Photosynthetic performance of benthic microbial mats in Lake Hoare, Antarctica
We measured in situ photosynthesis of benthic microbial mats at various depths in Lake Hoare, a permanently ice‐covered lake of the McMurdo Dry Valleys, Antarctica, using oxygen (O 2 ) microelectrodes. We further investigated the vertical distribution and activity of pigments in the microbial mats u...
Published in: | Limnology and Oceanography |
---|---|
Main Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Wiley
2006
|
Subjects: | |
Online Access: | http://dx.doi.org/10.4319/lo.2006.51.4.1801 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.4319%2Flo.2006.51.4.1801 https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.2006.51.4.1801 |
id |
crwiley:10.4319/lo.2006.51.4.1801 |
---|---|
record_format |
openpolar |
spelling |
crwiley:10.4319/lo.2006.51.4.1801 2024-09-15T17:46:42+00:00 Photosynthetic performance of benthic microbial mats in Lake Hoare, Antarctica Vopel, Kay Hawes, Ian 2006 http://dx.doi.org/10.4319/lo.2006.51.4.1801 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.4319%2Flo.2006.51.4.1801 https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.2006.51.4.1801 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Limnology and Oceanography volume 51, issue 4, page 1801-1812 ISSN 0024-3590 1939-5590 journal-article 2006 crwiley https://doi.org/10.4319/lo.2006.51.4.1801 2024-07-18T04:25:32Z We measured in situ photosynthesis of benthic microbial mats at various depths in Lake Hoare, a permanently ice‐covered lake of the McMurdo Dry Valleys, Antarctica, using oxygen (O 2 ) microelectrodes. We further investigated the vertical distribution and activity of pigments in the microbial mats using an imaging pulseamplitude‐ modulated fluorometer. Microbial mats to at least 16.6‐m water depth are net producers of O 2 during the summer period. Net O 2 production ranges from 100‐500 µmol m −2 h −1 at incident downwelling irradiances of photosynthetically active radiation (PAR) of 1.0‐4.6 µmol quanta m −2 s −1 . Photosynthesis of mat‐forming cyanobacteria and diatoms occurs at all lake depths at or close to maximum efficiency. We measured absorption by the pigment arrays at a single water depth and, by assuming that absorption is water‐depth invariant, we estimated an area‐specific maximum community quantum yield of 0.073 mol carbon per mol photons. A community compensation irradiance of 0.1 µmol quanta m −2 s −1 was estimated, reflecting extreme shade acclimation. These results confirm estimates previously derived from laboratory gas‐exchange measurements and imply that even minor changes in the intensity of the incident downwelling irradiance of PAR caused by, for example, changes in the transparency of the ice cover or the optical properties of the water column can significantly alter rates of benthic carbon fixation. In situ measurements were confined to mats with flat surfaces. Laboratory measurements at the surface of mats with pinnacled surfaces revealed a complex small‐scale chemical structure at the mat‐water interface. Article in Journal/Newspaper Antarc* Antarctica McMurdo Dry Valleys Wiley Online Library Limnology and Oceanography 51 4 1801 1812 |
institution |
Open Polar |
collection |
Wiley Online Library |
op_collection_id |
crwiley |
language |
English |
description |
We measured in situ photosynthesis of benthic microbial mats at various depths in Lake Hoare, a permanently ice‐covered lake of the McMurdo Dry Valleys, Antarctica, using oxygen (O 2 ) microelectrodes. We further investigated the vertical distribution and activity of pigments in the microbial mats using an imaging pulseamplitude‐ modulated fluorometer. Microbial mats to at least 16.6‐m water depth are net producers of O 2 during the summer period. Net O 2 production ranges from 100‐500 µmol m −2 h −1 at incident downwelling irradiances of photosynthetically active radiation (PAR) of 1.0‐4.6 µmol quanta m −2 s −1 . Photosynthesis of mat‐forming cyanobacteria and diatoms occurs at all lake depths at or close to maximum efficiency. We measured absorption by the pigment arrays at a single water depth and, by assuming that absorption is water‐depth invariant, we estimated an area‐specific maximum community quantum yield of 0.073 mol carbon per mol photons. A community compensation irradiance of 0.1 µmol quanta m −2 s −1 was estimated, reflecting extreme shade acclimation. These results confirm estimates previously derived from laboratory gas‐exchange measurements and imply that even minor changes in the intensity of the incident downwelling irradiance of PAR caused by, for example, changes in the transparency of the ice cover or the optical properties of the water column can significantly alter rates of benthic carbon fixation. In situ measurements were confined to mats with flat surfaces. Laboratory measurements at the surface of mats with pinnacled surfaces revealed a complex small‐scale chemical structure at the mat‐water interface. |
format |
Article in Journal/Newspaper |
author |
Vopel, Kay Hawes, Ian |
spellingShingle |
Vopel, Kay Hawes, Ian Photosynthetic performance of benthic microbial mats in Lake Hoare, Antarctica |
author_facet |
Vopel, Kay Hawes, Ian |
author_sort |
Vopel, Kay |
title |
Photosynthetic performance of benthic microbial mats in Lake Hoare, Antarctica |
title_short |
Photosynthetic performance of benthic microbial mats in Lake Hoare, Antarctica |
title_full |
Photosynthetic performance of benthic microbial mats in Lake Hoare, Antarctica |
title_fullStr |
Photosynthetic performance of benthic microbial mats in Lake Hoare, Antarctica |
title_full_unstemmed |
Photosynthetic performance of benthic microbial mats in Lake Hoare, Antarctica |
title_sort |
photosynthetic performance of benthic microbial mats in lake hoare, antarctica |
publisher |
Wiley |
publishDate |
2006 |
url |
http://dx.doi.org/10.4319/lo.2006.51.4.1801 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.4319%2Flo.2006.51.4.1801 https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.2006.51.4.1801 |
genre |
Antarc* Antarctica McMurdo Dry Valleys |
genre_facet |
Antarc* Antarctica McMurdo Dry Valleys |
op_source |
Limnology and Oceanography volume 51, issue 4, page 1801-1812 ISSN 0024-3590 1939-5590 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.4319/lo.2006.51.4.1801 |
container_title |
Limnology and Oceanography |
container_volume |
51 |
container_issue |
4 |
container_start_page |
1801 |
op_container_end_page |
1812 |
_version_ |
1810495046520143872 |