Carbon-use strategies in macroalgea: differential responses to lowered pH and implications for ocean acidification

Ocean acidification (OA) is a reduction in oceanicpH due to increased absorption of anthropogenicallyproduced CO 2 . This change alters the seawaterconcentrations of inorganic carbon species that areutilized by macroalgae for photosynthesis and calcification:CO 2 and HCO 3 increase; CO 3 2 decreases...

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Published in:Journal of Phycology
Main Authors: Cornwall, CE, Hepburn, CD, Pritchard, D, Currie, KI, McGraw, CM, Hunter, KA, Hurd, CL
Format: Article in Journal/Newspaper
Language:English
Published: Blackwell Publishing Inc 2012
Subjects:
Online Access:https://doi.org/10.1111/j.1529-8817.2011.01085.x
http://ecite.utas.edu.au/91468
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spelling ftunivtasecite:oai:ecite.utas.edu.au:91468 2023-05-15T17:49:51+02:00 Carbon-use strategies in macroalgea: differential responses to lowered pH and implications for ocean acidification Cornwall, CE Hepburn, CD Pritchard, D Currie, KI McGraw, CM Hunter, KA Hurd, CL 2012 https://doi.org/10.1111/j.1529-8817.2011.01085.x http://ecite.utas.edu.au/91468 en eng Blackwell Publishing Inc http://dx.doi.org/10.1111/j.1529-8817.2011.01085.x Cornwall, CE and Hepburn, CD and Pritchard, D and Currie, KI and McGraw, CM and Hunter, KA and Hurd, CL, Carbon-use strategies in macroalgea: differential responses to lowered pH and implications for ocean acidification, Journal of Phycology, 48, (1) pp. 137-144. ISSN 0022-3646 (2012) [Refereed Article] http://ecite.utas.edu.au/91468 Environmental Sciences Ecological Applications Ecological Impacts of Climate Change Refereed Article PeerReviewed 2012 ftunivtasecite https://doi.org/10.1111/j.1529-8817.2011.01085.x 2019-12-13T21:54:38Z Ocean acidification (OA) is a reduction in oceanicpH due to increased absorption of anthropogenicallyproduced CO 2 . This change alters the seawaterconcentrations of inorganic carbon species that areutilized by macroalgae for photosynthesis and calcification:CO 2 and HCO 3 increase; CO 3 2 decreases.Two common methods of experimentally reducingseawater pH differentially alter other aspects of carbonatechemistry: the addition of CO 2 gas mimicschanges predicted due to OA, while the addition ofHCl results in a comparatively lower [HCO 3 ]. Wemeasured the short-term photosynthetic responsesof five macroalgal species with various carbon-usestrategies in one of three seawater pH treatments:pH 7.5 lowered by bubbling CO 2 gas, pH 7.5 loweredby HCl, and ambient pH 7.9. There was no differencein photosynthetic rates between the CO 2 ,HCl, or pH 7.9 treatments for any of the speciesexamined. However, the ability of macroalgae toraise the pH of the surrounding seawater throughcarbon uptake was greatest in the pH 7.5 treatments.Modeling of pH change due to carbon assimilationindicated that macroalgal species that couldutilize HCO 3 increased their use of CO 2 in the pH7.5 treatments compared to pH 7.9 treatments. Speciesonly capable of using CO 2 did so exclusively inall treatments. Although CO 2 is not likely to be limitingfor photosynthesis for the macroalgal speciesexamined, the diffusive uptake of CO 2 is less energeticallyexpensive than active HCO 3 - uptake, andso HCO 3 - -using macroalgae may benefit in futureseawater with elevated CO 2 .Key index words: bicarbonate; carbon acquisition;carbon dioxide; climate change; dissolved inorganiccarbon; HCl; macroalgae; ocean acidification;pH drift; photosynthesisAbbreviations: AT, total alkalinity; CCM, carbonconcentratingmechanism; DIC, dissolvedinorganic carbon; OA, ocean acidification; PFD,photon flux density; PQ, photosynthetic quotient;PS, photosynthesis Article in Journal/Newspaper Ocean acidification eCite UTAS (University of Tasmania) Journal of Phycology 48 1 137 144
institution Open Polar
collection eCite UTAS (University of Tasmania)
op_collection_id ftunivtasecite
language English
topic Environmental Sciences
Ecological Applications
Ecological Impacts of Climate Change
spellingShingle Environmental Sciences
