A direct CO2 control system for ocean acidification experiments: testing effects on the coralline red algae Phymatolithon lusitanicum
Most ocean acidification (OA) experimental systems rely on pH as an indirect way to control CO2. However, accurate pH measurements are difficult to obtain and shifts in temperature and/or salinity alter the relationship between pH and pCO2. Here we describe a system in which the target pCO2 is contr...
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ftpubmed:oai:pubmedcentral.nih.gov:5045892 2023-05-15T17:50:38+02:00 A direct CO2 control system for ocean acidification experiments: testing effects on the coralline red algae Phymatolithon lusitanicum Sordo, Laura Santos, Rui Reis, Joao Shulika, Alona Silva, Joao 2016-09-27 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5045892/ http://www.ncbi.nlm.nih.gov/pubmed/27703853 https://doi.org/10.7717/peerj.2503 en eng PeerJ Inc. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5045892/ http://www.ncbi.nlm.nih.gov/pubmed/27703853 http://dx.doi.org/10.7717/peerj.2503 © 2016 Sordo et al. http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ) and either DOI or URL of the article must be cited. CC-BY Biochemistry Text 2016 ftpubmed https://doi.org/10.7717/peerj.2503 2016-10-09T00:15:05Z Most ocean acidification (OA) experimental systems rely on pH as an indirect way to control CO2. However, accurate pH measurements are difficult to obtain and shifts in temperature and/or salinity alter the relationship between pH and pCO2. Here we describe a system in which the target pCO2 is controlled via direct analysis of pCO2 in seawater. This direct type of control accommodates potential temperature and salinity shifts, as the target variable is directly measured instead of being estimated. Water in a header tank is permanently re-circulated through an air-water equilibrator. The equilibrated air is then routed to an infrared gas analyzer (IRGA) that measures pCO2 and conveys this value to a Proportional-Integral-Derivative (PID) controller. The controller commands a solenoid valve that opens and closes the CO2 flush that is bubbled into the header tank. This low-cost control system allows the maintenance of stabilized levels of pCO2 for extended periods of time ensuring accurate experimental conditions. This system was used to study the long term effect of OA on the coralline red algae Phymatolithon lusitanicum. We found that after 11 months of high CO2 exposure, photosynthesis increased with CO2 as opposed to respiration, which was positively affected by temperature. Results showed that this system is adequate to run long-term OA experiments and can be easily adapted to test other relevant variables simultaneously with CO2, such as temperature, irradiance and nutrients. Text Ocean acidification PubMed Central (PMC) PeerJ 4 e2503 |
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Biochemistry |
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Biochemistry Sordo, Laura Santos, Rui Reis, Joao Shulika, Alona Silva, Joao A direct CO2 control system for ocean acidification experiments: testing effects on the coralline red algae Phymatolithon lusitanicum |
topic_facet |
Biochemistry |
description |
Most ocean acidification (OA) experimental systems rely on pH as an indirect way to control CO2. However, accurate pH measurements are difficult to obtain and shifts in temperature and/or salinity alter the relationship between pH and pCO2. Here we describe a system in which the target pCO2 is controlled via direct analysis of pCO2 in seawater. This direct type of control accommodates potential temperature and salinity shifts, as the target variable is directly measured instead of being estimated. Water in a header tank is permanently re-circulated through an air-water equilibrator. The equilibrated air is then routed to an infrared gas analyzer (IRGA) that measures pCO2 and conveys this value to a Proportional-Integral-Derivative (PID) controller. The controller commands a solenoid valve that opens and closes the CO2 flush that is bubbled into the header tank. This low-cost control system allows the maintenance of stabilized levels of pCO2 for extended periods of time ensuring accurate experimental conditions. This system was used to study the long term effect of OA on the coralline red algae Phymatolithon lusitanicum. We found that after 11 months of high CO2 exposure, photosynthesis increased with CO2 as opposed to respiration, which was positively affected by temperature. Results showed that this system is adequate to run long-term OA experiments and can be easily adapted to test other relevant variables simultaneously with CO2, such as temperature, irradiance and nutrients. |
format |
Text |
author |
Sordo, Laura Santos, Rui Reis, Joao Shulika, Alona Silva, Joao |
author_facet |
Sordo, Laura Santos, Rui Reis, Joao Shulika, Alona Silva, Joao |
author_sort |
Sordo, Laura |
title |
A direct CO2 control system for ocean acidification experiments: testing effects on the coralline red algae Phymatolithon lusitanicum |
title_short |
A direct CO2 control system for ocean acidification experiments: testing effects on the coralline red algae Phymatolithon lusitanicum |
title_full |
A direct CO2 control system for ocean acidification experiments: testing effects on the coralline red algae Phymatolithon lusitanicum |
title_fullStr |
A direct CO2 control system for ocean acidification experiments: testing effects on the coralline red algae Phymatolithon lusitanicum |
title_full_unstemmed |
A direct CO2 control system for ocean acidification experiments: testing effects on the coralline red algae Phymatolithon lusitanicum |
title_sort |
direct co2 control system for ocean acidification experiments: testing effects on the coralline red algae phymatolithon lusitanicum |
publisher |
PeerJ Inc. |
publishDate |
2016 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5045892/ http://www.ncbi.nlm.nih.gov/pubmed/27703853 https://doi.org/10.7717/peerj.2503 |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5045892/ http://www.ncbi.nlm.nih.gov/pubmed/27703853 http://dx.doi.org/10.7717/peerj.2503 |
op_rights |
© 2016 Sordo et al. http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ) and either DOI or URL of the article must be cited. |
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CC-BY |
op_doi |
https://doi.org/10.7717/peerj.2503 |
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e2503 |
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