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A case study of ocean acidification and South Florida’s coral reefs.

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Date Issued:
2020-06-15
Abstract:
Levels of the greenhouse gas carbon dioxide have been increasing dramatically in the atmosphere since the onset of the Industrial Revolution with a sharp escalation occurring due to anthropogenic causes such as the burning of fossil fuels. The ocean acts as a carbon sink for this atmospheric CO2, absorbing a large majority of it. This process causes a chemical reaction that has been increasing the acidity level of ocean water and progressively lowering the average pH value. When a carbon dioxide molecule is absorbed into sea water, two positively charged ions are produced. Because pH value is a measurement of hydrogen ion concentration in any given solution, these added hydrogen ions effectively lower the pH value of the ocean. Since these hydrogen ions are positively charged, they go on to interact with the negatively charged bases already present in the ocean. One of these bases is CaCO3, or the carbonate ion. Carbonate is essential to calcifying marine organisms, who use this ion to build and maintain their shells and skeletons. However, as atmospheric carbon dioxide levels increase and the resulting chemical reactions occur, the ocean’s carbonate saturation decreases. Coral is one such calcifying organism that essential to the aquatic ecosystem in a number of ways, most of which can be attributed to the fact that coral reefs are one of the planet’s most biodiverse ecosystems despite inhabiting only a very small portion of the ocean. Several studies have linked coral’s carbonate production to their ability to create functional skeletons. One such study was published by Kuffner et al in 2013 in the Florida Keys. Four sites ranging from Miami to the Dry Tortugas were selected, and two batches of forty Siderastrea siderea (massive starlet coral) each were selected for two experimental runs. At six-month intervals, these samples were analyzed to determine linear expansion rates and calcification levels. After analysis in both runs, a strong correlation between linear expansion rates and calcification levels was determined. Corals that experienced heightened calcification rates also experienced heightened linear expansion. This experiment solidified the negative affect ocean acidification will have in future years on coral reefs if left unacknowledged. Langdon et al also published an experiment done in the Florida Keys in 2013 that determined a relationship between increased atmospheric CO2 levels and decreased calcification rates of coral. Eleven samples of a combination of Siderastrea radians (shallow water starlet coral) and Solenastrea hyades (smooth star coral) were epoxied to cinderblocks with sensors recording environmental data at thirty-minute intervals. Random samples were incubated in tanks in situ and given a treatment regime designed to simulate increased ocean acidification conditions through chemical injections of NaHCO3 (sodium bicarbonate) and HCl (hydrogen chloride). This treatment lowered pH value in the incubation chambers by 0.1 to 0.2 units. Calcification rates of the incubated coral samples were determined through statistical analysis. Coral samples that experienced a 0.1 unit drop in pH value experienced decreased calcification rates of 50% and coral samples that experiences a 0.2 unit drop in pH value experienced a decreased calcification rate of 52%. Both of these studies combined showcases the two-part threat ocean acidification is placing on coral reefs in the Florida Keys. As the average pH of ocean water drops, corals are unable to achieve net carbonate accretion and calcification rates drop. This causes corals to experience stunted linear expansion, density, rugosity, and reproduction rates. As coral population dwindles, Florida will experience several negative socio-economic impacts such as diminished coastal protection from storms, tourism, income and jobs created by fisheries, and medicinal opportunities as new life-saving medicines will no longer be able to be harvested from dying reefs. Mitigation and adaptation methods must include reducing other local stressors to coral.
Title: A case study of ocean acidification and South Florida’s coral reefs.
