EFFECTS OF CLIMATE CHANGE AND EUTROPHICATION ON PHOTOSYNTHESIS AND CARBON-CONCENTRATING MECHANISMS: SURPRISING DIVERSITY AMONG REEF ALGAE

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dc.contributor.advisor Smith, Celia M.
dc.contributor.author Kawachi, Migiwa Shimashita
dc.contributor.department Botany
dc.date.accessioned 2023-07-11T00:20:12Z
dc.date.available 2023-07-11T00:20:12Z
dc.date.issued 2023
dc.description.degree Ph.D.
dc.identifier.uri https://hdl.handle.net/10125/105066
dc.subject Plant sciences
dc.subject Botany
dc.subject Biological oceanography
dc.subject Algae
dc.subject Carbon-concentrating mechanisms
dc.subject Climate change
dc.subject Coral reef
dc.subject Eutrophication
dc.subject Pyrenoid
dc.title EFFECTS OF CLIMATE CHANGE AND EUTROPHICATION ON PHOTOSYNTHESIS AND CARBON-CONCENTRATING MECHANISMS: SURPRISING DIVERSITY AMONG REEF ALGAE
dc.type Thesis
dcterms.abstract Increased anthropogenic CO2 emission since the start of the Industrial Revolution has brought a changing climate and various threats to coastal ecosystems including ocean warming, ocean acidification (OA), and sea level rise. Coral reef ecosystems are especially vulnerable to the climate change, because ocean warming and acidification decrease calcification and increase bleaching in coral. In addition to these impacts of climate change, coastal ecosystems are already experiencing local anthropogenic impacts such as chronic eutrophication and continuing arrival of new invasive species. In Hawai‘i, large-scale blooms of both native and invasive macroalgae are often observed in the region with coastal eutrophication by land-based anthropogenic nutrient input. Predicting the effects of OA (increased CO2 concentration in the ocean) on algae is not straightforward because many algae are already equipped with carbon-concentrating mechanisms (CCMs) with which algae can increase their internal CO2 concentration for photosynthesis. Further, nutrient availability especially that of the macronutrient, nitrogen (N) could alter the operation of algal CCMs because CCMs involve specific, large proteins such as ribulose-1,5-biphosphate carboxylase-oxygenase (RUBISCO) and carbonic anhydrases (CA). This study experimentally investigated how OA and eutrophication, independently and synergistically, affect photosynthesis and CCMs in common Hawaiian reef algae. Algae can quickly change their maximum photosynthetic rates and CCMs when grown under elevated CO2 and N. Further, we found a surprising diversity among reef algae in how they react to elevated CO2 and N with their CCMs. The results of this study suggest that many Hawaiian algae will thrive under future climate change conditions, and OA and eutrophication will likely work in their favor, accelerating the phase shift from coral-dominated to macroalgal-dominated reefs in unpredictably faster paces and with players that are not easily predicted.
dcterms.language en
dcterms.publisher University of Hawai'i at Manoa
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
local.identifier.alturi http://dissertations.umi.com/hawii:11800
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