The effects of ocean acidification and temperature change on the West Coast rock lobster (Jasus lalandii)
Thesis (PhD)--Stellenbosch University, 2015. ENGLISH ABSTRACT: The West Coast rock lobster (WCRL), Jasus lalandii, is a critical marine fisheries resource for South Africa and may in future be negatively affected by the changes in seawater parameters associated with the ongoing anthropogenic carbon...
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ftunstellenbosch:oai:scholar.sun.ac.za:10019.1/97802 2023-11-12T04:23:52+01:00 The effects of ocean acidification and temperature change on the West Coast rock lobster (Jasus lalandii) Knapp, Jarred Lee Auerswald, Lutz Hoffman, Louwrens C. Stellenbosch University. Faculty of Agrisciences. Dept. of Animal Sciences. 2015-12 x, 147 pages : illustrations application/pdf http://hdl.handle.net/10019.1/97802 en_ZA eng Stellenbosch : Stellenbosch University http://hdl.handle.net/10019.1/97802 Stellenbosch University Rock lobster (Jasus lalandii) Rock lobster (Jasus lalandii) -- Environmental aspects Rock lobster (Jasus lalandii) -- West Coast UCTD Thesis 2015 ftunstellenbosch 2023-10-22T07:35:40Z Thesis (PhD)--Stellenbosch University, 2015. ENGLISH ABSTRACT: The West Coast rock lobster (WCRL), Jasus lalandii, is a critical marine fisheries resource for South Africa and may in future be negatively affected by the changes in seawater parameters associated with the ongoing anthropogenic carbon dioxide (CO2) emissions. These CO2 emissions have been linked to a global decrease in ocean pH (termed “ocean acidification”) and an increase in temperature. There are strong estimates that these changes are to worsen in coming centuries. This warranted research because of 1) the low current level of the resource (2.6% of pristine) and 2) the relatively unexplored physiological- and other biological responses of the WCRL to environmental stressors. This information is essential for the sustainable management of the resource by government scientists in times of global- and regional climate change. In the short term, it was found that the WCRL was able to rapidly and reversibly respond to acute changes in seawater pH (pH 7.4), this was achieved primarily through the active up-regulation of bicarbonate levels in the haemolymph. Maintaining extracellular pH protects oxygen transport mechanisms, which are sensitive to pH changes due to the large Bohr effect that this study also revealed, in the respiratory protein, haemocyanin of adult WCRL. The energy cost of actively maintaining extracellular pH, however, is expected to affect growth and potentially survival in the long term. This was tested on juvenile WCRL that were exposed to a reduced seawater pH of 7.3 (18.8 °C) over a period of 28 weeks. Results revealed that survival was not influenced and acid-base regulation in the hypercapnia-exposed lobsters was maintained throughout the duration of the trial, however, this led to a reduced growth rate. Subsequently, in order to replicate field conditions more closely, a combination of effects, namely seawater pCO2 (pH 8 and 7.3) and different temperatures (15.6 and 19 °C) on the growth of juvenile WCRL were assessed over an ... Thesis Ocean acidification Stellenbosch University: SUNScholar Research Repository |
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Open Polar |
collection |
Stellenbosch University: SUNScholar Research Repository |
op_collection_id |
ftunstellenbosch |
language |
English |
topic |
Rock lobster (Jasus lalandii) Rock lobster (Jasus lalandii) -- Environmental aspects Rock lobster (Jasus lalandii) -- West Coast UCTD |
spellingShingle |
Rock lobster (Jasus lalandii) Rock lobster (Jasus lalandii) -- Environmental aspects Rock lobster (Jasus lalandii) -- West Coast UCTD Knapp, Jarred Lee The effects of ocean acidification and temperature change on the West Coast rock lobster (Jasus lalandii) |
topic_facet |
Rock lobster (Jasus lalandii) Rock lobster (Jasus lalandii) -- Environmental aspects Rock lobster (Jasus lalandii) -- West Coast UCTD |
description |
Thesis (PhD)--Stellenbosch University, 2015. ENGLISH ABSTRACT: The West Coast rock lobster (WCRL), Jasus lalandii, is a critical marine fisheries resource for South Africa and may in future be negatively affected by the changes in seawater parameters associated with the ongoing anthropogenic carbon dioxide (CO2) emissions. These CO2 emissions have been linked to a global decrease in ocean pH (termed “ocean acidification”) and an increase in temperature. There are strong estimates that these changes are to worsen in coming centuries. This warranted research because of 1) the low current level of the resource (2.6% of pristine) and 2) the relatively unexplored physiological- and other biological responses of the WCRL to environmental stressors. This information is essential for the sustainable management of the resource by government scientists in times of global- and regional climate change. In the short term, it was found that the WCRL was able to rapidly and reversibly respond to acute changes in seawater pH (pH 7.4), this was achieved primarily through the active up-regulation of bicarbonate levels in the haemolymph. Maintaining extracellular pH protects oxygen transport mechanisms, which are sensitive to pH changes due to the large Bohr effect that this study also revealed, in the respiratory protein, haemocyanin of adult WCRL. The energy cost of actively maintaining extracellular pH, however, is expected to affect growth and potentially survival in the long term. This was tested on juvenile WCRL that were exposed to a reduced seawater pH of 7.3 (18.8 °C) over a period of 28 weeks. Results revealed that survival was not influenced and acid-base regulation in the hypercapnia-exposed lobsters was maintained throughout the duration of the trial, however, this led to a reduced growth rate. Subsequently, in order to replicate field conditions more closely, a combination of effects, namely seawater pCO2 (pH 8 and 7.3) and different temperatures (15.6 and 19 °C) on the growth of juvenile WCRL were assessed over an ... |
author2 |
Auerswald, Lutz Hoffman, Louwrens C. Stellenbosch University. Faculty of Agrisciences. Dept. of Animal Sciences. |
format |
Thesis |
author |
Knapp, Jarred Lee |
author_facet |
Knapp, Jarred Lee |
author_sort |
Knapp, Jarred Lee |
title |
The effects of ocean acidification and temperature change on the West Coast rock lobster (Jasus lalandii) |
title_short |
The effects of ocean acidification and temperature change on the West Coast rock lobster (Jasus lalandii) |
title_full |
The effects of ocean acidification and temperature change on the West Coast rock lobster (Jasus lalandii) |
title_fullStr |
The effects of ocean acidification and temperature change on the West Coast rock lobster (Jasus lalandii) |
title_full_unstemmed |
The effects of ocean acidification and temperature change on the West Coast rock lobster (Jasus lalandii) |
title_sort |
effects of ocean acidification and temperature change on the west coast rock lobster (jasus lalandii) |
publisher |
Stellenbosch : Stellenbosch University |
publishDate |
2015 |
url |
http://hdl.handle.net/10019.1/97802 |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_relation |
http://hdl.handle.net/10019.1/97802 |
op_rights |
Stellenbosch University |
_version_ |
1782338504564408320 |