1007/s10498-004-2262-2 unknown LSU Digital Commons https://digitalcommons.lsu.edu/geo_pubs/662 doi:10.1007/s10498-004-2262-2 Faculty Publications Antarctica Carbon stable isotope Dry valleys Limnology Nitrogen stable isotope Organic matter Taylor Valley text 2004 ftlouisianastuir https://doi.org/10.1007/s10498-004-2262-2 2023-05-28T18:16:59Z The perennially ice-covered lakes in the McMurdo Dry Valleys, Antarctica, are part of the coldest and driest ecosystem on earth. To understand lacustrine carbon and nitrogen cycling in this end-member ecosystem, and to define paleolimnological proxies for ice-covered lakes, we measured the stable carbon and nitrogen isotopic composition of particulate organic matter (POM) and benthic organic matter (BOM) within the lakes of Taylor Valley. The δ13C compositions of seasonally ice-free edges of the lakes (moats) are enriched relative to under-ice organic matter. Thus, the organic carbon isotopic composition of buried sediments may be a proxy for sample position within the lake. In the moats, δ13C values are governed by limited CO2 diffusion across benthic cyanobacterial cell membranes. During a high glacial melt (2001-2002) season, both δ13CPOM and δ13 CBOM in the moats were more depleted than during previous low melt years. We propose that this occurred in response to higher [CO2](aq) and/or reduced growth rates resulting from turbidity-induced light limitation. Though moats and under-ice environments are usually poorly connected, during the 2001-2002 season, the enrichment of the δ13CPOM values at 6 m depth in the stream-proximal sites relative to deep-profile sites implies enhanced connectivity between these environments. The δ13C compositions of BOM and POM profiles in Lake Hoare and Lake Fryxell indicate that these lakes are dominated by benthic productivity. In contrast, in Lake Bonney, the similarity of the δ13C values of BOM and POM indicates the pelagic component dominance in the carbon cycle. © 2004 Kluwer Academic Publishers. Text Antarc* Antarctica McMurdo Dry Valleys LSU Digital Commons (Louisiana State University) McMurdo Dry Valleys Taylor Valley ENVELOPE(163.000,163.000,-77.617,-77.617) Bonney ENVELOPE(162.417,162.417,-77.717,-77.717) Fryxell ENVELOPE(163.183,163.183,-77.617,-77.617) Hoare ENVELOPE(162.850,162.850,-77.633,-77.633) Lake Bonney ENVELOPE(-25.588,-25.588,-80.361,-80.361) Lake Fryxell ENVELOPE(163.183,163.183,-77.617,-77.617) Lake Hoare ENVELOPE(162.850,162.850,-77.633,-77.633) Aquatic Geochemistry 10 3-4 269 301 |
institution |
Open Polar |
collection |
LSU Digital Commons (Louisiana State University) |
op_collection_id |
ftlouisianastuir |
language |
unknown |
topic |
Antarctica Carbon stable isotope Dry valleys Limnology Nitrogen stable isotope Organic matter Taylor Valley |
spellingShingle |
Antarctica Carbon stable isotope Dry valleys Limnology Nitrogen stable isotope Organic matter Taylor Valley Lawson, Jennifer Doran, Peter T. Kenig, Fabien Des Marais, David J. Priscu, John C. Stable carbon and nitrogen isotopic composition of benthic and pelagic organic matter in lakes of the McMurdo Dry Valleys, Antarctica |
topic_facet |
Antarctica Carbon stable isotope Dry valleys Limnology Nitrogen stable isotope Organic matter Taylor Valley |
description |