Ecological Applications
Ecological Impacts of Climate Change
Cornwall, CE
Hepburn, CD
Pritchard, D
Currie, KI
McGraw, CM
Hunter, KA
Hurd, CL
Carbon-use strategies in macroalgea: differential responses to lowered pH and implications for ocean acidification
topic_facet Environmental Sciences
Ecological Applications
Ecological Impacts of Climate Change
description Ocean acidification (OA) is a reduction in oceanicpH due to increased absorption of anthropogenicallyproduced CO 2 . This change alters the seawaterconcentrations of inorganic carbon species that areutilized by macroalgae for photosynthesis and calcification:CO 2 and HCO 3 increase; CO 3 2 decreases.Two common methods of experimentally reducingseawater pH differentially alter other aspects of carbonatechemistry: the addition of CO 2 gas mimicschanges predicted due to OA, while the addition ofHCl results in a comparatively lower [HCO 3 ]. Wemeasured the short-term photosynthetic responsesof five macroalgal species with various carbon-usestrategies in one of three seawater pH treatments:pH 7.5 lowered by bubbling CO 2 gas, pH 7.5 loweredby HCl, and ambient pH 7.9. There was no differencein photosynthetic rates between the CO 2 ,HCl, or pH 7.9 treatments for any of the speciesexamined. However, the ability of macroalgae toraise the pH of the surrounding seawater throughcarbon uptake was greatest in the pH 7.5 treatments.Modeling of pH change due to carbon assimilationindicated that macroalgal species that couldutilize HCO 3 increased their use of CO 2 in the pH7.5 treatments compared to pH 7.9 treatments. Speciesonly capable of using CO 2 did so exclusively inall treatments. Although CO 2 is not likely to be limitingfor photosynthesis for the macroalgal speciesexamined, the diffusive uptake of CO 2 is less energeticallyexpensive than active HCO 3 - uptake, andso HCO 3 - -using macroalgae may benefit in futureseawater with elevated CO 2 .Key index words: bicarbonate; carbon acquisition;carbon dioxide; climate change; dissolved inorganiccarbon; HCl; macroalgae; ocean acidification;pH drift; photosynthesisAbbreviations: AT, total alkalinity; CCM, carbonconcentratingmechanism; DIC, dissolvedinorganic carbon; OA, ocean acidification; PFD,photon flux density; PQ, photosynthetic quotient;PS, photosynthesis
format Article in Journal/Newspaper
author Cornwall, CE
Hepburn, CD
Pritchard, D
Currie, KI
McGraw, CM
Hunter, KA
Hurd, CL
author_facet Cornwall, CE
Hepburn, CD
Pritchard, D
Currie, KI
McGraw, CM
Hunter, KA
Hurd, CL
author_sort Cornwall, CE
title Carbon-use strategies in macroalgea: differential responses to lowered pH and implications for ocean acidification
title_short Carbon-use strategies in macroalgea: differential responses to lowered pH and implications for ocean acidification
title_full Carbon-use strategies in macroalgea: differential responses to lowered pH and implications for ocean acidification
title_fullStr Carbon-use strategies in macroalgea: differential responses to lowered pH and implications for ocean acidification
title_full_unstemmed Carbon-use strategies in macroalgea: differential responses to lowered pH and implications for ocean acidification
title_sort carbon-use strategies in macroalgea: differential responses to lowered ph and implications for ocean acidification
publisher Blackwell Publishing Inc
publishDate 2012
url https://doi.org/10.1111/j.1529-8817.2011.01085.x
http://ecite.utas.edu.au/91468
genre Ocean acidification
genre_facet Ocean acidification
op_relation http://dx.doi.org/10.1111/j.1529-8817.2011.01085.x
Cornwall, CE and Hepburn, CD and Pritchard, D and Currie, KI and McGraw, CM and Hunter, KA and Hurd, CL, Carbon-use strategies in macroalgea: differential responses to lowered pH and implications for ocean acidification, Journal of Phycology, 48, (1) pp. 137-144. ISSN 0022-3646 (2012) [Refereed Article]
http://ecite.utas.edu.au/91468
op_doi https://doi.org/10.1111/j.1529-8817.2011.01085.x
container_title Journal of Phycology
container_volume 48
container_issue 1
container_start_page 137
op_container_end_page 144
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