Photosynthesis and calcification in two Halimeda species from Phuket, Thailand
Abstract Calcification rates, as well as rates of photosynthetic inorganic carbon (Ci) uptake and relative electron transport (rETR), were measured by alkalinity titrations and pulse-amplitude-modulated (PAM) fluorometry in a simple experimental set up for Halimeda macroloba and Halimeda borneensis...
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crdegruyter:10.1515/bot-2016-0003 2024-09-15T18:28:12+00:00 Photosynthesis and calcification in two Halimeda species from Phuket, Thailand Kaewsrikhaw, Ratchanee Prathep, Anchana Darakrai, Anuchit Beer, Sven National Science and Technology Development Agency 2016 http://dx.doi.org/10.1515/bot-2016-0003 https://www.degruyter.com/document/doi/10.1515/bot-2016-0003/xml https://www.degruyter.com/document/doi/10.1515/bot-2016-0003/pdf en eng Walter de Gruyter GmbH Botanica Marina volume 59, issue 2-3, page 187-192 ISSN 1437-4323 0006-8055 journal-article 2016 crdegruyter https://doi.org/10.1515/bot-2016-0003 2024-07-22T04:11:05Z Abstract Calcification rates, as well as rates of photosynthetic inorganic carbon (Ci) uptake and relative electron transport (rETR), were measured by alkalinity titrations and pulse-amplitude-modulated (PAM) fluorometry in a simple experimental set up for Halimeda macroloba and Halimeda borneensis from Tangkhen Bay, Phuket, Thailand. While calcification was saturated at bulk seawater concentrations of ~0.3 and ~0.2 m m CO 3 2- , respectively, for the two species, photosynthetic Ci uptake was saturated at ~1.0 and 0.6 m m HCO 3 - , respectively. Thus, the normal seawater concentrations of these two Ci forms (0.3 m m CO 3 2- and 1.7 m m HCO 3 - ) were viewed as saturating for both processes. rETR increased towards the end of the incubations as a function of irradiance despite the decrease in Ci uptake. This implies that part of the photosynthetic electron flow was diverted to processes other than CO 2 reduction under Ci-limiting conditions, and shows that fluorometry is not a good way to estimate photosynthetic efficiencies under such conditions. Based on the responses to pH and Ci reported here, we estimate that the predicted range of ocean acidification for 2100 will still allow for positive rates of calcification in these two Halimeda species. Article in Journal/Newspaper Ocean acidification De Gruyter Botanica Marina 59 2-3 187 192 |
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English |
description |
Abstract Calcification rates, as well as rates of photosynthetic inorganic carbon (Ci) uptake and relative electron transport (rETR), were measured by alkalinity titrations and pulse-amplitude-modulated (PAM) fluorometry in a simple experimental set up for Halimeda macroloba and Halimeda borneensis from Tangkhen Bay, Phuket, Thailand. While calcification was saturated at bulk seawater concentrations of ~0.3 and ~0.2 m m CO 3 2- , respectively, for the two species, photosynthetic Ci uptake was saturated at ~1.0 and 0.6 m m HCO 3 - , respectively. Thus, the normal seawater concentrations of these two Ci forms (0.3 m m CO 3 2- and 1.7 m m HCO 3 - ) were viewed as saturating for both processes. rETR increased towards the end of the incubations as a function of irradiance despite the decrease in Ci uptake. This implies that part of the photosynthetic electron flow was diverted to processes other than CO 2 reduction under Ci-limiting conditions, and shows that fluorometry is not a good way to estimate photosynthetic efficiencies under such conditions. Based on the responses to pH and Ci reported here, we estimate that the predicted range of ocean acidification for 2100 will still allow for positive rates of calcification in these two Halimeda species. |
author2 |
National Science and Technology Development Agency |
format |
Article in Journal/Newspaper |
author |
Kaewsrikhaw, Ratchanee Prathep, Anchana Darakrai, Anuchit Beer, Sven |
spellingShingle |
Kaewsrikhaw, Ratchanee Prathep, Anchana Darakrai, Anuchit Beer, Sven Photosynthesis and calcification in two Halimeda species from Phuket, Thailand |
author_facet |
Kaewsrikhaw, Ratchanee Prathep, Anchana Darakrai, Anuchit Beer, Sven |
author_sort |
Kaewsrikhaw, Ratchanee |
title |
Photosynthesis and calcification in two Halimeda species from Phuket, Thailand |
title_short |
Photosynthesis and calcification in two Halimeda species from Phuket, Thailand |
title_full |
Photosynthesis and calcification in two Halimeda species from Phuket, Thailand |
title_fullStr |
Photosynthesis and calcification in two Halimeda species from Phuket, Thailand |
title_full_unstemmed |
Photosynthesis and calcification in two Halimeda species from Phuket, Thailand |
title_sort |
photosynthesis and calcification in two halimeda species from phuket, thailand |
publisher |
Walter de Gruyter GmbH |
publishDate |
2016 |
url |
http://dx.doi.org/10.1515/bot-2016-0003 https://www.degruyter.com/document/doi/10.1515/bot-2016-0003/xml https://www.degruyter.com/document/doi/10.1515/bot-2016-0003/pdf |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_source |
Botanica Marina volume 59, issue 2-3, page 187-192 ISSN 1437-4323 0006-8055 |
op_doi |
https://doi.org/10.1515/bot-2016-0003 |
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Botanica Marina |
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59 |
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2-3 |
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187 |
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192 |
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1810469524866072576 |