The Effect of Increased Temperature and PCO2 on Respiration and Photosynthetic Rates in the Red Alga Gracilaria salicornia.

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dc.contributor.author Onuma, Megan A.
dc.contributor.department Marine Biology
dc.date.accessioned 2019-05-28T20:09:55Z
dc.date.available 2019-05-28T20:09:55Z
dc.date.issued 2017-08
dc.identifier.uri http://hdl.handle.net/10125/62515
dc.subject algae
dc.subject respiration
dc.subject photosynthesis
dc.subject climate change
dc.subject temperature
dc.subject pCO2
dc.title The Effect of Increased Temperature and PCO2 on Respiration and Photosynthetic Rates in the Red Alga Gracilaria salicornia.
dc.type Thesis
dcterms.abstract Increasing temperatures and ocean acidification are causing widespread damage to coral reefs. Since corals and macroalgae compete for resources, this may lead to the proliferation of some macroalgal species. Understanding how macroalgae will be affected by climate change will be useful knowledge for conservation management. This study focuses on how the interactive factors of temperature and pCO2 affect the respiration and photosynthesis rates of Gracilaria salicornia, an invasive alga in Hawaiʻi originally from the eastern Pacific. Using an outdoor, continuous-flow seawater system with natural sunlight, G. salicornia (n=8) tissue was exposed to different temperatures and pCO2 levels using a full-factorial design. At the end of a three-day exposure to treatment conditions, respiration was measured using oxygen evolution methods and photosynthesis was measured using a fluorometer to obtain rapid light curves. Each response variable was analyzed independently using multiple regression models. The models suggest temperature and temperature2 had significant effects on respiration rates (P<0.03 and P<0.03, respectively). Analysis indicates pCO2 had a slight but significant effect on maximum electron transfer rate (ETRmax) (P<0.04). Results indicate G. salicornia experiences carbon limitation, which has also been demonstrated in other species of the genus Gracilaria. The increase in carbon availability that accompanies ocean acidification may encourage growth in these carbonlimited species. These analyses show an increase in respiration and photosynthesis rates under select climate change scenarios, though further research will be needed to determine how these metabolic increases affect the growth and distribution of the organism.
dcterms.description M.S. Thesis. University of Hawaiʻi at Mānoa 2017.
dcterms.language eng
dcterms.publisher University of Hawaiʻi at Mānoa
dcterms.rights All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
dcterms.type Text
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