The role of Sargassum pacificum in ocean acidification effects on corals
Ocean acidification (OA), the decrease in the seawater pH and carbonate ion concentration due to the uptake of anthropogenic carbon dioxide (CO2) with no change in total alkalinity, threatens coral reefs worldwide as studies predict the decline of calcifiers and increasing growth of non-calcified ma...
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California State University, Northridge
2015
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ftcalifstateuniv:oai:scholarworks:12579v93c 2024-09-30T14:40:42+00:00 The role of Sargassum pacificum in ocean acidification effects on corals Hillard, Heather Carpenter, Robert C Edmunds, Peter J Steele, Mark A 2015-06-26 http://hdl.handle.net/10211.3/141722 English eng California State University, Northridge Biology http://hdl.handle.net/10211.3/141722 algae coral reef coral reef ecology Dissertations Academic -- CSUN -- Biology coral ocean acidification climate change macroalgae Masters Thesis 2015 ftcalifstateuniv 2024-09-10T17:06:19Z Ocean acidification (OA), the decrease in the seawater pH and carbonate ion concentration due to the uptake of anthropogenic carbon dioxide (CO2) with no change in total alkalinity, threatens coral reefs worldwide as studies predict the decline of calcifiers and increasing growth of non-calcified macroalgae. Future recovery of coral reefs may depend on the ability of corals to survive in association with macroalgae. However, few studies have incorporated multiple species into OA experiments. This research sought to explore the understudied combined impact of macroalgae and elevated pCO2 on corals. Macroalgae can indirectly (e.g., shading, allelochemicals) and directly (e.g., abrasion, overgrowth) harm corals. Alternatively, algae could facilitate coral calcification by reducing pH through photosynthesis. The reef crest surrounding Moorea, French Polynesia, is covered by the fleshy, macroalgal species Sargassum pacificum. Results from photoquadrat surveys showed that scleractinian corals and other biogenic calcifiers covered 15% of the sub-canopy habitat. The same microenvironment experiences on average, increases in pH by 0.031 ± 0.012 pHT and decreases in irradiance by ~98% compared to surrounding, above-canopy conditions. On a larger scale, diel fluctuations in pH (up to 0.197 pHT) were recorded behind the S. pacificum-dominated reef crest. To help predict the future of coral reef dynamics accurately, the present research examined how non-calcifying macroalgae could mitigate, by metabolically reducing CO2 levels, or exacerbate, by shading, the effects of OA on associated scleractinian corals. In Chapter 2, the role of macroalgae as a chemical refuge from OA was addressed through a combined laboratory and field experiment testing the effect of the presence/absence of Sargassum pacificum on juvenile Porites rus exposed to ambient and elevated pCO2. In the field, corals with S. pacificum exhibited less bleaching but did not significantly alter their net calcification rates. P. rus in the laboratory experiment ... Master Thesis Ocean acidification Scholarworks from California State University Rus’ ENVELOPE(155.950,155.950,54.200,54.200) |
institution |
Open Polar |
collection |
Scholarworks from California State University |
op_collection_id |
ftcalifstateuniv |
language |
English |
topic |
algae coral reef coral reef ecology Dissertations Academic -- CSUN -- Biology coral ocean acidification climate change macroalgae |
spellingShingle |
algae coral reef coral reef ecology Dissertations Academic -- CSUN -- Biology coral ocean acidification climate change macroalgae Hillard, Heather The role of Sargassum pacificum in ocean acidification effects on corals |
topic_facet |
algae coral reef coral reef ecology Dissertations Academic -- CSUN -- Biology coral ocean acidification climate change macroalgae |
description |
Ocean acidification (OA), the decrease in the seawater pH and carbonate ion concentration due to the uptake of anthropogenic carbon dioxide (CO2) with no change in total alkalinity, threatens coral reefs worldwide as studies predict the decline of calcifiers and increasing growth of non-calcified macroalgae. Future recovery of coral reefs may depend on the ability of corals to survive in association with macroalgae. However, few studies have incorporated multiple species into OA experiments. This research sought to explore the understudied combined impact of macroalgae and elevated pCO2 on corals. Macroalgae can indirectly (e.g., shading, allelochemicals) and directly (e.g., abrasion, overgrowth) harm corals. Alternatively, algae could facilitate coral calcification by reducing pH through photosynthesis. The reef crest surrounding Moorea, French Polynesia, is covered by the fleshy, macroalgal species Sargassum pacificum. Results from photoquadrat surveys showed that scleractinian corals and other biogenic calcifiers covered 15% of the sub-canopy habitat. The same microenvironment experiences on average, increases in pH by 0.031 ± 0.012 pHT and decreases in irradiance by ~98% compared to surrounding, above-canopy conditions. On a larger scale, diel fluctuations in pH (up to 0.197 pHT) were recorded behind the S. pacificum-dominated reef crest. To help predict the future of coral reef dynamics accurately, the present research examined how non-calcifying macroalgae could mitigate, by metabolically reducing CO2 levels, or exacerbate, by shading, the effects of OA on associated scleractinian corals. In Chapter 2, the role of macroalgae as a chemical refuge from OA was addressed through a combined laboratory and field experiment testing the effect of the presence/absence of Sargassum pacificum on juvenile Porites rus exposed to ambient and elevated pCO2. In the field, corals with S. pacificum exhibited less bleaching but did not significantly alter their net calcification rates. P. rus in the laboratory experiment ... |
author2 |
Carpenter, Robert C Edmunds, Peter J Steele, Mark A |
format |
Master Thesis |
author |
Hillard, Heather |
author_facet |
Hillard, Heather |
author_sort |
Hillard, Heather |
title |
The role of Sargassum pacificum in ocean acidification effects on corals |
title_short |
The role of Sargassum pacificum in ocean acidification effects on corals |
title_full |
The role of Sargassum pacificum in ocean acidification effects on corals |
title_fullStr |
The role of Sargassum pacificum in ocean acidification effects on corals |
title_full_unstemmed |
The role of Sargassum pacificum in ocean acidification effects on corals |
title_sort |
role of sargassum pacificum in ocean acidification effects on corals |
publisher |
California State University, Northridge |
publishDate |
2015 |
url |
http://hdl.handle.net/10211.3/141722 |
long_lat |
ENVELOPE(155.950,155.950,54.200,54.200) |
geographic |
Rus’ |
geographic_facet |
Rus’ |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_relation |
http://hdl.handle.net/10211.3/141722 |
_version_ |
1811643181135036416 |