Karenia brevis is a marine dinoflagellate commonly found in the Gulf of Mexico and important both ecologically and economically due to
its production of the neurotoxin brevetoxin, which can cause respiratory illness in humans and widespread death of marine animals. K. brevis
strains have previously shown to be sensitive to changes in CO2, both in terms of growth as well as toxin production. Our study aimed to
understand this sensitivity by measuring underlying mechanisms, such as photosynthesis, carbon acquisition, and photophysiology. K. brevis
(CCFWC-126) did not show a significant response in growth, cellular composition of carbon and nitrogen, nor in photosynthetic rates between pCO2
concentrations of 150, 400 or 780 µatm. However, a strong response in its acquisition of inorganic carbon was found. Half saturation values for
CO2 increased from 1.5 to 3.3 µM, inorganic carbon preference switched from HCO3- to CO2 (14% to 56% CO2 usage), and external carbonic anhydrase
activity was downregulated by 23% when comparing low and high pCO2. We conclude that K. brevis must employ an efficient and regulated carbon
concentration mechanism (CCM) to maintain constant carbon fixation and growth across pCO2 levels. A positive correlation with pCO2, although not
statistically significant, in cellular brevetoxin content was found. This study is the first explaining how this socioeconomically important
species is able to efficiently supply inorganic carbon for photosynthesis which can potentially prolong bloom situations. This study also
highlights that enhanced CO2, as projected for a future ocean, can affect underlying physiological processes of K. brevis, some of which could
lead to increases in cellular brevetoxin production and therefore increased impacts on coastal ecosystems and economies. / A Thesis submitted to the Department of Earth, Ocean, and Atmospheric Science in partial fulfillment of the
requirements for the degree of Master of Science. / Fall Semester 2018. / September 17, 2018. / Brevetoxins, Carbon Concentrating Mechanism, Climate Change, Ocean Acidification, Photosynthesis, Red Tides / Includes bibliographical references. / Sven Kranz, Professor Directing Thesis; Angela Knapp, Committee Member; Olivia Mason, Committee Member;
Michael Stukel, Committee Member; Janie Wulff, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_661123 |
| Contributors | Bercel, Tristyn Lee (author), Kranz, Sven Alexander (professor directing thesis), Knapp, Angela Noel, 1976- (committee member), Mason, Olivia Underwood (committee member), Stukel, Michael R (committee member), Wulff, Janie L. (committee member), Florida State University (degree granting institution), College of Arts and Sciences (degree granting college), Department of Earth, Ocean and Atmospheric Science (degree granting departmentdgg) |
| Publisher | Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text, master thesis |
| Format | 1 online resource (61 pages), computer, application/pdf |
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