Acid-base regulation in the sea urchin Parechinus angulosus during CO₂-induced seawater acidification
Ocean acidification is predicted to have adverse effects on the physiologies of marine organisms, particularly those that produce calcified structures. Extracellular homeostasis is considered to be critical to mediating the effects of ocean acidification. Due to their low metabolic rates and weak ab...
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University of Cape Town
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Online Access: | http://hdl.handle.net/11427/7631 https://open.uct.ac.za/bitstream/11427/7631/1/thesis_sci_2013_dyer_urchins.pdf |
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ftunivcapetownir:oai:localhost:11427/7631 2023-05-15T17:50:55+02:00 Acid-base regulation in the sea urchin Parechinus angulosus during CO₂-induced seawater acidification Dyer, Alexei Lucas, Mike 2013 application/pdf http://hdl.handle.net/11427/7631 https://open.uct.ac.za/bitstream/11427/7631/1/thesis_sci_2013_dyer_urchins.pdf eng eng University of Cape Town Faculty of Science Department of Biological Sciences http://hdl.handle.net/11427/7631 https://open.uct.ac.za/bitstream/11427/7631/1/thesis_sci_2013_dyer_urchins.pdf Bachelor Thesis Honours BSc 2013 ftunivcapetownir 2022-09-13T05:55:01Z Ocean acidification is predicted to have adverse effects on the physiologies of marine organisms, particularly those that produce calcified structures. Extracellular homeostasis is considered to be critical to mediating the effects of ocean acidification. Due to their low metabolic rates and weak ability to regulate ion exchange, sea urchins are thought to be particularly weak acid-base regulators. Recent findings showing species-specific capacities for extracellular pH regulation however suggest that species currently exposed to natural CO₂ elevations, such as upwelling events, may have a higher capacity tolerate elevated CO₂. The sea urchin Parechinus angulosus currently experiences natural CO₂ variations within the Benguela upwelling system and is therefore predicted to possess the capacity to compensate moderate acid-base disturbances. Urchins were submitted to control (8.0), intermediate (7.7) and low (7.4) seawater pH treatments for 14 days to investigate the capacity to regulate extracellular acid-base status. Extracellular pH changes induced by exposure to intermediate (pH 7.7) seawater acidification were fully compensated through the accumulation of approximately 2.0 mmol l-1 of bicarbonate. The bicarbonate accumulation was only sufficient to partially compensate extracellular acid-base status during exposure to low (7.4) seawater pH. Results from acute (24 hour) exposure to low (7.4) seawater pH reveal that bicarbonate accumulation, despite being evident within 24 hours, is not sufficient to compensate extracellular pH. This study provides further support that sea urchins exposed to natural CO₂ variability possess a limited capacity to regulate extracellular acid-base disturbances. P.angulosus may therefore already be adapted to deal with a moderate reduction in seawater pH to 7.7, but lacks the iono-regulatory capacity to accumulate sufficient bicarbonate to deal with a reduction of seawater pH to 7.3. Long-term studies are needed to assess the role of acid-base regulation as a mediator of broader ... Bachelor Thesis Ocean acidification University of Cape Town: OpenUCT |
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University of Cape Town: OpenUCT |
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English |
description |
Ocean acidification is predicted to have adverse effects on the physiologies of marine organisms, particularly those that produce calcified structures. Extracellular homeostasis is considered to be critical to mediating the effects of ocean acidification. Due to their low metabolic rates and weak ability to regulate ion exchange, sea urchins are thought to be particularly weak acid-base regulators. Recent findings showing species-specific capacities for extracellular pH regulation however suggest that species currently exposed to natural CO₂ elevations, such as upwelling events, may have a higher capacity tolerate elevated CO₂. The sea urchin Parechinus angulosus currently experiences natural CO₂ variations within the Benguela upwelling system and is therefore predicted to possess the capacity to compensate moderate acid-base disturbances. Urchins were submitted to control (8.0), intermediate (7.7) and low (7.4) seawater pH treatments for 14 days to investigate the capacity to regulate extracellular acid-base status. Extracellular pH changes induced by exposure to intermediate (pH 7.7) seawater acidification were fully compensated through the accumulation of approximately 2.0 mmol l-1 of bicarbonate. The bicarbonate accumulation was only sufficient to partially compensate extracellular acid-base status during exposure to low (7.4) seawater pH. Results from acute (24 hour) exposure to low (7.4) seawater pH reveal that bicarbonate accumulation, despite being evident within 24 hours, is not sufficient to compensate extracellular pH. This study provides further support that sea urchins exposed to natural CO₂ variability possess a limited capacity to regulate extracellular acid-base disturbances. P.angulosus may therefore already be adapted to deal with a moderate reduction in seawater pH to 7.7, but lacks the iono-regulatory capacity to accumulate sufficient bicarbonate to deal with a reduction of seawater pH to 7.3. Long-term studies are needed to assess the role of acid-base regulation as a mediator of broader ... |
author2 |
Lucas, Mike |
format |
Bachelor Thesis |
author |
Dyer, Alexei |
spellingShingle |
Dyer, Alexei Acid-base regulation in the sea urchin Parechinus angulosus during CO₂-induced seawater acidification |
author_facet |
Dyer, Alexei |
author_sort |
Dyer, Alexei |
title |
Acid-base regulation in the sea urchin Parechinus angulosus during CO₂-induced seawater acidification |
title_short |
Acid-base regulation in the sea urchin Parechinus angulosus during CO₂-induced seawater acidification |
title_full |
Acid-base regulation in the sea urchin Parechinus angulosus during CO₂-induced seawater acidification |
title_fullStr |
Acid-base regulation in the sea urchin Parechinus angulosus during CO₂-induced seawater acidification |
title_full_unstemmed |
Acid-base regulation in the sea urchin Parechinus angulosus during CO₂-induced seawater acidification |
title_sort |
acid-base regulation in the sea urchin parechinus angulosus during co₂-induced seawater acidification |
publisher |
University of Cape Town |
publishDate |
2013 |
url |
http://hdl.handle.net/11427/7631 https://open.uct.ac.za/bitstream/11427/7631/1/thesis_sci_2013_dyer_urchins.pdf |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_relation |
http://hdl.handle.net/11427/7631 https://open.uct.ac.za/bitstream/11427/7631/1/thesis_sci_2013_dyer_urchins.pdf |
_version_ |
1766157858948251648 |