Estimating photosynthetic activity in microbial mats in an ice‐covered Antarctic lake using automated oxygen microelectrode profiling and variable chlorophyll fluorescence
An automated oxygen microprofiler measured a positive flux of oxygen from microbial mats in ice‐covered Lake Hoare, Antarctica, from noon, at a photon flux of 20 µmol m −2 s −1 , through to midnight (< 2 µmol photons m −2 s −1 ). Daily average oxygen flux was 200 µmol m −2 h −1 and, whereas it wa...
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crwiley:10.4319/lo.2014.59.3.0674 2024-05-19T07:31:27+00:00 Estimating photosynthetic activity in microbial mats in an ice‐covered Antarctic lake using automated oxygen microelectrode profiling and variable chlorophyll fluorescence Hawes, Ian Giles, Hilke Doran, Peter T. 2014 http://dx.doi.org/10.4319/lo.2014.59.3.0674 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.4319%2Flo.2014.59.3.0674 https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.2014.59.3.0674 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Limnology and Oceanography volume 59, issue 3, page 674-688 ISSN 0024-3590 1939-5590 Aquatic Science Oceanography journal-article 2014 crwiley https://doi.org/10.4319/lo.2014.59.3.0674 2024-04-22T07:35:34Z An automated oxygen microprofiler measured a positive flux of oxygen from microbial mats in ice‐covered Lake Hoare, Antarctica, from noon, at a photon flux of 20 µmol m −2 s −1 , through to midnight (< 2 µmol photons m −2 s −1 ). Daily average oxygen flux was 200 µmol m −2 h −1 and, whereas it was maximal at noon, when a 10 mm broad concentration peak was observed 5 mm below the mat surface, flux correlated only weakly with irradiance. In contrast, relative electron transfer rate, estimated from variable chlorophyll fluorescence, suggested a linear relationship between photosystem activity and irradiance. This contradiction arose because of the conjunction of photosynthetic production of oxygen deep into these transparent, gelatinous mats (diel oxygen change was observed to 17 mm depth) and oxygen diffusion rates too slow to allow equilibration of oxygen concentration profiles with instantaneous production and consumption of oxygen. To confirm this, we developed a mathematical simulation of oxygen dynamics that included diffusion, photosynthesis, and respiration. The simulation further indicated that (1) net oxygen evolution is light limited is and confined to the upper few millimeters of the mat, (2) below 5–7 mm, respiration balanced photosynthesis, (3) below 17 mm, respiration and photosynthesis approached zero, even though organic carbon and dissolved oxygen were present, and (4) photosynthesis deep into the mat was dependent on high light transmission through the gelatinous matrix. These conclusions are consistent with current understanding of mat growth dynamics and point to approaches for long‐term analysis of microbial mat productivity. Article in Journal/Newspaper Antarc* Antarctic Antarctica Wiley Online Library Limnology and Oceanography 59 3 674 688 |
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English |
topic |
Aquatic Science Oceanography |
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Aquatic Science Oceanography Hawes, Ian Giles, Hilke Doran, Peter T. Estimating photosynthetic activity in microbial mats in an ice‐covered Antarctic lake using automated oxygen microelectrode profiling and variable chlorophyll fluorescence |
topic_facet |
Aquatic Science Oceanography |
description |
An automated oxygen microprofiler measured a positive flux of oxygen from microbial mats in ice‐covered Lake Hoare, Antarctica, from noon, at a photon flux of 20 µmol m −2 s −1 , through to midnight (< 2 µmol photons m −2 s −1 ). Daily average oxygen flux was 200 µmol m −2 h −1 and, whereas it was maximal at noon, when a 10 mm broad concentration peak was observed 5 mm below the mat surface, flux correlated only weakly with irradiance. In contrast, relative electron transfer rate, estimated from variable chlorophyll fluorescence, suggested a linear relationship between photosystem activity and irradiance. This contradiction arose because of the conjunction of photosynthetic production of oxygen deep into these transparent, gelatinous mats (diel oxygen change was observed to 17 mm depth) and oxygen diffusion rates too slow to allow equilibration of oxygen concentration profiles with instantaneous production and consumption of oxygen. To confirm this, we developed a mathematical simulation of oxygen dynamics that included diffusion, photosynthesis, and respiration. The simulation further indicated that (1) net oxygen evolution is light limited is and confined to the upper few millimeters of the mat, (2) below 5–7 mm, respiration balanced photosynthesis, (3) below 17 mm, respiration and photosynthesis approached zero, even though organic carbon and dissolved oxygen were present, and (4) photosynthesis deep into the mat was dependent on high light transmission through the gelatinous matrix. These conclusions are consistent with current understanding of mat growth dynamics and point to approaches for long‐term analysis of microbial mat productivity. |
format |
Article in Journal/Newspaper |
author |
Hawes, Ian Giles, Hilke Doran, Peter T. |
author_facet |
Hawes, Ian Giles, Hilke Doran, Peter T. |
author_sort |
Hawes, Ian |
title |
Estimating photosynthetic activity in microbial mats in an ice‐covered Antarctic lake using automated oxygen microelectrode profiling and variable chlorophyll fluorescence |
title_short |
Estimating photosynthetic activity in microbial mats in an ice‐covered Antarctic lake using automated oxygen microelectrode profiling and variable chlorophyll fluorescence |
title_full |
Estimating photosynthetic activity in microbial mats in an ice‐covered Antarctic lake using automated oxygen microelectrode profiling and variable chlorophyll fluorescence |
title_fullStr |
Estimating photosynthetic activity in microbial mats in an ice‐covered Antarctic lake using automated oxygen microelectrode profiling and variable chlorophyll fluorescence |
title_full_unstemmed |
Estimating photosynthetic activity in microbial mats in an ice‐covered Antarctic lake using automated oxygen microelectrode profiling and variable chlorophyll fluorescence |
title_sort |
estimating photosynthetic activity in microbial mats in an ice‐covered antarctic lake using automated oxygen microelectrode profiling and variable chlorophyll fluorescence |
publisher |
Wiley |
publishDate |
2014 |
url |
http://dx.doi.org/10.4319/lo.2014.59.3.0674 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.4319%2Flo.2014.59.3.0674 https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.2014.59.3.0674 |
genre |
Antarc* Antarctic Antarctica |
genre_facet |
Antarc* Antarctic Antarctica |
op_source |
Limnology and Oceanography volume 59, issue 3, page 674-688 ISSN 0024-3590 1939-5590 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.4319/lo.2014.59.3.0674 |
container_title |
Limnology and Oceanography |
container_volume |
59 |
container_issue |
3 |
container_start_page |
674 |
op_container_end_page |
688 |
_version_ |
1799469307799797760 |