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Effect of CO(2)-induced seawater acidification on growth, photosynthesis and inorganic carbon acquisition of the harmful bloom-forming marine microalga, Karenia mikimotoi

Karenia mikimotoi is a widespread, toxic and non-calcifying dinoflagellate, which can release and produce ichthyotoxins and hemolytic toxins affecting the food web within the area of its bloom. Shifts in the physiological characteristics of K. mikimotoi due to CO(2)-induced seawater acidification co...

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Detalles Bibliográficos
Autores principales: Hu, Shunxin, Zhou, Bin, Wang, You, Wang, Ying, Zhang, Xinxin, Zhao, Yan, Zhao, Xinyu, Tang, Xuexi
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5558969/
https://www.ncbi.nlm.nih.gov/pubmed/28813504
http://dx.doi.org/10.1371/journal.pone.0183289
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author Hu, Shunxin
Zhou, Bin
Wang, You
Wang, Ying
Zhang, Xinxin
Zhao, Yan
Zhao, Xinyu
Tang, Xuexi
author_facet Hu, Shunxin
Zhou, Bin
Wang, You
Wang, Ying
Zhang, Xinxin
Zhao, Yan
Zhao, Xinyu
Tang, Xuexi
author_sort Hu, Shunxin
collection PubMed
description Karenia mikimotoi is a widespread, toxic and non-calcifying dinoflagellate, which can release and produce ichthyotoxins and hemolytic toxins affecting the food web within the area of its bloom. Shifts in the physiological characteristics of K. mikimotoi due to CO(2)-induced seawater acidification could alter the occurrence, severity and impacts of harmful algal blooms (HABs). Here, we investigated the effects of elevated pCO(2) on the physiology of K. mikimotoi. Using semi-continuous cultures under controlled laboratory conditions, growth, photosynthesis and inorganic carbon acquisition were determined over 4–6 week incubations at ambient (390ppmv) and elevated pCO(2) levels (1000 ppmv and 2000 ppmv). pH-drift and inhibitor-experiments suggested that K. mikimotoi was capable of acquiring HCO(3)(-), and that the utilization of HCO(3)(-) was predominantly mediated by anion-exchange proteins, but that HCO(3)(-) dehydration catalyzed by external carbonic anhydrase (CA(ext)) only played a minor role in K. mikimotoi. Even though down-regulated CO(2) concentrating mechanisms (CCMs) and enhanced gross photosynthetic O(2) evolution were observed under 1000 ppmv CO(2) conditions, the saved energy did not stimulate growth of K. mikimotoi under 1000 ppmv CO(2), probably due to the increased dark respiration. However, significantly higher growth and photosynthesis [in terms of photosynthetic oxygen evolution, effective quantum Yield (Yield), photosynthetic efficiency (α), light saturation point (E(k)) and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity] were observed under 2000 ppmv CO(2) conditions. Furthermore, elevated pCO(2) increased the photo-inhibition rate of photosystem II (β) and non-photochemical quenching (NPQ) at high light. We suggest that the energy saved through the down-regulation of CCMs might lead to the additional light stress and photo-damage. Therefore, the response of this species to elevated CO(2) conditions will be determined by more than regulation and efficiency of CCMs.
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spelling pubmed-55589692017-08-25 Effect of CO(2)-induced seawater acidification on growth, photosynthesis and inorganic carbon acquisition of the harmful bloom-forming marine microalga, Karenia mikimotoi Hu, Shunxin Zhou, Bin Wang, You Wang, Ying Zhang, Xinxin Zhao, Yan Zhao, Xinyu Tang, Xuexi PLoS One Research Article Karenia mikimotoi is a widespread, toxic and non-calcifying dinoflagellate, which can release and produce ichthyotoxins and hemolytic toxins affecting the food web within the area of its bloom. Shifts in the physiological characteristics of K. mikimotoi due to CO(2)-induced seawater acidification could alter the occurrence, severity and impacts of harmful algal blooms (HABs). Here, we investigated the effects of elevated pCO(2) on the physiology of K. mikimotoi. Using semi-continuous cultures under controlled laboratory conditions, growth, photosynthesis and inorganic carbon acquisition were determined over 4–6 week incubations at ambient (390ppmv) and elevated pCO(2) levels (1000 ppmv and 2000 ppmv). pH-drift and inhibitor-experiments suggested that K. mikimotoi was capable of acquiring HCO(3)(-), and that the utilization of HCO(3)(-) was predominantly mediated by anion-exchange proteins, but that HCO(3)(-) dehydration catalyzed by external carbonic anhydrase (CA(ext)) only played a minor role in K. mikimotoi. Even though down-regulated CO(2) concentrating mechanisms (CCMs) and enhanced gross photosynthetic O(2) evolution were observed under 1000 ppmv CO(2) conditions, the saved energy did not stimulate growth of K. mikimotoi under 1000 ppmv CO(2), probably due to the increased dark respiration. However, significantly higher growth and photosynthesis [in terms of photosynthetic oxygen evolution, effective quantum Yield (Yield), photosynthetic efficiency (α), light saturation point (E(k)) and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity] were observed under 2000 ppmv CO(2) conditions. Furthermore, elevated pCO(2) increased the photo-inhibition rate of photosystem II (β) and non-photochemical quenching (NPQ) at high light. We suggest that the energy saved through the down-regulation of CCMs might lead to the additional light stress and photo-damage. Therefore, the response of this species to elevated CO(2) conditions will be determined by more than regulation and efficiency of CCMs. Public Library of Science 2017-08-16 /pmc/articles/PMC5558969/ /pubmed/28813504 http://dx.doi.org/10.1371/journal.pone.0183289 Text en © 2017 Hu 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, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Hu, Shunxin
Zhou, Bin
Wang, You
Wang, Ying
Zhang, Xinxin
Zhao, Yan
Zhao, Xinyu
Tang, Xuexi
Effect of CO(2)-induced seawater acidification on growth, photosynthesis and inorganic carbon acquisition of the harmful bloom-forming marine microalga, Karenia mikimotoi
title Effect of CO(2)-induced seawater acidification on growth, photosynthesis and inorganic carbon acquisition of the harmful bloom-forming marine microalga, Karenia mikimotoi
title_full Effect of CO(2)-induced seawater acidification on growth, photosynthesis and inorganic carbon acquisition of the harmful bloom-forming marine microalga, Karenia mikimotoi
title_fullStr Effect of CO(2)-induced seawater acidification on growth, photosynthesis and inorganic carbon acquisition of the harmful bloom-forming marine microalga, Karenia mikimotoi
title_full_unstemmed Effect of CO(2)-induced seawater acidification on growth, photosynthesis and inorganic carbon acquisition of the harmful bloom-forming marine microalga, Karenia mikimotoi
title_short Effect of CO(2)-induced seawater acidification on growth, photosynthesis and inorganic carbon acquisition of the harmful bloom-forming marine microalga, Karenia mikimotoi
title_sort effect of co(2)-induced seawater acidification on growth, photosynthesis and inorganic carbon acquisition of the harmful bloom-forming marine microalga, karenia mikimotoi
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5558969/
https://www.ncbi.nlm.nih.gov/pubmed/28813504
http://dx.doi.org/10.1371/journal.pone.0183289
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