Periodicity of benthic photosynthesis in Lake Fryxell, Antarctica
Filamentous forms of cyanobacteria, the earliest known oxygenic photosynthesising organisms, are the primary structuring agents in modern-day benthic microbial mat consortia. Under conditions of low sedimentation rates and slow water flow, gliding and colliding of the filaments create peaked and rid...
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ftautuniv:oai:openrepository.aut.ac.nz:10292/1433 2023-10-01T03:50:35+02:00 Periodicity of benthic photosynthesis in Lake Fryxell, Antarctica Vopel, K Hawes, I Doran, PD 2011 application/pdf https://hdl.handle.net/10292/1433 unknown AUT University 2011 New Zealand Annual Antarctic Conference, Hamilton, New Zealand, 2011-07-04 - 2011-07-06 https://hdl.handle.net/10292/1433 OpenAccess Conference Contribution 2011 ftautuniv 2023-09-06T14:00:13Z Filamentous forms of cyanobacteria, the earliest known oxygenic photosynthesising organisms, are the primary structuring agents in modern-day benthic microbial mat consortia. Under conditions of low sedimentation rates and slow water flow, gliding and colliding of the filaments create peaked and ridged structures with regular centimeter-scale spacing. Petroff et al. (2010) suggest that this spacing is set to minimise competition between individual structures. In support of this hypothesis they show that the spacing between structures corresponds to diffusive distances generated by a rhythmically fluctuating metabolism with a period of approximately 20 hours — the periodicity of photosynthesis. Fossil stromatolites show similar structures and spacing, which supports the still-contentious view that they are evidence of early photosynthetic communities and provides constraints on the origin of phototrophic communities in the early evolution of life on earth. Ridge-peak microbial mats of the type and spacing considered by Petroff are common in ice-covered Antarctic lakes. Such lakes provide a useful test of the diffusive mechanism of pinnacle spacing, since the weak diurnal variability in irradiance reaching the mats could be hypothesised as insufficient to generate diurnal metabolic periodicities. Centimetre-scale structures cannot relate to diffusive distances if metabolic cycles do not generate a marked diel pattern in resource availability in the water between structures, and the universal applicability of the Petroff model would be undermined. To test this model, we simultaneously measured, for the first time, a 30-hour time-series of in situ vertical oxygen concentration gradients in a pinnacle mat and incident irradiance. We found that the oxygen concentration gradient and irradiance were significantly linearly correlated despite a diurnal irradiance change of only 1.8 μmol quanta m-2 s-1. This result supports the model by Petroff et al. and confirms our own previous conclusions regarding the mats ... Conference Object Antarc* Antarctic Antarctica Auckland University of Technology: Tuwhera Open Research Antarctic Fryxell ENVELOPE(163.183,163.183,-77.617,-77.617) Pinnacle ENVELOPE(-54.900,-54.900,-61.067,-61.067) Lake Fryxell ENVELOPE(163.183,163.183,-77.617,-77.617) Ridge Peak ENVELOPE(-57.053,-57.053,-63.505,-63.505) |
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Open Polar |
collection |
Auckland University of Technology: Tuwhera Open Research |
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ftautuniv |
language |
unknown |
description |
Filamentous forms of cyanobacteria, the earliest known oxygenic photosynthesising organisms, are the primary structuring agents in modern-day benthic microbial mat consortia. Under conditions of low sedimentation rates and slow water flow, gliding and colliding of the filaments create peaked and ridged structures with regular centimeter-scale spacing. Petroff et al. (2010) suggest that this spacing is set to minimise competition between individual structures. In support of this hypothesis they show that the spacing between structures corresponds to diffusive distances generated by a rhythmically fluctuating metabolism with a period of approximately 20 hours — the periodicity of photosynthesis. Fossil stromatolites show similar structures and spacing, which supports the still-contentious view that they are evidence of early photosynthetic communities and provides constraints on the origin of phototrophic communities in the early evolution of life on earth. Ridge-peak microbial mats of the type and spacing considered by Petroff are common in ice-covered Antarctic lakes. Such lakes provide a useful test of the diffusive mechanism of pinnacle spacing, since the weak diurnal variability in irradiance reaching the mats could be hypothesised as insufficient to generate diurnal metabolic periodicities. Centimetre-scale structures cannot relate to diffusive distances if metabolic cycles do not generate a marked diel pattern in resource availability in the water between structures, and the universal applicability of the Petroff model would be undermined. To test this model, we simultaneously measured, for the first time, a 30-hour time-series of in situ vertical oxygen concentration gradients in a pinnacle mat and incident irradiance. We found that the oxygen concentration gradient and irradiance were significantly linearly correlated despite a diurnal irradiance change of only 1.8 μmol quanta m-2 s-1. This result supports the model by Petroff et al. and confirms our own previous conclusions regarding the mats ... |
format |
Conference Object |
author |
Vopel, K Hawes, I Doran, PD |
spellingShingle |
Vopel, K Hawes, I Doran, PD Periodicity of benthic photosynthesis in Lake Fryxell, Antarctica |
author_facet |
Vopel, K Hawes, I Doran, PD |
author_sort |
Vopel, K |
title |
Periodicity of benthic photosynthesis in Lake Fryxell, Antarctica |
title_short |
Periodicity of benthic photosynthesis in Lake Fryxell, Antarctica |
title_full |
Periodicity of benthic photosynthesis in Lake Fryxell, Antarctica |
title_fullStr |
Periodicity of benthic photosynthesis in Lake Fryxell, Antarctica |
title_full_unstemmed |
Periodicity of benthic photosynthesis in Lake Fryxell, Antarctica |
title_sort |
periodicity of benthic photosynthesis in lake fryxell, antarctica |
publisher |
AUT University |
publishDate |
2011 |
url |
https://hdl.handle.net/10292/1433 |
long_lat |
ENVELOPE(163.183,163.183,-77.617,-77.617) ENVELOPE(-54.900,-54.900,-61.067,-61.067) ENVELOPE(163.183,163.183,-77.617,-77.617) ENVELOPE(-57.053,-57.053,-63.505,-63.505) |
geographic |
Antarctic Fryxell Pinnacle Lake Fryxell Ridge Peak |
geographic_facet |
Antarctic Fryxell Pinnacle Lake Fryxell Ridge Peak |
genre |
Antarc* Antarctic Antarctica |
genre_facet |
Antarc* Antarctic Antarctica |
op_relation |
2011 New Zealand Annual Antarctic Conference, Hamilton, New Zealand, 2011-07-04 - 2011-07-06 https://hdl.handle.net/10292/1433 |
op_rights |
OpenAccess |
_version_ |
1778524879940747264 |