The perennially ice-covered lakes in the McMurdo Dry Valleys, Antarctica, are part of the coldest and driest ecosystem on earth. To understand lacustrine carbon and nitrogen cycling in this end-member ecosystem, and to define paleolimnological proxies for ice-covered lakes, we measured the stable carbon and nitrogen isotopic composition of particulate organic matter (POM) and benthic organic matter (BOM) within the lakes of Taylor Valley. The δ13C compositions of seasonally ice-free edges of the lakes (moats) are enriched relative to under-ice organic matter. Thus, the organic carbon isotopic composition of buried sediments may be a proxy for sample position within the lake. In the moats, δ13C values are governed by limited CO2 diffusion across benthic cyanobacterial cell membranes. During a high glacial melt (2001-2002) season, both δ13CPOM and δ13 CBOM in the moats were more depleted than during previous low melt years. We propose that this occurred in response to higher [CO2](aq) and/or reduced growth rates resulting from turbidity-induced light limitation. Though moats and under-ice environments are usually poorly connected, during the 2001-2002 season, the enrichment of the δ13CPOM values at 6 m depth in the stream-proximal sites relative to deep-profile sites implies enhanced connectivity between these environments. The δ13C compositions of BOM and POM profiles in Lake Hoare and Lake Fryxell indicate that these lakes are dominated by benthic productivity. In contrast, in Lake Bonney, the similarity of the δ13C values of BOM and POM indicates the pelagic component dominance in the carbon cycle. © 2004 Kluwer Academic Publishers. |
format |
Text |
author |
Lawson, Jennifer Doran, Peter T. Kenig, Fabien Des Marais, David J. Priscu, John C. |
author_facet |
Lawson, Jennifer Doran, Peter T. Kenig, Fabien Des Marais, David J. Priscu, John C. |
author_sort |
Lawson, Jennifer |
title |
Stable carbon and nitrogen isotopic composition of benthic and pelagic organic matter in lakes of the McMurdo Dry Valleys, Antarctica |
title_short |
Stable carbon and nitrogen isotopic composition of benthic and pelagic organic matter in lakes of the McMurdo Dry Valleys, Antarctica |
title_full |
Stable carbon and nitrogen isotopic composition of benthic and pelagic organic matter in lakes of the McMurdo Dry Valleys, Antarctica |
title_fullStr |
Stable carbon and nitrogen isotopic composition of benthic and pelagic organic matter in lakes of the McMurdo Dry Valleys, Antarctica |
title_full_unstemmed |
Stable carbon and nitrogen isotopic composition of benthic and pelagic organic matter in lakes of the McMurdo Dry Valleys, Antarctica |
title_sort |
stable carbon and nitrogen isotopic composition of benthic and pelagic organic matter in lakes of the mcmurdo dry valleys, antarctica |
publisher |
LSU Digital Commons |
publishDate |
2004 |
url |
https://digitalcommons.lsu.edu/geo_pubs/662 https://doi.org/10.1007/s10498-004-2262-2 |
long_lat |
ENVELOPE(163.000,163.000,-77.617,-77.617) ENVELOPE(162.417,162.417,-77.717,-77.717) ENVELOPE(163.183,163.183,-77.617,-77.617) ENVELOPE(162.850,162.850,-77.633,-77.633) ENVELOPE(-25.588,-25.588,-80.361,-80.361) ENVELOPE(163.183,163.183,-77.617,-77.617) ENVELOPE(162.850,162.850,-77.633,-77.633) |
geographic |
McMurdo Dry Valleys Taylor Valley Bonney Fryxell Hoare Lake Bonney Lake Fryxell Lake Hoare |
geographic_facet |
McMurdo Dry Valleys Taylor Valley Bonney Fryxell Hoare Lake Bonney Lake Fryxell Lake Hoare |
genre |
Antarc* Antarctica McMurdo Dry Valleys |
genre_facet |
Antarc* Antarctica McMurdo Dry Valleys |
op_source |
Faculty Publications |
op_relation |
https://digitalcommons.lsu.edu/geo_pubs/662 doi:10.1007/s10498-004-2262-2 |
op_doi |
https://doi.org/10.1007/s10498-004-2262-2 |
container_title |
Aquatic Geochemistry |
container_volume |
10 |
container_issue |
3-4 |
container_start_page |
269 |
op_container_end_page |
301 |
_version_ |
1768380220950183936 |