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Name(s): Camden, Lauren, creator
Type of Resource: text
Genre: Research Posters
Posters
Date Issued: 2020-06-15
Physical Form: electronic
Extent: 1 poster
Language(s): English
Abstract: Levels of the greenhouse gas carbon dioxide have been increasing dramatically in the atmosphere since the onset of the Industrial Revolution with a sharp escalation occurring due to anthropogenic causes such as the burning of fossil fuels. The ocean acts as a carbon sink for this atmospheric CO2, absorbing a large majority of it. This process causes a chemical reaction that has been increasing the acidity level of ocean water and progressively lowering the average pH value. When a carbon dioxide molecule is absorbed into sea water, two positively charged ions are produced. Because pH value is a measurement of hydrogen ion concentration in any given solution, these added hydrogen ions effectively lower the pH value of the ocean. Since these hydrogen ions are positively charged, they go on to interact with the negatively charged bases already present in the ocean. One of these bases is CaCO3, or the carbonate ion. Carbonate is essential to calcifying marine organisms, who use this ion to build and maintain their shells and skeletons. However, as atmospheric carbon dioxide levels increase and the resulting chemical reactions occur, the ocean’s carbonate saturation decreases. Coral is one such calcifying organism that essential to the aquatic ecosystem in a number of ways, most of which can be attributed to the fact that coral reefs are one of the planet’s most biodiverse ecosystems despite inhabiting only a very small portion of the ocean. Several studies have linked coral’s carbonate production to their ability to create functional skeletons. One such study was published by Kuffner et al in 2013 in the Florida Keys. Four sites ranging from Miami to the Dry Tortugas were selected, and two batches of forty Siderastrea siderea (massive starlet coral) each were selected for two experimental runs. At six-month intervals, these samples were analyzed to determine linear expansion rates and calcification levels. After analysis in both runs, a strong correlation between linear expansion rates and calcification levels was determined. Corals that experienced heightened calcification rates also experienced heightened linear expansion. This experiment solidified the negative affect ocean acidification will have in future years on coral reefs if left unacknowledged. Langdon et al also published an experiment done in the Florida Keys in 2013 that determined a relationship between increased atmospheric CO2 levels and decreased calcification rates of coral. Eleven samples of a combination of Siderastrea radians (shallow water starlet coral) and Solenastrea hyades (smooth star coral) were epoxied to cinderblocks with sensors recording environmental data at thirty-minute intervals. Random samples were incubated in tanks in situ and given a treatment regime designed to simulate increased ocean acidification conditions through chemical injections of NaHCO3 (sodium bicarbonate) and HCl (hydrogen chloride). This treatment lowered pH value in the incubation chambers by 0.1 to 0.2 units. Calcification rates of the incubated coral samples were determined through statistical analysis. Coral samples that experienced a 0.1 unit drop in pH value experienced decreased calcification rates of 50% and coral samples that experiences a 0.2 unit drop in pH value experienced a decreased calcification rate of 52%. Both of these studies combined showcases the two-part threat ocean acidification is placing on coral reefs in the Florida Keys. As the average pH of ocean water drops, corals are unable to achieve net carbonate accretion and calcification rates drop. This causes corals to experience stunted linear expansion, density, rugosity, and reproduction rates. As coral population dwindles, Florida will experience several negative socio-economic impacts such as diminished coastal protection from storms, tourism, income and jobs created by fisheries, and medicinal opportunities as new life-saving medicines will no longer be able to be harvested from dying reefs. Mitigation and adaptation methods must include reducing other local stressors to coral.
Identifier: BC744 (IID)
Affiliation: Lauren Camden. Broward College, undergraduate student.
Note(s): Poster presented to the Student Research Symposium Environmental Science event of the University/College Library’s annual Literary Festival on June 15, 2020.
The Student Research Symposium event of the University/College Library’s annual Literary Festival of 2020 was transitioned to a virtual setting due to COVID-19.
A project-based learning approach was implemented during the 2020 Spring semester in Dr. Pamela Fletcher’s Environmental Science courses where students created posters based on their research topics.
Subject(s): Broward College
Environmental sciences
Corals
Coral declines
Ocean acidification
Florida Keys (Fla.)
Florida
2020
Held by: Broward College Archives and Special Collections
Persistent Link to This Record: http://purl.flvc.org/broward/fd/BC744
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Host Institution: Broward