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dc.contributor.advisorArmstrong, Roy A.
dc.contributor.authorTorres-Pérez, Juan L.
dc.description.abstractClear coral reefs waters are highly transparent to ultraviolet radiation (UVR) and therefore, reef organisms should be adapted to tolerate present levels of UVR. However, UVR can severely damage coral tissues and overall physiology. The effects of changes in UVR on the growth, fecundity, and photosynthetic and photoprotective pigments production of the Caribbean shallow-water branching corals Acropora cervicornis (Lamarck 1816) and Porites furcata (Lamarck 1816) were studied by either reducing or enhancing normal UVR doses in two separate experiments. First, UVR was artificially depleted with Hyzod® acrylic panels and Saran® meshes. Second, different colonies were exposed to enhanced UVR by either transplanting colonies of A. cervicornis from deep to shallow areas, or exposing colonies of P. furcata to 10% increased UVR in aquariums located under UV fluorescent bulbs. Growth rates were measured using the Alizarin Red staining method. Fecundity was estimated after histological analysis. Pigments were quantified through High Performance Liquid Chromatography (HPLC) analysis. A positive correlation was found between growth and photosynthetic pigments concentration, and reduced UVR, while the concentration of UV-absorbing compounds (mycosporine-like amino acids or MAA’s) was negatively correlated with reduced UVR. Severe bleaching experienced by A. cervicornis colonies transplanted from deep to shallow areas resulted in significantly decreased growth rates and photosynthetic pigments concentration compared to controls, although no significant changes were observed in zooxanthellae densities. This suggests that a specific targeted effect of UVR on the photosynthetic capacity of the zooxanthellae caused the bleaching. Bleached colonies survived by significantly increasing the UVR protection with increased MAA’s concentrations and a possible relocation of resources. Similarly, colonies of P. furcata exposed to artificially enhanced UVR significantly reduced their growth rates and photosynthetic pigments concentrations compared to controls exposed to normal UVR. A significant increase in MAA’s was also found in colonies of P. furcata under enhanced UVR, while no differences were observed in fecundity compared to controls. While several physical factors may influence reef corals physiology, these results suggest that shallow-water corals could be significantly affected by increases in UVR resulting from the thinning of the Earth’s ozone layer.en_US
dc.description.abstractLas aguas arrecifales claras son altamente transparentes a la radiación ultravioleta (UVR) por lo que los organismos arrecifales deben estar adaptados a tolerar niveles actuales de UVR. Sin embargo, UVR puede dañar severamente los tejidos y la fisiología de los corales escleractínidos. Los efectos de cambios en UVR en el crecimiento, fecundidad, y producción de pigmentos de los corales ramificados caribeños Acropora cervicornis (Lamarck 1816) y Porites furcata (Lamarck 1816) fueron estudiados en dos experimentos separados. Primero, UVR fue reducida artificialmente con paneles de acrílico Hyzod® y mallas de Saran®. Segundo, diferentes colonias fueron expuestas a aumentos en UVR ya sea transplantando colonias de A. cervicornis desde áreas profundas hacia áreas llanas, ó exponiendo colonias de P. furcata a un aumento de 10% en UVR en acuarios localizados debajo de lámparas fluorescentes de luz ultravioleta. Las tasas de crecimiento fueron medidas usando Alizarina Roja. La fecundidad fue estimada con análisis histológico. Los pigmentos fueron cuantificados utilizando análisis de Cromatografía Líquida de Alta Precisión (HPLC). El crecimiento y la concentración de pigmentos fotosintéticos correlacionaron positivamente con UVR reducida, mientras que la concentración de pigmentos absorbentes de UVR (MAA’s) correlacionó negativamente con UVR reducida. Un blanqueamiento severo en las colonias de A. cervicornis transplantadas de aguas profundas a aguas llanas resultó en una disminución significativa en el crecimiento y en la concentración de pigmentos fotosintéticos, sin ocurrir cambios significativos en la densidad de zooxantelas, comparadas con los controles, sugiriendo un efecto específico de UVR en la capacidad fotosintética de las zooxantelas. Las colonias blanqueadas sobrevivieron aumentando significativamente los niveles de MAA’s y una posible relocalización de recursos. Igualmente, colonias de P. furcata expuestas artificialmente a aumentos en UVR redujeron significativamente su crecimiento y concentraciones de pigmentos fotosintéticos, y aumentaron significativamente las concentraciones de MAA’s en comparación con controles expuestos a niveles normales de UVR, pero no se observaron diferencias significativas en la fecundidad. Mientras que otros factores físicos pueden influenciar la fisiología de los corales escleractínidos, estos resultados sugieren que corales de aguas llanas pueden ser afectados significativamente por aumentos en UVR a consecuencia del adelgazamiento de la capa de ozono terrestre.en_US
dc.description.sponsorshipFisheries Investigations Laboratory of the Puerto Rico Commonwealth, Department of Natural and Environmental Resources; Chemical Oceanography Laboratory at Magueyes Island.; NASA grant NCCW-0088; Alliance for Graduate Education and the Professoriate (AGEP) and the Department of Biology of the University of Puerto Rico at Mayagüez; National Science Foundation’s program Puerto Rico Graduate Teaching Fellows in K-12 Education; National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Habitat Conservation Division’s Caribbean Field Officeen_US
dc.subjectAcropora cervicornis (Lamarck 1816) – Photosynthesis - Effect of ultraviolet radiation on - Caribbeanen_US
dc.subjectPorites furcata (Lamarck 1816) – Growth - Effect of ultraviolet radiation on - Caribbeanen_US
dc.subjectCoral reefs – Fecundity - Effect of ultraviolet radiation on - Caribbeanen_US
dc.subjectCoral reefs – Physiology - Caribbeanen_US
dc.subject.lcshAcropora cervicornis--Effect of ultraviolet radiation on.en_US
dc.subject.lcshPorites--Effect of ultraviolet radiation on.en_US
dc.subject.lcshCorals--Effect of ultraviolet radiation on.en_US
dc.titleResponses of two species of Caribbean shallow-water branching corals to changes in ultraviolet radiationen_US
dc.rights.licenseAll rights reserveden_US
dc.rights.holder(c) 2005 Juan Luis Torres-Pérezen_US
dc.contributor.committeeGilbes, Fernando
dc.contributor.committeeCorredor, Jorge
dc.contributor.committeeWeil, Ernesto
dc.contributor.committeeAponte, Nilda
dc.contributor.representativeMartínez Cruzado, Juan C. Sciencesen_US
dc.contributor.collegeCollege of Arts and Sciences - Sciencesen_US
dc.contributor.departmentDepartment of Marine Sciencesen_US

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